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linux-zen-server/drivers/spi/spi.c

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// SPDX-License-Identifier: GPL-2.0-or-later
// SPI init/core code
//
// Copyright (C) 2005 David Brownell
// Copyright (C) 2008 Secret Lab Technologies Ltd.
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/clk/clk-conf.h>
#include <linux/slab.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>
#include <linux/gpio/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/pm_domain.h>
#include <linux/property.h>
#include <linux/export.h>
#include <linux/sched/rt.h>
#include <uapi/linux/sched/types.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/ioport.h>
#include <linux/acpi.h>
#include <linux/highmem.h>
#include <linux/idr.h>
#include <linux/platform_data/x86/apple.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/percpu.h>
#define CREATE_TRACE_POINTS
#include <trace/events/spi.h>
EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
#include "internals.h"
static DEFINE_IDR(spi_master_idr);
static void spidev_release(struct device *dev)
{
struct spi_device *spi = to_spi_device(dev);
spi_controller_put(spi->controller);
kfree(spi->driver_override);
free_percpu(spi->pcpu_statistics);
kfree(spi);
}
static ssize_t
modalias_show(struct device *dev, struct device_attribute *a, char *buf)
{
const struct spi_device *spi = to_spi_device(dev);
int len;
len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
if (len != -ENODEV)
return len;
return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
}
static DEVICE_ATTR_RO(modalias);
static ssize_t driver_override_store(struct device *dev,
struct device_attribute *a,
const char *buf, size_t count)
{
struct spi_device *spi = to_spi_device(dev);
int ret;
ret = driver_set_override(dev, &spi->driver_override, buf, count);
if (ret)
return ret;
return count;
}
static ssize_t driver_override_show(struct device *dev,
struct device_attribute *a, char *buf)
{
const struct spi_device *spi = to_spi_device(dev);
ssize_t len;
device_lock(dev);
len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
device_unlock(dev);
return len;
}
static DEVICE_ATTR_RW(driver_override);
static struct spi_statistics __percpu *spi_alloc_pcpu_stats(struct device *dev)
{
struct spi_statistics __percpu *pcpu_stats;
if (dev)
pcpu_stats = devm_alloc_percpu(dev, struct spi_statistics);
else
pcpu_stats = alloc_percpu_gfp(struct spi_statistics, GFP_KERNEL);
if (pcpu_stats) {
int cpu;
for_each_possible_cpu(cpu) {
struct spi_statistics *stat;
stat = per_cpu_ptr(pcpu_stats, cpu);
u64_stats_init(&stat->syncp);
}
}
return pcpu_stats;
}
#define spi_pcpu_stats_totalize(ret, in, field) \
do { \
int i; \
ret = 0; \
for_each_possible_cpu(i) { \
const struct spi_statistics *pcpu_stats; \
u64 inc; \
unsigned int start; \
pcpu_stats = per_cpu_ptr(in, i); \
do { \
start = u64_stats_fetch_begin( \
&pcpu_stats->syncp); \
inc = u64_stats_read(&pcpu_stats->field); \
} while (u64_stats_fetch_retry( \
&pcpu_stats->syncp, start)); \
ret += inc; \
} \
} while (0)
#define SPI_STATISTICS_ATTRS(field, file) \
static ssize_t spi_controller_##field##_show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct spi_controller *ctlr = container_of(dev, \
struct spi_controller, dev); \
return spi_statistics_##field##_show(ctlr->pcpu_statistics, buf); \
} \
static struct device_attribute dev_attr_spi_controller_##field = { \
.attr = { .name = file, .mode = 0444 }, \
.show = spi_controller_##field##_show, \
}; \
static ssize_t spi_device_##field##_show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct spi_device *spi = to_spi_device(dev); \
return spi_statistics_##field##_show(spi->pcpu_statistics, buf); \
} \
static struct device_attribute dev_attr_spi_device_##field = { \
.attr = { .name = file, .mode = 0444 }, \
.show = spi_device_##field##_show, \
}
#define SPI_STATISTICS_SHOW_NAME(name, file, field) \
static ssize_t spi_statistics_##name##_show(struct spi_statistics __percpu *stat, \
char *buf) \
{ \
ssize_t len; \
u64 val; \
spi_pcpu_stats_totalize(val, stat, field); \
len = sysfs_emit(buf, "%llu\n", val); \
return len; \
} \
SPI_STATISTICS_ATTRS(name, file)
#define SPI_STATISTICS_SHOW(field) \
SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
field)
SPI_STATISTICS_SHOW(messages);
SPI_STATISTICS_SHOW(transfers);
SPI_STATISTICS_SHOW(errors);
SPI_STATISTICS_SHOW(timedout);
SPI_STATISTICS_SHOW(spi_sync);
SPI_STATISTICS_SHOW(spi_sync_immediate);
SPI_STATISTICS_SHOW(spi_async);
SPI_STATISTICS_SHOW(bytes);
SPI_STATISTICS_SHOW(bytes_rx);
SPI_STATISTICS_SHOW(bytes_tx);
#define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
"transfer_bytes_histo_" number, \
transfer_bytes_histo[index])
SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
SPI_STATISTICS_SHOW(transfers_split_maxsize);
static struct attribute *spi_dev_attrs[] = {
&dev_attr_modalias.attr,
&dev_attr_driver_override.attr,
NULL,
};
static const struct attribute_group spi_dev_group = {
.attrs = spi_dev_attrs,
};
static struct attribute *spi_device_statistics_attrs[] = {
&dev_attr_spi_device_messages.attr,
&dev_attr_spi_device_transfers.attr,
&dev_attr_spi_device_errors.attr,
&dev_attr_spi_device_timedout.attr,
&dev_attr_spi_device_spi_sync.attr,
&dev_attr_spi_device_spi_sync_immediate.attr,
&dev_attr_spi_device_spi_async.attr,
&dev_attr_spi_device_bytes.attr,
&dev_attr_spi_device_bytes_rx.attr,
&dev_attr_spi_device_bytes_tx.attr,
&dev_attr_spi_device_transfer_bytes_histo0.attr,
&dev_attr_spi_device_transfer_bytes_histo1.attr,
&dev_attr_spi_device_transfer_bytes_histo2.attr,
&dev_attr_spi_device_transfer_bytes_histo3.attr,
&dev_attr_spi_device_transfer_bytes_histo4.attr,
&dev_attr_spi_device_transfer_bytes_histo5.attr,
&dev_attr_spi_device_transfer_bytes_histo6.attr,
&dev_attr_spi_device_transfer_bytes_histo7.attr,
&dev_attr_spi_device_transfer_bytes_histo8.attr,
&dev_attr_spi_device_transfer_bytes_histo9.attr,
&dev_attr_spi_device_transfer_bytes_histo10.attr,
&dev_attr_spi_device_transfer_bytes_histo11.attr,
&dev_attr_spi_device_transfer_bytes_histo12.attr,
&dev_attr_spi_device_transfer_bytes_histo13.attr,
&dev_attr_spi_device_transfer_bytes_histo14.attr,
&dev_attr_spi_device_transfer_bytes_histo15.attr,
&dev_attr_spi_device_transfer_bytes_histo16.attr,
&dev_attr_spi_device_transfers_split_maxsize.attr,
NULL,
};
static const struct attribute_group spi_device_statistics_group = {
.name = "statistics",
.attrs = spi_device_statistics_attrs,
};
static const struct attribute_group *spi_dev_groups[] = {
&spi_dev_group,
&spi_device_statistics_group,
NULL,
};
static struct attribute *spi_controller_statistics_attrs[] = {
&dev_attr_spi_controller_messages.attr,
&dev_attr_spi_controller_transfers.attr,
&dev_attr_spi_controller_errors.attr,
&dev_attr_spi_controller_timedout.attr,
&dev_attr_spi_controller_spi_sync.attr,
&dev_attr_spi_controller_spi_sync_immediate.attr,
&dev_attr_spi_controller_spi_async.attr,
&dev_attr_spi_controller_bytes.attr,
&dev_attr_spi_controller_bytes_rx.attr,
&dev_attr_spi_controller_bytes_tx.attr,
&dev_attr_spi_controller_transfer_bytes_histo0.attr,
&dev_attr_spi_controller_transfer_bytes_histo1.attr,
&dev_attr_spi_controller_transfer_bytes_histo2.attr,
&dev_attr_spi_controller_transfer_bytes_histo3.attr,
&dev_attr_spi_controller_transfer_bytes_histo4.attr,
&dev_attr_spi_controller_transfer_bytes_histo5.attr,
&dev_attr_spi_controller_transfer_bytes_histo6.attr,
&dev_attr_spi_controller_transfer_bytes_histo7.attr,
&dev_attr_spi_controller_transfer_bytes_histo8.attr,
&dev_attr_spi_controller_transfer_bytes_histo9.attr,
&dev_attr_spi_controller_transfer_bytes_histo10.attr,
&dev_attr_spi_controller_transfer_bytes_histo11.attr,
&dev_attr_spi_controller_transfer_bytes_histo12.attr,
&dev_attr_spi_controller_transfer_bytes_histo13.attr,
&dev_attr_spi_controller_transfer_bytes_histo14.attr,
&dev_attr_spi_controller_transfer_bytes_histo15.attr,
&dev_attr_spi_controller_transfer_bytes_histo16.attr,
&dev_attr_spi_controller_transfers_split_maxsize.attr,
NULL,
};
static const struct attribute_group spi_controller_statistics_group = {
.name = "statistics",
.attrs = spi_controller_statistics_attrs,
};
static const struct attribute_group *spi_master_groups[] = {
&spi_controller_statistics_group,
NULL,
};
static void spi_statistics_add_transfer_stats(struct spi_statistics __percpu *pcpu_stats,
struct spi_transfer *xfer,
struct spi_controller *ctlr)
{
int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
struct spi_statistics *stats;
if (l2len < 0)
l2len = 0;
get_cpu();
stats = this_cpu_ptr(pcpu_stats);
u64_stats_update_begin(&stats->syncp);
u64_stats_inc(&stats->transfers);
u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
u64_stats_add(&stats->bytes, xfer->len);
if ((xfer->tx_buf) &&
(xfer->tx_buf != ctlr->dummy_tx))
u64_stats_add(&stats->bytes_tx, xfer->len);
if ((xfer->rx_buf) &&
(xfer->rx_buf != ctlr->dummy_rx))
u64_stats_add(&stats->bytes_rx, xfer->len);
u64_stats_update_end(&stats->syncp);
put_cpu();
}
/*
* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
* and the sysfs version makes coldplug work too.
*/
static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name)
{
while (id->name[0]) {
if (!strcmp(name, id->name))
return id;
id++;
}
return NULL;
}
const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
{
const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
return spi_match_id(sdrv->id_table, sdev->modalias);
}
EXPORT_SYMBOL_GPL(spi_get_device_id);
const void *spi_get_device_match_data(const struct spi_device *sdev)
{
const void *match;
match = device_get_match_data(&sdev->dev);
if (match)
return match;
return (const void *)spi_get_device_id(sdev)->driver_data;
}
EXPORT_SYMBOL_GPL(spi_get_device_match_data);
static int spi_match_device(struct device *dev, struct device_driver *drv)
{
const struct spi_device *spi = to_spi_device(dev);
const struct spi_driver *sdrv = to_spi_driver(drv);
/* Check override first, and if set, only use the named driver */
if (spi->driver_override)
return strcmp(spi->driver_override, drv->name) == 0;
/* Attempt an OF style match */
if (of_driver_match_device(dev, drv))
return 1;
/* Then try ACPI */
if (acpi_driver_match_device(dev, drv))
return 1;
if (sdrv->id_table)
return !!spi_match_id(sdrv->id_table, spi->modalias);
return strcmp(spi->modalias, drv->name) == 0;
}
static int spi_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
const struct spi_device *spi = to_spi_device(dev);
int rc;
rc = acpi_device_uevent_modalias(dev, env);
if (rc != -ENODEV)
return rc;
return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
}
static int spi_probe(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
struct spi_device *spi = to_spi_device(dev);
int ret;
ret = of_clk_set_defaults(dev->of_node, false);
if (ret)
return ret;
if (dev->of_node) {
spi->irq = of_irq_get(dev->of_node, 0);
if (spi->irq == -EPROBE_DEFER)
return -EPROBE_DEFER;
if (spi->irq < 0)
spi->irq = 0;
}
ret = dev_pm_domain_attach(dev, true);
if (ret)
return ret;
if (sdrv->probe) {
ret = sdrv->probe(spi);
if (ret)
dev_pm_domain_detach(dev, true);
}
return ret;
}
static void spi_remove(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
if (sdrv->remove)
sdrv->remove(to_spi_device(dev));
dev_pm_domain_detach(dev, true);
}
static void spi_shutdown(struct device *dev)
{
if (dev->driver) {
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
if (sdrv->shutdown)
sdrv->shutdown(to_spi_device(dev));
}
}
struct bus_type spi_bus_type = {
.name = "spi",
.dev_groups = spi_dev_groups,
.match = spi_match_device,
.uevent = spi_uevent,
.probe = spi_probe,
.remove = spi_remove,
.shutdown = spi_shutdown,
};
EXPORT_SYMBOL_GPL(spi_bus_type);
/**
* __spi_register_driver - register a SPI driver
* @owner: owner module of the driver to register
* @sdrv: the driver to register
* Context: can sleep
*
* Return: zero on success, else a negative error code.
*/
int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
{
sdrv->driver.owner = owner;
sdrv->driver.bus = &spi_bus_type;
/*
* For Really Good Reasons we use spi: modaliases not of:
* modaliases for DT so module autoloading won't work if we
* don't have a spi_device_id as well as a compatible string.
*/
if (sdrv->driver.of_match_table) {
const struct of_device_id *of_id;
for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
of_id++) {
const char *of_name;
/* Strip off any vendor prefix */
of_name = strnchr(of_id->compatible,
sizeof(of_id->compatible), ',');
if (of_name)
of_name++;
else
of_name = of_id->compatible;
if (sdrv->id_table) {
const struct spi_device_id *spi_id;
spi_id = spi_match_id(sdrv->id_table, of_name);
if (spi_id)
continue;
} else {
if (strcmp(sdrv->driver.name, of_name) == 0)
continue;
}
pr_warn("SPI driver %s has no spi_device_id for %s\n",
sdrv->driver.name, of_id->compatible);
}
}
return driver_register(&sdrv->driver);
}
EXPORT_SYMBOL_GPL(__spi_register_driver);
/*-------------------------------------------------------------------------*/
/*
* SPI devices should normally not be created by SPI device drivers; that
* would make them board-specific. Similarly with SPI controller drivers.
* Device registration normally goes into like arch/.../mach.../board-YYY.c
* with other readonly (flashable) information about mainboard devices.
*/
struct boardinfo {
struct list_head list;
struct spi_board_info board_info;
};
static LIST_HEAD(board_list);
static LIST_HEAD(spi_controller_list);
/*
* Used to protect add/del operation for board_info list and
* spi_controller list, and their matching process also used
* to protect object of type struct idr.
*/
static DEFINE_MUTEX(board_lock);
/**
* spi_alloc_device - Allocate a new SPI device
* @ctlr: Controller to which device is connected
* Context: can sleep
*
* Allows a driver to allocate and initialize a spi_device without
* registering it immediately. This allows a driver to directly
* fill the spi_device with device parameters before calling
* spi_add_device() on it.
*
* Caller is responsible to call spi_add_device() on the returned
* spi_device structure to add it to the SPI controller. If the caller
* needs to discard the spi_device without adding it, then it should
* call spi_dev_put() on it.
*
* Return: a pointer to the new device, or NULL.
*/
struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
{
struct spi_device *spi;
if (!spi_controller_get(ctlr))
return NULL;
spi = kzalloc(sizeof(*spi), GFP_KERNEL);
if (!spi) {
spi_controller_put(ctlr);
return NULL;
}
spi->pcpu_statistics = spi_alloc_pcpu_stats(NULL);
if (!spi->pcpu_statistics) {
kfree(spi);
spi_controller_put(ctlr);
return NULL;
}
spi->master = spi->controller = ctlr;
spi->dev.parent = &ctlr->dev;
spi->dev.bus = &spi_bus_type;
spi->dev.release = spidev_release;
spi->mode = ctlr->buswidth_override_bits;
device_initialize(&spi->dev);
return spi;
}
EXPORT_SYMBOL_GPL(spi_alloc_device);
static void spi_dev_set_name(struct spi_device *spi)
{
struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
if (adev) {
dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
return;
}
dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
spi_get_chipselect(spi, 0));
}
static int spi_dev_check(struct device *dev, void *data)
{
struct spi_device *spi = to_spi_device(dev);
struct spi_device *new_spi = data;
if (spi->controller == new_spi->controller &&
spi_get_chipselect(spi, 0) == spi_get_chipselect(new_spi, 0))
return -EBUSY;
return 0;
}
static void spi_cleanup(struct spi_device *spi)
{
if (spi->controller->cleanup)
spi->controller->cleanup(spi);
}
static int __spi_add_device(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
struct device *dev = ctlr->dev.parent;
int status;
/*
* We need to make sure there's no other device with this
* chipselect **BEFORE** we call setup(), else we'll trash
* its configuration.
*/
status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
if (status) {
dev_err(dev, "chipselect %d already in use\n",
spi_get_chipselect(spi, 0));
return status;
}
/* Controller may unregister concurrently */
if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
!device_is_registered(&ctlr->dev)) {
return -ENODEV;
}
if (ctlr->cs_gpiods)
spi_set_csgpiod(spi, 0, ctlr->cs_gpiods[spi_get_chipselect(spi, 0)]);
/*
* Drivers may modify this initial i/o setup, but will
* normally rely on the device being setup. Devices
* using SPI_CS_HIGH can't coexist well otherwise...
*/
status = spi_setup(spi);
if (status < 0) {
dev_err(dev, "can't setup %s, status %d\n",
dev_name(&spi->dev), status);
return status;
}
/* Device may be bound to an active driver when this returns */
status = device_add(&spi->dev);
if (status < 0) {
dev_err(dev, "can't add %s, status %d\n",
dev_name(&spi->dev), status);
spi_cleanup(spi);
} else {
dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
}
return status;
}
/**
* spi_add_device - Add spi_device allocated with spi_alloc_device
* @spi: spi_device to register
*
* Companion function to spi_alloc_device. Devices allocated with
* spi_alloc_device can be added onto the spi bus with this function.
*
* Return: 0 on success; negative errno on failure
*/
int spi_add_device(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
struct device *dev = ctlr->dev.parent;
int status;
/* Chipselects are numbered 0..max; validate. */
if (spi_get_chipselect(spi, 0) >= ctlr->num_chipselect) {
dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, 0),
ctlr->num_chipselect);
return -EINVAL;
}
/* Set the bus ID string */
spi_dev_set_name(spi);
mutex_lock(&ctlr->add_lock);
status = __spi_add_device(spi);
mutex_unlock(&ctlr->add_lock);
return status;
}
EXPORT_SYMBOL_GPL(spi_add_device);
static int spi_add_device_locked(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
struct device *dev = ctlr->dev.parent;
/* Chipselects are numbered 0..max; validate. */
if (spi_get_chipselect(spi, 0) >= ctlr->num_chipselect) {
dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, 0),
ctlr->num_chipselect);
return -EINVAL;
}
/* Set the bus ID string */
spi_dev_set_name(spi);
WARN_ON(!mutex_is_locked(&ctlr->add_lock));
return __spi_add_device(spi);
}
/**
* spi_new_device - instantiate one new SPI device
* @ctlr: Controller to which device is connected
* @chip: Describes the SPI device
* Context: can sleep
*
* On typical mainboards, this is purely internal; and it's not needed
* after board init creates the hard-wired devices. Some development
* platforms may not be able to use spi_register_board_info though, and
* this is exported so that for example a USB or parport based adapter
* driver could add devices (which it would learn about out-of-band).
*
* Return: the new device, or NULL.
*/
struct spi_device *spi_new_device(struct spi_controller *ctlr,
struct spi_board_info *chip)
{
struct spi_device *proxy;
int status;
/*
* NOTE: caller did any chip->bus_num checks necessary.
*
* Also, unless we change the return value convention to use
* error-or-pointer (not NULL-or-pointer), troubleshootability
* suggests syslogged diagnostics are best here (ugh).
*/
proxy = spi_alloc_device(ctlr);
if (!proxy)
return NULL;
WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
spi_set_chipselect(proxy, 0, chip->chip_select);
proxy->max_speed_hz = chip->max_speed_hz;
proxy->mode = chip->mode;
proxy->irq = chip->irq;
strscpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
proxy->dev.platform_data = (void *) chip->platform_data;
proxy->controller_data = chip->controller_data;
proxy->controller_state = NULL;
if (chip->swnode) {
status = device_add_software_node(&proxy->dev, chip->swnode);
if (status) {
dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
chip->modalias, status);
goto err_dev_put;
}
}
status = spi_add_device(proxy);
if (status < 0)
goto err_dev_put;
return proxy;
err_dev_put:
device_remove_software_node(&proxy->dev);
spi_dev_put(proxy);
return NULL;
}
EXPORT_SYMBOL_GPL(spi_new_device);
/**
* spi_unregister_device - unregister a single SPI device
* @spi: spi_device to unregister
*
* Start making the passed SPI device vanish. Normally this would be handled
* by spi_unregister_controller().
*/
void spi_unregister_device(struct spi_device *spi)
{
if (!spi)
return;
if (spi->dev.of_node) {
of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
of_node_put(spi->dev.of_node);
}
if (ACPI_COMPANION(&spi->dev))
acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
device_remove_software_node(&spi->dev);
device_del(&spi->dev);
spi_cleanup(spi);
put_device(&spi->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_device);
static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
struct spi_board_info *bi)
{
struct spi_device *dev;
if (ctlr->bus_num != bi->bus_num)
return;
dev = spi_new_device(ctlr, bi);
if (!dev)
dev_err(ctlr->dev.parent, "can't create new device for %s\n",
bi->modalias);
}
/**
* spi_register_board_info - register SPI devices for a given board
* @info: array of chip descriptors
* @n: how many descriptors are provided
* Context: can sleep
*
* Board-specific early init code calls this (probably during arch_initcall)
* with segments of the SPI device table. Any device nodes are created later,
* after the relevant parent SPI controller (bus_num) is defined. We keep
* this table of devices forever, so that reloading a controller driver will
* not make Linux forget about these hard-wired devices.
*
* Other code can also call this, e.g. a particular add-on board might provide
* SPI devices through its expansion connector, so code initializing that board
* would naturally declare its SPI devices.
*
* The board info passed can safely be __initdata ... but be careful of
* any embedded pointers (platform_data, etc), they're copied as-is.
*
* Return: zero on success, else a negative error code.
*/
int spi_register_board_info(struct spi_board_info const *info, unsigned n)
{
struct boardinfo *bi;
int i;
if (!n)
return 0;
bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
if (!bi)
return -ENOMEM;
for (i = 0; i < n; i++, bi++, info++) {
struct spi_controller *ctlr;
memcpy(&bi->board_info, info, sizeof(*info));
mutex_lock(&board_lock);
list_add_tail(&bi->list, &board_list);
list_for_each_entry(ctlr, &spi_controller_list, list)
spi_match_controller_to_boardinfo(ctlr,
&bi->board_info);
mutex_unlock(&board_lock);
}
return 0;
}
/*-------------------------------------------------------------------------*/
/* Core methods for SPI resource management */
/**
* spi_res_alloc - allocate a spi resource that is life-cycle managed
* during the processing of a spi_message while using
* spi_transfer_one
* @spi: the spi device for which we allocate memory
* @release: the release code to execute for this resource
* @size: size to alloc and return
* @gfp: GFP allocation flags
*
* Return: the pointer to the allocated data
*
* This may get enhanced in the future to allocate from a memory pool
* of the @spi_device or @spi_controller to avoid repeated allocations.
*/
static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
size_t size, gfp_t gfp)
{
struct spi_res *sres;
sres = kzalloc(sizeof(*sres) + size, gfp);
if (!sres)
return NULL;
INIT_LIST_HEAD(&sres->entry);
sres->release = release;
return sres->data;
}
/**
* spi_res_free - free an spi resource
* @res: pointer to the custom data of a resource
*/
static void spi_res_free(void *res)
{
struct spi_res *sres = container_of(res, struct spi_res, data);
if (!res)
return;
WARN_ON(!list_empty(&sres->entry));
kfree(sres);
}
/**
* spi_res_add - add a spi_res to the spi_message
* @message: the spi message
* @res: the spi_resource
*/
static void spi_res_add(struct spi_message *message, void *res)
{
struct spi_res *sres = container_of(res, struct spi_res, data);
WARN_ON(!list_empty(&sres->entry));
list_add_tail(&sres->entry, &message->resources);
}
/**
* spi_res_release - release all spi resources for this message
* @ctlr: the @spi_controller
* @message: the @spi_message
*/
static void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
{
struct spi_res *res, *tmp;
list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
if (res->release)
res->release(ctlr, message, res->data);
list_del(&res->entry);
kfree(res);
}
}
/*-------------------------------------------------------------------------*/
static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
{
bool activate = enable;
/*
* Avoid calling into the driver (or doing delays) if the chip select
* isn't actually changing from the last time this was called.
*/
if (!force && ((enable && spi->controller->last_cs == spi_get_chipselect(spi, 0)) ||
(!enable && spi->controller->last_cs != spi_get_chipselect(spi, 0))) &&
(spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
return;
trace_spi_set_cs(spi, activate);
spi->controller->last_cs = enable ? spi_get_chipselect(spi, 0) : -1;
spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
if ((spi_get_csgpiod(spi, 0) || !spi->controller->set_cs_timing) && !activate)
spi_delay_exec(&spi->cs_hold, NULL);
if (spi->mode & SPI_CS_HIGH)
enable = !enable;
if (spi_get_csgpiod(spi, 0)) {
if (!(spi->mode & SPI_NO_CS)) {
/*
* Historically ACPI has no means of the GPIO polarity and
* thus the SPISerialBus() resource defines it on the per-chip
* basis. In order to avoid a chain of negations, the GPIO
* polarity is considered being Active High. Even for the cases
* when _DSD() is involved (in the updated versions of ACPI)
* the GPIO CS polarity must be defined Active High to avoid
* ambiguity. That's why we use enable, that takes SPI_CS_HIGH
* into account.
*/
if (has_acpi_companion(&spi->dev))
gpiod_set_value_cansleep(spi_get_csgpiod(spi, 0), !enable);
else
/* Polarity handled by GPIO library */
gpiod_set_value_cansleep(spi_get_csgpiod(spi, 0), activate);
}
/* Some SPI masters need both GPIO CS & slave_select */
if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
spi->controller->set_cs)
spi->controller->set_cs(spi, !enable);
} else if (spi->controller->set_cs) {
spi->controller->set_cs(spi, !enable);
}
if (spi_get_csgpiod(spi, 0) || !spi->controller->set_cs_timing) {
if (activate)
spi_delay_exec(&spi->cs_setup, NULL);
else
spi_delay_exec(&spi->cs_inactive, NULL);
}
}
#ifdef CONFIG_HAS_DMA
static int spi_map_buf_attrs(struct spi_controller *ctlr, struct device *dev,
struct sg_table *sgt, void *buf, size_t len,
enum dma_data_direction dir, unsigned long attrs)
{
const bool vmalloced_buf = is_vmalloc_addr(buf);
unsigned int max_seg_size = dma_get_max_seg_size(dev);
#ifdef CONFIG_HIGHMEM
const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
(unsigned long)buf < (PKMAP_BASE +
(LAST_PKMAP * PAGE_SIZE)));
#else
const bool kmap_buf = false;
#endif
int desc_len;
int sgs;
struct page *vm_page;
struct scatterlist *sg;
void *sg_buf;
size_t min;
int i, ret;
if (vmalloced_buf || kmap_buf) {
desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
} else if (virt_addr_valid(buf)) {
desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
sgs = DIV_ROUND_UP(len, desc_len);
} else {
return -EINVAL;
}
ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
if (ret != 0)
return ret;
sg = &sgt->sgl[0];
for (i = 0; i < sgs; i++) {
if (vmalloced_buf || kmap_buf) {
/*
* Next scatterlist entry size is the minimum between
* the desc_len and the remaining buffer length that
* fits in a page.
*/
min = min_t(size_t, desc_len,
min_t(size_t, len,
PAGE_SIZE - offset_in_page(buf)));
if (vmalloced_buf)
vm_page = vmalloc_to_page(buf);
else
vm_page = kmap_to_page(buf);
if (!vm_page) {
sg_free_table(sgt);
return -ENOMEM;
}
sg_set_page(sg, vm_page,
min, offset_in_page(buf));
} else {
min = min_t(size_t, len, desc_len);
sg_buf = buf;
sg_set_buf(sg, sg_buf, min);
}
buf += min;
len -= min;
sg = sg_next(sg);
}
ret = dma_map_sgtable(dev, sgt, dir, attrs);
if (ret < 0) {
sg_free_table(sgt);
return ret;
}
return 0;
}
int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
struct sg_table *sgt, void *buf, size_t len,
enum dma_data_direction dir)
{
return spi_map_buf_attrs(ctlr, dev, sgt, buf, len, dir, 0);
}
static void spi_unmap_buf_attrs(struct spi_controller *ctlr,
struct device *dev, struct sg_table *sgt,
enum dma_data_direction dir,
unsigned long attrs)
{
if (sgt->orig_nents) {
dma_unmap_sgtable(dev, sgt, dir, attrs);
sg_free_table(sgt);
sgt->orig_nents = 0;
sgt->nents = 0;
}
}
void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
struct sg_table *sgt, enum dma_data_direction dir)
{
spi_unmap_buf_attrs(ctlr, dev, sgt, dir, 0);
}
static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
{
struct device *tx_dev, *rx_dev;
struct spi_transfer *xfer;
int ret;
if (!ctlr->can_dma)
return 0;
if (ctlr->dma_tx)
tx_dev = ctlr->dma_tx->device->dev;
else if (ctlr->dma_map_dev)
tx_dev = ctlr->dma_map_dev;
else
tx_dev = ctlr->dev.parent;
if (ctlr->dma_rx)
rx_dev = ctlr->dma_rx->device->dev;
else if (ctlr->dma_map_dev)
rx_dev = ctlr->dma_map_dev;
else
rx_dev = ctlr->dev.parent;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
/* The sync is done before each transfer. */
unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
if (!ctlr->can_dma(ctlr, msg->spi, xfer))
continue;
if (xfer->tx_buf != NULL) {
ret = spi_map_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
(void *)xfer->tx_buf,
xfer->len, DMA_TO_DEVICE,
attrs);
if (ret != 0)
return ret;
}
if (xfer->rx_buf != NULL) {
ret = spi_map_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
xfer->rx_buf, xfer->len,
DMA_FROM_DEVICE, attrs);
if (ret != 0) {
spi_unmap_buf_attrs(ctlr, tx_dev,
&xfer->tx_sg, DMA_TO_DEVICE,
attrs);
return ret;
}
}
}
ctlr->cur_rx_dma_dev = rx_dev;
ctlr->cur_tx_dma_dev = tx_dev;
ctlr->cur_msg_mapped = true;
return 0;
}
static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
{
struct device *rx_dev = ctlr->cur_rx_dma_dev;
struct device *tx_dev = ctlr->cur_tx_dma_dev;
struct spi_transfer *xfer;
if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
return 0;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
/* The sync has already been done after each transfer. */
unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
if (!ctlr->can_dma(ctlr, msg->spi, xfer))
continue;
spi_unmap_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
DMA_FROM_DEVICE, attrs);
spi_unmap_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
DMA_TO_DEVICE, attrs);
}
ctlr->cur_msg_mapped = false;
return 0;
}
static void spi_dma_sync_for_device(struct spi_controller *ctlr,
struct spi_transfer *xfer)
{
struct device *rx_dev = ctlr->cur_rx_dma_dev;
struct device *tx_dev = ctlr->cur_tx_dma_dev;
if (!ctlr->cur_msg_mapped)
return;
if (xfer->tx_sg.orig_nents)
dma_sync_sgtable_for_device(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
if (xfer->rx_sg.orig_nents)
dma_sync_sgtable_for_device(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
}
static void spi_dma_sync_for_cpu(struct spi_controller *ctlr,
struct spi_transfer *xfer)
{
struct device *rx_dev = ctlr->cur_rx_dma_dev;
struct device *tx_dev = ctlr->cur_tx_dma_dev;
if (!ctlr->cur_msg_mapped)
return;
if (xfer->rx_sg.orig_nents)
dma_sync_sgtable_for_cpu(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
if (xfer->tx_sg.orig_nents)
dma_sync_sgtable_for_cpu(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
}
#else /* !CONFIG_HAS_DMA */
static inline int __spi_map_msg(struct spi_controller *ctlr,
struct spi_message *msg)
{
return 0;
}
static inline int __spi_unmap_msg(struct spi_controller *ctlr,
struct spi_message *msg)
{
return 0;
}
static void spi_dma_sync_for_device(struct spi_controller *ctrl,
struct spi_transfer *xfer)
{
}
static void spi_dma_sync_for_cpu(struct spi_controller *ctrl,
struct spi_transfer *xfer)
{
}
#endif /* !CONFIG_HAS_DMA */
static inline int spi_unmap_msg(struct spi_controller *ctlr,
struct spi_message *msg)
{
struct spi_transfer *xfer;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
/*
* Restore the original value of tx_buf or rx_buf if they are
* NULL.
*/
if (xfer->tx_buf == ctlr->dummy_tx)
xfer->tx_buf = NULL;
if (xfer->rx_buf == ctlr->dummy_rx)
xfer->rx_buf = NULL;
}
return __spi_unmap_msg(ctlr, msg);
}
static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
{
struct spi_transfer *xfer;
void *tmp;
unsigned int max_tx, max_rx;
if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
&& !(msg->spi->mode & SPI_3WIRE)) {
max_tx = 0;
max_rx = 0;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
!xfer->tx_buf)
max_tx = max(xfer->len, max_tx);
if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
!xfer->rx_buf)
max_rx = max(xfer->len, max_rx);
}
if (max_tx) {
tmp = krealloc(ctlr->dummy_tx, max_tx,
GFP_KERNEL | GFP_DMA | __GFP_ZERO);
if (!tmp)
return -ENOMEM;
ctlr->dummy_tx = tmp;
}
if (max_rx) {
tmp = krealloc(ctlr->dummy_rx, max_rx,
GFP_KERNEL | GFP_DMA);
if (!tmp)
return -ENOMEM;
ctlr->dummy_rx = tmp;
}
if (max_tx || max_rx) {
list_for_each_entry(xfer, &msg->transfers,
transfer_list) {
if (!xfer->len)
continue;
if (!xfer->tx_buf)
xfer->tx_buf = ctlr->dummy_tx;
if (!xfer->rx_buf)
xfer->rx_buf = ctlr->dummy_rx;
}
}
}
return __spi_map_msg(ctlr, msg);
}
static int spi_transfer_wait(struct spi_controller *ctlr,
struct spi_message *msg,
struct spi_transfer *xfer)
{
struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
u32 speed_hz = xfer->speed_hz;
unsigned long long ms;
if (spi_controller_is_slave(ctlr)) {
if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
return -EINTR;
}
} else {
if (!speed_hz)
speed_hz = 100000;
/*
* For each byte we wait for 8 cycles of the SPI clock.
* Since speed is defined in Hz and we want milliseconds,
* use respective multiplier, but before the division,
* otherwise we may get 0 for short transfers.
*/
ms = 8LL * MSEC_PER_SEC * xfer->len;
do_div(ms, speed_hz);
/*
* Increase it twice and add 200 ms tolerance, use
* predefined maximum in case of overflow.
*/
ms += ms + 200;
if (ms > UINT_MAX)
ms = UINT_MAX;
ms = wait_for_completion_timeout(&ctlr->xfer_completion,
msecs_to_jiffies(ms));
if (ms == 0) {
SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
dev_err(&msg->spi->dev,
"SPI transfer timed out\n");
return -ETIMEDOUT;
}
}
return 0;
}
static void _spi_transfer_delay_ns(u32 ns)
{
if (!ns)
return;
if (ns <= NSEC_PER_USEC) {
ndelay(ns);
} else {
u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
if (us <= 10)
udelay(us);
else
usleep_range(us, us + DIV_ROUND_UP(us, 10));
}
}
int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
{
u32 delay = _delay->value;
u32 unit = _delay->unit;
u32 hz;
if (!delay)
return 0;
switch (unit) {
case SPI_DELAY_UNIT_USECS:
delay *= NSEC_PER_USEC;
break;
case SPI_DELAY_UNIT_NSECS:
/* Nothing to do here */
break;
case SPI_DELAY_UNIT_SCK:
/* Clock cycles need to be obtained from spi_transfer */
if (!xfer)
return -EINVAL;
/*
* If there is unknown effective speed, approximate it
* by underestimating with half of the requested hz.
*/
hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
if (!hz)
return -EINVAL;
/* Convert delay to nanoseconds */
delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
break;
default:
return -EINVAL;
}
return delay;
}
EXPORT_SYMBOL_GPL(spi_delay_to_ns);
int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
{
int delay;
might_sleep();
if (!_delay)
return -EINVAL;
delay = spi_delay_to_ns(_delay, xfer);
if (delay < 0)
return delay;
_spi_transfer_delay_ns(delay);
return 0;
}
EXPORT_SYMBOL_GPL(spi_delay_exec);
static void _spi_transfer_cs_change_delay(struct spi_message *msg,
struct spi_transfer *xfer)
{
u32 default_delay_ns = 10 * NSEC_PER_USEC;
u32 delay = xfer->cs_change_delay.value;
u32 unit = xfer->cs_change_delay.unit;
int ret;
/* Return early on "fast" mode - for everything but USECS */
if (!delay) {
if (unit == SPI_DELAY_UNIT_USECS)
_spi_transfer_delay_ns(default_delay_ns);
return;
}
ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
if (ret) {
dev_err_once(&msg->spi->dev,
"Use of unsupported delay unit %i, using default of %luus\n",
unit, default_delay_ns / NSEC_PER_USEC);
_spi_transfer_delay_ns(default_delay_ns);
}
}
void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
struct spi_transfer *xfer)
{
_spi_transfer_cs_change_delay(msg, xfer);
}
EXPORT_SYMBOL_GPL(spi_transfer_cs_change_delay_exec);
/*
* spi_transfer_one_message - Default implementation of transfer_one_message()
*
* This is a standard implementation of transfer_one_message() for
* drivers which implement a transfer_one() operation. It provides
* standard handling of delays and chip select management.
*/
static int spi_transfer_one_message(struct spi_controller *ctlr,
struct spi_message *msg)
{
struct spi_transfer *xfer;
bool keep_cs = false;
int ret = 0;
struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list);
spi_set_cs(msg->spi, !xfer->cs_off, false);
SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
trace_spi_transfer_start(msg, xfer);
spi_statistics_add_transfer_stats(statm, xfer, ctlr);
spi_statistics_add_transfer_stats(stats, xfer, ctlr);
if (!ctlr->ptp_sts_supported) {
xfer->ptp_sts_word_pre = 0;
ptp_read_system_prets(xfer->ptp_sts);
}
if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
reinit_completion(&ctlr->xfer_completion);
fallback_pio:
spi_dma_sync_for_device(ctlr, xfer);
ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
if (ret < 0) {
spi_dma_sync_for_cpu(ctlr, xfer);
if (ctlr->cur_msg_mapped &&
(xfer->error & SPI_TRANS_FAIL_NO_START)) {
__spi_unmap_msg(ctlr, msg);
ctlr->fallback = true;
xfer->error &= ~SPI_TRANS_FAIL_NO_START;
goto fallback_pio;
}
SPI_STATISTICS_INCREMENT_FIELD(statm,
errors);
SPI_STATISTICS_INCREMENT_FIELD(stats,
errors);
dev_err(&msg->spi->dev,
"SPI transfer failed: %d\n", ret);
goto out;
}
if (ret > 0) {
ret = spi_transfer_wait(ctlr, msg, xfer);
if (ret < 0)
msg->status = ret;
}
spi_dma_sync_for_cpu(ctlr, xfer);
} else {
if (xfer->len)
dev_err(&msg->spi->dev,
"Bufferless transfer has length %u\n",
xfer->len);
}
if (!ctlr->ptp_sts_supported) {
ptp_read_system_postts(xfer->ptp_sts);
xfer->ptp_sts_word_post = xfer->len;
}
trace_spi_transfer_stop(msg, xfer);
if (msg->status != -EINPROGRESS)
goto out;
spi_transfer_delay_exec(xfer);
if (xfer->cs_change) {
if (list_is_last(&xfer->transfer_list,
&msg->transfers)) {
keep_cs = true;
} else {
if (!xfer->cs_off)
spi_set_cs(msg->spi, false, false);
_spi_transfer_cs_change_delay(msg, xfer);
if (!list_next_entry(xfer, transfer_list)->cs_off)
spi_set_cs(msg->spi, true, false);
}
} else if (!list_is_last(&xfer->transfer_list, &msg->transfers) &&
xfer->cs_off != list_next_entry(xfer, transfer_list)->cs_off) {
spi_set_cs(msg->spi, xfer->cs_off, false);
}
msg->actual_length += xfer->len;
}
out:
if (ret != 0 || !keep_cs)
spi_set_cs(msg->spi, false, false);
if (msg->status == -EINPROGRESS)
msg->status = ret;
if (msg->status && ctlr->handle_err)
ctlr->handle_err(ctlr, msg);
spi_finalize_current_message(ctlr);
return ret;
}
/**
* spi_finalize_current_transfer - report completion of a transfer
* @ctlr: the controller reporting completion
*
* Called by SPI drivers using the core transfer_one_message()
* implementation to notify it that the current interrupt driven
* transfer has finished and the next one may be scheduled.
*/
void spi_finalize_current_transfer(struct spi_controller *ctlr)
{
complete(&ctlr->xfer_completion);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
static void spi_idle_runtime_pm(struct spi_controller *ctlr)
{
if (ctlr->auto_runtime_pm) {
pm_runtime_mark_last_busy(ctlr->dev.parent);
pm_runtime_put_autosuspend(ctlr->dev.parent);
}
}
static int __spi_pump_transfer_message(struct spi_controller *ctlr,
struct spi_message *msg, bool was_busy)
{
struct spi_transfer *xfer;
int ret;
if (!was_busy && ctlr->auto_runtime_pm) {
ret = pm_runtime_get_sync(ctlr->dev.parent);
if (ret < 0) {
pm_runtime_put_noidle(ctlr->dev.parent);
dev_err(&ctlr->dev, "Failed to power device: %d\n",
ret);
return ret;
}
}
if (!was_busy)
trace_spi_controller_busy(ctlr);
if (!was_busy && ctlr->prepare_transfer_hardware) {
ret = ctlr->prepare_transfer_hardware(ctlr);
if (ret) {
dev_err(&ctlr->dev,
"failed to prepare transfer hardware: %d\n",
ret);
if (ctlr->auto_runtime_pm)
pm_runtime_put(ctlr->dev.parent);
msg->status = ret;
spi_finalize_current_message(ctlr);
return ret;
}
}
trace_spi_message_start(msg);
ret = spi_split_transfers_maxsize(ctlr, msg,
spi_max_transfer_size(msg->spi),
GFP_KERNEL | GFP_DMA);
if (ret) {
msg->status = ret;
spi_finalize_current_message(ctlr);
return ret;
}
if (ctlr->prepare_message) {
ret = ctlr->prepare_message(ctlr, msg);
if (ret) {
dev_err(&ctlr->dev, "failed to prepare message: %d\n",
ret);
msg->status = ret;
spi_finalize_current_message(ctlr);
return ret;
}
msg->prepared = true;
}
ret = spi_map_msg(ctlr, msg);
if (ret) {
msg->status = ret;
spi_finalize_current_message(ctlr);
return ret;
}
if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
xfer->ptp_sts_word_pre = 0;
ptp_read_system_prets(xfer->ptp_sts);
}
}
/*
* Drivers implementation of transfer_one_message() must arrange for
* spi_finalize_current_message() to get called. Most drivers will do
* this in the calling context, but some don't. For those cases, a
* completion is used to guarantee that this function does not return
* until spi_finalize_current_message() is done accessing
* ctlr->cur_msg.
* Use of the following two flags enable to opportunistically skip the
* use of the completion since its use involves expensive spin locks.
* In case of a race with the context that calls
* spi_finalize_current_message() the completion will always be used,
* due to strict ordering of these flags using barriers.
*/
WRITE_ONCE(ctlr->cur_msg_incomplete, true);
WRITE_ONCE(ctlr->cur_msg_need_completion, false);
reinit_completion(&ctlr->cur_msg_completion);
smp_wmb(); /* Make these available to spi_finalize_current_message() */
ret = ctlr->transfer_one_message(ctlr, msg);
if (ret) {
dev_err(&ctlr->dev,
"failed to transfer one message from queue\n");
return ret;
}
WRITE_ONCE(ctlr->cur_msg_need_completion, true);
smp_mb(); /* See spi_finalize_current_message()... */
if (READ_ONCE(ctlr->cur_msg_incomplete))
wait_for_completion(&ctlr->cur_msg_completion);
return 0;
}
/**
* __spi_pump_messages - function which processes spi message queue
* @ctlr: controller to process queue for
* @in_kthread: true if we are in the context of the message pump thread
*
* This function checks if there is any spi message in the queue that
* needs processing and if so call out to the driver to initialize hardware
* and transfer each message.
*
* Note that it is called both from the kthread itself and also from
* inside spi_sync(); the queue extraction handling at the top of the
* function should deal with this safely.
*/
static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
{
struct spi_message *msg;
bool was_busy = false;
unsigned long flags;
int ret;
/* Take the IO mutex */
mutex_lock(&ctlr->io_mutex);
/* Lock queue */
spin_lock_irqsave(&ctlr->queue_lock, flags);
/* Make sure we are not already running a message */
if (ctlr->cur_msg)
goto out_unlock;
/* Check if the queue is idle */
if (list_empty(&ctlr->queue) || !ctlr->running) {
if (!ctlr->busy)
goto out_unlock;
/* Defer any non-atomic teardown to the thread */
if (!in_kthread) {
if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
!ctlr->unprepare_transfer_hardware) {
spi_idle_runtime_pm(ctlr);
ctlr->busy = false;
ctlr->queue_empty = true;
trace_spi_controller_idle(ctlr);
} else {
kthread_queue_work(ctlr->kworker,
&ctlr->pump_messages);
}
goto out_unlock;
}
ctlr->busy = false;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
kfree(ctlr->dummy_rx);
ctlr->dummy_rx = NULL;
kfree(ctlr->dummy_tx);
ctlr->dummy_tx = NULL;
if (ctlr->unprepare_transfer_hardware &&
ctlr->unprepare_transfer_hardware(ctlr))
dev_err(&ctlr->dev,
"failed to unprepare transfer hardware\n");
spi_idle_runtime_pm(ctlr);
trace_spi_controller_idle(ctlr);
spin_lock_irqsave(&ctlr->queue_lock, flags);
ctlr->queue_empty = true;
goto out_unlock;
}
/* Extract head of queue */
msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
ctlr->cur_msg = msg;
list_del_init(&msg->queue);
if (ctlr->busy)
was_busy = true;
else
ctlr->busy = true;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
ctlr->cur_msg = NULL;
ctlr->fallback = false;
mutex_unlock(&ctlr->io_mutex);
/* Prod the scheduler in case transfer_one() was busy waiting */
if (!ret)
cond_resched();
return;
out_unlock:
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
mutex_unlock(&ctlr->io_mutex);
}
/**
* spi_pump_messages - kthread work function which processes spi message queue
* @work: pointer to kthread work struct contained in the controller struct
*/
static void spi_pump_messages(struct kthread_work *work)
{
struct spi_controller *ctlr =
container_of(work, struct spi_controller, pump_messages);
__spi_pump_messages(ctlr, true);
}
/**
* spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp
* @ctlr: Pointer to the spi_controller structure of the driver
* @xfer: Pointer to the transfer being timestamped
* @progress: How many words (not bytes) have been transferred so far
* @irqs_off: If true, will disable IRQs and preemption for the duration of the
* transfer, for less jitter in time measurement. Only compatible
* with PIO drivers. If true, must follow up with
* spi_take_timestamp_post or otherwise system will crash.
* WARNING: for fully predictable results, the CPU frequency must
* also be under control (governor).
*
* This is a helper for drivers to collect the beginning of the TX timestamp
* for the requested byte from the SPI transfer. The frequency with which this
* function must be called (once per word, once for the whole transfer, once
* per batch of words etc) is arbitrary as long as the @tx buffer offset is
* greater than or equal to the requested byte at the time of the call. The
* timestamp is only taken once, at the first such call. It is assumed that
* the driver advances its @tx buffer pointer monotonically.
*/
void spi_take_timestamp_pre(struct spi_controller *ctlr,
struct spi_transfer *xfer,
size_t progress, bool irqs_off)
{
if (!xfer->ptp_sts)
return;
if (xfer->timestamped)
return;
if (progress > xfer->ptp_sts_word_pre)
return;
/* Capture the resolution of the timestamp */
xfer->ptp_sts_word_pre = progress;
if (irqs_off) {
local_irq_save(ctlr->irq_flags);
preempt_disable();
}
ptp_read_system_prets(xfer->ptp_sts);
}
EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
/**
* spi_take_timestamp_post - helper to collect the end of the TX timestamp
* @ctlr: Pointer to the spi_controller structure of the driver
* @xfer: Pointer to the transfer being timestamped
* @progress: How many words (not bytes) have been transferred so far
* @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
*
* This is a helper for drivers to collect the end of the TX timestamp for
* the requested byte from the SPI transfer. Can be called with an arbitrary
* frequency: only the first call where @tx exceeds or is equal to the
* requested word will be timestamped.
*/
void spi_take_timestamp_post(struct spi_controller *ctlr,
struct spi_transfer *xfer,
size_t progress, bool irqs_off)
{
if (!xfer->ptp_sts)
return;
if (xfer->timestamped)
return;
if (progress < xfer->ptp_sts_word_post)
return;
ptp_read_system_postts(xfer->ptp_sts);
if (irqs_off) {
local_irq_restore(ctlr->irq_flags);
preempt_enable();
}
/* Capture the resolution of the timestamp */
xfer->ptp_sts_word_post = progress;
xfer->timestamped = 1;
}
EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
/**
* spi_set_thread_rt - set the controller to pump at realtime priority
* @ctlr: controller to boost priority of
*
* This can be called because the controller requested realtime priority
* (by setting the ->rt value before calling spi_register_controller()) or
* because a device on the bus said that its transfers needed realtime
* priority.
*
* NOTE: at the moment if any device on a bus says it needs realtime then
* the thread will be at realtime priority for all transfers on that
* controller. If this eventually becomes a problem we may see if we can
* find a way to boost the priority only temporarily during relevant
* transfers.
*/
static void spi_set_thread_rt(struct spi_controller *ctlr)
{
dev_info(&ctlr->dev,
"will run message pump with realtime priority\n");
sched_set_fifo(ctlr->kworker->task);
}
static int spi_init_queue(struct spi_controller *ctlr)
{
ctlr->running = false;
ctlr->busy = false;
ctlr->queue_empty = true;
ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
if (IS_ERR(ctlr->kworker)) {
dev_err(&ctlr->dev, "failed to create message pump kworker\n");
return PTR_ERR(ctlr->kworker);
}
kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
/*
* Controller config will indicate if this controller should run the
* message pump with high (realtime) priority to reduce the transfer
* latency on the bus by minimising the delay between a transfer
* request and the scheduling of the message pump thread. Without this
* setting the message pump thread will remain at default priority.
*/
if (ctlr->rt)
spi_set_thread_rt(ctlr);
return 0;
}
/**
* spi_get_next_queued_message() - called by driver to check for queued
* messages
* @ctlr: the controller to check for queued messages
*
* If there are more messages in the queue, the next message is returned from
* this call.
*
* Return: the next message in the queue, else NULL if the queue is empty.
*/
struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
{
struct spi_message *next;
unsigned long flags;
/* Get a pointer to the next message, if any */
spin_lock_irqsave(&ctlr->queue_lock, flags);
next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
queue);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return next;
}
EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
/**
* spi_finalize_current_message() - the current message is complete
* @ctlr: the controller to return the message to
*
* Called by the driver to notify the core that the message in the front of the
* queue is complete and can be removed from the queue.
*/
void spi_finalize_current_message(struct spi_controller *ctlr)
{
struct spi_transfer *xfer;
struct spi_message *mesg;
int ret;
mesg = ctlr->cur_msg;
if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
ptp_read_system_postts(xfer->ptp_sts);
xfer->ptp_sts_word_post = xfer->len;
}
}
if (unlikely(ctlr->ptp_sts_supported))
list_for_each_entry(xfer, &mesg->transfers, transfer_list)
WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
spi_unmap_msg(ctlr, mesg);
/*
* In the prepare_messages callback the SPI bus has the opportunity
* to split a transfer to smaller chunks.
*
* Release the split transfers here since spi_map_msg() is done on
* the split transfers.
*/
spi_res_release(ctlr, mesg);
if (mesg->prepared && ctlr->unprepare_message) {
ret = ctlr->unprepare_message(ctlr, mesg);
if (ret) {
dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
ret);
}
}
mesg->prepared = false;
WRITE_ONCE(ctlr->cur_msg_incomplete, false);
smp_mb(); /* See __spi_pump_transfer_message()... */
if (READ_ONCE(ctlr->cur_msg_need_completion))
complete(&ctlr->cur_msg_completion);
trace_spi_message_done(mesg);
mesg->state = NULL;
if (mesg->complete)
mesg->complete(mesg->context);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_message);
static int spi_start_queue(struct spi_controller *ctlr)
{
unsigned long flags;
spin_lock_irqsave(&ctlr->queue_lock, flags);
if (ctlr->running || ctlr->busy) {
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return -EBUSY;
}
ctlr->running = true;
ctlr->cur_msg = NULL;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
return 0;
}
static int spi_stop_queue(struct spi_controller *ctlr)
{
unsigned long flags;
unsigned limit = 500;
int ret = 0;
spin_lock_irqsave(&ctlr->queue_lock, flags);
/*
* This is a bit lame, but is optimized for the common execution path.
* A wait_queue on the ctlr->busy could be used, but then the common
* execution path (pump_messages) would be required to call wake_up or
* friends on every SPI message. Do this instead.
*/
while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
usleep_range(10000, 11000);
spin_lock_irqsave(&ctlr->queue_lock, flags);
}
if (!list_empty(&ctlr->queue) || ctlr->busy)
ret = -EBUSY;
else
ctlr->running = false;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
if (ret) {
dev_warn(&ctlr->dev, "could not stop message queue\n");
return ret;
}
return ret;
}
static int spi_destroy_queue(struct spi_controller *ctlr)
{
int ret;
ret = spi_stop_queue(ctlr);
/*
* kthread_flush_worker will block until all work is done.
* If the reason that stop_queue timed out is that the work will never
* finish, then it does no good to call flush/stop thread, so
* return anyway.
*/
if (ret) {
dev_err(&ctlr->dev, "problem destroying queue\n");
return ret;
}
kthread_destroy_worker(ctlr->kworker);
return 0;
}
static int __spi_queued_transfer(struct spi_device *spi,
struct spi_message *msg,
bool need_pump)
{
struct spi_controller *ctlr = spi->controller;
unsigned long flags;
spin_lock_irqsave(&ctlr->queue_lock, flags);
if (!ctlr->running) {
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return -ESHUTDOWN;
}
msg->actual_length = 0;
msg->status = -EINPROGRESS;
list_add_tail(&msg->queue, &ctlr->queue);
ctlr->queue_empty = false;
if (!ctlr->busy && need_pump)
kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return 0;
}
/**
* spi_queued_transfer - transfer function for queued transfers
* @spi: spi device which is requesting transfer
* @msg: spi message which is to handled is queued to driver queue
*
* Return: zero on success, else a negative error code.
*/
static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
{
return __spi_queued_transfer(spi, msg, true);
}
static int spi_controller_initialize_queue(struct spi_controller *ctlr)
{
int ret;
ctlr->transfer = spi_queued_transfer;
if (!ctlr->transfer_one_message)
ctlr->transfer_one_message = spi_transfer_one_message;
/* Initialize and start queue */
ret = spi_init_queue(ctlr);
if (ret) {
dev_err(&ctlr->dev, "problem initializing queue\n");
goto err_init_queue;
}
ctlr->queued = true;
ret = spi_start_queue(ctlr);
if (ret) {
dev_err(&ctlr->dev, "problem starting queue\n");
goto err_start_queue;
}
return 0;
err_start_queue:
spi_destroy_queue(ctlr);
err_init_queue:
return ret;
}
/**
* spi_flush_queue - Send all pending messages in the queue from the callers'
* context
* @ctlr: controller to process queue for
*
* This should be used when one wants to ensure all pending messages have been
* sent before doing something. Is used by the spi-mem code to make sure SPI
* memory operations do not preempt regular SPI transfers that have been queued
* before the spi-mem operation.
*/
void spi_flush_queue(struct spi_controller *ctlr)
{
if (ctlr->transfer == spi_queued_transfer)
__spi_pump_messages(ctlr, false);
}
/*-------------------------------------------------------------------------*/
#if defined(CONFIG_OF)
static void of_spi_parse_dt_cs_delay(struct device_node *nc,
struct spi_delay *delay, const char *prop)
{
u32 value;
if (!of_property_read_u32(nc, prop, &value)) {
if (value > U16_MAX) {
delay->value = DIV_ROUND_UP(value, 1000);
delay->unit = SPI_DELAY_UNIT_USECS;
} else {
delay->value = value;
delay->unit = SPI_DELAY_UNIT_NSECS;
}
}
}
static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
struct device_node *nc)
{
u32 value;
int rc;
/* Mode (clock phase/polarity/etc.) */
if (of_property_read_bool(nc, "spi-cpha"))
spi->mode |= SPI_CPHA;
if (of_property_read_bool(nc, "spi-cpol"))
spi->mode |= SPI_CPOL;
if (of_property_read_bool(nc, "spi-3wire"))
spi->mode |= SPI_3WIRE;
if (of_property_read_bool(nc, "spi-lsb-first"))
spi->mode |= SPI_LSB_FIRST;
if (of_property_read_bool(nc, "spi-cs-high"))
spi->mode |= SPI_CS_HIGH;
/* Device DUAL/QUAD mode */
if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
switch (value) {
case 0:
spi->mode |= SPI_NO_TX;
break;
case 1:
break;
case 2:
spi->mode |= SPI_TX_DUAL;
break;
case 4:
spi->mode |= SPI_TX_QUAD;
break;
case 8:
spi->mode |= SPI_TX_OCTAL;
break;
default:
dev_warn(&ctlr->dev,
"spi-tx-bus-width %d not supported\n",
value);
break;
}
}
if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
switch (value) {
case 0:
spi->mode |= SPI_NO_RX;
break;
case 1:
break;
case 2:
spi->mode |= SPI_RX_DUAL;
break;
case 4:
spi->mode |= SPI_RX_QUAD;
break;
case 8:
spi->mode |= SPI_RX_OCTAL;
break;
default:
dev_warn(&ctlr->dev,
"spi-rx-bus-width %d not supported\n",
value);
break;
}
}
if (spi_controller_is_slave(ctlr)) {
if (!of_node_name_eq(nc, "slave")) {
dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
nc);
return -EINVAL;
}
return 0;
}
/* Device address */
rc = of_property_read_u32(nc, "reg", &value);
if (rc) {
dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
nc, rc);
return rc;
}
spi_set_chipselect(spi, 0, value);
/* Device speed */
if (!of_property_read_u32(nc, "spi-max-frequency", &value))
spi->max_speed_hz = value;
/* Device CS delays */
of_spi_parse_dt_cs_delay(nc, &spi->cs_setup, "spi-cs-setup-delay-ns");
of_spi_parse_dt_cs_delay(nc, &spi->cs_hold, "spi-cs-hold-delay-ns");
of_spi_parse_dt_cs_delay(nc, &spi->cs_inactive, "spi-cs-inactive-delay-ns");
return 0;
}
static struct spi_device *
of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
{
struct spi_device *spi;
int rc;
/* Alloc an spi_device */
spi = spi_alloc_device(ctlr);
if (!spi) {
dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
rc = -ENOMEM;
goto err_out;
}
/* Select device driver */
rc = of_modalias_node(nc, spi->modalias,
sizeof(spi->modalias));
if (rc < 0) {
dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
goto err_out;
}
rc = of_spi_parse_dt(ctlr, spi, nc);
if (rc)
goto err_out;
/* Store a pointer to the node in the device structure */
of_node_get(nc);
spi->dev.of_node = nc;
spi->dev.fwnode = of_fwnode_handle(nc);
/* Register the new device */
rc = spi_add_device(spi);
if (rc) {
dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
goto err_of_node_put;
}
return spi;
err_of_node_put:
of_node_put(nc);
err_out:
spi_dev_put(spi);
return ERR_PTR(rc);
}
/**
* of_register_spi_devices() - Register child devices onto the SPI bus
* @ctlr: Pointer to spi_controller device
*
* Registers an spi_device for each child node of controller node which
* represents a valid SPI slave.
*/
static void of_register_spi_devices(struct spi_controller *ctlr)
{
struct spi_device *spi;
struct device_node *nc;
if (!ctlr->dev.of_node)
return;
for_each_available_child_of_node(ctlr->dev.of_node, nc) {
if (of_node_test_and_set_flag(nc, OF_POPULATED))
continue;
spi = of_register_spi_device(ctlr, nc);
if (IS_ERR(spi)) {
dev_warn(&ctlr->dev,
"Failed to create SPI device for %pOF\n", nc);
of_node_clear_flag(nc, OF_POPULATED);
}
}
}
#else
static void of_register_spi_devices(struct spi_controller *ctlr) { }
#endif
/**
* spi_new_ancillary_device() - Register ancillary SPI device
* @spi: Pointer to the main SPI device registering the ancillary device
* @chip_select: Chip Select of the ancillary device
*
* Register an ancillary SPI device; for example some chips have a chip-select
* for normal device usage and another one for setup/firmware upload.
*
* This may only be called from main SPI device's probe routine.
*
* Return: 0 on success; negative errno on failure
*/
struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
u8 chip_select)
{
struct spi_device *ancillary;
int rc = 0;
/* Alloc an spi_device */
ancillary = spi_alloc_device(spi->controller);
if (!ancillary) {
rc = -ENOMEM;
goto err_out;
}
strscpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
/* Use provided chip-select for ancillary device */
spi_set_chipselect(ancillary, 0, chip_select);
/* Take over SPI mode/speed from SPI main device */
ancillary->max_speed_hz = spi->max_speed_hz;
ancillary->mode = spi->mode;
/* Register the new device */
rc = spi_add_device_locked(ancillary);
if (rc) {
dev_err(&spi->dev, "failed to register ancillary device\n");
goto err_out;
}
return ancillary;
err_out:
spi_dev_put(ancillary);
return ERR_PTR(rc);
}
EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
#ifdef CONFIG_ACPI
struct acpi_spi_lookup {
struct spi_controller *ctlr;
u32 max_speed_hz;
u32 mode;
int irq;
u8 bits_per_word;
u8 chip_select;
int n;
int index;
};
static int acpi_spi_count(struct acpi_resource *ares, void *data)
{
struct acpi_resource_spi_serialbus *sb;
int *count = data;
if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
return 1;
sb = &ares->data.spi_serial_bus;
if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
return 1;
*count = *count + 1;
return 1;
}
/**
* acpi_spi_count_resources - Count the number of SpiSerialBus resources
* @adev: ACPI device
*
* Returns the number of SpiSerialBus resources in the ACPI-device's
* resource-list; or a negative error code.
*/
int acpi_spi_count_resources(struct acpi_device *adev)
{
LIST_HEAD(r);
int count = 0;
int ret;
ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count);
if (ret < 0)
return ret;
acpi_dev_free_resource_list(&r);
return count;
}
EXPORT_SYMBOL_GPL(acpi_spi_count_resources);
static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
struct acpi_spi_lookup *lookup)
{
const union acpi_object *obj;
if (!x86_apple_machine)
return;
if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length >= 4)
lookup->max_speed_hz = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length == 8)
lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
lookup->mode |= SPI_LSB_FIRST;
if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
lookup->mode |= SPI_CPOL;
if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
lookup->mode |= SPI_CPHA;
}
static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
{
struct acpi_spi_lookup *lookup = data;
struct spi_controller *ctlr = lookup->ctlr;
if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
struct acpi_resource_spi_serialbus *sb;
acpi_handle parent_handle;
acpi_status status;
sb = &ares->data.spi_serial_bus;
if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
if (lookup->index != -1 && lookup->n++ != lookup->index)
return 1;
status = acpi_get_handle(NULL,
sb->resource_source.string_ptr,
&parent_handle);
if (ACPI_FAILURE(status))
return -ENODEV;
if (ctlr) {
if (ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
return -ENODEV;
} else {
struct acpi_device *adev;
adev = acpi_fetch_acpi_dev(parent_handle);
if (!adev)
return -ENODEV;
ctlr = acpi_spi_find_controller_by_adev(adev);
if (!ctlr)
return -EPROBE_DEFER;
lookup->ctlr = ctlr;
}
/*
* ACPI DeviceSelection numbering is handled by the
* host controller driver in Windows and can vary
* from driver to driver. In Linux we always expect
* 0 .. max - 1 so we need to ask the driver to
* translate between the two schemes.
*/
if (ctlr->fw_translate_cs) {
int cs = ctlr->fw_translate_cs(ctlr,
sb->device_selection);
if (cs < 0)
return cs;
lookup->chip_select = cs;
} else {
lookup->chip_select = sb->device_selection;
}
lookup->max_speed_hz = sb->connection_speed;
lookup->bits_per_word = sb->data_bit_length;
if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
lookup->mode |= SPI_CPHA;
if (sb->clock_polarity == ACPI_SPI_START_HIGH)
lookup->mode |= SPI_CPOL;
if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
lookup->mode |= SPI_CS_HIGH;
}
} else if (lookup->irq < 0) {
struct resource r;
if (acpi_dev_resource_interrupt(ares, 0, &r))
lookup->irq = r.start;
}
/* Always tell the ACPI core to skip this resource */
return 1;
}
/**
* acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
* @ctlr: controller to which the spi device belongs
* @adev: ACPI Device for the spi device
* @index: Index of the spi resource inside the ACPI Node
*
* This should be used to allocate a new spi device from and ACPI Node.
* The caller is responsible for calling spi_add_device to register the spi device.
*
* If ctlr is set to NULL, the Controller for the spi device will be looked up
* using the resource.
* If index is set to -1, index is not used.
* Note: If index is -1, ctlr must be set.
*
* Return: a pointer to the new device, or ERR_PTR on error.
*/
struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
struct acpi_device *adev,
int index)
{
acpi_handle parent_handle = NULL;
struct list_head resource_list;
struct acpi_spi_lookup lookup = {};
struct spi_device *spi;
int ret;
if (!ctlr && index == -1)
return ERR_PTR(-EINVAL);
lookup.ctlr = ctlr;
lookup.irq = -1;
lookup.index = index;
lookup.n = 0;
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
acpi_spi_add_resource, &lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0)
/* Found SPI in _CRS but it points to another controller */
return ERR_PTR(ret);
if (!lookup.max_speed_hz &&
ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
ACPI_HANDLE(lookup.ctlr->dev.parent) == parent_handle) {
/* Apple does not use _CRS but nested devices for SPI slaves */
acpi_spi_parse_apple_properties(adev, &lookup);
}
if (!lookup.max_speed_hz)
return ERR_PTR(-ENODEV);
spi = spi_alloc_device(lookup.ctlr);
if (!spi) {
dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
dev_name(&adev->dev));
return ERR_PTR(-ENOMEM);
}
ACPI_COMPANION_SET(&spi->dev, adev);
spi->max_speed_hz = lookup.max_speed_hz;
spi->mode |= lookup.mode;
spi->irq = lookup.irq;
spi->bits_per_word = lookup.bits_per_word;
spi_set_chipselect(spi, 0, lookup.chip_select);
return spi;
}
EXPORT_SYMBOL_GPL(acpi_spi_device_alloc);
static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
struct acpi_device *adev)
{
struct spi_device *spi;
if (acpi_bus_get_status(adev) || !adev->status.present ||
acpi_device_enumerated(adev))
return AE_OK;
spi = acpi_spi_device_alloc(ctlr, adev, -1);
if (IS_ERR(spi)) {
if (PTR_ERR(spi) == -ENOMEM)
return AE_NO_MEMORY;
else
return AE_OK;
}
acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
sizeof(spi->modalias));
if (spi->irq < 0)
spi->irq = acpi_dev_gpio_irq_get(adev, 0);
acpi_device_set_enumerated(adev);
adev->power.flags.ignore_parent = true;
if (spi_add_device(spi)) {
adev->power.flags.ignore_parent = false;
dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
dev_name(&adev->dev));
spi_dev_put(spi);
}
return AE_OK;
}
static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
struct spi_controller *ctlr = data;
if (!adev)
return AE_OK;
return acpi_register_spi_device(ctlr, adev);
}
#define SPI_ACPI_ENUMERATE_MAX_DEPTH 32
static void acpi_register_spi_devices(struct spi_controller *ctlr)
{
acpi_status status;
acpi_handle handle;
handle = ACPI_HANDLE(ctlr->dev.parent);
if (!handle)
return;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
SPI_ACPI_ENUMERATE_MAX_DEPTH,
acpi_spi_add_device, NULL, ctlr, NULL);
if (ACPI_FAILURE(status))
dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
}
#else
static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
#endif /* CONFIG_ACPI */
static void spi_controller_release(struct device *dev)
{
struct spi_controller *ctlr;
ctlr = container_of(dev, struct spi_controller, dev);
kfree(ctlr);
}
static struct class spi_master_class = {
.name = "spi_master",
.owner = THIS_MODULE,
.dev_release = spi_controller_release,
.dev_groups = spi_master_groups,
};
#ifdef CONFIG_SPI_SLAVE
/**
* spi_slave_abort - abort the ongoing transfer request on an SPI slave
* controller
* @spi: device used for the current transfer
*/
int spi_slave_abort(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
return ctlr->slave_abort(ctlr);
return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(spi_slave_abort);
int spi_target_abort(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
if (spi_controller_is_target(ctlr) && ctlr->target_abort)
return ctlr->target_abort(ctlr);
return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(spi_target_abort);
static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct spi_controller *ctlr = container_of(dev, struct spi_controller,
dev);
struct device *child;
child = device_find_any_child(&ctlr->dev);
return sprintf(buf, "%s\n",
child ? to_spi_device(child)->modalias : NULL);
}
static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct spi_controller *ctlr = container_of(dev, struct spi_controller,
dev);
struct spi_device *spi;
struct device *child;
char name[32];
int rc;
rc = sscanf(buf, "%31s", name);
if (rc != 1 || !name[0])
return -EINVAL;
child = device_find_any_child(&ctlr->dev);
if (child) {
/* Remove registered slave */
device_unregister(child);
put_device(child);
}
if (strcmp(name, "(null)")) {
/* Register new slave */
spi = spi_alloc_device(ctlr);
if (!spi)
return -ENOMEM;
strscpy(spi->modalias, name, sizeof(spi->modalias));
rc = spi_add_device(spi);
if (rc) {
spi_dev_put(spi);
return rc;
}
}
return count;
}
static DEVICE_ATTR_RW(slave);
static struct attribute *spi_slave_attrs[] = {
&dev_attr_slave.attr,
NULL,
};
static const struct attribute_group spi_slave_group = {
.attrs = spi_slave_attrs,
};
static const struct attribute_group *spi_slave_groups[] = {
&spi_controller_statistics_group,
&spi_slave_group,
NULL,
};
static struct class spi_slave_class = {
.name = "spi_slave",
.owner = THIS_MODULE,
.dev_release = spi_controller_release,
.dev_groups = spi_slave_groups,
};
#else
extern struct class spi_slave_class; /* dummy */
#endif
/**
* __spi_alloc_controller - allocate an SPI master or slave controller
* @dev: the controller, possibly using the platform_bus
* @size: how much zeroed driver-private data to allocate; the pointer to this
* memory is in the driver_data field of the returned device, accessible
* with spi_controller_get_devdata(); the memory is cacheline aligned;
* drivers granting DMA access to portions of their private data need to
* round up @size using ALIGN(size, dma_get_cache_alignment()).
* @slave: flag indicating whether to allocate an SPI master (false) or SPI
* slave (true) controller
* Context: can sleep
*
* This call is used only by SPI controller drivers, which are the
* only ones directly touching chip registers. It's how they allocate
* an spi_controller structure, prior to calling spi_register_controller().
*
* This must be called from context that can sleep.
*
* The caller is responsible for assigning the bus number and initializing the
* controller's methods before calling spi_register_controller(); and (after
* errors adding the device) calling spi_controller_put() to prevent a memory
* leak.
*
* Return: the SPI controller structure on success, else NULL.
*/
struct spi_controller *__spi_alloc_controller(struct device *dev,
unsigned int size, bool slave)
{
struct spi_controller *ctlr;
size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
if (!dev)
return NULL;
ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
if (!ctlr)
return NULL;
device_initialize(&ctlr->dev);
INIT_LIST_HEAD(&ctlr->queue);
spin_lock_init(&ctlr->queue_lock);
spin_lock_init(&ctlr->bus_lock_spinlock);
mutex_init(&ctlr->bus_lock_mutex);
mutex_init(&ctlr->io_mutex);
mutex_init(&ctlr->add_lock);
ctlr->bus_num = -1;
ctlr->num_chipselect = 1;
ctlr->slave = slave;
if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
ctlr->dev.class = &spi_slave_class;
else
ctlr->dev.class = &spi_master_class;
ctlr->dev.parent = dev;
pm_suspend_ignore_children(&ctlr->dev, true);
spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
return ctlr;
}
EXPORT_SYMBOL_GPL(__spi_alloc_controller);
static void devm_spi_release_controller(struct device *dev, void *ctlr)
{
spi_controller_put(*(struct spi_controller **)ctlr);
}
/**
* __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
* @dev: physical device of SPI controller
* @size: how much zeroed driver-private data to allocate
* @slave: whether to allocate an SPI master (false) or SPI slave (true)
* Context: can sleep
*
* Allocate an SPI controller and automatically release a reference on it
* when @dev is unbound from its driver. Drivers are thus relieved from
* having to call spi_controller_put().
*
* The arguments to this function are identical to __spi_alloc_controller().
*
* Return: the SPI controller structure on success, else NULL.
*/
struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
unsigned int size,
bool slave)
{
struct spi_controller **ptr, *ctlr;
ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return NULL;
ctlr = __spi_alloc_controller(dev, size, slave);
if (ctlr) {
ctlr->devm_allocated = true;
*ptr = ctlr;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return ctlr;
}
EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
/**
* spi_get_gpio_descs() - grab chip select GPIOs for the master
* @ctlr: The SPI master to grab GPIO descriptors for
*/
static int spi_get_gpio_descs(struct spi_controller *ctlr)
{
int nb, i;
struct gpio_desc **cs;
struct device *dev = &ctlr->dev;
unsigned long native_cs_mask = 0;
unsigned int num_cs_gpios = 0;
nb = gpiod_count(dev, "cs");
if (nb < 0) {
/* No GPIOs at all is fine, else return the error */
if (nb == -ENOENT)
return 0;
return nb;
}
ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
GFP_KERNEL);
if (!cs)
return -ENOMEM;
ctlr->cs_gpiods = cs;
for (i = 0; i < nb; i++) {
/*
* Most chipselects are active low, the inverted
* semantics are handled by special quirks in gpiolib,
* so initializing them GPIOD_OUT_LOW here means
* "unasserted", in most cases this will drive the physical
* line high.
*/
cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
GPIOD_OUT_LOW);
if (IS_ERR(cs[i]))
return PTR_ERR(cs[i]);
if (cs[i]) {
/*
* If we find a CS GPIO, name it after the device and
* chip select line.
*/
char *gpioname;
gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
dev_name(dev), i);
if (!gpioname)
return -ENOMEM;
gpiod_set_consumer_name(cs[i], gpioname);
num_cs_gpios++;
continue;
}
if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
dev_err(dev, "Invalid native chip select %d\n", i);
return -EINVAL;
}
native_cs_mask |= BIT(i);
}
ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios &&
ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
dev_err(dev, "No unused native chip select available\n");
return -EINVAL;
}
return 0;
}
static int spi_controller_check_ops(struct spi_controller *ctlr)
{
/*
* The controller may implement only the high-level SPI-memory like
* operations if it does not support regular SPI transfers, and this is
* valid use case.
* If ->mem_ops or ->mem_ops->exec_op is NULL, we request that at least
* one of the ->transfer_xxx() method be implemented.
*/
if (!ctlr->mem_ops || (ctlr->mem_ops && !ctlr->mem_ops->exec_op)) {
if (!ctlr->transfer && !ctlr->transfer_one &&
!ctlr->transfer_one_message) {
return -EINVAL;
}
}
return 0;
}
/**
* spi_register_controller - register SPI master or slave controller
* @ctlr: initialized master, originally from spi_alloc_master() or
* spi_alloc_slave()
* Context: can sleep
*
* SPI controllers connect to their drivers using some non-SPI bus,
* such as the platform bus. The final stage of probe() in that code
* includes calling spi_register_controller() to hook up to this SPI bus glue.
*
* SPI controllers use board specific (often SOC specific) bus numbers,
* and board-specific addressing for SPI devices combines those numbers
* with chip select numbers. Since SPI does not directly support dynamic
* device identification, boards need configuration tables telling which
* chip is at which address.
*
* This must be called from context that can sleep. It returns zero on
* success, else a negative error code (dropping the controller's refcount).
* After a successful return, the caller is responsible for calling
* spi_unregister_controller().
*
* Return: zero on success, else a negative error code.
*/
int spi_register_controller(struct spi_controller *ctlr)
{
struct device *dev = ctlr->dev.parent;
struct boardinfo *bi;
int status;
int id, first_dynamic;
if (!dev)
return -ENODEV;
/*
* Make sure all necessary hooks are implemented before registering
* the SPI controller.
*/
status = spi_controller_check_ops(ctlr);
if (status)
return status;
if (ctlr->bus_num >= 0) {
/* Devices with a fixed bus num must check-in with the num */
mutex_lock(&board_lock);
id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
ctlr->bus_num + 1, GFP_KERNEL);
mutex_unlock(&board_lock);
if (WARN(id < 0, "couldn't get idr"))
return id == -ENOSPC ? -EBUSY : id;
ctlr->bus_num = id;
} else if (ctlr->dev.of_node) {
/* Allocate dynamic bus number using Linux idr */
id = of_alias_get_id(ctlr->dev.of_node, "spi");
if (id >= 0) {
ctlr->bus_num = id;
mutex_lock(&board_lock);
id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
ctlr->bus_num + 1, GFP_KERNEL);
mutex_unlock(&board_lock);
if (WARN(id < 0, "couldn't get idr"))
return id == -ENOSPC ? -EBUSY : id;
}
}
if (ctlr->bus_num < 0) {
first_dynamic = of_alias_get_highest_id("spi");
if (first_dynamic < 0)
first_dynamic = 0;
else
first_dynamic++;
mutex_lock(&board_lock);
id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
0, GFP_KERNEL);
mutex_unlock(&board_lock);
if (WARN(id < 0, "couldn't get idr"))
return id;
ctlr->bus_num = id;
}
ctlr->bus_lock_flag = 0;
init_completion(&ctlr->xfer_completion);
init_completion(&ctlr->cur_msg_completion);
if (!ctlr->max_dma_len)
ctlr->max_dma_len = INT_MAX;
/*
* Register the device, then userspace will see it.
* Registration fails if the bus ID is in use.
*/
dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
if (!spi_controller_is_slave(ctlr) && ctlr->use_gpio_descriptors) {
status = spi_get_gpio_descs(ctlr);
if (status)
goto free_bus_id;
/*
* A controller using GPIO descriptors always
* supports SPI_CS_HIGH if need be.
*/
ctlr->mode_bits |= SPI_CS_HIGH;
}
/*
* Even if it's just one always-selected device, there must
* be at least one chipselect.
*/
if (!ctlr->num_chipselect) {
status = -EINVAL;
goto free_bus_id;
}
/* Setting last_cs to -1 means no chip selected */
ctlr->last_cs = -1;
status = device_add(&ctlr->dev);
if (status < 0)
goto free_bus_id;
dev_dbg(dev, "registered %s %s\n",
spi_controller_is_slave(ctlr) ? "slave" : "master",
dev_name(&ctlr->dev));
/*
* If we're using a queued driver, start the queue. Note that we don't
* need the queueing logic if the driver is only supporting high-level
* memory operations.
*/
if (ctlr->transfer) {
dev_info(dev, "controller is unqueued, this is deprecated\n");
} else if (ctlr->transfer_one || ctlr->transfer_one_message) {
status = spi_controller_initialize_queue(ctlr);
if (status) {
device_del(&ctlr->dev);
goto free_bus_id;
}
}
/* Add statistics */
ctlr->pcpu_statistics = spi_alloc_pcpu_stats(dev);
if (!ctlr->pcpu_statistics) {
dev_err(dev, "Error allocating per-cpu statistics\n");
status = -ENOMEM;
goto destroy_queue;
}
mutex_lock(&board_lock);
list_add_tail(&ctlr->list, &spi_controller_list);
list_for_each_entry(bi, &board_list, list)
spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
mutex_unlock(&board_lock);
/* Register devices from the device tree and ACPI */
of_register_spi_devices(ctlr);
acpi_register_spi_devices(ctlr);
return status;
destroy_queue:
spi_destroy_queue(ctlr);
free_bus_id:
mutex_lock(&board_lock);
idr_remove(&spi_master_idr, ctlr->bus_num);
mutex_unlock(&board_lock);
return status;
}
EXPORT_SYMBOL_GPL(spi_register_controller);
static void devm_spi_unregister(struct device *dev, void *res)
{
spi_unregister_controller(*(struct spi_controller **)res);
}
/**
* devm_spi_register_controller - register managed SPI master or slave
* controller
* @dev: device managing SPI controller
* @ctlr: initialized controller, originally from spi_alloc_master() or
* spi_alloc_slave()
* Context: can sleep
*
* Register a SPI device as with spi_register_controller() which will
* automatically be unregistered and freed.
*
* Return: zero on success, else a negative error code.
*/
int devm_spi_register_controller(struct device *dev,
struct spi_controller *ctlr)
{
struct spi_controller **ptr;
int ret;
ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return -ENOMEM;
ret = spi_register_controller(ctlr);
if (!ret) {
*ptr = ctlr;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return ret;
}
EXPORT_SYMBOL_GPL(devm_spi_register_controller);
static int __unregister(struct device *dev, void *null)
{
spi_unregister_device(to_spi_device(dev));
return 0;
}
/**
* spi_unregister_controller - unregister SPI master or slave controller
* @ctlr: the controller being unregistered
* Context: can sleep
*
* This call is used only by SPI controller drivers, which are the
* only ones directly touching chip registers.
*
* This must be called from context that can sleep.
*
* Note that this function also drops a reference to the controller.
*/
void spi_unregister_controller(struct spi_controller *ctlr)
{
struct spi_controller *found;
int id = ctlr->bus_num;
/* Prevent addition of new devices, unregister existing ones */
if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_lock(&ctlr->add_lock);
device_for_each_child(&ctlr->dev, NULL, __unregister);
/* First make sure that this controller was ever added */
mutex_lock(&board_lock);
found = idr_find(&spi_master_idr, id);
mutex_unlock(&board_lock);
if (ctlr->queued) {
if (spi_destroy_queue(ctlr))
dev_err(&ctlr->dev, "queue remove failed\n");
}
mutex_lock(&board_lock);
list_del(&ctlr->list);
mutex_unlock(&board_lock);
device_del(&ctlr->dev);
/* Free bus id */
mutex_lock(&board_lock);
if (found == ctlr)
idr_remove(&spi_master_idr, id);
mutex_unlock(&board_lock);
if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_unlock(&ctlr->add_lock);
/* Release the last reference on the controller if its driver
* has not yet been converted to devm_spi_alloc_master/slave().
*/
if (!ctlr->devm_allocated)
put_device(&ctlr->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);
int spi_controller_suspend(struct spi_controller *ctlr)
{
int ret;
/* Basically no-ops for non-queued controllers */
if (!ctlr->queued)
return 0;
ret = spi_stop_queue(ctlr);
if (ret)
dev_err(&ctlr->dev, "queue stop failed\n");
return ret;
}
EXPORT_SYMBOL_GPL(spi_controller_suspend);
int spi_controller_resume(struct spi_controller *ctlr)
{
int ret;
if (!ctlr->queued)
return 0;
ret = spi_start_queue(ctlr);
if (ret)
dev_err(&ctlr->dev, "queue restart failed\n");
return ret;
}
EXPORT_SYMBOL_GPL(spi_controller_resume);
/*-------------------------------------------------------------------------*/
/* Core methods for spi_message alterations */
static void __spi_replace_transfers_release(struct spi_controller *ctlr,
struct spi_message *msg,
void *res)
{
struct spi_replaced_transfers *rxfer = res;
size_t i;
/* Call extra callback if requested */
if (rxfer->release)
rxfer->release(ctlr, msg, res);
/* Insert replaced transfers back into the message */
list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
/* Remove the formerly inserted entries */
for (i = 0; i < rxfer->inserted; i++)
list_del(&rxfer->inserted_transfers[i].transfer_list);
}
/**
* spi_replace_transfers - replace transfers with several transfers
* and register change with spi_message.resources
* @msg: the spi_message we work upon
* @xfer_first: the first spi_transfer we want to replace
* @remove: number of transfers to remove
* @insert: the number of transfers we want to insert instead
* @release: extra release code necessary in some circumstances
* @extradatasize: extra data to allocate (with alignment guarantees
* of struct @spi_transfer)
* @gfp: gfp flags
*
* Returns: pointer to @spi_replaced_transfers,
* PTR_ERR(...) in case of errors.
*/
static struct spi_replaced_transfers *spi_replace_transfers(
struct spi_message *msg,
struct spi_transfer *xfer_first,
size_t remove,
size_t insert,
spi_replaced_release_t release,
size_t extradatasize,
gfp_t gfp)
{
struct spi_replaced_transfers *rxfer;
struct spi_transfer *xfer;
size_t i;
/* Allocate the structure using spi_res */
rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
struct_size(rxfer, inserted_transfers, insert)
+ extradatasize,
gfp);
if (!rxfer)
return ERR_PTR(-ENOMEM);
/* The release code to invoke before running the generic release */
rxfer->release = release;
/* Assign extradata */
if (extradatasize)
rxfer->extradata =
&rxfer->inserted_transfers[insert];
/* Init the replaced_transfers list */
INIT_LIST_HEAD(&rxfer->replaced_transfers);
/*
* Assign the list_entry after which we should reinsert
* the @replaced_transfers - it may be spi_message.messages!
*/
rxfer->replaced_after = xfer_first->transfer_list.prev;
/* Remove the requested number of transfers */
for (i = 0; i < remove; i++) {
/*
* If the entry after replaced_after it is msg->transfers
* then we have been requested to remove more transfers
* than are in the list.
*/
if (rxfer->replaced_after->next == &msg->transfers) {
dev_err(&msg->spi->dev,
"requested to remove more spi_transfers than are available\n");
/* Insert replaced transfers back into the message */
list_splice(&rxfer->replaced_transfers,
rxfer->replaced_after);
/* Free the spi_replace_transfer structure... */
spi_res_free(rxfer);
/* ...and return with an error */
return ERR_PTR(-EINVAL);
}
/*
* Remove the entry after replaced_after from list of
* transfers and add it to list of replaced_transfers.
*/
list_move_tail(rxfer->replaced_after->next,
&rxfer->replaced_transfers);
}
/*
* Create copy of the given xfer with identical settings
* based on the first transfer to get removed.
*/
for (i = 0; i < insert; i++) {
/* We need to run in reverse order */
xfer = &rxfer->inserted_transfers[insert - 1 - i];
/* Copy all spi_transfer data */
memcpy(xfer, xfer_first, sizeof(*xfer));
/* Add to list */
list_add(&xfer->transfer_list, rxfer->replaced_after);
/* Clear cs_change and delay for all but the last */
if (i) {
xfer->cs_change = false;
xfer->delay.value = 0;
}
}
/* Set up inserted... */
rxfer->inserted = insert;
/* ...and register it with spi_res/spi_message */
spi_res_add(msg, rxfer);
return rxfer;
}
static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
struct spi_message *msg,
struct spi_transfer **xferp,
size_t maxsize,
gfp_t gfp)
{
struct spi_transfer *xfer = *xferp, *xfers;
struct spi_replaced_transfers *srt;
size_t offset;
size_t count, i;
/* Calculate how many we have to replace */
count = DIV_ROUND_UP(xfer->len, maxsize);
/* Create replacement */
srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
if (IS_ERR(srt))
return PTR_ERR(srt);
xfers = srt->inserted_transfers;
/*
* Now handle each of those newly inserted spi_transfers.
* Note that the replacements spi_transfers all are preset
* to the same values as *xferp, so tx_buf, rx_buf and len
* are all identical (as well as most others)
* so we just have to fix up len and the pointers.
*
* This also includes support for the depreciated
* spi_message.is_dma_mapped interface.
*/
/*
* The first transfer just needs the length modified, so we
* run it outside the loop.
*/
xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
/* All the others need rx_buf/tx_buf also set */
for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
/* Update rx_buf, tx_buf and dma */
if (xfers[i].rx_buf)
xfers[i].rx_buf += offset;
if (xfers[i].rx_dma)
xfers[i].rx_dma += offset;
if (xfers[i].tx_buf)
xfers[i].tx_buf += offset;
if (xfers[i].tx_dma)
xfers[i].tx_dma += offset;
/* Update length */
xfers[i].len = min(maxsize, xfers[i].len - offset);
}
/*
* We set up xferp to the last entry we have inserted,
* so that we skip those already split transfers.
*/
*xferp = &xfers[count - 1];
/* Increment statistics counters */
SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics,
transfers_split_maxsize);
SPI_STATISTICS_INCREMENT_FIELD(msg->spi->pcpu_statistics,
transfers_split_maxsize);
return 0;
}
/**
* spi_split_transfers_maxsize - split spi transfers into multiple transfers
* when an individual transfer exceeds a
* certain size
* @ctlr: the @spi_controller for this transfer
* @msg: the @spi_message to transform
* @maxsize: the maximum when to apply this
* @gfp: GFP allocation flags
*
* Return: status of transformation
*/
int spi_split_transfers_maxsize(struct spi_controller *ctlr,
struct spi_message *msg,
size_t maxsize,
gfp_t gfp)
{
struct spi_transfer *xfer;
int ret;
/*
* Iterate over the transfer_list,
* but note that xfer is advanced to the last transfer inserted
* to avoid checking sizes again unnecessarily (also xfer does
* potentially belong to a different list by the time the
* replacement has happened).
*/
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (xfer->len > maxsize) {
ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
maxsize, gfp);
if (ret)
return ret;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
/*-------------------------------------------------------------------------*/
/* Core methods for SPI controller protocol drivers. Some of the
* other core methods are currently defined as inline functions.
*/
static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
u8 bits_per_word)
{
if (ctlr->bits_per_word_mask) {
/* Only 32 bits fit in the mask */
if (bits_per_word > 32)
return -EINVAL;
if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
return -EINVAL;
}
return 0;
}
/**
* spi_set_cs_timing - configure CS setup, hold, and inactive delays
* @spi: the device that requires specific CS timing configuration
*
* Return: zero on success, else a negative error code.
*/
static int spi_set_cs_timing(struct spi_device *spi)
{
struct device *parent = spi->controller->dev.parent;
int status = 0;
if (spi->controller->set_cs_timing && !spi_get_csgpiod(spi, 0)) {
if (spi->controller->auto_runtime_pm) {
status = pm_runtime_get_sync(parent);
if (status < 0) {
pm_runtime_put_noidle(parent);
dev_err(&spi->controller->dev, "Failed to power device: %d\n",
status);
return status;
}
status = spi->controller->set_cs_timing(spi);
pm_runtime_mark_last_busy(parent);
pm_runtime_put_autosuspend(parent);
} else {
status = spi->controller->set_cs_timing(spi);
}
}
return status;
}
/**
* spi_setup - setup SPI mode and clock rate
* @spi: the device whose settings are being modified
* Context: can sleep, and no requests are queued to the device
*
* SPI protocol drivers may need to update the transfer mode if the
* device doesn't work with its default. They may likewise need
* to update clock rates or word sizes from initial values. This function
* changes those settings, and must be called from a context that can sleep.
* Except for SPI_CS_HIGH, which takes effect immediately, the changes take
* effect the next time the device is selected and data is transferred to
* or from it. When this function returns, the spi device is deselected.
*
* Note that this call will fail if the protocol driver specifies an option
* that the underlying controller or its driver does not support. For
* example, not all hardware supports wire transfers using nine bit words,
* LSB-first wire encoding, or active-high chipselects.
*
* Return: zero on success, else a negative error code.
*/
int spi_setup(struct spi_device *spi)
{
unsigned bad_bits, ugly_bits;
int status = 0;
/*
* Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
* are set at the same time.
*/
if ((hweight_long(spi->mode &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
(hweight_long(spi->mode &
(SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
dev_err(&spi->dev,
"setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
return -EINVAL;
}
/* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */
if ((spi->mode & SPI_3WIRE) && (spi->mode &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
return -EINVAL;
/*
* Help drivers fail *cleanly* when they need options
* that aren't supported with their current controller.
* SPI_CS_WORD has a fallback software implementation,
* so it is ignored here.
*/
bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
SPI_NO_TX | SPI_NO_RX);
ugly_bits = bad_bits &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
if (ugly_bits) {
dev_warn(&spi->dev,
"setup: ignoring unsupported mode bits %x\n",
ugly_bits);
spi->mode &= ~ugly_bits;
bad_bits &= ~ugly_bits;
}
if (bad_bits) {
dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
bad_bits);
return -EINVAL;
}
if (!spi->bits_per_word) {
spi->bits_per_word = 8;
} else {
/*
* Some controllers may not support the default 8 bits-per-word
* so only perform the check when this is explicitly provided.
*/
status = __spi_validate_bits_per_word(spi->controller,
spi->bits_per_word);
if (status)
return status;
}
if (spi->controller->max_speed_hz &&
(!spi->max_speed_hz ||
spi->max_speed_hz > spi->controller->max_speed_hz))
spi->max_speed_hz = spi->controller->max_speed_hz;
mutex_lock(&spi->controller->io_mutex);
if (spi->controller->setup) {
status = spi->controller->setup(spi);
if (status) {
mutex_unlock(&spi->controller->io_mutex);
dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
status);
return status;
}
}
status = spi_set_cs_timing(spi);
if (status) {
mutex_unlock(&spi->controller->io_mutex);
return status;
}
if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
status = pm_runtime_resume_and_get(spi->controller->dev.parent);
if (status < 0) {
mutex_unlock(&spi->controller->io_mutex);
dev_err(&spi->controller->dev, "Failed to power device: %d\n",
status);
return status;
}
/*
* We do not want to return positive value from pm_runtime_get,
* there are many instances of devices calling spi_setup() and
* checking for a non-zero return value instead of a negative
* return value.
*/
status = 0;
spi_set_cs(spi, false, true);
pm_runtime_mark_last_busy(spi->controller->dev.parent);
pm_runtime_put_autosuspend(spi->controller->dev.parent);
} else {
spi_set_cs(spi, false, true);
}
mutex_unlock(&spi->controller->io_mutex);
if (spi->rt && !spi->controller->rt) {
spi->controller->rt = true;
spi_set_thread_rt(spi->controller);
}
trace_spi_setup(spi, status);
dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
spi->mode & SPI_MODE_X_MASK,
(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
(spi->mode & SPI_3WIRE) ? "3wire, " : "",
(spi->mode & SPI_LOOP) ? "loopback, " : "",
spi->bits_per_word, spi->max_speed_hz,
status);
return status;
}
EXPORT_SYMBOL_GPL(spi_setup);
static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
struct spi_device *spi)
{
int delay1, delay2;
delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
if (delay1 < 0)
return delay1;
delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
if (delay2 < 0)
return delay2;
if (delay1 < delay2)
memcpy(&xfer->word_delay, &spi->word_delay,
sizeof(xfer->word_delay));
return 0;
}
static int __spi_validate(struct spi_device *spi, struct spi_message *message)
{
struct spi_controller *ctlr = spi->controller;
struct spi_transfer *xfer;
int w_size;
if (list_empty(&message->transfers))
return -EINVAL;
/*
* If an SPI controller does not support toggling the CS line on each
* transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
* for the CS line, we can emulate the CS-per-word hardware function by
* splitting transfers into one-word transfers and ensuring that
* cs_change is set for each transfer.
*/
if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
spi_get_csgpiod(spi, 0))) {
size_t maxsize;
int ret;
maxsize = (spi->bits_per_word + 7) / 8;
/* spi_split_transfers_maxsize() requires message->spi */
message->spi = spi;
ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
GFP_KERNEL);
if (ret)
return ret;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
/* Don't change cs_change on the last entry in the list */
if (list_is_last(&xfer->transfer_list, &message->transfers))
break;
xfer->cs_change = 1;
}
}
/*
* Half-duplex links include original MicroWire, and ones with
* only one data pin like SPI_3WIRE (switches direction) or where
* either MOSI or MISO is missing. They can also be caused by
* software limitations.
*/
if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
(spi->mode & SPI_3WIRE)) {
unsigned flags = ctlr->flags;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
if (xfer->rx_buf && xfer->tx_buf)
return -EINVAL;
if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
return -EINVAL;
if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
return -EINVAL;
}
}
/*
* Set transfer bits_per_word and max speed as spi device default if
* it is not set for this transfer.
* Set transfer tx_nbits and rx_nbits as single transfer default
* (SPI_NBITS_SINGLE) if it is not set for this transfer.
* Ensure transfer word_delay is at least as long as that required by
* device itself.
*/
message->frame_length = 0;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
xfer->effective_speed_hz = 0;
message->frame_length += xfer->len;
if (!xfer->bits_per_word)
xfer->bits_per_word = spi->bits_per_word;
if (!xfer->speed_hz)
xfer->speed_hz = spi->max_speed_hz;
if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
xfer->speed_hz = ctlr->max_speed_hz;
if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
return -EINVAL;
/*
* SPI transfer length should be multiple of SPI word size
* where SPI word size should be power-of-two multiple.
*/
if (xfer->bits_per_word <= 8)
w_size = 1;
else if (xfer->bits_per_word <= 16)
w_size = 2;
else
w_size = 4;
/* No partial transfers accepted */
if (xfer->len % w_size)
return -EINVAL;
if (xfer->speed_hz && ctlr->min_speed_hz &&
xfer->speed_hz < ctlr->min_speed_hz)
return -EINVAL;
if (xfer->tx_buf && !xfer->tx_nbits)
xfer->tx_nbits = SPI_NBITS_SINGLE;
if (xfer->rx_buf && !xfer->rx_nbits)
xfer->rx_nbits = SPI_NBITS_SINGLE;
/*
* Check transfer tx/rx_nbits:
* 1. check the value matches one of single, dual and quad
* 2. check tx/rx_nbits match the mode in spi_device
*/
if (xfer->tx_buf) {
if (spi->mode & SPI_NO_TX)
return -EINVAL;
if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
xfer->tx_nbits != SPI_NBITS_DUAL &&
xfer->tx_nbits != SPI_NBITS_QUAD)
return -EINVAL;
if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
return -EINVAL;
if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
!(spi->mode & SPI_TX_QUAD))
return -EINVAL;
}
/* Check transfer rx_nbits */
if (xfer->rx_buf) {
if (spi->mode & SPI_NO_RX)
return -EINVAL;
if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
xfer->rx_nbits != SPI_NBITS_DUAL &&
xfer->rx_nbits != SPI_NBITS_QUAD)
return -EINVAL;
if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
return -EINVAL;
if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
!(spi->mode & SPI_RX_QUAD))
return -EINVAL;
}
if (_spi_xfer_word_delay_update(xfer, spi))
return -EINVAL;
}
message->status = -EINPROGRESS;
return 0;
}
static int __spi_async(struct spi_device *spi, struct spi_message *message)
{
struct spi_controller *ctlr = spi->controller;
struct spi_transfer *xfer;
/*
* Some controllers do not support doing regular SPI transfers. Return
* ENOTSUPP when this is the case.
*/
if (!ctlr->transfer)
return -ENOTSUPP;
message->spi = spi;
SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_async);
SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_async);
trace_spi_message_submit(message);
if (!ctlr->ptp_sts_supported) {
list_for_each_entry(xfer, &message->transfers, transfer_list) {
xfer->ptp_sts_word_pre = 0;
ptp_read_system_prets(xfer->ptp_sts);
}
}
return ctlr->transfer(spi, message);
}
/**
* spi_async - asynchronous SPI transfer
* @spi: device with which data will be exchanged
* @message: describes the data transfers, including completion callback
* Context: any (irqs may be blocked, etc)
*
* This call may be used in_irq and other contexts which can't sleep,
* as well as from task contexts which can sleep.
*
* The completion callback is invoked in a context which can't sleep.
* Before that invocation, the value of message->status is undefined.
* When the callback is issued, message->status holds either zero (to
* indicate complete success) or a negative error code. After that
* callback returns, the driver which issued the transfer request may
* deallocate the associated memory; it's no longer in use by any SPI
* core or controller driver code.
*
* Note that although all messages to a spi_device are handled in
* FIFO order, messages may go to different devices in other orders.
* Some device might be higher priority, or have various "hard" access
* time requirements, for example.
*
* On detection of any fault during the transfer, processing of
* the entire message is aborted, and the device is deselected.
* Until returning from the associated message completion callback,
* no other spi_message queued to that device will be processed.
* (This rule applies equally to all the synchronous transfer calls,
* which are wrappers around this core asynchronous primitive.)
*
* Return: zero on success, else a negative error code.
*/
int spi_async(struct spi_device *spi, struct spi_message *message)
{
struct spi_controller *ctlr = spi->controller;
int ret;
unsigned long flags;
ret = __spi_validate(spi, message);
if (ret != 0)
return ret;
spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
if (ctlr->bus_lock_flag)
ret = -EBUSY;
else
ret = __spi_async(spi, message);
spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(spi_async);
/**
* spi_async_locked - version of spi_async with exclusive bus usage
* @spi: device with which data will be exchanged
* @message: describes the data transfers, including completion callback
* Context: any (irqs may be blocked, etc)
*
* This call may be used in_irq and other contexts which can't sleep,
* as well as from task contexts which can sleep.
*
* The completion callback is invoked in a context which can't sleep.
* Before that invocation, the value of message->status is undefined.
* When the callback is issued, message->status holds either zero (to
* indicate complete success) or a negative error code. After that
* callback returns, the driver which issued the transfer request may
* deallocate the associated memory; it's no longer in use by any SPI
* core or controller driver code.
*
* Note that although all messages to a spi_device are handled in
* FIFO order, messages may go to different devices in other orders.
* Some device might be higher priority, or have various "hard" access
* time requirements, for example.
*
* On detection of any fault during the transfer, processing of
* the entire message is aborted, and the device is deselected.
* Until returning from the associated message completion callback,
* no other spi_message queued to that device will be processed.
* (This rule applies equally to all the synchronous transfer calls,
* which are wrappers around this core asynchronous primitive.)
*
* Return: zero on success, else a negative error code.
*/
static int spi_async_locked(struct spi_device *spi, struct spi_message *message)
{
struct spi_controller *ctlr = spi->controller;
int ret;
unsigned long flags;
ret = __spi_validate(spi, message);
if (ret != 0)
return ret;
spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
ret = __spi_async(spi, message);
spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
return ret;
}
static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct spi_message *msg)
{
bool was_busy;
int ret;
mutex_lock(&ctlr->io_mutex);
was_busy = ctlr->busy;
ctlr->cur_msg = msg;
ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
if (ret)
goto out;
ctlr->cur_msg = NULL;
ctlr->fallback = false;
if (!was_busy) {
kfree(ctlr->dummy_rx);
ctlr->dummy_rx = NULL;
kfree(ctlr->dummy_tx);
ctlr->dummy_tx = NULL;
if (ctlr->unprepare_transfer_hardware &&
ctlr->unprepare_transfer_hardware(ctlr))
dev_err(&ctlr->dev,
"failed to unprepare transfer hardware\n");
spi_idle_runtime_pm(ctlr);
}
out:
mutex_unlock(&ctlr->io_mutex);
}
/*-------------------------------------------------------------------------*/
/*
* Utility methods for SPI protocol drivers, layered on
* top of the core. Some other utility methods are defined as
* inline functions.
*/
static void spi_complete(void *arg)
{
complete(arg);
}
static int __spi_sync(struct spi_device *spi, struct spi_message *message)
{
DECLARE_COMPLETION_ONSTACK(done);
int status;
struct spi_controller *ctlr = spi->controller;
status = __spi_validate(spi, message);
if (status != 0)
return status;
message->spi = spi;
SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync);
SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync);
/*
* Checking queue_empty here only guarantees async/sync message
* ordering when coming from the same context. It does not need to
* guard against reentrancy from a different context. The io_mutex
* will catch those cases.
*/
if (READ_ONCE(ctlr->queue_empty) && !ctlr->must_async) {
message->actual_length = 0;
message->status = -EINPROGRESS;
trace_spi_message_submit(message);
SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync_immediate);
SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync_immediate);
__spi_transfer_message_noqueue(ctlr, message);
return message->status;
}
/*
* There are messages in the async queue that could have originated
* from the same context, so we need to preserve ordering.
* Therefor we send the message to the async queue and wait until they
* are completed.
*/
message->complete = spi_complete;
message->context = &done;
status = spi_async_locked(spi, message);
if (status == 0) {
wait_for_completion(&done);
status = message->status;
}
message->context = NULL;
return status;
}
/**
* spi_sync - blocking/synchronous SPI data transfers
* @spi: device with which data will be exchanged
* @message: describes the data transfers
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout. Low-overhead controller
* drivers may DMA directly into and out of the message buffers.
*
* Note that the SPI device's chip select is active during the message,
* and then is normally disabled between messages. Drivers for some
* frequently-used devices may want to minimize costs of selecting a chip,
* by leaving it selected in anticipation that the next message will go
* to the same chip. (That may increase power usage.)
*
* Also, the caller is guaranteeing that the memory associated with the
* message will not be freed before this call returns.
*
* Return: zero on success, else a negative error code.
*/
int spi_sync(struct spi_device *spi, struct spi_message *message)
{
int ret;
mutex_lock(&spi->controller->bus_lock_mutex);
ret = __spi_sync(spi, message);
mutex_unlock(&spi->controller->bus_lock_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(spi_sync);
/**
* spi_sync_locked - version of spi_sync with exclusive bus usage
* @spi: device with which data will be exchanged
* @message: describes the data transfers
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout. Low-overhead controller
* drivers may DMA directly into and out of the message buffers.
*
* This call should be used by drivers that require exclusive access to the
* SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
* be released by a spi_bus_unlock call when the exclusive access is over.
*
* Return: zero on success, else a negative error code.
*/
int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
{
return __spi_sync(spi, message);
}
EXPORT_SYMBOL_GPL(spi_sync_locked);
/**
* spi_bus_lock - obtain a lock for exclusive SPI bus usage
* @ctlr: SPI bus master that should be locked for exclusive bus access
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout.
*
* This call should be used by drivers that require exclusive access to the
* SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
* exclusive access is over. Data transfer must be done by spi_sync_locked
* and spi_async_locked calls when the SPI bus lock is held.
*
* Return: always zero.
*/
int spi_bus_lock(struct spi_controller *ctlr)
{
unsigned long flags;
mutex_lock(&ctlr->bus_lock_mutex);
spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
ctlr->bus_lock_flag = 1;
spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
/* Mutex remains locked until spi_bus_unlock() is called */
return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_lock);
/**
* spi_bus_unlock - release the lock for exclusive SPI bus usage
* @ctlr: SPI bus master that was locked for exclusive bus access
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout.
*
* This call releases an SPI bus lock previously obtained by an spi_bus_lock
* call.
*
* Return: always zero.
*/
int spi_bus_unlock(struct spi_controller *ctlr)
{
ctlr->bus_lock_flag = 0;
mutex_unlock(&ctlr->bus_lock_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_unlock);
/* Portable code must never pass more than 32 bytes */
#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
static u8 *buf;
/**
* spi_write_then_read - SPI synchronous write followed by read
* @spi: device with which data will be exchanged
* @txbuf: data to be written (need not be dma-safe)
* @n_tx: size of txbuf, in bytes
* @rxbuf: buffer into which data will be read (need not be dma-safe)
* @n_rx: size of rxbuf, in bytes
* Context: can sleep
*
* This performs a half duplex MicroWire style transaction with the
* device, sending txbuf and then reading rxbuf. The return value
* is zero for success, else a negative errno status code.
* This call may only be used from a context that may sleep.
*
* Parameters to this routine are always copied using a small buffer.
* Performance-sensitive or bulk transfer code should instead use
* spi_{async,sync}() calls with dma-safe buffers.
*
* Return: zero on success, else a negative error code.
*/
int spi_write_then_read(struct spi_device *spi,
const void *txbuf, unsigned n_tx,
void *rxbuf, unsigned n_rx)
{
static DEFINE_MUTEX(lock);
int status;
struct spi_message message;
struct spi_transfer x[2];
u8 *local_buf;
/*
* Use preallocated DMA-safe buffer if we can. We can't avoid
* copying here, (as a pure convenience thing), but we can
* keep heap costs out of the hot path unless someone else is
* using the pre-allocated buffer or the transfer is too large.
*/
if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
GFP_KERNEL | GFP_DMA);
if (!local_buf)
return -ENOMEM;
} else {
local_buf = buf;
}
spi_message_init(&message);
memset(x, 0, sizeof(x));
if (n_tx) {
x[0].len = n_tx;
spi_message_add_tail(&x[0], &message);
}
if (n_rx) {
x[1].len = n_rx;
spi_message_add_tail(&x[1], &message);
}
memcpy(local_buf, txbuf, n_tx);
x[0].tx_buf = local_buf;
x[1].rx_buf = local_buf + n_tx;
/* Do the i/o */
status = spi_sync(spi, &message);
if (status == 0)
memcpy(rxbuf, x[1].rx_buf, n_rx);
if (x[0].tx_buf == buf)
mutex_unlock(&lock);
else
kfree(local_buf);
return status;
}
EXPORT_SYMBOL_GPL(spi_write_then_read);
/*-------------------------------------------------------------------------*/
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
/* Must call put_device() when done with returned spi_device device */
static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
{
struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
return dev ? to_spi_device(dev) : NULL;
}
/* The spi controllers are not using spi_bus, so we find it with another way */
static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
{
struct device *dev;
dev = class_find_device_by_of_node(&spi_master_class, node);
if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
dev = class_find_device_by_of_node(&spi_slave_class, node);
if (!dev)
return NULL;
/* Reference got in class_find_device */
return container_of(dev, struct spi_controller, dev);
}
static int of_spi_notify(struct notifier_block *nb, unsigned long action,
void *arg)
{
struct of_reconfig_data *rd = arg;
struct spi_controller *ctlr;
struct spi_device *spi;
switch (of_reconfig_get_state_change(action, arg)) {
case OF_RECONFIG_CHANGE_ADD:
ctlr = of_find_spi_controller_by_node(rd->dn->parent);
if (ctlr == NULL)
return NOTIFY_OK; /* Not for us */
if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
put_device(&ctlr->dev);
return NOTIFY_OK;
}
/*
* Clear the flag before adding the device so that fw_devlink
* doesn't skip adding consumers to this device.
*/
rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
spi = of_register_spi_device(ctlr, rd->dn);
put_device(&ctlr->dev);
if (IS_ERR(spi)) {
pr_err("%s: failed to create for '%pOF'\n",
__func__, rd->dn);
of_node_clear_flag(rd->dn, OF_POPULATED);
return notifier_from_errno(PTR_ERR(spi));
}
break;
case OF_RECONFIG_CHANGE_REMOVE:
/* Already depopulated? */
if (!of_node_check_flag(rd->dn, OF_POPULATED))
return NOTIFY_OK;
/* Find our device by node */
spi = of_find_spi_device_by_node(rd->dn);
if (spi == NULL)
return NOTIFY_OK; /* No? not meant for us */
/* Unregister takes one ref away */
spi_unregister_device(spi);
/* And put the reference of the find */
put_device(&spi->dev);
break;
}
return NOTIFY_OK;
}
static struct notifier_block spi_of_notifier = {
.notifier_call = of_spi_notify,
};
#else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
extern struct notifier_block spi_of_notifier;
#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
#if IS_ENABLED(CONFIG_ACPI)
static int spi_acpi_controller_match(struct device *dev, const void *data)
{
return ACPI_COMPANION(dev->parent) == data;
}
static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
{
struct device *dev;
dev = class_find_device(&spi_master_class, NULL, adev,
spi_acpi_controller_match);
if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
dev = class_find_device(&spi_slave_class, NULL, adev,
spi_acpi_controller_match);
if (!dev)
return NULL;
return container_of(dev, struct spi_controller, dev);
}
static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
{
struct device *dev;
dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
return to_spi_device(dev);
}
static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
void *arg)
{
struct acpi_device *adev = arg;
struct spi_controller *ctlr;
struct spi_device *spi;
switch (value) {
case ACPI_RECONFIG_DEVICE_ADD:
ctlr = acpi_spi_find_controller_by_adev(acpi_dev_parent(adev));
if (!ctlr)
break;
acpi_register_spi_device(ctlr, adev);
put_device(&ctlr->dev);
break;
case ACPI_RECONFIG_DEVICE_REMOVE:
if (!acpi_device_enumerated(adev))
break;
spi = acpi_spi_find_device_by_adev(adev);
if (!spi)
break;
spi_unregister_device(spi);
put_device(&spi->dev);
break;
}
return NOTIFY_OK;
}
static struct notifier_block spi_acpi_notifier = {
.notifier_call = acpi_spi_notify,
};
#else
extern struct notifier_block spi_acpi_notifier;
#endif
static int __init spi_init(void)
{
int status;
buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
if (!buf) {
status = -ENOMEM;
goto err0;
}
status = bus_register(&spi_bus_type);
if (status < 0)
goto err1;
status = class_register(&spi_master_class);
if (status < 0)
goto err2;
if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
status = class_register(&spi_slave_class);
if (status < 0)
goto err3;
}
if (IS_ENABLED(CONFIG_OF_DYNAMIC))
WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
if (IS_ENABLED(CONFIG_ACPI))
WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
return 0;
err3:
class_unregister(&spi_master_class);
err2:
bus_unregister(&spi_bus_type);
err1:
kfree(buf);
buf = NULL;
err0:
return status;
}
/*
* A board_info is normally registered in arch_initcall(),
* but even essential drivers wait till later.
*
* REVISIT only boardinfo really needs static linking. The rest (device and
* driver registration) _could_ be dynamically linked (modular) ... Costs
* include needing to have boardinfo data structures be much more public.
*/
postcore_initcall(spi_init);
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