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linux-zen-desktop/drivers/dma/stm32-dma.c

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Initial commit
2023-08-30 17:31:07 +02:00
// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for STM32 DMA controller
*
* Inspired by dma-jz4740.c and tegra20-apb-dma.c
*
* Copyright (C) M'boumba Cedric Madianga 2015
* Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
* Pierre-Yves Mordret <pierre-yves.mordret@st.com>
*/
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/iopoll.h>
#include <linux/jiffies.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_dma.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "virt-dma.h"
#define STM32_DMA_LISR 0x0000 /* DMA Low Int Status Reg */
#define STM32_DMA_HISR 0x0004 /* DMA High Int Status Reg */
#define STM32_DMA_ISR(n) (((n) & 4) ? STM32_DMA_HISR : STM32_DMA_LISR)
#define STM32_DMA_LIFCR 0x0008 /* DMA Low Int Flag Clear Reg */
#define STM32_DMA_HIFCR 0x000c /* DMA High Int Flag Clear Reg */
#define STM32_DMA_IFCR(n) (((n) & 4) ? STM32_DMA_HIFCR : STM32_DMA_LIFCR)
#define STM32_DMA_TCI BIT(5) /* Transfer Complete Interrupt */
#define STM32_DMA_HTI BIT(4) /* Half Transfer Interrupt */
#define STM32_DMA_TEI BIT(3) /* Transfer Error Interrupt */
#define STM32_DMA_DMEI BIT(2) /* Direct Mode Error Interrupt */
#define STM32_DMA_FEI BIT(0) /* FIFO Error Interrupt */
#define STM32_DMA_MASKI (STM32_DMA_TCI \
| STM32_DMA_TEI \
| STM32_DMA_DMEI \
| STM32_DMA_FEI)
/*
* If (chan->id % 4) is 2 or 3, left shift the mask by 16 bits;
* if (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits.
*/
#define STM32_DMA_FLAGS_SHIFT(n) ({ typeof(n) (_n) = (n); \
(((_n) & 2) << 3) | (((_n) & 1) * 6); })
/* DMA Stream x Configuration Register */
#define STM32_DMA_SCR(x) (0x0010 + 0x18 * (x)) /* x = 0..7 */
#define STM32_DMA_SCR_REQ_MASK GENMASK(27, 25)
#define STM32_DMA_SCR_MBURST_MASK GENMASK(24, 23)
#define STM32_DMA_SCR_PBURST_MASK GENMASK(22, 21)
#define STM32_DMA_SCR_PL_MASK GENMASK(17, 16)
#define STM32_DMA_SCR_MSIZE_MASK GENMASK(14, 13)
#define STM32_DMA_SCR_PSIZE_MASK GENMASK(12, 11)
#define STM32_DMA_SCR_DIR_MASK GENMASK(7, 6)
#define STM32_DMA_SCR_TRBUFF BIT(20) /* Bufferable transfer for USART/UART */
#define STM32_DMA_SCR_CT BIT(19) /* Target in double buffer */
#define STM32_DMA_SCR_DBM BIT(18) /* Double Buffer Mode */
#define STM32_DMA_SCR_PINCOS BIT(15) /* Peripheral inc offset size */
#define STM32_DMA_SCR_MINC BIT(10) /* Memory increment mode */
#define STM32_DMA_SCR_PINC BIT(9) /* Peripheral increment mode */
#define STM32_DMA_SCR_CIRC BIT(8) /* Circular mode */
#define STM32_DMA_SCR_PFCTRL BIT(5) /* Peripheral Flow Controller */
#define STM32_DMA_SCR_TCIE BIT(4) /* Transfer Complete Int Enable
*/
#define STM32_DMA_SCR_TEIE BIT(2) /* Transfer Error Int Enable */
#define STM32_DMA_SCR_DMEIE BIT(1) /* Direct Mode Err Int Enable */
#define STM32_DMA_SCR_EN BIT(0) /* Stream Enable */
#define STM32_DMA_SCR_CFG_MASK (STM32_DMA_SCR_PINC \
| STM32_DMA_SCR_MINC \
| STM32_DMA_SCR_PINCOS \
| STM32_DMA_SCR_PL_MASK)
#define STM32_DMA_SCR_IRQ_MASK (STM32_DMA_SCR_TCIE \
| STM32_DMA_SCR_TEIE \
| STM32_DMA_SCR_DMEIE)
/* DMA Stream x number of data register */
#define STM32_DMA_SNDTR(x) (0x0014 + 0x18 * (x))
/* DMA stream peripheral address register */
#define STM32_DMA_SPAR(x) (0x0018 + 0x18 * (x))
/* DMA stream x memory 0 address register */
#define STM32_DMA_SM0AR(x) (0x001c + 0x18 * (x))
/* DMA stream x memory 1 address register */
#define STM32_DMA_SM1AR(x) (0x0020 + 0x18 * (x))
/* DMA stream x FIFO control register */
#define STM32_DMA_SFCR(x) (0x0024 + 0x18 * (x))
#define STM32_DMA_SFCR_FTH_MASK GENMASK(1, 0)
#define STM32_DMA_SFCR_FEIE BIT(7) /* FIFO error interrupt enable */
#define STM32_DMA_SFCR_DMDIS BIT(2) /* Direct mode disable */
#define STM32_DMA_SFCR_MASK (STM32_DMA_SFCR_FEIE \
| STM32_DMA_SFCR_DMDIS)
/* DMA direction */
#define STM32_DMA_DEV_TO_MEM 0x00
#define STM32_DMA_MEM_TO_DEV 0x01
#define STM32_DMA_MEM_TO_MEM 0x02
/* DMA priority level */
#define STM32_DMA_PRIORITY_LOW 0x00
#define STM32_DMA_PRIORITY_MEDIUM 0x01
#define STM32_DMA_PRIORITY_HIGH 0x02
#define STM32_DMA_PRIORITY_VERY_HIGH 0x03
/* DMA FIFO threshold selection */
#define STM32_DMA_FIFO_THRESHOLD_1QUARTERFULL 0x00
#define STM32_DMA_FIFO_THRESHOLD_HALFFULL 0x01
#define STM32_DMA_FIFO_THRESHOLD_3QUARTERSFULL 0x02
#define STM32_DMA_FIFO_THRESHOLD_FULL 0x03
#define STM32_DMA_FIFO_THRESHOLD_NONE 0x04
#define STM32_DMA_MAX_DATA_ITEMS 0xffff
/*
* Valid transfer starts from @0 to @0xFFFE leading to unaligned scatter
* gather at boundary. Thus it's safer to round down this value on FIFO
* size (16 Bytes)
*/
#define STM32_DMA_ALIGNED_MAX_DATA_ITEMS \
ALIGN_DOWN(STM32_DMA_MAX_DATA_ITEMS, 16)
#define STM32_DMA_MAX_CHANNELS 0x08
#define STM32_DMA_MAX_REQUEST_ID 0x08
#define STM32_DMA_MAX_DATA_PARAM 0x03
#define STM32_DMA_FIFO_SIZE 16 /* FIFO is 16 bytes */
#define STM32_DMA_MIN_BURST 4
#define STM32_DMA_MAX_BURST 16
/* DMA Features */
#define STM32_DMA_THRESHOLD_FTR_MASK GENMASK(1, 0)
#define STM32_DMA_DIRECT_MODE_MASK BIT(2)
#define STM32_DMA_ALT_ACK_MODE_MASK BIT(4)
#define STM32_DMA_MDMA_STREAM_ID_MASK GENMASK(19, 16)
enum stm32_dma_width {
STM32_DMA_BYTE,
STM32_DMA_HALF_WORD,
STM32_DMA_WORD,
};
enum stm32_dma_burst_size {
STM32_DMA_BURST_SINGLE,
STM32_DMA_BURST_INCR4,
STM32_DMA_BURST_INCR8,
STM32_DMA_BURST_INCR16,
};
/**
* struct stm32_dma_cfg - STM32 DMA custom configuration
* @channel_id: channel ID
* @request_line: DMA request
* @stream_config: 32bit mask specifying the DMA channel configuration
* @features: 32bit mask specifying the DMA Feature list
*/
struct stm32_dma_cfg {
u32 channel_id;
u32 request_line;
u32 stream_config;
u32 features;
};
struct stm32_dma_chan_reg {
u32 dma_lisr;
u32 dma_hisr;
u32 dma_lifcr;
u32 dma_hifcr;
u32 dma_scr;
u32 dma_sndtr;
u32 dma_spar;
u32 dma_sm0ar;
u32 dma_sm1ar;
u32 dma_sfcr;
};
struct stm32_dma_sg_req {
u32 len;
struct stm32_dma_chan_reg chan_reg;
};
struct stm32_dma_desc {
struct virt_dma_desc vdesc;
bool cyclic;
u32 num_sgs;
struct stm32_dma_sg_req sg_req[];
};
/**
* struct stm32_dma_mdma_config - STM32 DMA MDMA configuration
* @stream_id: DMA request to trigger STM32 MDMA transfer
* @ifcr: DMA interrupt flag clear register address,
* used by STM32 MDMA to clear DMA Transfer Complete flag
* @tcf: DMA Transfer Complete flag
*/
struct stm32_dma_mdma_config {
u32 stream_id;
u32 ifcr;
u32 tcf;
};
struct stm32_dma_chan {
struct virt_dma_chan vchan;
bool config_init;
bool busy;
u32 id;
u32 irq;
struct stm32_dma_desc *desc;
u32 next_sg;
struct dma_slave_config dma_sconfig;
struct stm32_dma_chan_reg chan_reg;
u32 threshold;
u32 mem_burst;
u32 mem_width;
enum dma_status status;
bool trig_mdma;
struct stm32_dma_mdma_config mdma_config;
};
struct stm32_dma_device {
struct dma_device ddev;
void __iomem *base;
struct clk *clk;
bool mem2mem;
struct stm32_dma_chan chan[STM32_DMA_MAX_CHANNELS];
};
static struct stm32_dma_device *stm32_dma_get_dev(struct stm32_dma_chan *chan)
{
return container_of(chan->vchan.chan.device, struct stm32_dma_device,
ddev);
}
static struct stm32_dma_chan *to_stm32_dma_chan(struct dma_chan *c)
{
return container_of(c, struct stm32_dma_chan, vchan.chan);
}
static struct stm32_dma_desc *to_stm32_dma_desc(struct virt_dma_desc *vdesc)
{
return container_of(vdesc, struct stm32_dma_desc, vdesc);
}
static struct device *chan2dev(struct stm32_dma_chan *chan)
{
return &chan->vchan.chan.dev->device;
}
static u32 stm32_dma_read(struct stm32_dma_device *dmadev, u32 reg)
{
return readl_relaxed(dmadev->base + reg);
}
static void stm32_dma_write(struct stm32_dma_device *dmadev, u32 reg, u32 val)
{
writel_relaxed(val, dmadev->base + reg);
}
static int stm32_dma_get_width(struct stm32_dma_chan *chan,
enum dma_slave_buswidth width)
{
switch (width) {
case DMA_SLAVE_BUSWIDTH_1_BYTE:
return STM32_DMA_BYTE;
case DMA_SLAVE_BUSWIDTH_2_BYTES:
return STM32_DMA_HALF_WORD;
case DMA_SLAVE_BUSWIDTH_4_BYTES:
return STM32_DMA_WORD;
default:
dev_err(chan2dev(chan), "Dma bus width not supported\n");
return -EINVAL;
}
}
static enum dma_slave_buswidth stm32_dma_get_max_width(u32 buf_len,
dma_addr_t buf_addr,
u32 threshold)
{
enum dma_slave_buswidth max_width;
if (threshold == STM32_DMA_FIFO_THRESHOLD_FULL)
max_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
else
max_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
while ((buf_len < max_width || buf_len % max_width) &&
max_width > DMA_SLAVE_BUSWIDTH_1_BYTE)
max_width = max_width >> 1;
if (buf_addr & (max_width - 1))
max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
return max_width;
}
static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold,
enum dma_slave_buswidth width)
{
u32 remaining;
if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE)
return false;
if (width != DMA_SLAVE_BUSWIDTH_UNDEFINED) {
if (burst != 0) {
/*
* If number of beats fit in several whole bursts
* this configuration is allowed.
*/
remaining = ((STM32_DMA_FIFO_SIZE / width) *
(threshold + 1) / 4) % burst;
if (remaining == 0)
return true;
} else {
return true;
}
}
return false;
}
static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold)
{
/* If FIFO direct mode, burst is not possible */
if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE)
return false;
/*
* Buffer or period length has to be aligned on FIFO depth.
* Otherwise bytes may be stuck within FIFO at buffer or period
* length.
*/
return ((buf_len % ((threshold + 1) * 4)) == 0);
}
static u32 stm32_dma_get_best_burst(u32 buf_len, u32 max_burst, u32 threshold,
enum dma_slave_buswidth width)
{
u32 best_burst = max_burst;
if (best_burst == 1 || !stm32_dma_is_burst_possible(buf_len, threshold))
return 0;
while ((buf_len < best_burst * width && best_burst > 1) ||
!stm32_dma_fifo_threshold_is_allowed(best_burst, threshold,
width)) {
if (best_burst > STM32_DMA_MIN_BURST)
best_burst = best_burst >> 1;
else
best_burst = 0;
}
return best_burst;
}
static int stm32_dma_get_burst(struct stm32_dma_chan *chan, u32 maxburst)
{
switch (maxburst) {
case 0:
case 1:
return STM32_DMA_BURST_SINGLE;
case 4:
return STM32_DMA_BURST_INCR4;
case 8:
return STM32_DMA_BURST_INCR8;
case 16:
return STM32_DMA_BURST_INCR16;
default:
dev_err(chan2dev(chan), "Dma burst size not supported\n");
return -EINVAL;
}
}
static void stm32_dma_set_fifo_config(struct stm32_dma_chan *chan,
u32 src_burst, u32 dst_burst)
{
chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_MASK;
chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_DMEIE;
if (!src_burst && !dst_burst) {
/* Using direct mode */
chan->chan_reg.dma_scr |= STM32_DMA_SCR_DMEIE;
} else {
/* Using FIFO mode */
chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
}
}
static int stm32_dma_slave_config(struct dma_chan *c,
struct dma_slave_config *config)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
memcpy(&chan->dma_sconfig, config, sizeof(*config));
/* Check if user is requesting DMA to trigger STM32 MDMA */
if (config->peripheral_size) {
config->peripheral_config = &chan->mdma_config;
config->peripheral_size = sizeof(chan->mdma_config);
chan->trig_mdma = true;
}
chan->config_init = true;
return 0;
}
static u32 stm32_dma_irq_status(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
u32 flags, dma_isr;
/*
* Read "flags" from DMA_xISR register corresponding to the selected
* DMA channel at the correct bit offset inside that register.
*/
dma_isr = stm32_dma_read(dmadev, STM32_DMA_ISR(chan->id));
flags = dma_isr >> STM32_DMA_FLAGS_SHIFT(chan->id);
return flags & STM32_DMA_MASKI;
}
static void stm32_dma_irq_clear(struct stm32_dma_chan *chan, u32 flags)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
u32 dma_ifcr;
/*
* Write "flags" to the DMA_xIFCR register corresponding to the selected
* DMA channel at the correct bit offset inside that register.
*/
flags &= STM32_DMA_MASKI;
dma_ifcr = flags << STM32_DMA_FLAGS_SHIFT(chan->id);
stm32_dma_write(dmadev, STM32_DMA_IFCR(chan->id), dma_ifcr);
}
static int stm32_dma_disable_chan(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
u32 dma_scr, id, reg;
id = chan->id;
reg = STM32_DMA_SCR(id);
dma_scr = stm32_dma_read(dmadev, reg);
if (dma_scr & STM32_DMA_SCR_EN) {
dma_scr &= ~STM32_DMA_SCR_EN;
stm32_dma_write(dmadev, reg, dma_scr);
return readl_relaxed_poll_timeout_atomic(dmadev->base + reg,
dma_scr, !(dma_scr & STM32_DMA_SCR_EN),
10, 1000000);
}
return 0;
}
static void stm32_dma_stop(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
u32 dma_scr, dma_sfcr, status;
int ret;
/* Disable interrupts */
dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
dma_scr &= ~STM32_DMA_SCR_IRQ_MASK;
stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
dma_sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
dma_sfcr &= ~STM32_DMA_SFCR_FEIE;
stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), dma_sfcr);
/* Disable DMA */
ret = stm32_dma_disable_chan(chan);
if (ret < 0)
return;
/* Clear interrupt status if it is there */
status = stm32_dma_irq_status(chan);
if (status) {
dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n",
__func__, status);
stm32_dma_irq_clear(chan, status);
}
chan->busy = false;
chan->status = DMA_COMPLETE;
}
static int stm32_dma_terminate_all(struct dma_chan *c)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
unsigned long flags;
LIST_HEAD(head);
spin_lock_irqsave(&chan->vchan.lock, flags);
if (chan->desc) {
dma_cookie_complete(&chan->desc->vdesc.tx);
vchan_terminate_vdesc(&chan->desc->vdesc);
if (chan->busy)
stm32_dma_stop(chan);
chan->desc = NULL;
}
vchan_get_all_descriptors(&chan->vchan, &head);
spin_unlock_irqrestore(&chan->vchan.lock, flags);
vchan_dma_desc_free_list(&chan->vchan, &head);
return 0;
}
static void stm32_dma_synchronize(struct dma_chan *c)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
vchan_synchronize(&chan->vchan);
}
static void stm32_dma_dump_reg(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
u32 scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
u32 ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
u32 spar = stm32_dma_read(dmadev, STM32_DMA_SPAR(chan->id));
u32 sm0ar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(chan->id));
u32 sm1ar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(chan->id));
u32 sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
dev_dbg(chan2dev(chan), "SCR: 0x%08x\n", scr);
dev_dbg(chan2dev(chan), "NDTR: 0x%08x\n", ndtr);
dev_dbg(chan2dev(chan), "SPAR: 0x%08x\n", spar);
dev_dbg(chan2dev(chan), "SM0AR: 0x%08x\n", sm0ar);
dev_dbg(chan2dev(chan), "SM1AR: 0x%08x\n", sm1ar);
dev_dbg(chan2dev(chan), "SFCR: 0x%08x\n", sfcr);
}
static void stm32_dma_sg_inc(struct stm32_dma_chan *chan)
{
chan->next_sg++;
if (chan->desc->cyclic && (chan->next_sg == chan->desc->num_sgs))
chan->next_sg = 0;
}
static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan);
static void stm32_dma_start_transfer(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
struct virt_dma_desc *vdesc;
struct stm32_dma_sg_req *sg_req;
struct stm32_dma_chan_reg *reg;
u32 status;
int ret;
ret = stm32_dma_disable_chan(chan);
if (ret < 0)
return;
if (!chan->desc) {
vdesc = vchan_next_desc(&chan->vchan);
if (!vdesc)
return;
list_del(&vdesc->node);
chan->desc = to_stm32_dma_desc(vdesc);
chan->next_sg = 0;
}
if (chan->next_sg == chan->desc->num_sgs)
chan->next_sg = 0;
sg_req = &chan->desc->sg_req[chan->next_sg];
reg = &sg_req->chan_reg;
/* When DMA triggers STM32 MDMA, DMA Transfer Complete is managed by STM32 MDMA */
if (chan->trig_mdma && chan->dma_sconfig.direction != DMA_MEM_TO_DEV)
reg->dma_scr &= ~STM32_DMA_SCR_TCIE;
reg->dma_scr &= ~STM32_DMA_SCR_EN;
stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
stm32_dma_write(dmadev, STM32_DMA_SPAR(chan->id), reg->dma_spar);
stm32_dma_write(dmadev, STM32_DMA_SM0AR(chan->id), reg->dma_sm0ar);
stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), reg->dma_sfcr);
stm32_dma_write(dmadev, STM32_DMA_SM1AR(chan->id), reg->dma_sm1ar);
stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), reg->dma_sndtr);
stm32_dma_sg_inc(chan);
/* Clear interrupt status if it is there */
status = stm32_dma_irq_status(chan);
if (status)
stm32_dma_irq_clear(chan, status);
if (chan->desc->cyclic)
stm32_dma_configure_next_sg(chan);
stm32_dma_dump_reg(chan);
/* Start DMA */
chan->busy = true;
chan->status = DMA_IN_PROGRESS;
reg->dma_scr |= STM32_DMA_SCR_EN;
stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
dev_dbg(chan2dev(chan), "vchan %pK: started\n", &chan->vchan);
}
static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
struct stm32_dma_sg_req *sg_req;
u32 dma_scr, dma_sm0ar, dma_sm1ar, id;
id = chan->id;
dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
sg_req = &chan->desc->sg_req[chan->next_sg];
if (dma_scr & STM32_DMA_SCR_CT) {
dma_sm0ar = sg_req->chan_reg.dma_sm0ar;
stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), dma_sm0ar);
dev_dbg(chan2dev(chan), "CT=1 <=> SM0AR: 0x%08x\n",
stm32_dma_read(dmadev, STM32_DMA_SM0AR(id)));
} else {
dma_sm1ar = sg_req->chan_reg.dma_sm1ar;
stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), dma_sm1ar);
dev_dbg(chan2dev(chan), "CT=0 <=> SM1AR: 0x%08x\n",
stm32_dma_read(dmadev, STM32_DMA_SM1AR(id)));
}
}
static void stm32_dma_handle_chan_paused(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
u32 dma_scr;
/*
* Read and store current remaining data items and peripheral/memory addresses to be
* updated on resume
*/
dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
/*
* Transfer can be paused while between a previous resume and reconfiguration on transfer
* complete. If transfer is cyclic and CIRC and DBM have been deactivated for resume, need
* to set it here in SCR backup to ensure a good reconfiguration on transfer complete.
*/
if (chan->desc && chan->desc->cyclic) {
if (chan->desc->num_sgs == 1)
dma_scr |= STM32_DMA_SCR_CIRC;
else
dma_scr |= STM32_DMA_SCR_DBM;
}
chan->chan_reg.dma_scr = dma_scr;
/*
* Need to temporarily deactivate CIRC/DBM until next Transfer Complete interrupt, otherwise
* on resume NDTR autoreload value will be wrong (lower than the initial period length)
*/
if (chan->desc && chan->desc->cyclic) {
dma_scr &= ~(STM32_DMA_SCR_DBM | STM32_DMA_SCR_CIRC);
stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
}
chan->chan_reg.dma_sndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
chan->status = DMA_PAUSED;
dev_dbg(chan2dev(chan), "vchan %pK: paused\n", &chan->vchan);
}
static void stm32_dma_post_resume_reconfigure(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
struct stm32_dma_sg_req *sg_req;
u32 dma_scr, status, id;
id = chan->id;
dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
/* Clear interrupt status if it is there */
status = stm32_dma_irq_status(chan);
if (status)
stm32_dma_irq_clear(chan, status);
if (!chan->next_sg)
sg_req = &chan->desc->sg_req[chan->desc->num_sgs - 1];
else
sg_req = &chan->desc->sg_req[chan->next_sg - 1];
/* Reconfigure NDTR with the initial value */
stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), sg_req->chan_reg.dma_sndtr);
/* Restore SPAR */
stm32_dma_write(dmadev, STM32_DMA_SPAR(id), sg_req->chan_reg.dma_spar);
/* Restore SM0AR/SM1AR whatever DBM/CT as they may have been modified */
stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), sg_req->chan_reg.dma_sm0ar);
stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), sg_req->chan_reg.dma_sm1ar);
/* Reactivate CIRC/DBM if needed */
if (chan->chan_reg.dma_scr & STM32_DMA_SCR_DBM) {
dma_scr |= STM32_DMA_SCR_DBM;
/* Restore CT */
if (chan->chan_reg.dma_scr & STM32_DMA_SCR_CT)
dma_scr &= ~STM32_DMA_SCR_CT;
else
dma_scr |= STM32_DMA_SCR_CT;
} else if (chan->chan_reg.dma_scr & STM32_DMA_SCR_CIRC) {
dma_scr |= STM32_DMA_SCR_CIRC;
}
stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
stm32_dma_configure_next_sg(chan);
stm32_dma_dump_reg(chan);
dma_scr |= STM32_DMA_SCR_EN;
stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
dev_dbg(chan2dev(chan), "vchan %pK: reconfigured after pause/resume\n", &chan->vchan);
}
static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan, u32 scr)
{
if (!chan->desc)
return;
if (chan->desc->cyclic) {
vchan_cyclic_callback(&chan->desc->vdesc);
if (chan->trig_mdma)
return;
stm32_dma_sg_inc(chan);
/* cyclic while CIRC/DBM disable => post resume reconfiguration needed */
if (!(scr & (STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM)))
stm32_dma_post_resume_reconfigure(chan);
else if (scr & STM32_DMA_SCR_DBM)
stm32_dma_configure_next_sg(chan);
} else {
chan->busy = false;
chan->status = DMA_COMPLETE;
if (chan->next_sg == chan->desc->num_sgs) {
vchan_cookie_complete(&chan->desc->vdesc);
chan->desc = NULL;
}
stm32_dma_start_transfer(chan);
}
}
static irqreturn_t stm32_dma_chan_irq(int irq, void *devid)
{
struct stm32_dma_chan *chan = devid;
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
u32 status, scr, sfcr;
spin_lock(&chan->vchan.lock);
status = stm32_dma_irq_status(chan);
scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
if (status & STM32_DMA_FEI) {
stm32_dma_irq_clear(chan, STM32_DMA_FEI);
status &= ~STM32_DMA_FEI;
if (sfcr & STM32_DMA_SFCR_FEIE) {
if (!(scr & STM32_DMA_SCR_EN) &&
!(status & STM32_DMA_TCI))
dev_err(chan2dev(chan), "FIFO Error\n");
else
dev_dbg(chan2dev(chan), "FIFO over/underrun\n");
}
}
if (status & STM32_DMA_DMEI) {
stm32_dma_irq_clear(chan, STM32_DMA_DMEI);
status &= ~STM32_DMA_DMEI;
if (sfcr & STM32_DMA_SCR_DMEIE)
dev_dbg(chan2dev(chan), "Direct mode overrun\n");
}
if (status & STM32_DMA_TCI) {
stm32_dma_irq_clear(chan, STM32_DMA_TCI);
if (scr & STM32_DMA_SCR_TCIE) {
if (chan->status != DMA_PAUSED)
stm32_dma_handle_chan_done(chan, scr);
}
status &= ~STM32_DMA_TCI;
}
if (status & STM32_DMA_HTI) {
stm32_dma_irq_clear(chan, STM32_DMA_HTI);
status &= ~STM32_DMA_HTI;
}
if (status) {
stm32_dma_irq_clear(chan, status);
dev_err(chan2dev(chan), "DMA error: status=0x%08x\n", status);
if (!(scr & STM32_DMA_SCR_EN))
dev_err(chan2dev(chan), "chan disabled by HW\n");
}
spin_unlock(&chan->vchan.lock);
return IRQ_HANDLED;
}
static void stm32_dma_issue_pending(struct dma_chan *c)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
unsigned long flags;
spin_lock_irqsave(&chan->vchan.lock, flags);
if (vchan_issue_pending(&chan->vchan) && !chan->desc && !chan->busy) {
dev_dbg(chan2dev(chan), "vchan %pK: issued\n", &chan->vchan);
stm32_dma_start_transfer(chan);
}
spin_unlock_irqrestore(&chan->vchan.lock, flags);
}
static int stm32_dma_pause(struct dma_chan *c)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
unsigned long flags;
int ret;
if (chan->status != DMA_IN_PROGRESS)
return -EPERM;
spin_lock_irqsave(&chan->vchan.lock, flags);
ret = stm32_dma_disable_chan(chan);
if (!ret)
stm32_dma_handle_chan_paused(chan);
spin_unlock_irqrestore(&chan->vchan.lock, flags);
return ret;
}
static int stm32_dma_resume(struct dma_chan *c)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
struct stm32_dma_chan_reg chan_reg = chan->chan_reg;
u32 id = chan->id, scr, ndtr, offset, spar, sm0ar, sm1ar;
struct stm32_dma_sg_req *sg_req;
unsigned long flags;
if (chan->status != DMA_PAUSED)
return -EPERM;
scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
if (WARN_ON(scr & STM32_DMA_SCR_EN))
return -EPERM;
spin_lock_irqsave(&chan->vchan.lock, flags);
/* sg_reg[prev_sg] contains original ndtr, sm0ar and sm1ar before pausing the transfer */
if (!chan->next_sg)
sg_req = &chan->desc->sg_req[chan->desc->num_sgs - 1];
else
sg_req = &chan->desc->sg_req[chan->next_sg - 1];
ndtr = sg_req->chan_reg.dma_sndtr;
offset = (ndtr - chan_reg.dma_sndtr);
offset <<= FIELD_GET(STM32_DMA_SCR_PSIZE_MASK, chan_reg.dma_scr);
spar = sg_req->chan_reg.dma_spar;
sm0ar = sg_req->chan_reg.dma_sm0ar;
sm1ar = sg_req->chan_reg.dma_sm1ar;
/*
* The peripheral and/or memory addresses have to be updated in order to adjust the
* address pointers. Need to check increment.
*/
if (chan_reg.dma_scr & STM32_DMA_SCR_PINC)
stm32_dma_write(dmadev, STM32_DMA_SPAR(id), spar + offset);
else
stm32_dma_write(dmadev, STM32_DMA_SPAR(id), spar);
if (!(chan_reg.dma_scr & STM32_DMA_SCR_MINC))
offset = 0;
/*
* In case of DBM, the current target could be SM1AR.
* Need to temporarily deactivate CIRC/DBM to finish the current transfer, so
* SM0AR becomes the current target and must be updated with SM1AR + offset if CT=1.
*/
if ((chan_reg.dma_scr & STM32_DMA_SCR_DBM) && (chan_reg.dma_scr & STM32_DMA_SCR_CT))
stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), sm1ar + offset);
else
stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), sm0ar + offset);
/* NDTR must be restored otherwise internal HW counter won't be correctly reset */
stm32_dma_write(dmadev, STM32_DMA_SNDTR(id), chan_reg.dma_sndtr);
/*
* Need to temporarily deactivate CIRC/DBM until next Transfer Complete interrupt,
* otherwise NDTR autoreload value will be wrong (lower than the initial period length)
*/
if (chan_reg.dma_scr & (STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM))
chan_reg.dma_scr &= ~(STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM);
if (chan_reg.dma_scr & STM32_DMA_SCR_DBM)
stm32_dma_configure_next_sg(chan);
stm32_dma_dump_reg(chan);
/* The stream may then be re-enabled to restart transfer from the point it was stopped */
chan->status = DMA_IN_PROGRESS;
chan_reg.dma_scr |= STM32_DMA_SCR_EN;
stm32_dma_write(dmadev, STM32_DMA_SCR(id), chan_reg.dma_scr);
spin_unlock_irqrestore(&chan->vchan.lock, flags);
dev_dbg(chan2dev(chan), "vchan %pK: resumed\n", &chan->vchan);
return 0;
}
static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
enum dma_transfer_direction direction,
enum dma_slave_buswidth *buswidth,
u32 buf_len, dma_addr_t buf_addr)
{
enum dma_slave_buswidth src_addr_width, dst_addr_width;
int src_bus_width, dst_bus_width;
int src_burst_size, dst_burst_size;
u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
u32 dma_scr, fifoth;
src_addr_width = chan->dma_sconfig.src_addr_width;
dst_addr_width = chan->dma_sconfig.dst_addr_width;
src_maxburst = chan->dma_sconfig.src_maxburst;
dst_maxburst = chan->dma_sconfig.dst_maxburst;
fifoth = chan->threshold;
switch (direction) {
case DMA_MEM_TO_DEV:
/* Set device data size */
dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
if (dst_bus_width < 0)
return dst_bus_width;
/* Set device burst size */
dst_best_burst = stm32_dma_get_best_burst(buf_len,
dst_maxburst,
fifoth,
dst_addr_width);
dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
if (dst_burst_size < 0)
return dst_burst_size;
/* Set memory data size */
src_addr_width = stm32_dma_get_max_width(buf_len, buf_addr,
fifoth);
chan->mem_width = src_addr_width;
src_bus_width = stm32_dma_get_width(chan, src_addr_width);
if (src_bus_width < 0)
return src_bus_width;
/*
* Set memory burst size - burst not possible if address is not aligned on
* the address boundary equal to the size of the transfer
*/
if (buf_addr & (buf_len - 1))
src_maxburst = 1;
else
src_maxburst = STM32_DMA_MAX_BURST;
src_best_burst = stm32_dma_get_best_burst(buf_len,
src_maxburst,
fifoth,
src_addr_width);
src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
if (src_burst_size < 0)
return src_burst_size;
dma_scr = FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_MEM_TO_DEV) |
FIELD_PREP(STM32_DMA_SCR_PSIZE_MASK, dst_bus_width) |
FIELD_PREP(STM32_DMA_SCR_MSIZE_MASK, src_bus_width) |
FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, dst_burst_size) |
FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, src_burst_size);
/* Set FIFO threshold */
chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE)
chan->chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, fifoth);
/* Set peripheral address */
chan->chan_reg.dma_spar = chan->dma_sconfig.dst_addr;
*buswidth = dst_addr_width;
break;
case DMA_DEV_TO_MEM:
/* Set device data size */
src_bus_width = stm32_dma_get_width(chan, src_addr_width);
if (src_bus_width < 0)
return src_bus_width;
/* Set device burst size */
src_best_burst = stm32_dma_get_best_burst(buf_len,
src_maxburst,
fifoth,
src_addr_width);
chan->mem_burst = src_best_burst;
src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
if (src_burst_size < 0)
return src_burst_size;
/* Set memory data size */
dst_addr_width = stm32_dma_get_max_width(buf_len, buf_addr,
fifoth);
chan->mem_width = dst_addr_width;
dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
if (dst_bus_width < 0)
return dst_bus_width;
/*
* Set memory burst size - burst not possible if address is not aligned on
* the address boundary equal to the size of the transfer
*/
if (buf_addr & (buf_len - 1))
dst_maxburst = 1;
else
dst_maxburst = STM32_DMA_MAX_BURST;
dst_best_burst = stm32_dma_get_best_burst(buf_len,
dst_maxburst,
fifoth,
dst_addr_width);
chan->mem_burst = dst_best_burst;
dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
if (dst_burst_size < 0)
return dst_burst_size;
dma_scr = FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_DEV_TO_MEM) |
FIELD_PREP(STM32_DMA_SCR_PSIZE_MASK, src_bus_width) |
FIELD_PREP(STM32_DMA_SCR_MSIZE_MASK, dst_bus_width) |
FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, src_burst_size) |
FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, dst_burst_size);
/* Set FIFO threshold */
chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE)
chan->chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, fifoth);
/* Set peripheral address */
chan->chan_reg.dma_spar = chan->dma_sconfig.src_addr;
*buswidth = chan->dma_sconfig.src_addr_width;
break;
default:
dev_err(chan2dev(chan), "Dma direction is not supported\n");
return -EINVAL;
}
stm32_dma_set_fifo_config(chan, src_best_burst, dst_best_burst);
/* Set DMA control register */
chan->chan_reg.dma_scr &= ~(STM32_DMA_SCR_DIR_MASK |
STM32_DMA_SCR_PSIZE_MASK | STM32_DMA_SCR_MSIZE_MASK |
STM32_DMA_SCR_PBURST_MASK | STM32_DMA_SCR_MBURST_MASK);
chan->chan_reg.dma_scr |= dma_scr;
return 0;
}
static void stm32_dma_clear_reg(struct stm32_dma_chan_reg *regs)
{
memset(regs, 0, sizeof(struct stm32_dma_chan_reg));
}
static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg(
struct dma_chan *c, struct scatterlist *sgl,
u32 sg_len, enum dma_transfer_direction direction,
unsigned long flags, void *context)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
struct stm32_dma_desc *desc;
struct scatterlist *sg;
enum dma_slave_buswidth buswidth;
u32 nb_data_items;
int i, ret;
if (!chan->config_init) {
dev_err(chan2dev(chan), "dma channel is not configured\n");
return NULL;
}
if (sg_len < 1) {
dev_err(chan2dev(chan), "Invalid segment length %d\n", sg_len);
return NULL;
}
desc = kzalloc(struct_size(desc, sg_req, sg_len), GFP_NOWAIT);
if (!desc)
return NULL;
/* Set peripheral flow controller */
if (chan->dma_sconfig.device_fc)
chan->chan_reg.dma_scr |= STM32_DMA_SCR_PFCTRL;
else
chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
/* Activate Double Buffer Mode if DMA triggers STM32 MDMA and more than 1 sg */
if (chan->trig_mdma && sg_len > 1)
chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM;
for_each_sg(sgl, sg, sg_len, i) {
ret = stm32_dma_set_xfer_param(chan, direction, &buswidth,
sg_dma_len(sg),
sg_dma_address(sg));
if (ret < 0)
goto err;
desc->sg_req[i].len = sg_dma_len(sg);
nb_data_items = desc->sg_req[i].len / buswidth;
if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) {
dev_err(chan2dev(chan), "nb items not supported\n");
goto err;
}
stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
desc->sg_req[i].chan_reg.dma_sm0ar = sg_dma_address(sg);
desc->sg_req[i].chan_reg.dma_sm1ar = sg_dma_address(sg);
if (chan->trig_mdma)
desc->sg_req[i].chan_reg.dma_sm1ar += sg_dma_len(sg);
desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
}
desc->num_sgs = sg_len;
desc->cyclic = false;
return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
err:
kfree(desc);
return NULL;
}
static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic(
struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
size_t period_len, enum dma_transfer_direction direction,
unsigned long flags)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
struct stm32_dma_desc *desc;
enum dma_slave_buswidth buswidth;
u32 num_periods, nb_data_items;
int i, ret;
if (!buf_len || !period_len) {
dev_err(chan2dev(chan), "Invalid buffer/period len\n");
return NULL;
}
if (!chan->config_init) {
dev_err(chan2dev(chan), "dma channel is not configured\n");
return NULL;
}
if (buf_len % period_len) {
dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
return NULL;
}
/*
* We allow to take more number of requests till DMA is
* not started. The driver will loop over all requests.
* Once DMA is started then new requests can be queued only after
* terminating the DMA.
*/
if (chan->busy) {
dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
return NULL;
}
ret = stm32_dma_set_xfer_param(chan, direction, &buswidth, period_len,
buf_addr);
if (ret < 0)
return NULL;
nb_data_items = period_len / buswidth;
if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) {
dev_err(chan2dev(chan), "number of items not supported\n");
return NULL;
}
/* Enable Circular mode or double buffer mode */
if (buf_len == period_len) {
chan->chan_reg.dma_scr |= STM32_DMA_SCR_CIRC;
} else {
chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM;
chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_CT;
}
/* Clear periph ctrl if client set it */
chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
num_periods = buf_len / period_len;
desc = kzalloc(struct_size(desc, sg_req, num_periods), GFP_NOWAIT);
if (!desc)
return NULL;
for (i = 0; i < num_periods; i++) {
desc->sg_req[i].len = period_len;
stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
desc->sg_req[i].chan_reg.dma_sm0ar = buf_addr;
desc->sg_req[i].chan_reg.dma_sm1ar = buf_addr;
if (chan->trig_mdma)
desc->sg_req[i].chan_reg.dma_sm1ar += period_len;
desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
if (!chan->trig_mdma)
buf_addr += period_len;
}
desc->num_sgs = num_periods;
desc->cyclic = true;
return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
}
static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
struct dma_chan *c, dma_addr_t dest,
dma_addr_t src, size_t len, unsigned long flags)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
enum dma_slave_buswidth max_width;
struct stm32_dma_desc *desc;
size_t xfer_count, offset;
u32 num_sgs, best_burst, dma_burst, threshold;
int i;
num_sgs = DIV_ROUND_UP(len, STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
desc = kzalloc(struct_size(desc, sg_req, num_sgs), GFP_NOWAIT);
if (!desc)
return NULL;
threshold = chan->threshold;
for (offset = 0, i = 0; offset < len; offset += xfer_count, i++) {
xfer_count = min_t(size_t, len - offset,
STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
/* Compute best burst size */
max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
best_burst = stm32_dma_get_best_burst(len, STM32_DMA_MAX_BURST,
threshold, max_width);
dma_burst = stm32_dma_get_burst(chan, best_burst);
stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
desc->sg_req[i].chan_reg.dma_scr =
FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_MEM_TO_MEM) |
FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, dma_burst) |
FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, dma_burst) |
STM32_DMA_SCR_MINC |
STM32_DMA_SCR_PINC |
STM32_DMA_SCR_TCIE |
STM32_DMA_SCR_TEIE;
desc->sg_req[i].chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
desc->sg_req[i].chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, threshold);
desc->sg_req[i].chan_reg.dma_spar = src + offset;
desc->sg_req[i].chan_reg.dma_sm0ar = dest + offset;
desc->sg_req[i].chan_reg.dma_sndtr = xfer_count;
desc->sg_req[i].len = xfer_count;
}
desc->num_sgs = num_sgs;
desc->cyclic = false;
return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
}
static u32 stm32_dma_get_remaining_bytes(struct stm32_dma_chan *chan)
{
u32 dma_scr, width, ndtr;
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
width = FIELD_GET(STM32_DMA_SCR_PSIZE_MASK, dma_scr);
ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
return ndtr << width;
}
/**
* stm32_dma_is_current_sg - check that expected sg_req is currently transferred
* @chan: dma channel
*
* This function called when IRQ are disable, checks that the hardware has not
* switched on the next transfer in double buffer mode. The test is done by
* comparing the next_sg memory address with the hardware related register
* (based on CT bit value).
*
* Returns true if expected current transfer is still running or double
* buffer mode is not activated.
*/
static bool stm32_dma_is_current_sg(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
struct stm32_dma_sg_req *sg_req;
u32 dma_scr, dma_smar, id, period_len;
id = chan->id;
dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
/* In cyclic CIRC but not DBM, CT is not used */
if (!(dma_scr & STM32_DMA_SCR_DBM))
return true;
sg_req = &chan->desc->sg_req[chan->next_sg];
period_len = sg_req->len;
/* DBM - take care of a previous pause/resume not yet post reconfigured */
if (dma_scr & STM32_DMA_SCR_CT) {
dma_smar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(id));
/*
* If transfer has been pause/resumed,
* SM0AR is in the range of [SM0AR:SM0AR+period_len]
*/
return (dma_smar >= sg_req->chan_reg.dma_sm0ar &&
dma_smar < sg_req->chan_reg.dma_sm0ar + period_len);
}
dma_smar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(id));
/*
* If transfer has been pause/resumed,
* SM1AR is in the range of [SM1AR:SM1AR+period_len]
*/
return (dma_smar >= sg_req->chan_reg.dma_sm1ar &&
dma_smar < sg_req->chan_reg.dma_sm1ar + period_len);
}
static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
struct stm32_dma_desc *desc,
u32 next_sg)
{
u32 modulo, burst_size;
u32 residue;
u32 n_sg = next_sg;
struct stm32_dma_sg_req *sg_req = &chan->desc->sg_req[chan->next_sg];
int i;
/*
* Calculate the residue means compute the descriptors
* information:
* - the sg_req currently transferred
* - the Hardware remaining position in this sg (NDTR bits field).
*
* A race condition may occur if DMA is running in cyclic or double
* buffer mode, since the DMA register are automatically reloaded at end
* of period transfer. The hardware may have switched to the next
* transfer (CT bit updated) just before the position (SxNDTR reg) is
* read.
* In this case the SxNDTR reg could (or not) correspond to the new
* transfer position, and not the expected one.
* The strategy implemented in the stm32 driver is to:
* - read the SxNDTR register
* - crosscheck that hardware is still in current transfer.
* In case of switch, we can assume that the DMA is at the beginning of
* the next transfer. So we approximate the residue in consequence, by
* pointing on the beginning of next transfer.
*
* This race condition doesn't apply for none cyclic mode, as double
* buffer is not used. In such situation registers are updated by the
* software.
*/
residue = stm32_dma_get_remaining_bytes(chan);
if (chan->desc->cyclic && !stm32_dma_is_current_sg(chan)) {
n_sg++;
if (n_sg == chan->desc->num_sgs)
n_sg = 0;
residue = sg_req->len;
}
/*
* In cyclic mode, for the last period, residue = remaining bytes
* from NDTR,
* else for all other periods in cyclic mode, and in sg mode,
* residue = remaining bytes from NDTR + remaining
* periods/sg to be transferred
*/
if (!chan->desc->cyclic || n_sg != 0)
for (i = n_sg; i < desc->num_sgs; i++)
residue += desc->sg_req[i].len;
if (!chan->mem_burst)
return residue;
burst_size = chan->mem_burst * chan->mem_width;
modulo = residue % burst_size;
if (modulo)
residue = residue - modulo + burst_size;
return residue;
}
static enum dma_status stm32_dma_tx_status(struct dma_chan *c,
dma_cookie_t cookie,
struct dma_tx_state *state)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
struct virt_dma_desc *vdesc;
enum dma_status status;
unsigned long flags;
u32 residue = 0;
status = dma_cookie_status(c, cookie, state);
if (status == DMA_COMPLETE)
return status;
status = chan->status;
if (!state)
return status;
spin_lock_irqsave(&chan->vchan.lock, flags);
vdesc = vchan_find_desc(&chan->vchan, cookie);
if (chan->desc && cookie == chan->desc->vdesc.tx.cookie)
residue = stm32_dma_desc_residue(chan, chan->desc,
chan->next_sg);
else if (vdesc)
residue = stm32_dma_desc_residue(chan,
to_stm32_dma_desc(vdesc), 0);
dma_set_residue(state, residue);
spin_unlock_irqrestore(&chan->vchan.lock, flags);
return status;
}
static int stm32_dma_alloc_chan_resources(struct dma_chan *c)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
int ret;
chan->config_init = false;
ret = pm_runtime_resume_and_get(dmadev->ddev.dev);
if (ret < 0)
return ret;
ret = stm32_dma_disable_chan(chan);
if (ret < 0)
pm_runtime_put(dmadev->ddev.dev);
return ret;
}
static void stm32_dma_free_chan_resources(struct dma_chan *c)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
unsigned long flags;
dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id);
if (chan->busy) {
spin_lock_irqsave(&chan->vchan.lock, flags);
stm32_dma_stop(chan);
chan->desc = NULL;
spin_unlock_irqrestore(&chan->vchan.lock, flags);
}
pm_runtime_put(dmadev->ddev.dev);
vchan_free_chan_resources(to_virt_chan(c));
stm32_dma_clear_reg(&chan->chan_reg);
chan->threshold = 0;
}
static void stm32_dma_desc_free(struct virt_dma_desc *vdesc)
{
kfree(container_of(vdesc, struct stm32_dma_desc, vdesc));
}
static void stm32_dma_set_config(struct stm32_dma_chan *chan,
struct stm32_dma_cfg *cfg)
{
stm32_dma_clear_reg(&chan->chan_reg);
chan->chan_reg.dma_scr = cfg->stream_config & STM32_DMA_SCR_CFG_MASK;
chan->chan_reg.dma_scr |= FIELD_PREP(STM32_DMA_SCR_REQ_MASK, cfg->request_line);
/* Enable Interrupts */
chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE;
chan->threshold = FIELD_GET(STM32_DMA_THRESHOLD_FTR_MASK, cfg->features);
if (FIELD_GET(STM32_DMA_DIRECT_MODE_MASK, cfg->features))
chan->threshold = STM32_DMA_FIFO_THRESHOLD_NONE;
if (FIELD_GET(STM32_DMA_ALT_ACK_MODE_MASK, cfg->features))
chan->chan_reg.dma_scr |= STM32_DMA_SCR_TRBUFF;
chan->mdma_config.stream_id = FIELD_GET(STM32_DMA_MDMA_STREAM_ID_MASK, cfg->features);
}
static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma)
{
struct stm32_dma_device *dmadev = ofdma->of_dma_data;
struct device *dev = dmadev->ddev.dev;
struct stm32_dma_cfg cfg;
struct stm32_dma_chan *chan;
struct dma_chan *c;
if (dma_spec->args_count < 4) {
dev_err(dev, "Bad number of cells\n");
return NULL;
}
cfg.channel_id = dma_spec->args[0];
cfg.request_line = dma_spec->args[1];
cfg.stream_config = dma_spec->args[2];
cfg.features = dma_spec->args[3];
if (cfg.channel_id >= STM32_DMA_MAX_CHANNELS ||
cfg.request_line >= STM32_DMA_MAX_REQUEST_ID) {
dev_err(dev, "Bad channel and/or request id\n");
return NULL;
}
chan = &dmadev->chan[cfg.channel_id];
c = dma_get_slave_channel(&chan->vchan.chan);
if (!c) {
dev_err(dev, "No more channels available\n");
return NULL;
}
stm32_dma_set_config(chan, &cfg);
return c;
}
static const struct of_device_id stm32_dma_of_match[] = {
{ .compatible = "st,stm32-dma", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, stm32_dma_of_match);
static int stm32_dma_probe(struct platform_device *pdev)
{
struct stm32_dma_chan *chan;
struct stm32_dma_device *dmadev;
struct dma_device *dd;
const struct of_device_id *match;
struct resource *res;
struct reset_control *rst;
int i, ret;
match = of_match_device(stm32_dma_of_match, &pdev->dev);
if (!match) {
dev_err(&pdev->dev, "Error: No device match found\n");
return -ENODEV;
}
dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
if (!dmadev)
return -ENOMEM;
dd = &dmadev->ddev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dmadev->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(dmadev->base))
return PTR_ERR(dmadev->base);
dmadev->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(dmadev->clk))
return dev_err_probe(&pdev->dev, PTR_ERR(dmadev->clk), "Can't get clock\n");
ret = clk_prepare_enable(dmadev->clk);
if (ret < 0) {
dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
return ret;
}
dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node,
"st,mem2mem");
rst = devm_reset_control_get(&pdev->dev, NULL);
if (IS_ERR(rst)) {
ret = PTR_ERR(rst);
if (ret == -EPROBE_DEFER)
goto clk_free;
} else {
reset_control_assert(rst);
udelay(2);
reset_control_deassert(rst);
}
dma_set_max_seg_size(&pdev->dev, STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
dma_cap_set(DMA_SLAVE, dd->cap_mask);
dma_cap_set(DMA_PRIVATE, dd->cap_mask);
dma_cap_set(DMA_CYCLIC, dd->cap_mask);
dd->device_alloc_chan_resources = stm32_dma_alloc_chan_resources;
dd->device_free_chan_resources = stm32_dma_free_chan_resources;
dd->device_tx_status = stm32_dma_tx_status;
dd->device_issue_pending = stm32_dma_issue_pending;
dd->device_prep_slave_sg = stm32_dma_prep_slave_sg;
dd->device_prep_dma_cyclic = stm32_dma_prep_dma_cyclic;
dd->device_config = stm32_dma_slave_config;
dd->device_pause = stm32_dma_pause;
dd->device_resume = stm32_dma_resume;
dd->device_terminate_all = stm32_dma_terminate_all;
dd->device_synchronize = stm32_dma_synchronize;
dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
dd->copy_align = DMAENGINE_ALIGN_32_BYTES;
dd->max_burst = STM32_DMA_MAX_BURST;
dd->max_sg_burst = STM32_DMA_ALIGNED_MAX_DATA_ITEMS;
dd->descriptor_reuse = true;
dd->dev = &pdev->dev;
INIT_LIST_HEAD(&dd->channels);
if (dmadev->mem2mem) {
dma_cap_set(DMA_MEMCPY, dd->cap_mask);
dd->device_prep_dma_memcpy = stm32_dma_prep_dma_memcpy;
dd->directions |= BIT(DMA_MEM_TO_MEM);
}
for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
chan = &dmadev->chan[i];
chan->id = i;
chan->vchan.desc_free = stm32_dma_desc_free;
vchan_init(&chan->vchan, dd);
chan->mdma_config.ifcr = res->start;
chan->mdma_config.ifcr += STM32_DMA_IFCR(chan->id);
chan->mdma_config.tcf = STM32_DMA_TCI;
chan->mdma_config.tcf <<= STM32_DMA_FLAGS_SHIFT(chan->id);
}
ret = dma_async_device_register(dd);
if (ret)
goto clk_free;
for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
chan = &dmadev->chan[i];
ret = platform_get_irq(pdev, i);
if (ret < 0)
goto err_unregister;
chan->irq = ret;
ret = devm_request_irq(&pdev->dev, chan->irq,
stm32_dma_chan_irq, 0,
dev_name(chan2dev(chan)), chan);
if (ret) {
dev_err(&pdev->dev,
"request_irq failed with err %d channel %d\n",
ret, i);
goto err_unregister;
}
}
ret = of_dma_controller_register(pdev->dev.of_node,
stm32_dma_of_xlate, dmadev);
if (ret < 0) {
dev_err(&pdev->dev,
"STM32 DMA DMA OF registration failed %d\n", ret);
goto err_unregister;
}
platform_set_drvdata(pdev, dmadev);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
pm_runtime_get_noresume(&pdev->dev);
pm_runtime_put(&pdev->dev);
dev_info(&pdev->dev, "STM32 DMA driver registered\n");
return 0;
err_unregister:
dma_async_device_unregister(dd);
clk_free:
clk_disable_unprepare(dmadev->clk);
return ret;
}
#ifdef CONFIG_PM
static int stm32_dma_runtime_suspend(struct device *dev)
{
struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
clk_disable_unprepare(dmadev->clk);
return 0;
}
static int stm32_dma_runtime_resume(struct device *dev)
{
struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
int ret;
ret = clk_prepare_enable(dmadev->clk);
if (ret) {
dev_err(dev, "failed to prepare_enable clock\n");
return ret;
}
return 0;
}
#endif
#ifdef CONFIG_PM_SLEEP
static int stm32_dma_pm_suspend(struct device *dev)
{
struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
int id, ret, scr;
ret = pm_runtime_resume_and_get(dev);
if (ret < 0)
return ret;
for (id = 0; id < STM32_DMA_MAX_CHANNELS; id++) {
scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
if (scr & STM32_DMA_SCR_EN) {
dev_warn(dev, "Suspend is prevented by Chan %i\n", id);
return -EBUSY;
}
}
pm_runtime_put_sync(dev);
pm_runtime_force_suspend(dev);
return 0;
}
static int stm32_dma_pm_resume(struct device *dev)
{
return pm_runtime_force_resume(dev);
}
#endif
static const struct dev_pm_ops stm32_dma_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(stm32_dma_pm_suspend, stm32_dma_pm_resume)
SET_RUNTIME_PM_OPS(stm32_dma_runtime_suspend,
stm32_dma_runtime_resume, NULL)
};
static struct platform_driver stm32_dma_driver = {
.driver = {
.name = "stm32-dma",
.of_match_table = stm32_dma_of_match,
.pm = &stm32_dma_pm_ops,
},
.probe = stm32_dma_probe,
};
static int __init stm32_dma_init(void)
{
return platform_driver_register(&stm32_dma_driver);
}
subsys_initcall(stm32_dma_init);