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linux-zen-server/drivers/tty/serial/8250/8250_port.c

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2023-08-30 17:53:23 +02:00
// SPDX-License-Identifier: GPL-2.0+
/*
* Base port operations for 8250/16550-type serial ports
*
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
* Split from 8250_core.c, Copyright (C) 2001 Russell King.
*
* A note about mapbase / membase
*
* mapbase is the physical address of the IO port.
* membase is an 'ioremapped' cookie.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/console.h>
#include <linux/gpio/consumer.h>
#include <linux/sysrq.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/ratelimit.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serial_8250.h>
#include <linux/nmi.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/pm_runtime.h>
#include <linux/ktime.h>
#include <asm/io.h>
#include <asm/irq.h>
#include "8250.h"
/* Nuvoton NPCM timeout register */
#define UART_NPCM_TOR 7
#define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */
/*
* Debugging.
*/
#if 0
#define DEBUG_AUTOCONF(fmt...) printk(fmt)
#else
#define DEBUG_AUTOCONF(fmt...) do { } while (0)
#endif
/*
* Here we define the default xmit fifo size used for each type of UART.
*/
static const struct serial8250_config uart_config[] = {
[PORT_UNKNOWN] = {
.name = "unknown",
.fifo_size = 1,
.tx_loadsz = 1,
},
[PORT_8250] = {
.name = "8250",
.fifo_size = 1,
.tx_loadsz = 1,
},
[PORT_16450] = {
.name = "16450",
.fifo_size = 1,
.tx_loadsz = 1,
},
[PORT_16550] = {
.name = "16550",
.fifo_size = 1,
.tx_loadsz = 1,
},
[PORT_16550A] = {
.name = "16550A",
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.rxtrig_bytes = {1, 4, 8, 14},
.flags = UART_CAP_FIFO,
},
[PORT_CIRRUS] = {
.name = "Cirrus",
.fifo_size = 1,
.tx_loadsz = 1,
},
[PORT_16650] = {
.name = "ST16650",
.fifo_size = 1,
.tx_loadsz = 1,
.flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
},
[PORT_16650V2] = {
.name = "ST16650V2",
.fifo_size = 32,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
UART_FCR_T_TRIG_00,
.rxtrig_bytes = {8, 16, 24, 28},
.flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
},
[PORT_16750] = {
.name = "TI16750",
.fifo_size = 64,
.tx_loadsz = 64,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
UART_FCR7_64BYTE,
.rxtrig_bytes = {1, 16, 32, 56},
.flags = UART_CAP_FIFO | UART_CAP_SLEEP | UART_CAP_AFE,
},
[PORT_STARTECH] = {
.name = "Startech",
.fifo_size = 1,
.tx_loadsz = 1,
},
[PORT_16C950] = {
.name = "16C950/954",
.fifo_size = 128,
.tx_loadsz = 128,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01,
.rxtrig_bytes = {16, 32, 112, 120},
/* UART_CAP_EFR breaks billionon CF bluetooth card. */
.flags = UART_CAP_FIFO | UART_CAP_SLEEP,
},
[PORT_16654] = {
.name = "ST16654",
.fifo_size = 64,
.tx_loadsz = 32,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
UART_FCR_T_TRIG_10,
.rxtrig_bytes = {8, 16, 56, 60},
.flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
},
[PORT_16850] = {
.name = "XR16850",
.fifo_size = 128,
.tx_loadsz = 128,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
},
[PORT_RSA] = {
.name = "RSA",
.fifo_size = 2048,
.tx_loadsz = 2048,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11,
.flags = UART_CAP_FIFO,
},
[PORT_NS16550A] = {
.name = "NS16550A",
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.flags = UART_CAP_FIFO | UART_NATSEMI,
},
[PORT_XSCALE] = {
.name = "XScale",
.fifo_size = 32,
.tx_loadsz = 32,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.flags = UART_CAP_FIFO | UART_CAP_UUE | UART_CAP_RTOIE,
},
[PORT_OCTEON] = {
.name = "OCTEON",
.fifo_size = 64,
.tx_loadsz = 64,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.flags = UART_CAP_FIFO,
},
[PORT_AR7] = {
.name = "AR7",
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00,
.flags = UART_CAP_FIFO /* | UART_CAP_AFE */,
},
[PORT_U6_16550A] = {
.name = "U6_16550A",
.fifo_size = 64,
.tx_loadsz = 64,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.flags = UART_CAP_FIFO | UART_CAP_AFE,
},
[PORT_TEGRA] = {
.name = "Tegra",
.fifo_size = 32,
.tx_loadsz = 8,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
UART_FCR_T_TRIG_01,
.rxtrig_bytes = {1, 4, 8, 14},
.flags = UART_CAP_FIFO | UART_CAP_RTOIE,
},
[PORT_XR17D15X] = {
.name = "XR17D15X",
.fifo_size = 64,
.tx_loadsz = 64,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.flags = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
UART_CAP_SLEEP,
},
[PORT_XR17V35X] = {
.name = "XR17V35X",
.fifo_size = 256,
.tx_loadsz = 256,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11 |
UART_FCR_T_TRIG_11,
.flags = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
UART_CAP_SLEEP,
},
[PORT_LPC3220] = {
.name = "LPC3220",
.fifo_size = 64,
.tx_loadsz = 32,
.fcr = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
UART_FCR_R_TRIG_00 | UART_FCR_T_TRIG_00,
.flags = UART_CAP_FIFO,
},
[PORT_BRCM_TRUMANAGE] = {
.name = "TruManage",
.fifo_size = 1,
.tx_loadsz = 1024,
.flags = UART_CAP_HFIFO,
},
[PORT_8250_CIR] = {
.name = "CIR port"
},
[PORT_ALTR_16550_F32] = {
.name = "Altera 16550 FIFO32",
.fifo_size = 32,
.tx_loadsz = 32,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.rxtrig_bytes = {1, 8, 16, 30},
.flags = UART_CAP_FIFO | UART_CAP_AFE,
},
[PORT_ALTR_16550_F64] = {
.name = "Altera 16550 FIFO64",
.fifo_size = 64,
.tx_loadsz = 64,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.rxtrig_bytes = {1, 16, 32, 62},
.flags = UART_CAP_FIFO | UART_CAP_AFE,
},
[PORT_ALTR_16550_F128] = {
.name = "Altera 16550 FIFO128",
.fifo_size = 128,
.tx_loadsz = 128,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.rxtrig_bytes = {1, 32, 64, 126},
.flags = UART_CAP_FIFO | UART_CAP_AFE,
},
/*
* tx_loadsz is set to 63-bytes instead of 64-bytes to implement
* workaround of errata A-008006 which states that tx_loadsz should
* be configured less than Maximum supported fifo bytes.
*/
[PORT_16550A_FSL64] = {
.name = "16550A_FSL64",
.fifo_size = 64,
.tx_loadsz = 63,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
UART_FCR7_64BYTE,
.flags = UART_CAP_FIFO | UART_CAP_NOTEMT,
},
[PORT_RT2880] = {
.name = "Palmchip BK-3103",
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.rxtrig_bytes = {1, 4, 8, 14},
.flags = UART_CAP_FIFO,
},
[PORT_DA830] = {
.name = "TI DA8xx/66AK2x",
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
UART_FCR_R_TRIG_10,
.rxtrig_bytes = {1, 4, 8, 14},
.flags = UART_CAP_FIFO | UART_CAP_AFE,
},
[PORT_MTK_BTIF] = {
.name = "MediaTek BTIF",
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO |
UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
.flags = UART_CAP_FIFO,
},
[PORT_NPCM] = {
.name = "Nuvoton 16550",
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
.rxtrig_bytes = {1, 4, 8, 14},
.flags = UART_CAP_FIFO,
},
[PORT_SUNIX] = {
.name = "Sunix",
.fifo_size = 128,
.tx_loadsz = 128,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.rxtrig_bytes = {1, 32, 64, 112},
.flags = UART_CAP_FIFO | UART_CAP_SLEEP,
},
[PORT_ASPEED_VUART] = {
.name = "ASPEED VUART",
.fifo_size = 16,
.tx_loadsz = 16,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00,
.rxtrig_bytes = {1, 4, 8, 14},
.flags = UART_CAP_FIFO,
},
[PORT_MCHP16550A] = {
.name = "MCHP16550A",
.fifo_size = 256,
.tx_loadsz = 256,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01,
.rxtrig_bytes = {2, 66, 130, 194},
.flags = UART_CAP_FIFO,
},
};
/* Uart divisor latch read */
static int default_serial_dl_read(struct uart_8250_port *up)
{
/* Assign these in pieces to truncate any bits above 7. */
unsigned char dll = serial_in(up, UART_DLL);
unsigned char dlm = serial_in(up, UART_DLM);
return dll | dlm << 8;
}
/* Uart divisor latch write */
static void default_serial_dl_write(struct uart_8250_port *up, int value)
{
serial_out(up, UART_DLL, value & 0xff);
serial_out(up, UART_DLM, value >> 8 & 0xff);
}
#ifdef CONFIG_SERIAL_8250_RT288X
#define UART_REG_UNMAPPED -1
/* Au1x00/RT288x UART hardware has a weird register layout */
static const s8 au_io_in_map[8] = {
[UART_RX] = 0,
[UART_IER] = 2,
[UART_IIR] = 3,
[UART_LCR] = 5,
[UART_MCR] = 6,
[UART_LSR] = 7,
[UART_MSR] = 8,
[UART_SCR] = UART_REG_UNMAPPED,
};
static const s8 au_io_out_map[8] = {
[UART_TX] = 1,
[UART_IER] = 2,
[UART_FCR] = 4,
[UART_LCR] = 5,
[UART_MCR] = 6,
[UART_LSR] = UART_REG_UNMAPPED,
[UART_MSR] = UART_REG_UNMAPPED,
[UART_SCR] = UART_REG_UNMAPPED,
};
unsigned int au_serial_in(struct uart_port *p, int offset)
{
if (offset >= ARRAY_SIZE(au_io_in_map))
return UINT_MAX;
offset = au_io_in_map[offset];
if (offset == UART_REG_UNMAPPED)
return UINT_MAX;
return __raw_readl(p->membase + (offset << p->regshift));
}
void au_serial_out(struct uart_port *p, int offset, int value)
{
if (offset >= ARRAY_SIZE(au_io_out_map))
return;
offset = au_io_out_map[offset];
if (offset == UART_REG_UNMAPPED)
return;
__raw_writel(value, p->membase + (offset << p->regshift));
}
/* Au1x00 haven't got a standard divisor latch */
static int au_serial_dl_read(struct uart_8250_port *up)
{
return __raw_readl(up->port.membase + 0x28);
}
static void au_serial_dl_write(struct uart_8250_port *up, int value)
{
__raw_writel(value, up->port.membase + 0x28);
}
#endif
static unsigned int hub6_serial_in(struct uart_port *p, int offset)
{
offset = offset << p->regshift;
outb(p->hub6 - 1 + offset, p->iobase);
return inb(p->iobase + 1);
}
static void hub6_serial_out(struct uart_port *p, int offset, int value)
{
offset = offset << p->regshift;
outb(p->hub6 - 1 + offset, p->iobase);
outb(value, p->iobase + 1);
}
static unsigned int mem_serial_in(struct uart_port *p, int offset)
{
offset = offset << p->regshift;
return readb(p->membase + offset);
}
static void mem_serial_out(struct uart_port *p, int offset, int value)
{
offset = offset << p->regshift;
writeb(value, p->membase + offset);
}
static void mem16_serial_out(struct uart_port *p, int offset, int value)
{
offset = offset << p->regshift;
writew(value, p->membase + offset);
}
static unsigned int mem16_serial_in(struct uart_port *p, int offset)
{
offset = offset << p->regshift;
return readw(p->membase + offset);
}
static void mem32_serial_out(struct uart_port *p, int offset, int value)
{
offset = offset << p->regshift;
writel(value, p->membase + offset);
}
static unsigned int mem32_serial_in(struct uart_port *p, int offset)
{
offset = offset << p->regshift;
return readl(p->membase + offset);
}
static void mem32be_serial_out(struct uart_port *p, int offset, int value)
{
offset = offset << p->regshift;
iowrite32be(value, p->membase + offset);
}
static unsigned int mem32be_serial_in(struct uart_port *p, int offset)
{
offset = offset << p->regshift;
return ioread32be(p->membase + offset);
}
static unsigned int io_serial_in(struct uart_port *p, int offset)
{
offset = offset << p->regshift;
return inb(p->iobase + offset);
}
static void io_serial_out(struct uart_port *p, int offset, int value)
{
offset = offset << p->regshift;
outb(value, p->iobase + offset);
}
static int serial8250_default_handle_irq(struct uart_port *port);
static void set_io_from_upio(struct uart_port *p)
{
struct uart_8250_port *up = up_to_u8250p(p);
up->dl_read = default_serial_dl_read;
up->dl_write = default_serial_dl_write;
switch (p->iotype) {
case UPIO_HUB6:
p->serial_in = hub6_serial_in;
p->serial_out = hub6_serial_out;
break;
case UPIO_MEM:
p->serial_in = mem_serial_in;
p->serial_out = mem_serial_out;
break;
case UPIO_MEM16:
p->serial_in = mem16_serial_in;
p->serial_out = mem16_serial_out;
break;
case UPIO_MEM32:
p->serial_in = mem32_serial_in;
p->serial_out = mem32_serial_out;
break;
case UPIO_MEM32BE:
p->serial_in = mem32be_serial_in;
p->serial_out = mem32be_serial_out;
break;
#ifdef CONFIG_SERIAL_8250_RT288X
case UPIO_AU:
p->serial_in = au_serial_in;
p->serial_out = au_serial_out;
up->dl_read = au_serial_dl_read;
up->dl_write = au_serial_dl_write;
break;
#endif
default:
p->serial_in = io_serial_in;
p->serial_out = io_serial_out;
break;
}
/* Remember loaded iotype */
up->cur_iotype = p->iotype;
p->handle_irq = serial8250_default_handle_irq;
}
static void
serial_port_out_sync(struct uart_port *p, int offset, int value)
{
switch (p->iotype) {
case UPIO_MEM:
case UPIO_MEM16:
case UPIO_MEM32:
case UPIO_MEM32BE:
case UPIO_AU:
p->serial_out(p, offset, value);
p->serial_in(p, UART_LCR); /* safe, no side-effects */
break;
default:
p->serial_out(p, offset, value);
}
}
/*
* FIFO support.
*/
static void serial8250_clear_fifos(struct uart_8250_port *p)
{
if (p->capabilities & UART_CAP_FIFO) {
serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO);
serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO |
UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
serial_out(p, UART_FCR, 0);
}
}
static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t);
static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t);
void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
{
serial8250_clear_fifos(p);
serial_out(p, UART_FCR, p->fcr);
}
EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
void serial8250_rpm_get(struct uart_8250_port *p)
{
if (!(p->capabilities & UART_CAP_RPM))
return;
pm_runtime_get_sync(p->port.dev);
}
EXPORT_SYMBOL_GPL(serial8250_rpm_get);
void serial8250_rpm_put(struct uart_8250_port *p)
{
if (!(p->capabilities & UART_CAP_RPM))
return;
pm_runtime_mark_last_busy(p->port.dev);
pm_runtime_put_autosuspend(p->port.dev);
}
EXPORT_SYMBOL_GPL(serial8250_rpm_put);
/**
* serial8250_em485_init() - put uart_8250_port into rs485 emulating
* @p: uart_8250_port port instance
*
* The function is used to start rs485 software emulating on the
* &struct uart_8250_port* @p. Namely, RTS is switched before/after
* transmission. The function is idempotent, so it is safe to call it
* multiple times.
*
* The caller MUST enable interrupt on empty shift register before
* calling serial8250_em485_init(). This interrupt is not a part of
* 8250 standard, but implementation defined.
*
* The function is supposed to be called from .rs485_config callback
* or from any other callback protected with p->port.lock spinlock.
*
* See also serial8250_em485_destroy()
*
* Return 0 - success, -errno - otherwise
*/
static int serial8250_em485_init(struct uart_8250_port *p)
{
if (p->em485)
goto deassert_rts;
p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_ATOMIC);
if (!p->em485)
return -ENOMEM;
hrtimer_init(&p->em485->stop_tx_timer, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
hrtimer_init(&p->em485->start_tx_timer, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
p->em485->stop_tx_timer.function = &serial8250_em485_handle_stop_tx;
p->em485->start_tx_timer.function = &serial8250_em485_handle_start_tx;
p->em485->port = p;
p->em485->active_timer = NULL;
p->em485->tx_stopped = true;
deassert_rts:
if (p->em485->tx_stopped)
p->rs485_stop_tx(p);
return 0;
}
/**
* serial8250_em485_destroy() - put uart_8250_port into normal state
* @p: uart_8250_port port instance
*
* The function is used to stop rs485 software emulating on the
* &struct uart_8250_port* @p. The function is idempotent, so it is safe to
* call it multiple times.
*
* The function is supposed to be called from .rs485_config callback
* or from any other callback protected with p->port.lock spinlock.
*
* See also serial8250_em485_init()
*/
void serial8250_em485_destroy(struct uart_8250_port *p)
{
if (!p->em485)
return;
hrtimer_cancel(&p->em485->start_tx_timer);
hrtimer_cancel(&p->em485->stop_tx_timer);
kfree(p->em485);
p->em485 = NULL;
}
EXPORT_SYMBOL_GPL(serial8250_em485_destroy);
struct serial_rs485 serial8250_em485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
SER_RS485_TERMINATE_BUS | SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1,
};
EXPORT_SYMBOL_GPL(serial8250_em485_supported);
/**
* serial8250_em485_config() - generic ->rs485_config() callback
* @port: uart port
* @rs485: rs485 settings
*
* Generic callback usable by 8250 uart drivers to activate rs485 settings
* if the uart is incapable of driving RTS as a Transmit Enable signal in
* hardware, relying on software emulation instead.
*/
int serial8250_em485_config(struct uart_port *port, struct ktermios *termios,
struct serial_rs485 *rs485)
{
struct uart_8250_port *up = up_to_u8250p(port);
/* pick sane settings if the user hasn't */
if (!!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
!!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
rs485->flags |= SER_RS485_RTS_ON_SEND;
rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
}
/*
* Both serial8250_em485_init() and serial8250_em485_destroy()
* are idempotent.
*/
if (rs485->flags & SER_RS485_ENABLED)
return serial8250_em485_init(up);
serial8250_em485_destroy(up);
return 0;
}
EXPORT_SYMBOL_GPL(serial8250_em485_config);
/*
* These two wrappers ensure that enable_runtime_pm_tx() can be called more than
* once and disable_runtime_pm_tx() will still disable RPM because the fifo is
* empty and the HW can idle again.
*/
void serial8250_rpm_get_tx(struct uart_8250_port *p)
{
unsigned char rpm_active;
if (!(p->capabilities & UART_CAP_RPM))
return;
rpm_active = xchg(&p->rpm_tx_active, 1);
if (rpm_active)
return;
pm_runtime_get_sync(p->port.dev);
}
EXPORT_SYMBOL_GPL(serial8250_rpm_get_tx);
void serial8250_rpm_put_tx(struct uart_8250_port *p)
{
unsigned char rpm_active;
if (!(p->capabilities & UART_CAP_RPM))
return;
rpm_active = xchg(&p->rpm_tx_active, 0);
if (!rpm_active)
return;
pm_runtime_mark_last_busy(p->port.dev);
pm_runtime_put_autosuspend(p->port.dev);
}
EXPORT_SYMBOL_GPL(serial8250_rpm_put_tx);
/*
* IER sleep support. UARTs which have EFRs need the "extended
* capability" bit enabled. Note that on XR16C850s, we need to
* reset LCR to write to IER.
*/
static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
{
unsigned char lcr = 0, efr = 0;
serial8250_rpm_get(p);
if (p->capabilities & UART_CAP_SLEEP) {
if (p->capabilities & UART_CAP_EFR) {
lcr = serial_in(p, UART_LCR);
efr = serial_in(p, UART_EFR);
serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
serial_out(p, UART_EFR, UART_EFR_ECB);
serial_out(p, UART_LCR, 0);
}
serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
if (p->capabilities & UART_CAP_EFR) {
serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
serial_out(p, UART_EFR, efr);
serial_out(p, UART_LCR, lcr);
}
}
serial8250_rpm_put(p);
}
static void serial8250_clear_IER(struct uart_8250_port *up)
{
if (up->capabilities & UART_CAP_UUE)
serial_out(up, UART_IER, UART_IER_UUE);
else
serial_out(up, UART_IER, 0);
}
#ifdef CONFIG_SERIAL_8250_RSA
/*
* Attempts to turn on the RSA FIFO. Returns zero on failure.
* We set the port uart clock rate if we succeed.
*/
static int __enable_rsa(struct uart_8250_port *up)
{
unsigned char mode;
int result;
mode = serial_in(up, UART_RSA_MSR);
result = mode & UART_RSA_MSR_FIFO;
if (!result) {
serial_out(up, UART_RSA_MSR, mode | UART_RSA_MSR_FIFO);
mode = serial_in(up, UART_RSA_MSR);
result = mode & UART_RSA_MSR_FIFO;
}
if (result)
up->port.uartclk = SERIAL_RSA_BAUD_BASE * 16;
return result;
}
static void enable_rsa(struct uart_8250_port *up)
{
if (up->port.type == PORT_RSA) {
if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
spin_lock_irq(&up->port.lock);
__enable_rsa(up);
spin_unlock_irq(&up->port.lock);
}
if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
serial_out(up, UART_RSA_FRR, 0);
}
}
/*
* Attempts to turn off the RSA FIFO. Returns zero on failure.
* It is unknown why interrupts were disabled in here. However,
* the caller is expected to preserve this behaviour by grabbing
* the spinlock before calling this function.
*/
static void disable_rsa(struct uart_8250_port *up)
{
unsigned char mode;
int result;
if (up->port.type == PORT_RSA &&
up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
spin_lock_irq(&up->port.lock);
mode = serial_in(up, UART_RSA_MSR);
result = !(mode & UART_RSA_MSR_FIFO);
if (!result) {
serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
mode = serial_in(up, UART_RSA_MSR);
result = !(mode & UART_RSA_MSR_FIFO);
}
if (result)
up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
spin_unlock_irq(&up->port.lock);
}
}
#endif /* CONFIG_SERIAL_8250_RSA */
/*
* This is a quickie test to see how big the FIFO is.
* It doesn't work at all the time, more's the pity.
*/
static int size_fifo(struct uart_8250_port *up)
{
unsigned char old_fcr, old_mcr, old_lcr;
unsigned short old_dl;
int count;
old_lcr = serial_in(up, UART_LCR);
serial_out(up, UART_LCR, 0);
old_fcr = serial_in(up, UART_FCR);
old_mcr = serial8250_in_MCR(up);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
serial8250_out_MCR(up, UART_MCR_LOOP);
serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
old_dl = serial_dl_read(up);
serial_dl_write(up, 0x0001);
serial_out(up, UART_LCR, UART_LCR_WLEN8);
for (count = 0; count < 256; count++)
serial_out(up, UART_TX, count);
mdelay(20);/* FIXME - schedule_timeout */
for (count = 0; (serial_in(up, UART_LSR) & UART_LSR_DR) &&
(count < 256); count++)
serial_in(up, UART_RX);
serial_out(up, UART_FCR, old_fcr);
serial8250_out_MCR(up, old_mcr);
serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
serial_dl_write(up, old_dl);
serial_out(up, UART_LCR, old_lcr);
return count;
}
/*
* Read UART ID using the divisor method - set DLL and DLM to zero
* and the revision will be in DLL and device type in DLM. We
* preserve the device state across this.
*/
static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
{
unsigned char old_lcr;
unsigned int id, old_dl;
old_lcr = serial_in(p, UART_LCR);
serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
old_dl = serial_dl_read(p);
serial_dl_write(p, 0);
id = serial_dl_read(p);
serial_dl_write(p, old_dl);
serial_out(p, UART_LCR, old_lcr);
return id;
}
/*
* This is a helper routine to autodetect StarTech/Exar/Oxsemi UART's.
* When this function is called we know it is at least a StarTech
* 16650 V2, but it might be one of several StarTech UARTs, or one of
* its clones. (We treat the broken original StarTech 16650 V1 as a
* 16550, and why not? Startech doesn't seem to even acknowledge its
* existence.)
*
* What evil have men's minds wrought...
*/
static void autoconfig_has_efr(struct uart_8250_port *up)
{
unsigned int id1, id2, id3, rev;
/*
* Everything with an EFR has SLEEP
*/
up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
/*
* First we check to see if it's an Oxford Semiconductor UART.
*
* If we have to do this here because some non-National
* Semiconductor clone chips lock up if you try writing to the
* LSR register (which serial_icr_read does)
*/
/*
* Check for Oxford Semiconductor 16C950.
*
* EFR [4] must be set else this test fails.
*
* This shouldn't be necessary, but Mike Hudson (Exoray@isys.ca)
* claims that it's needed for 952 dual UART's (which are not
* recommended for new designs).
*/
up->acr = 0;
serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
serial_out(up, UART_EFR, UART_EFR_ECB);
serial_out(up, UART_LCR, 0x00);
id1 = serial_icr_read(up, UART_ID1);
id2 = serial_icr_read(up, UART_ID2);
id3 = serial_icr_read(up, UART_ID3);
rev = serial_icr_read(up, UART_REV);
DEBUG_AUTOCONF("950id=%02x:%02x:%02x:%02x ", id1, id2, id3, rev);
if (id1 == 0x16 && id2 == 0xC9 &&
(id3 == 0x50 || id3 == 0x52 || id3 == 0x54)) {
up->port.type = PORT_16C950;
/*
* Enable work around for the Oxford Semiconductor 952 rev B
* chip which causes it to seriously miscalculate baud rates
* when DLL is 0.
*/
if (id3 == 0x52 && rev == 0x01)
up->bugs |= UART_BUG_QUOT;
return;
}
/*
* We check for a XR16C850 by setting DLL and DLM to 0, and then
* reading back DLL and DLM. The chip type depends on the DLM
* value read back:
* 0x10 - XR16C850 and the DLL contains the chip revision.
* 0x12 - XR16C2850.
* 0x14 - XR16C854.
*/
id1 = autoconfig_read_divisor_id(up);
DEBUG_AUTOCONF("850id=%04x ", id1);
id2 = id1 >> 8;
if (id2 == 0x10 || id2 == 0x12 || id2 == 0x14) {
up->port.type = PORT_16850;
return;
}
/*
* It wasn't an XR16C850.
*
* We distinguish between the '654 and the '650 by counting
* how many bytes are in the FIFO. I'm using this for now,
* since that's the technique that was sent to me in the
* serial driver update, but I'm not convinced this works.
* I've had problems doing this in the past. -TYT
*/
if (size_fifo(up) == 64)
up->port.type = PORT_16654;
else
up->port.type = PORT_16650V2;
}
/*
* We detected a chip without a FIFO. Only two fall into
* this category - the original 8250 and the 16450. The
* 16450 has a scratch register (accessible with LCR=0)
*/
static void autoconfig_8250(struct uart_8250_port *up)
{
unsigned char scratch, status1, status2;
up->port.type = PORT_8250;
scratch = serial_in(up, UART_SCR);
serial_out(up, UART_SCR, 0xa5);
status1 = serial_in(up, UART_SCR);
serial_out(up, UART_SCR, 0x5a);
status2 = serial_in(up, UART_SCR);
serial_out(up, UART_SCR, scratch);
if (status1 == 0xa5 && status2 == 0x5a)
up->port.type = PORT_16450;
}
static int broken_efr(struct uart_8250_port *up)
{
/*
* Exar ST16C2550 "A2" devices incorrectly detect as
* having an EFR, and report an ID of 0x0201. See
* http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-11/4812.html
*/
if (autoconfig_read_divisor_id(up) == 0x0201 && size_fifo(up) == 16)
return 1;
return 0;
}
/*
* We know that the chip has FIFOs. Does it have an EFR? The
* EFR is located in the same register position as the IIR and
* we know the top two bits of the IIR are currently set. The
* EFR should contain zero. Try to read the EFR.
*/
static void autoconfig_16550a(struct uart_8250_port *up)
{
unsigned char status1, status2;
unsigned int iersave;
up->port.type = PORT_16550A;
up->capabilities |= UART_CAP_FIFO;
if (!IS_ENABLED(CONFIG_SERIAL_8250_16550A_VARIANTS) &&
!(up->port.flags & UPF_FULL_PROBE))
return;
/*
* Check for presence of the EFR when DLAB is set.
* Only ST16C650V1 UARTs pass this test.
*/
serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
if (serial_in(up, UART_EFR) == 0) {
serial_out(up, UART_EFR, 0xA8);
if (serial_in(up, UART_EFR) != 0) {
DEBUG_AUTOCONF("EFRv1 ");
up->port.type = PORT_16650;
up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
} else {
serial_out(up, UART_LCR, 0);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
UART_FCR7_64BYTE);
status1 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO |
UART_IIR_FIFO_ENABLED);
serial_out(up, UART_FCR, 0);
serial_out(up, UART_LCR, 0);
if (status1 == (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED))
up->port.type = PORT_16550A_FSL64;
else
DEBUG_AUTOCONF("Motorola 8xxx DUART ");
}
serial_out(up, UART_EFR, 0);
return;
}
/*
* Maybe it requires 0xbf to be written to the LCR.
* (other ST16C650V2 UARTs, TI16C752A, etc)
*/
serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
if (serial_in(up, UART_EFR) == 0 && !broken_efr(up)) {
DEBUG_AUTOCONF("EFRv2 ");
autoconfig_has_efr(up);
return;
}
/*
* Check for a National Semiconductor SuperIO chip.
* Attempt to switch to bank 2, read the value of the LOOP bit
* from EXCR1. Switch back to bank 0, change it in MCR. Then
* switch back to bank 2, read it from EXCR1 again and check
* it's changed. If so, set baud_base in EXCR2 to 921600. -- dwmw2
*/
serial_out(up, UART_LCR, 0);
status1 = serial8250_in_MCR(up);
serial_out(up, UART_LCR, 0xE0);
status2 = serial_in(up, 0x02); /* EXCR1 */
if (!((status2 ^ status1) & UART_MCR_LOOP)) {
serial_out(up, UART_LCR, 0);
serial8250_out_MCR(up, status1 ^ UART_MCR_LOOP);
serial_out(up, UART_LCR, 0xE0);
status2 = serial_in(up, 0x02); /* EXCR1 */
serial_out(up, UART_LCR, 0);
serial8250_out_MCR(up, status1);
if ((status2 ^ status1) & UART_MCR_LOOP) {
unsigned short quot;
serial_out(up, UART_LCR, 0xE0);
quot = serial_dl_read(up);
quot <<= 3;
if (ns16550a_goto_highspeed(up))
serial_dl_write(up, quot);
serial_out(up, UART_LCR, 0);
up->port.uartclk = 921600*16;
up->port.type = PORT_NS16550A;
up->capabilities |= UART_NATSEMI;
return;
}
}
/*
* No EFR. Try to detect a TI16750, which only sets bit 5 of
* the IIR when 64 byte FIFO mode is enabled when DLAB is set.
* Try setting it with and without DLAB set. Cheap clones
* set bit 5 without DLAB set.
*/
serial_out(up, UART_LCR, 0);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
status1 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
status2 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
serial_out(up, UART_LCR, 0);
DEBUG_AUTOCONF("iir1=%d iir2=%d ", status1, status2);
if (status1 == UART_IIR_FIFO_ENABLED_16550A &&
status2 == (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED_16550A)) {
up->port.type = PORT_16750;
up->capabilities |= UART_CAP_AFE | UART_CAP_SLEEP;
return;
}
/*
* Try writing and reading the UART_IER_UUE bit (b6).
* If it works, this is probably one of the Xscale platform's
* internal UARTs.
* We're going to explicitly set the UUE bit to 0 before
* trying to write and read a 1 just to make sure it's not
* already a 1 and maybe locked there before we even start.
*/
iersave = serial_in(up, UART_IER);
serial_out(up, UART_IER, iersave & ~UART_IER_UUE);
if (!(serial_in(up, UART_IER) & UART_IER_UUE)) {
/*
* OK it's in a known zero state, try writing and reading
* without disturbing the current state of the other bits.
*/
serial_out(up, UART_IER, iersave | UART_IER_UUE);
if (serial_in(up, UART_IER) & UART_IER_UUE) {
/*
* It's an Xscale.
* We'll leave the UART_IER_UUE bit set to 1 (enabled).
*/
DEBUG_AUTOCONF("Xscale ");
up->port.type = PORT_XSCALE;
up->capabilities |= UART_CAP_UUE | UART_CAP_RTOIE;
return;
}
} else {
/*
* If we got here we couldn't force the IER_UUE bit to 0.
* Log it and continue.
*/
DEBUG_AUTOCONF("Couldn't force IER_UUE to 0 ");
}
serial_out(up, UART_IER, iersave);
/*
* We distinguish between 16550A and U6 16550A by counting
* how many bytes are in the FIFO.
*/
if (up->port.type == PORT_16550A && size_fifo(up) == 64) {
up->port.type = PORT_U6_16550A;
up->capabilities |= UART_CAP_AFE;
}
}
/*
* This routine is called by rs_init() to initialize a specific serial
* port. It determines what type of UART chip this serial port is
* using: 8250, 16450, 16550, 16550A. The important question is
* whether or not this UART is a 16550A or not, since this will
* determine whether or not we can use its FIFO features or not.
*/
static void autoconfig(struct uart_8250_port *up)
{
unsigned char status1, scratch, scratch2, scratch3;
unsigned char save_lcr, save_mcr;
struct uart_port *port = &up->port;
unsigned long flags;
unsigned int old_capabilities;
if (!port->iobase && !port->mapbase && !port->membase)
return;
DEBUG_AUTOCONF("%s: autoconf (0x%04lx, 0x%p): ",
port->name, port->iobase, port->membase);
/*
* We really do need global IRQs disabled here - we're going to
* be frobbing the chips IRQ enable register to see if it exists.
*/
spin_lock_irqsave(&port->lock, flags);
up->capabilities = 0;
up->bugs = 0;
if (!(port->flags & UPF_BUGGY_UART)) {
/*
* Do a simple existence test first; if we fail this,
* there's no point trying anything else.
*
* 0x80 is used as a nonsense port to prevent against
* false positives due to ISA bus float. The
* assumption is that 0x80 is a non-existent port;
* which should be safe since include/asm/io.h also
* makes this assumption.
*
* Note: this is safe as long as MCR bit 4 is clear
* and the device is in "PC" mode.
*/
scratch = serial_in(up, UART_IER);
serial_out(up, UART_IER, 0);
#ifdef __i386__
outb(0xff, 0x080);
#endif
/*
* Mask out IER[7:4] bits for test as some UARTs (e.g. TL
* 16C754B) allow only to modify them if an EFR bit is set.
*/
scratch2 = serial_in(up, UART_IER) & UART_IER_ALL_INTR;
serial_out(up, UART_IER, UART_IER_ALL_INTR);
#ifdef __i386__
outb(0, 0x080);
#endif
scratch3 = serial_in(up, UART_IER) & UART_IER_ALL_INTR;
serial_out(up, UART_IER, scratch);
if (scratch2 != 0 || scratch3 != UART_IER_ALL_INTR) {
/*
* We failed; there's nothing here
*/
spin_unlock_irqrestore(&port->lock, flags);
DEBUG_AUTOCONF("IER test failed (%02x, %02x) ",
scratch2, scratch3);
goto out;
}
}
save_mcr = serial8250_in_MCR(up);
save_lcr = serial_in(up, UART_LCR);
/*
* Check to see if a UART is really there. Certain broken
* internal modems based on the Rockwell chipset fail this
* test, because they apparently don't implement the loopback
* test mode. So this test is skipped on the COM 1 through
* COM 4 ports. This *should* be safe, since no board
* manufacturer would be stupid enough to design a board
* that conflicts with COM 1-4 --- we hope!
*/
if (!(port->flags & UPF_SKIP_TEST)) {
serial8250_out_MCR(up, UART_MCR_LOOP | UART_MCR_OUT2 | UART_MCR_RTS);
status1 = serial_in(up, UART_MSR) & UART_MSR_STATUS_BITS;
serial8250_out_MCR(up, save_mcr);
if (status1 != (UART_MSR_DCD | UART_MSR_CTS)) {
spin_unlock_irqrestore(&port->lock, flags);
DEBUG_AUTOCONF("LOOP test failed (%02x) ",
status1);
goto out;
}
}
/*
* We're pretty sure there's a port here. Lets find out what
* type of port it is. The IIR top two bits allows us to find
* out if it's 8250 or 16450, 16550, 16550A or later. This
* determines what we test for next.
*
* We also initialise the EFR (if any) to zero for later. The
* EFR occupies the same register location as the FCR and IIR.
*/
serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
serial_out(up, UART_EFR, 0);
serial_out(up, UART_LCR, 0);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
switch (serial_in(up, UART_IIR) & UART_IIR_FIFO_ENABLED) {
case UART_IIR_FIFO_ENABLED_8250:
autoconfig_8250(up);
break;
case UART_IIR_FIFO_ENABLED_16550:
port->type = PORT_16550;
break;
case UART_IIR_FIFO_ENABLED_16550A:
autoconfig_16550a(up);
break;
default:
port->type = PORT_UNKNOWN;
break;
}
#ifdef CONFIG_SERIAL_8250_RSA
/*
* Only probe for RSA ports if we got the region.
*/
if (port->type == PORT_16550A && up->probe & UART_PROBE_RSA &&
__enable_rsa(up))
port->type = PORT_RSA;
#endif
serial_out(up, UART_LCR, save_lcr);
port->fifosize = uart_config[up->port.type].fifo_size;
old_capabilities = up->capabilities;
up->capabilities = uart_config[port->type].flags;
up->tx_loadsz = uart_config[port->type].tx_loadsz;
if (port->type == PORT_UNKNOWN)
goto out_unlock;
/*
* Reset the UART.
*/
#ifdef CONFIG_SERIAL_8250_RSA
if (port->type == PORT_RSA)
serial_out(up, UART_RSA_FRR, 0);
#endif
serial8250_out_MCR(up, save_mcr);
serial8250_clear_fifos(up);
serial_in(up, UART_RX);
serial8250_clear_IER(up);
out_unlock:
spin_unlock_irqrestore(&port->lock, flags);
/*
* Check if the device is a Fintek F81216A
*/
if (port->type == PORT_16550A && port->iotype == UPIO_PORT)
fintek_8250_probe(up);
if (up->capabilities != old_capabilities) {
dev_warn(port->dev, "detected caps %08x should be %08x\n",
old_capabilities, up->capabilities);
}
out:
DEBUG_AUTOCONF("iir=%d ", scratch);
DEBUG_AUTOCONF("type=%s\n", uart_config[port->type].name);
}
static void autoconfig_irq(struct uart_8250_port *up)
{
struct uart_port *port = &up->port;
unsigned char save_mcr, save_ier;
unsigned char save_ICP = 0;
unsigned int ICP = 0;
unsigned long irqs;
int irq;
if (port->flags & UPF_FOURPORT) {
ICP = (port->iobase & 0xfe0) | 0x1f;
save_ICP = inb_p(ICP);
outb_p(0x80, ICP);
inb_p(ICP);
}
if (uart_console(port))
console_lock();
/* forget possible initially masked and pending IRQ */
probe_irq_off(probe_irq_on());
save_mcr = serial8250_in_MCR(up);
save_ier = serial_in(up, UART_IER);
serial8250_out_MCR(up, UART_MCR_OUT1 | UART_MCR_OUT2);
irqs = probe_irq_on();
serial8250_out_MCR(up, 0);
udelay(10);
if (port->flags & UPF_FOURPORT) {
serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
} else {
serial8250_out_MCR(up,
UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2);
}
serial_out(up, UART_IER, UART_IER_ALL_INTR);
serial_in(up, UART_LSR);
serial_in(up, UART_RX);
serial_in(up, UART_IIR);
serial_in(up, UART_MSR);
serial_out(up, UART_TX, 0xFF);
udelay(20);
irq = probe_irq_off(irqs);
serial8250_out_MCR(up, save_mcr);
serial_out(up, UART_IER, save_ier);
if (port->flags & UPF_FOURPORT)
outb_p(save_ICP, ICP);
if (uart_console(port))
console_unlock();
port->irq = (irq > 0) ? irq : 0;
}
static void serial8250_stop_rx(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
serial8250_rpm_get(up);
up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
up->port.read_status_mask &= ~UART_LSR_DR;
serial_port_out(port, UART_IER, up->ier);
serial8250_rpm_put(up);
}
/**
* serial8250_em485_stop_tx() - generic ->rs485_stop_tx() callback
* @p: uart 8250 port
*
* Generic callback usable by 8250 uart drivers to stop rs485 transmission.
*/
void serial8250_em485_stop_tx(struct uart_8250_port *p)
{
unsigned char mcr = serial8250_in_MCR(p);
if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND)
mcr |= UART_MCR_RTS;
else
mcr &= ~UART_MCR_RTS;
serial8250_out_MCR(p, mcr);
/*
* Empty the RX FIFO, we are not interested in anything
* received during the half-duplex transmission.
* Enable previously disabled RX interrupts.
*/
if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
serial8250_clear_and_reinit_fifos(p);
p->ier |= UART_IER_RLSI | UART_IER_RDI;
serial_port_out(&p->port, UART_IER, p->ier);
}
}
EXPORT_SYMBOL_GPL(serial8250_em485_stop_tx);
static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
{
struct uart_8250_em485 *em485 = container_of(t, struct uart_8250_em485,
stop_tx_timer);
struct uart_8250_port *p = em485->port;
unsigned long flags;
serial8250_rpm_get(p);
spin_lock_irqsave(&p->port.lock, flags);
if (em485->active_timer == &em485->stop_tx_timer) {
p->rs485_stop_tx(p);
em485->active_timer = NULL;
em485->tx_stopped = true;
}
spin_unlock_irqrestore(&p->port.lock, flags);
serial8250_rpm_put(p);
return HRTIMER_NORESTART;
}
static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
{
hrtimer_start(hrt, ms_to_ktime(msec), HRTIMER_MODE_REL);
}
static void __stop_tx_rs485(struct uart_8250_port *p, u64 stop_delay)
{
struct uart_8250_em485 *em485 = p->em485;
stop_delay += (u64)p->port.rs485.delay_rts_after_send * NSEC_PER_MSEC;
/*
* rs485_stop_tx() is going to set RTS according to config
* AND flush RX FIFO if required.
*/
if (stop_delay > 0) {
em485->active_timer = &em485->stop_tx_timer;
hrtimer_start(&em485->stop_tx_timer, ns_to_ktime(stop_delay), HRTIMER_MODE_REL);
} else {
p->rs485_stop_tx(p);
em485->active_timer = NULL;
em485->tx_stopped = true;
}
}
static inline void __stop_tx(struct uart_8250_port *p)
{
struct uart_8250_em485 *em485 = p->em485;
if (em485) {
u16 lsr = serial_lsr_in(p);
u64 stop_delay = 0;
if (!(lsr & UART_LSR_THRE))
return;
/*
* To provide required timing and allow FIFO transfer,
* __stop_tx_rs485() must be called only when both FIFO and
* shift register are empty. The device driver should either
* enable interrupt on TEMT or set UART_CAP_NOTEMT that will
* enlarge stop_tx_timer by the tx time of one frame to cover
* for emptying of the shift register.
*/
if (!(lsr & UART_LSR_TEMT)) {
if (!(p->capabilities & UART_CAP_NOTEMT))
return;
/*
* RTS might get deasserted too early with the normal
* frame timing formula. It seems to suggest THRE might
* get asserted already during tx of the stop bit
* rather than after it is fully sent.
* Roughly estimate 1 extra bit here with / 7.
*/
stop_delay = p->port.frame_time + DIV_ROUND_UP(p->port.frame_time, 7);
}
__stop_tx_rs485(p, stop_delay);
}
if (serial8250_clear_THRI(p))
serial8250_rpm_put_tx(p);
}
static void serial8250_stop_tx(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
serial8250_rpm_get(up);
__stop_tx(up);
/*
* We really want to stop the transmitter from sending.
*/
if (port->type == PORT_16C950) {
up->acr |= UART_ACR_TXDIS;
serial_icr_write(up, UART_ACR, up->acr);
}
serial8250_rpm_put(up);
}
static inline void __start_tx(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
if (up->dma && !up->dma->tx_dma(up))
return;
if (serial8250_set_THRI(up)) {
if (up->bugs & UART_BUG_TXEN) {
u16 lsr = serial_lsr_in(up);
if (lsr & UART_LSR_THRE)
serial8250_tx_chars(up);
}
}
/*
* Re-enable the transmitter if we disabled it.
*/
if (port->type == PORT_16C950 && up->acr & UART_ACR_TXDIS) {
up->acr &= ~UART_ACR_TXDIS;
serial_icr_write(up, UART_ACR, up->acr);
}
}
/**
* serial8250_em485_start_tx() - generic ->rs485_start_tx() callback
* @up: uart 8250 port
*
* Generic callback usable by 8250 uart drivers to start rs485 transmission.
* Assumes that setting the RTS bit in the MCR register means RTS is high.
* (Some chips use inverse semantics.) Further assumes that reception is
* stoppable by disabling the UART_IER_RDI interrupt. (Some chips set the
* UART_LSR_DR bit even when UART_IER_RDI is disabled, foiling this approach.)
*/
void serial8250_em485_start_tx(struct uart_8250_port *up)
{
unsigned char mcr = serial8250_in_MCR(up);
if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
serial8250_stop_rx(&up->port);
if (up->port.rs485.flags & SER_RS485_RTS_ON_SEND)
mcr |= UART_MCR_RTS;
else
mcr &= ~UART_MCR_RTS;
serial8250_out_MCR(up, mcr);
}
EXPORT_SYMBOL_GPL(serial8250_em485_start_tx);
/* Returns false, if start_tx_timer was setup to defer TX start */
static bool start_tx_rs485(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
struct uart_8250_em485 *em485 = up->em485;
/*
* While serial8250_em485_handle_stop_tx() is a noop if
* em485->active_timer != &em485->stop_tx_timer, it might happen that
* the timer is still armed and triggers only after the current bunch of
* chars is send and em485->active_timer == &em485->stop_tx_timer again.
* So cancel the timer. There is still a theoretical race condition if
* the timer is already running and only comes around to check for
* em485->active_timer when &em485->stop_tx_timer is armed again.
*/
if (em485->active_timer == &em485->stop_tx_timer)
hrtimer_try_to_cancel(&em485->stop_tx_timer);
em485->active_timer = NULL;
if (em485->tx_stopped) {
em485->tx_stopped = false;
up->rs485_start_tx(up);
if (up->port.rs485.delay_rts_before_send > 0) {
em485->active_timer = &em485->start_tx_timer;
start_hrtimer_ms(&em485->start_tx_timer,
up->port.rs485.delay_rts_before_send);
return false;
}
}
return true;
}
static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t)
{
struct uart_8250_em485 *em485 = container_of(t, struct uart_8250_em485,
start_tx_timer);
struct uart_8250_port *p = em485->port;
unsigned long flags;
spin_lock_irqsave(&p->port.lock, flags);
if (em485->active_timer == &em485->start_tx_timer) {
__start_tx(&p->port);
em485->active_timer = NULL;
}
spin_unlock_irqrestore(&p->port.lock, flags);
return HRTIMER_NORESTART;
}
static void serial8250_start_tx(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
struct uart_8250_em485 *em485 = up->em485;
if (!port->x_char && uart_circ_empty(&port->state->xmit))
return;
serial8250_rpm_get_tx(up);
if (em485) {
if ((em485->active_timer == &em485->start_tx_timer) ||
!start_tx_rs485(port))
return;
}
__start_tx(port);
}
static void serial8250_throttle(struct uart_port *port)
{
port->throttle(port);
}
static void serial8250_unthrottle(struct uart_port *port)
{
port->unthrottle(port);
}
static void serial8250_disable_ms(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
/* no MSR capabilities */
if (up->bugs & UART_BUG_NOMSR)
return;
mctrl_gpio_disable_ms(up->gpios);
up->ier &= ~UART_IER_MSI;
serial_port_out(port, UART_IER, up->ier);
}
static void serial8250_enable_ms(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
/* no MSR capabilities */
if (up->bugs & UART_BUG_NOMSR)
return;
mctrl_gpio_enable_ms(up->gpios);
up->ier |= UART_IER_MSI;
serial8250_rpm_get(up);
serial_port_out(port, UART_IER, up->ier);
serial8250_rpm_put(up);
}
void serial8250_read_char(struct uart_8250_port *up, u16 lsr)
{
struct uart_port *port = &up->port;
unsigned char ch;
char flag = TTY_NORMAL;
if (likely(lsr & UART_LSR_DR))
ch = serial_in(up, UART_RX);
else
/*
* Intel 82571 has a Serial Over Lan device that will
* set UART_LSR_BI without setting UART_LSR_DR when
* it receives a break. To avoid reading from the
* receive buffer without UART_LSR_DR bit set, we
* just force the read character to be 0
*/
ch = 0;
port->icount.rx++;
lsr |= up->lsr_saved_flags;
up->lsr_saved_flags = 0;
if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
if (lsr & UART_LSR_BI) {
lsr &= ~(UART_LSR_FE | UART_LSR_PE);
port->icount.brk++;
/*
* We do the SysRQ and SAK checking
* here because otherwise the break
* may get masked by ignore_status_mask
* or read_status_mask.
*/
if (uart_handle_break(port))
return;
} else if (lsr & UART_LSR_PE)
port->icount.parity++;
else if (lsr & UART_LSR_FE)
port->icount.frame++;
if (lsr & UART_LSR_OE)
port->icount.overrun++;
/*
* Mask off conditions which should be ignored.
*/
lsr &= port->read_status_mask;
if (lsr & UART_LSR_BI) {
dev_dbg(port->dev, "handling break\n");
flag = TTY_BREAK;
} else if (lsr & UART_LSR_PE)
flag = TTY_PARITY;
else if (lsr & UART_LSR_FE)
flag = TTY_FRAME;
}
if (uart_prepare_sysrq_char(port, ch))
return;
uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
}
EXPORT_SYMBOL_GPL(serial8250_read_char);
/*
* serial8250_rx_chars - Read characters. The first LSR value must be passed in.
*
* Returns LSR bits. The caller should rely only on non-Rx related LSR bits
* (such as THRE) because the LSR value might come from an already consumed
* character.
*/
u16 serial8250_rx_chars(struct uart_8250_port *up, u16 lsr)
{
struct uart_port *port = &up->port;
int max_count = 256;
do {
serial8250_read_char(up, lsr);
if (--max_count == 0)
break;
lsr = serial_in(up, UART_LSR);
} while (lsr & (UART_LSR_DR | UART_LSR_BI));
tty_flip_buffer_push(&port->state->port);
return lsr;
}
EXPORT_SYMBOL_GPL(serial8250_rx_chars);
void serial8250_tx_chars(struct uart_8250_port *up)
{
struct uart_port *port = &up->port;
struct circ_buf *xmit = &port->state->xmit;
int count;
if (port->x_char) {
uart_xchar_out(port, UART_TX);
return;
}
if (uart_tx_stopped(port)) {
serial8250_stop_tx(port);
return;
}
if (uart_circ_empty(xmit)) {
__stop_tx(up);
return;
}
count = up->tx_loadsz;
do {
serial_out(up, UART_TX, xmit->buf[xmit->tail]);
if (up->bugs & UART_BUG_TXRACE) {
/*
* The Aspeed BMC virtual UARTs have a bug where data
* may get stuck in the BMC's Tx FIFO from bursts of
* writes on the APB interface.
*
* Delay back-to-back writes by a read cycle to avoid
* stalling the VUART. Read a register that won't have
* side-effects and discard the result.
*/
serial_in(up, UART_SCR);
}
uart_xmit_advance(port, 1);
if (uart_circ_empty(xmit))
break;
if ((up->capabilities & UART_CAP_HFIFO) &&
!uart_lsr_tx_empty(serial_in(up, UART_LSR)))
break;
/* The BCM2835 MINI UART THRE bit is really a not-full bit. */
if ((up->capabilities & UART_CAP_MINI) &&
!(serial_in(up, UART_LSR) & UART_LSR_THRE))
break;
} while (--count > 0);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
/*
* With RPM enabled, we have to wait until the FIFO is empty before the
* HW can go idle. So we get here once again with empty FIFO and disable
* the interrupt and RPM in __stop_tx()
*/
if (uart_circ_empty(xmit) && !(up->capabilities & UART_CAP_RPM))
__stop_tx(up);
}
EXPORT_SYMBOL_GPL(serial8250_tx_chars);
/* Caller holds uart port lock */
unsigned int serial8250_modem_status(struct uart_8250_port *up)
{
struct uart_port *port = &up->port;
unsigned int status = serial_in(up, UART_MSR);
status |= up->msr_saved_flags;
up->msr_saved_flags = 0;
if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
port->state != NULL) {
if (status & UART_MSR_TERI)
port->icount.rng++;
if (status & UART_MSR_DDSR)
port->icount.dsr++;
if (status & UART_MSR_DDCD)
uart_handle_dcd_change(port, status & UART_MSR_DCD);
if (status & UART_MSR_DCTS)
uart_handle_cts_change(port, status & UART_MSR_CTS);
wake_up_interruptible(&port->state->port.delta_msr_wait);
}
return status;
}
EXPORT_SYMBOL_GPL(serial8250_modem_status);
static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
{
switch (iir & 0x3f) {
case UART_IIR_THRI:
/*
* Postpone DMA or not decision to IIR_RDI or IIR_RX_TIMEOUT
* because it's impossible to do an informed decision about
* that with IIR_THRI.
*
* This also fixes one known DMA Rx corruption issue where
* DR is asserted but DMA Rx only gets a corrupted zero byte
* (too early DR?).
*/
return false;
case UART_IIR_RDI:
if (!up->dma->rx_running)
break;
fallthrough;
case UART_IIR_RLSI:
case UART_IIR_RX_TIMEOUT:
serial8250_rx_dma_flush(up);
return true;
}
return up->dma->rx_dma(up);
}
/*
* This handles the interrupt from one port.
*/
int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
{
struct uart_8250_port *up = up_to_u8250p(port);
struct tty_port *tport = &port->state->port;
bool skip_rx = false;
unsigned long flags;
u16 status;
if (iir & UART_IIR_NO_INT)
return 0;
spin_lock_irqsave(&port->lock, flags);
status = serial_lsr_in(up);
/*
* If port is stopped and there are no error conditions in the
* FIFO, then don't drain the FIFO, as this may lead to TTY buffer
* overflow. Not servicing, RX FIFO would trigger auto HW flow
* control when FIFO occupancy reaches preset threshold, thus
* halting RX. This only works when auto HW flow control is
* available.
*/
if (!(status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) &&
(port->status & (UPSTAT_AUTOCTS | UPSTAT_AUTORTS)) &&
!(port->read_status_mask & UART_LSR_DR))
skip_rx = true;
if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) {
if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
pm_wakeup_event(tport->tty->dev, 0);
if (!up->dma || handle_rx_dma(up, iir))
status = serial8250_rx_chars(up, status);
}
serial8250_modem_status(up);
if ((status & UART_LSR_THRE) && (up->ier & UART_IER_THRI)) {
if (!up->dma || up->dma->tx_err)
serial8250_tx_chars(up);
else if (!up->dma->tx_running)
__stop_tx(up);
}
uart_unlock_and_check_sysrq_irqrestore(port, flags);
return 1;
}
EXPORT_SYMBOL_GPL(serial8250_handle_irq);
static int serial8250_default_handle_irq(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
unsigned int iir;
int ret;
serial8250_rpm_get(up);
iir = serial_port_in(port, UART_IIR);
ret = serial8250_handle_irq(port, iir);
serial8250_rpm_put(up);
return ret;
}
/*
* Newer 16550 compatible parts such as the SC16C650 & Altera 16550 Soft IP
* have a programmable TX threshold that triggers the THRE interrupt in
* the IIR register. In this case, the THRE interrupt indicates the FIFO
* has space available. Load it up with tx_loadsz bytes.
*/
static int serial8250_tx_threshold_handle_irq(struct uart_port *port)
{
unsigned long flags;
unsigned int iir = serial_port_in(port, UART_IIR);
/* TX Threshold IRQ triggered so load up FIFO */
if ((iir & UART_IIR_ID) == UART_IIR_THRI) {
struct uart_8250_port *up = up_to_u8250p(port);
spin_lock_irqsave(&port->lock, flags);
serial8250_tx_chars(up);
spin_unlock_irqrestore(&port->lock, flags);
}
iir = serial_port_in(port, UART_IIR);
return serial8250_handle_irq(port, iir);
}
static unsigned int serial8250_tx_empty(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
unsigned int result = 0;
unsigned long flags;
serial8250_rpm_get(up);
spin_lock_irqsave(&port->lock, flags);
if (!serial8250_tx_dma_running(up) && uart_lsr_tx_empty(serial_lsr_in(up)))
result = TIOCSER_TEMT;
spin_unlock_irqrestore(&port->lock, flags);
serial8250_rpm_put(up);
return result;
}
unsigned int serial8250_do_get_mctrl(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
unsigned int status;
unsigned int val;
serial8250_rpm_get(up);
status = serial8250_modem_status(up);
serial8250_rpm_put(up);
val = serial8250_MSR_to_TIOCM(status);
if (up->gpios)
return mctrl_gpio_get(up->gpios, &val);
return val;
}
EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl);
static unsigned int serial8250_get_mctrl(struct uart_port *port)
{
if (port->get_mctrl)
return port->get_mctrl(port);
return serial8250_do_get_mctrl(port);
}
void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct uart_8250_port *up = up_to_u8250p(port);
unsigned char mcr;
mcr = serial8250_TIOCM_to_MCR(mctrl);
mcr |= up->mcr;
serial8250_out_MCR(up, mcr);
}
EXPORT_SYMBOL_GPL(serial8250_do_set_mctrl);
static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
if (port->rs485.flags & SER_RS485_ENABLED)
return;
if (port->set_mctrl)
port->set_mctrl(port, mctrl);
else
serial8250_do_set_mctrl(port, mctrl);
}
static void serial8250_break_ctl(struct uart_port *port, int break_state)
{
struct uart_8250_port *up = up_to_u8250p(port);
unsigned long flags;
serial8250_rpm_get(up);
spin_lock_irqsave(&port->lock, flags);
if (break_state == -1)
up->lcr |= UART_LCR_SBC;
else
up->lcr &= ~UART_LCR_SBC;
serial_port_out(port, UART_LCR, up->lcr);
spin_unlock_irqrestore(&port->lock, flags);
serial8250_rpm_put(up);
}
static void wait_for_lsr(struct uart_8250_port *up, int bits)
{
unsigned int status, tmout = 10000;
/* Wait up to 10ms for the character(s) to be sent. */
for (;;) {
status = serial_lsr_in(up);
if ((status & bits) == bits)
break;
if (--tmout == 0)
break;
udelay(1);
touch_nmi_watchdog();
}
}
/*
* Wait for transmitter & holding register to empty
*/
static void wait_for_xmitr(struct uart_8250_port *up, int bits)
{
unsigned int tmout;
wait_for_lsr(up, bits);
/* Wait up to 1s for flow control if necessary */
if (up->port.flags & UPF_CONS_FLOW) {
for (tmout = 1000000; tmout; tmout--) {
unsigned int msr = serial_in(up, UART_MSR);
up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
if (msr & UART_MSR_CTS)
break;
udelay(1);
touch_nmi_watchdog();
}
}
}
#ifdef CONFIG_CONSOLE_POLL
/*
* Console polling routines for writing and reading from the uart while
* in an interrupt or debug context.
*/
static int serial8250_get_poll_char(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
int status;
u16 lsr;
serial8250_rpm_get(up);
lsr = serial_port_in(port, UART_LSR);
if (!(lsr & UART_LSR_DR)) {
status = NO_POLL_CHAR;
goto out;
}
status = serial_port_in(port, UART_RX);
out:
serial8250_rpm_put(up);
return status;
}
static void serial8250_put_poll_char(struct uart_port *port,
unsigned char c)
{
unsigned int ier;
struct uart_8250_port *up = up_to_u8250p(port);
serial8250_rpm_get(up);
/*
* First save the IER then disable the interrupts
*/
ier = serial_port_in(port, UART_IER);
serial8250_clear_IER(up);
wait_for_xmitr(up, UART_LSR_BOTH_EMPTY);
/*
* Send the character out.
*/
serial_port_out(port, UART_TX, c);
/*
* Finally, wait for transmitter to become empty
* and restore the IER
*/
wait_for_xmitr(up, UART_LSR_BOTH_EMPTY);
serial_port_out(port, UART_IER, ier);
serial8250_rpm_put(up);
}
#endif /* CONFIG_CONSOLE_POLL */
int serial8250_do_startup(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
unsigned long flags;
unsigned char iir;
int retval;
u16 lsr;
if (!port->fifosize)
port->fifosize = uart_config[port->type].fifo_size;
if (!up->tx_loadsz)
up->tx_loadsz = uart_config[port->type].tx_loadsz;
if (!up->capabilities)
up->capabilities = uart_config[port->type].flags;
up->mcr = 0;
if (port->iotype != up->cur_iotype)
set_io_from_upio(port);
serial8250_rpm_get(up);
if (port->type == PORT_16C950) {
/* Wake up and initialize UART */
up->acr = 0;
serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
serial_port_out(port, UART_EFR, UART_EFR_ECB);
serial_port_out(port, UART_IER, 0);
serial_port_out(port, UART_LCR, 0);
serial_icr_write(up, UART_CSR, 0); /* Reset the UART */
serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
serial_port_out(port, UART_EFR, UART_EFR_ECB);
serial_port_out(port, UART_LCR, 0);
}
if (port->type == PORT_DA830) {
/* Reset the port */
serial_port_out(port, UART_IER, 0);
serial_port_out(port, UART_DA830_PWREMU_MGMT, 0);
mdelay(10);
/* Enable Tx, Rx and free run mode */
serial_port_out(port, UART_DA830_PWREMU_MGMT,
UART_DA830_PWREMU_MGMT_UTRST |
UART_DA830_PWREMU_MGMT_URRST |
UART_DA830_PWREMU_MGMT_FREE);
}
if (port->type == PORT_NPCM) {
/*
* Nuvoton calls the scratch register 'UART_TOR' (timeout
* register). Enable it, and set TIOC (timeout interrupt
* comparator) to be 0x20 for correct operation.
*/
serial_port_out(port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20);
}
#ifdef CONFIG_SERIAL_8250_RSA
/*
* If this is an RSA port, see if we can kick it up to the
* higher speed clock.
*/
enable_rsa(up);
#endif
/*
* Clear the FIFO buffers and disable them.
* (they will be reenabled in set_termios())
*/
serial8250_clear_fifos(up);
/*
* Clear the interrupt registers.
*/
serial_port_in(port, UART_LSR);
serial_port_in(port, UART_RX);
serial_port_in(port, UART_IIR);
serial_port_in(port, UART_MSR);
/*
* At this point, there's no way the LSR could still be 0xff;
* if it is, then bail out, because there's likely no UART
* here.
*/
if (!(port->flags & UPF_BUGGY_UART) &&
(serial_port_in(port, UART_LSR) == 0xff)) {
dev_info_ratelimited(port->dev, "LSR safety check engaged!\n");
retval = -ENODEV;
goto out;
}
/*
* For a XR16C850, we need to set the trigger levels
*/
if (port->type == PORT_16850) {
unsigned char fctr;
serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
fctr = serial_in(up, UART_FCTR) & ~(UART_FCTR_RX|UART_FCTR_TX);
serial_port_out(port, UART_FCTR,
fctr | UART_FCTR_TRGD | UART_FCTR_RX);
serial_port_out(port, UART_TRG, UART_TRG_96);
serial_port_out(port, UART_FCTR,
fctr | UART_FCTR_TRGD | UART_FCTR_TX);
serial_port_out(port, UART_TRG, UART_TRG_96);
serial_port_out(port, UART_LCR, 0);
}
/*
* For the Altera 16550 variants, set TX threshold trigger level.
*/
if (((port->type == PORT_ALTR_16550_F32) ||
(port->type == PORT_ALTR_16550_F64) ||
(port->type == PORT_ALTR_16550_F128)) && (port->fifosize > 1)) {
/* Bounds checking of TX threshold (valid 0 to fifosize-2) */
if ((up->tx_loadsz < 2) || (up->tx_loadsz > port->fifosize)) {
dev_err(port->dev, "TX FIFO Threshold errors, skipping\n");
} else {
serial_port_out(port, UART_ALTR_AFR,
UART_ALTR_EN_TXFIFO_LW);
serial_port_out(port, UART_ALTR_TX_LOW,
port->fifosize - up->tx_loadsz);
port->handle_irq = serial8250_tx_threshold_handle_irq;
}
}
/* Check if we need to have shared IRQs */
if (port->irq && (up->port.flags & UPF_SHARE_IRQ))
up->port.irqflags |= IRQF_SHARED;
retval = up->ops->setup_irq(up);
if (retval)
goto out;
if (port->irq && !(up->port.flags & UPF_NO_THRE_TEST)) {
unsigned char iir1;
if (port->irqflags & IRQF_SHARED)
disable_irq_nosync(port->irq);
/*
* Test for UARTs that do not reassert THRE when the
* transmitter is idle and the interrupt has already
* been cleared. Real 16550s should always reassert
* this interrupt whenever the transmitter is idle and
* the interrupt is enabled. Delays are necessary to
* allow register changes to become visible.
*/
spin_lock_irqsave(&port->lock, flags);
wait_for_xmitr(up, UART_LSR_THRE);
serial_port_out_sync(port, UART_IER, UART_IER_THRI);
udelay(1); /* allow THRE to set */
iir1 = serial_port_in(port, UART_IIR);
serial_port_out(port, UART_IER, 0);
serial_port_out_sync(port, UART_IER, UART_IER_THRI);
udelay(1); /* allow a working UART time to re-assert THRE */
iir = serial_port_in(port, UART_IIR);
serial_port_out(port, UART_IER, 0);
spin_unlock_irqrestore(&port->lock, flags);
if (port->irqflags & IRQF_SHARED)
enable_irq(port->irq);
/*
* If the interrupt is not reasserted, or we otherwise
* don't trust the iir, setup a timer to kick the UART
* on a regular basis.
*/
if ((!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) ||
up->port.flags & UPF_BUG_THRE) {
up->bugs |= UART_BUG_THRE;
}
}
up->ops->setup_timer(up);
/*
* Now, initialize the UART
*/
serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
spin_lock_irqsave(&port->lock, flags);
if (up->port.flags & UPF_FOURPORT) {
if (!up->port.irq)
up->port.mctrl |= TIOCM_OUT1;
} else
/*
* Most PC uarts need OUT2 raised to enable interrupts.
*/
if (port->irq)
up->port.mctrl |= TIOCM_OUT2;
serial8250_set_mctrl(port, port->mctrl);
/*
* Serial over Lan (SoL) hack:
* Intel 8257x Gigabit ethernet chips have a 16550 emulation, to be
* used for Serial Over Lan. Those chips take a longer time than a
* normal serial device to signalize that a transmission data was
* queued. Due to that, the above test generally fails. One solution
* would be to delay the reading of iir. However, this is not
* reliable, since the timeout is variable. So, let's just don't
* test if we receive TX irq. This way, we'll never enable
* UART_BUG_TXEN.
*/
if (up->port.quirks & UPQ_NO_TXEN_TEST)
goto dont_test_tx_en;
/*
* Do a quick test to see if we receive an interrupt when we enable
* the TX irq.
*/
serial_port_out(port, UART_IER, UART_IER_THRI);
lsr = serial_port_in(port, UART_LSR);
iir = serial_port_in(port, UART_IIR);
serial_port_out(port, UART_IER, 0);
if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) {
if (!(up->bugs & UART_BUG_TXEN)) {
up->bugs |= UART_BUG_TXEN;
dev_dbg(port->dev, "enabling bad tx status workarounds\n");
}
} else {
up->bugs &= ~UART_BUG_TXEN;
}
dont_test_tx_en:
spin_unlock_irqrestore(&port->lock, flags);
/*
* Clear the interrupt registers again for luck, and clear the
* saved flags to avoid getting false values from polling
* routines or the previous session.
*/
serial_port_in(port, UART_LSR);
serial_port_in(port, UART_RX);
serial_port_in(port, UART_IIR);
serial_port_in(port, UART_MSR);
up->lsr_saved_flags = 0;
up->msr_saved_flags = 0;
/*
* Request DMA channels for both RX and TX.
*/
if (up->dma) {
const char *msg = NULL;
if (uart_console(port))
msg = "forbid DMA for kernel console";
else if (serial8250_request_dma(up))
msg = "failed to request DMA";
if (msg) {
dev_warn_ratelimited(port->dev, "%s\n", msg);
up->dma = NULL;
}
}
/*
* Set the IER shadow for rx interrupts but defer actual interrupt
* enable until after the FIFOs are enabled; otherwise, an already-
* active sender can swamp the interrupt handler with "too much work".
*/
up->ier = UART_IER_RLSI | UART_IER_RDI;
if (port->flags & UPF_FOURPORT) {
unsigned int icp;
/*
* Enable interrupts on the AST Fourport board
*/
icp = (port->iobase & 0xfe0) | 0x01f;
outb_p(0x80, icp);
inb_p(icp);
}
retval = 0;
out:
serial8250_rpm_put(up);
return retval;
}
EXPORT_SYMBOL_GPL(serial8250_do_startup);
static int serial8250_startup(struct uart_port *port)
{
if (port->startup)
return port->startup(port);
return serial8250_do_startup(port);
}
void serial8250_do_shutdown(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
unsigned long flags;
serial8250_rpm_get(up);
/*
* Disable interrupts from this port
*/
spin_lock_irqsave(&port->lock, flags);
up->ier = 0;
serial_port_out(port, UART_IER, 0);
spin_unlock_irqrestore(&port->lock, flags);
synchronize_irq(port->irq);
if (up->dma)
serial8250_release_dma(up);
spin_lock_irqsave(&port->lock, flags);
if (port->flags & UPF_FOURPORT) {
/* reset interrupts on the AST Fourport board */
inb((port->iobase & 0xfe0) | 0x1f);
port->mctrl |= TIOCM_OUT1;
} else
port->mctrl &= ~TIOCM_OUT2;
serial8250_set_mctrl(port, port->mctrl);
spin_unlock_irqrestore(&port->lock, flags);
/*
* Disable break condition and FIFOs
*/
serial_port_out(port, UART_LCR,
serial_port_in(port, UART_LCR) & ~UART_LCR_SBC);
serial8250_clear_fifos(up);
#ifdef CONFIG_SERIAL_8250_RSA
/*
* Reset the RSA board back to 115kbps compat mode.
*/
disable_rsa(up);
#endif
/*
* Read data port to reset things, and then unlink from
* the IRQ chain.
*/
serial_port_in(port, UART_RX);
serial8250_rpm_put(up);
up->ops->release_irq(up);
}
EXPORT_SYMBOL_GPL(serial8250_do_shutdown);
static void serial8250_shutdown(struct uart_port *port)
{
if (port->shutdown)
port->shutdown(port);
else
serial8250_do_shutdown(port);
}
/* Nuvoton NPCM UARTs have a custom divisor calculation */
static unsigned int npcm_get_divisor(struct uart_8250_port *up,
unsigned int baud)
{
struct uart_port *port = &up->port;
return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
}
static unsigned int serial8250_do_get_divisor(struct uart_port *port,
unsigned int baud,
unsigned int *frac)
{
upf_t magic_multiplier = port->flags & UPF_MAGIC_MULTIPLIER;
struct uart_8250_port *up = up_to_u8250p(port);
unsigned int quot;
/*
* Handle magic divisors for baud rates above baud_base on SMSC
* Super I/O chips. We clamp custom rates from clk/6 and clk/12
* up to clk/4 (0x8001) and clk/8 (0x8002) respectively. These
* magic divisors actually reprogram the baud rate generator's
* reference clock derived from chips's 14.318MHz clock input.
*
* Documentation claims that with these magic divisors the base
* frequencies of 7.3728MHz and 3.6864MHz are used respectively
* for the extra baud rates of 460800bps and 230400bps rather
* than the usual base frequency of 1.8462MHz. However empirical
* evidence contradicts that.
*
* Instead bit 7 of the DLM register (bit 15 of the divisor) is
* effectively used as a clock prescaler selection bit for the
* base frequency of 7.3728MHz, always used. If set to 0, then
* the base frequency is divided by 4 for use by the Baud Rate
* Generator, for the usual arrangement where the value of 1 of
* the divisor produces the baud rate of 115200bps. Conversely,
* if set to 1 and high-speed operation has been enabled with the
* Serial Port Mode Register in the Device Configuration Space,
* then the base frequency is supplied directly to the Baud Rate
* Generator, so for the divisor values of 0x8001, 0x8002, 0x8003,
* 0x8004, etc. the respective baud rates produced are 460800bps,
* 230400bps, 153600bps, 115200bps, etc.
*
* In all cases only low 15 bits of the divisor are used to divide
* the baud base and therefore 32767 is the maximum divisor value
* possible, even though documentation says that the programmable
* Baud Rate Generator is capable of dividing the internal PLL
* clock by any divisor from 1 to 65535.
*/
if (magic_multiplier && baud >= port->uartclk / 6)
quot = 0x8001;
else if (magic_multiplier && baud >= port->uartclk / 12)
quot = 0x8002;
else if (up->port.type == PORT_NPCM)
quot = npcm_get_divisor(up, baud);
else
quot = uart_get_divisor(port, baud);
/*
* Oxford Semi 952 rev B workaround
*/
if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0)
quot++;
return quot;
}
static unsigned int serial8250_get_divisor(struct uart_port *port,
unsigned int baud,
unsigned int *frac)
{
if (port->get_divisor)
return port->get_divisor(port, baud, frac);
return serial8250_do_get_divisor(port, baud, frac);
}
static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
tcflag_t c_cflag)
{
unsigned char cval;
cval = UART_LCR_WLEN(tty_get_char_size(c_cflag));
if (c_cflag & CSTOPB)
cval |= UART_LCR_STOP;
if (c_cflag & PARENB) {
cval |= UART_LCR_PARITY;
if (up->bugs & UART_BUG_PARITY)
up->fifo_bug = true;
}
if (!(c_cflag & PARODD))
cval |= UART_LCR_EPAR;
if (c_cflag & CMSPAR)
cval |= UART_LCR_SPAR;
return cval;
}
void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
unsigned int quot, unsigned int quot_frac)
{
struct uart_8250_port *up = up_to_u8250p(port);
/* Workaround to enable 115200 baud on OMAP1510 internal ports */
if (is_omap1510_8250(up)) {
if (baud == 115200) {
quot = 1;
serial_port_out(port, UART_OMAP_OSC_12M_SEL, 1);
} else
serial_port_out(port, UART_OMAP_OSC_12M_SEL, 0);
}
/*
* For NatSemi, switch to bank 2 not bank 1, to avoid resetting EXCR2,
* otherwise just set DLAB
*/
if (up->capabilities & UART_NATSEMI)
serial_port_out(port, UART_LCR, 0xe0);
else
serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
serial_dl_write(up, quot);
}
EXPORT_SYMBOL_GPL(serial8250_do_set_divisor);
static void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
unsigned int quot, unsigned int quot_frac)
{
if (port->set_divisor)
port->set_divisor(port, baud, quot, quot_frac);
else
serial8250_do_set_divisor(port, baud, quot, quot_frac);
}
static unsigned int serial8250_get_baud_rate(struct uart_port *port,
struct ktermios *termios,
const struct ktermios *old)
{
unsigned int tolerance = port->uartclk / 100;
unsigned int min;
unsigned int max;
/*
* Handle magic divisors for baud rates above baud_base on SMSC
* Super I/O chips. Enable custom rates of clk/4 and clk/8, but
* disable divisor values beyond 32767, which are unavailable.
*/
if (port->flags & UPF_MAGIC_MULTIPLIER) {
min = port->uartclk / 16 / UART_DIV_MAX >> 1;
max = (port->uartclk + tolerance) / 4;
} else {
min = port->uartclk / 16 / UART_DIV_MAX;
max = (port->uartclk + tolerance) / 16;
}
/*
* Ask the core to calculate the divisor for us.
* Allow 1% tolerance at the upper limit so uart clks marginally
* slower than nominal still match standard baud rates without
* causing transmission errors.
*/
return uart_get_baud_rate(port, termios, old, min, max);
}
/*
* Note in order to avoid the tty port mutex deadlock don't use the next method
* within the uart port callbacks. Primarily it's supposed to be utilized to
* handle a sudden reference clock rate change.
*/
void serial8250_update_uartclk(struct uart_port *port, unsigned int uartclk)
{
struct uart_8250_port *up = up_to_u8250p(port);
struct tty_port *tport = &port->state->port;
unsigned int baud, quot, frac = 0;
struct ktermios *termios;
struct tty_struct *tty;
unsigned long flags;
tty = tty_port_tty_get(tport);
if (!tty) {
mutex_lock(&tport->mutex);
port->uartclk = uartclk;
mutex_unlock(&tport->mutex);
return;
}
down_write(&tty->termios_rwsem);
mutex_lock(&tport->mutex);
if (port->uartclk == uartclk)
goto out_unlock;
port->uartclk = uartclk;
if (!tty_port_initialized(tport))
goto out_unlock;
termios = &tty->termios;
baud = serial8250_get_baud_rate(port, termios, NULL);
quot = serial8250_get_divisor(port, baud, &frac);
serial8250_rpm_get(up);
spin_lock_irqsave(&port->lock, flags);
uart_update_timeout(port, termios->c_cflag, baud);
serial8250_set_divisor(port, baud, quot, frac);
serial_port_out(port, UART_LCR, up->lcr);
spin_unlock_irqrestore(&port->lock, flags);
serial8250_rpm_put(up);
out_unlock:
mutex_unlock(&tport->mutex);
up_write(&tty->termios_rwsem);
tty_kref_put(tty);
}
EXPORT_SYMBOL_GPL(serial8250_update_uartclk);
void
serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
const struct ktermios *old)
{
struct uart_8250_port *up = up_to_u8250p(port);
unsigned char cval;
unsigned long flags;
unsigned int baud, quot, frac = 0;
if (up->capabilities & UART_CAP_MINI) {
termios->c_cflag &= ~(CSTOPB | PARENB | PARODD | CMSPAR);
if ((termios->c_cflag & CSIZE) == CS5 ||
(termios->c_cflag & CSIZE) == CS6)
termios->c_cflag = (termios->c_cflag & ~CSIZE) | CS7;
}
cval = serial8250_compute_lcr(up, termios->c_cflag);
baud = serial8250_get_baud_rate(port, termios, old);
quot = serial8250_get_divisor(port, baud, &frac);
/*
* Ok, we're now changing the port state. Do it with
* interrupts disabled.
*/
serial8250_rpm_get(up);
spin_lock_irqsave(&port->lock, flags);
up->lcr = cval; /* Save computed LCR */
if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
/* NOTE: If fifo_bug is not set, a user can set RX_trigger. */
if ((baud < 2400 && !up->dma) || up->fifo_bug) {
up->fcr &= ~UART_FCR_TRIGGER_MASK;
up->fcr |= UART_FCR_TRIGGER_1;
}
}
/*
* MCR-based auto flow control. When AFE is enabled, RTS will be
* deasserted when the receive FIFO contains more characters than
* the trigger, or the MCR RTS bit is cleared.
*/
if (up->capabilities & UART_CAP_AFE) {
up->mcr &= ~UART_MCR_AFE;
if (termios->c_cflag & CRTSCTS)
up->mcr |= UART_MCR_AFE;
}
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
if (termios->c_iflag & INPCK)
port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
port->read_status_mask |= UART_LSR_BI;
/*
* Characters to ignore
*/
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
if (termios->c_iflag & IGNBRK) {
port->ignore_status_mask |= UART_LSR_BI;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UART_LSR_OE;
}
/*
* ignore all characters if CREAD is not set
*/
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= UART_LSR_DR;
/*
* CTS flow control flag and modem status interrupts
*/
up->ier &= ~UART_IER_MSI;
if (!(up->bugs & UART_BUG_NOMSR) &&
UART_ENABLE_MS(&up->port, termios->c_cflag))
up->ier |= UART_IER_MSI;
if (up->capabilities & UART_CAP_UUE)
up->ier |= UART_IER_UUE;
if (up->capabilities & UART_CAP_RTOIE)
up->ier |= UART_IER_RTOIE;
serial_port_out(port, UART_IER, up->ier);
if (up->capabilities & UART_CAP_EFR) {
unsigned char efr = 0;
/*
* TI16C752/Startech hardware flow control. FIXME:
* - TI16C752 requires control thresholds to be set.
* - UART_MCR_RTS is ineffective if auto-RTS mode is enabled.
*/
if (termios->c_cflag & CRTSCTS)
efr |= UART_EFR_CTS;
serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
if (port->flags & UPF_EXAR_EFR)
serial_port_out(port, UART_XR_EFR, efr);
else
serial_port_out(port, UART_EFR, efr);
}
serial8250_set_divisor(port, baud, quot, frac);
/*
* LCR DLAB must be set to enable 64-byte FIFO mode. If the FCR
* is written without DLAB set, this mode will be disabled.
*/
if (port->type == PORT_16750)
serial_port_out(port, UART_FCR, up->fcr);
serial_port_out(port, UART_LCR, up->lcr); /* reset DLAB */
if (port->type != PORT_16750) {
/* emulated UARTs (Lucent Venus 167x) need two steps */
if (up->fcr & UART_FCR_ENABLE_FIFO)
serial_port_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
serial_port_out(port, UART_FCR, up->fcr); /* set fcr */
}
serial8250_set_mctrl(port, port->mctrl);
spin_unlock_irqrestore(&port->lock, flags);
serial8250_rpm_put(up);
/* Don't rewrite B0 */
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
}
EXPORT_SYMBOL(serial8250_do_set_termios);
static void
serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
const struct ktermios *old)
{
if (port->set_termios)
port->set_termios(port, termios, old);
else
serial8250_do_set_termios(port, termios, old);
}
void serial8250_do_set_ldisc(struct uart_port *port, struct ktermios *termios)
{
if (termios->c_line == N_PPS) {
port->flags |= UPF_HARDPPS_CD;
spin_lock_irq(&port->lock);
serial8250_enable_ms(port);
spin_unlock_irq(&port->lock);
} else {
port->flags &= ~UPF_HARDPPS_CD;
if (!UART_ENABLE_MS(port, termios->c_cflag)) {
spin_lock_irq(&port->lock);
serial8250_disable_ms(port);
spin_unlock_irq(&port->lock);
}
}
}
EXPORT_SYMBOL_GPL(serial8250_do_set_ldisc);
static void
serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
{
if (port->set_ldisc)
port->set_ldisc(port, termios);
else
serial8250_do_set_ldisc(port, termios);
}
void serial8250_do_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
struct uart_8250_port *p = up_to_u8250p(port);
serial8250_set_sleep(p, state != 0);
}
EXPORT_SYMBOL(serial8250_do_pm);
static void
serial8250_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
if (port->pm)
port->pm(port, state, oldstate);
else
serial8250_do_pm(port, state, oldstate);
}
static unsigned int serial8250_port_size(struct uart_8250_port *pt)
{
if (pt->port.mapsize)
return pt->port.mapsize;
if (pt->port.iotype == UPIO_AU) {
if (pt->port.type == PORT_RT2880)
return 0x100;
return 0x1000;
}
if (is_omap1_8250(pt))
return 0x16 << pt->port.regshift;
return 8 << pt->port.regshift;
}
/*
* Resource handling.
*/
static int serial8250_request_std_resource(struct uart_8250_port *up)
{
unsigned int size = serial8250_port_size(up);
struct uart_port *port = &up->port;
int ret = 0;
switch (port->iotype) {
case UPIO_AU:
case UPIO_TSI:
case UPIO_MEM32:
case UPIO_MEM32BE:
case UPIO_MEM16:
case UPIO_MEM:
if (!port->mapbase) {
ret = -EINVAL;
break;
}
if (!request_mem_region(port->mapbase, size, "serial")) {
ret = -EBUSY;
break;
}
if (port->flags & UPF_IOREMAP) {
port->membase = ioremap(port->mapbase, size);
if (!port->membase) {
release_mem_region(port->mapbase, size);
ret = -ENOMEM;
}
}
break;
case UPIO_HUB6:
case UPIO_PORT:
if (!request_region(port->iobase, size, "serial"))
ret = -EBUSY;
break;
}
return ret;
}
static void serial8250_release_std_resource(struct uart_8250_port *up)
{
unsigned int size = serial8250_port_size(up);
struct uart_port *port = &up->port;
switch (port->iotype) {
case UPIO_AU:
case UPIO_TSI:
case UPIO_MEM32:
case UPIO_MEM32BE:
case UPIO_MEM16:
case UPIO_MEM:
if (!port->mapbase)
break;
if (port->flags & UPF_IOREMAP) {
iounmap(port->membase);
port->membase = NULL;
}
release_mem_region(port->mapbase, size);
break;
case UPIO_HUB6:
case UPIO_PORT:
release_region(port->iobase, size);
break;
}
}
static void serial8250_release_port(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
serial8250_release_std_resource(up);
}
static int serial8250_request_port(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
return serial8250_request_std_resource(up);
}
static int fcr_get_rxtrig_bytes(struct uart_8250_port *up)
{
const struct serial8250_config *conf_type = &uart_config[up->port.type];
unsigned char bytes;
bytes = conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(up->fcr)];
return bytes ? bytes : -EOPNOTSUPP;
}
static int bytes_to_fcr_rxtrig(struct uart_8250_port *up, unsigned char bytes)
{
const struct serial8250_config *conf_type = &uart_config[up->port.type];
int i;
if (!conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(UART_FCR_R_TRIG_00)])
return -EOPNOTSUPP;
for (i = 1; i < UART_FCR_R_TRIG_MAX_STATE; i++) {
if (bytes < conf_type->rxtrig_bytes[i])
/* Use the nearest lower value */
return (--i) << UART_FCR_R_TRIG_SHIFT;
}
return UART_FCR_R_TRIG_11;
}
static int do_get_rxtrig(struct tty_port *port)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport = state->uart_port;
struct uart_8250_port *up = up_to_u8250p(uport);
if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1)
return -EINVAL;
return fcr_get_rxtrig_bytes(up);
}
static int do_serial8250_get_rxtrig(struct tty_port *port)
{
int rxtrig_bytes;
mutex_lock(&port->mutex);
rxtrig_bytes = do_get_rxtrig(port);
mutex_unlock(&port->mutex);
return rxtrig_bytes;
}
static ssize_t rx_trig_bytes_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct tty_port *port = dev_get_drvdata(dev);
int rxtrig_bytes;
rxtrig_bytes = do_serial8250_get_rxtrig(port);
if (rxtrig_bytes < 0)
return rxtrig_bytes;
return sysfs_emit(buf, "%d\n", rxtrig_bytes);
}
static int do_set_rxtrig(struct tty_port *port, unsigned char bytes)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport = state->uart_port;
struct uart_8250_port *up = up_to_u8250p(uport);
int rxtrig;
if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1 ||
up->fifo_bug)
return -EINVAL;
rxtrig = bytes_to_fcr_rxtrig(up, bytes);
if (rxtrig < 0)
return rxtrig;
serial8250_clear_fifos(up);
up->fcr &= ~UART_FCR_TRIGGER_MASK;
up->fcr |= (unsigned char)rxtrig;
serial_out(up, UART_FCR, up->fcr);
return 0;
}
static int do_serial8250_set_rxtrig(struct tty_port *port, unsigned char bytes)
{
int ret;
mutex_lock(&port->mutex);
ret = do_set_rxtrig(port, bytes);
mutex_unlock(&port->mutex);
return ret;
}
static ssize_t rx_trig_bytes_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct tty_port *port = dev_get_drvdata(dev);
unsigned char bytes;
int ret;
if (!count)
return -EINVAL;
ret = kstrtou8(buf, 10, &bytes);
if (ret < 0)
return ret;
ret = do_serial8250_set_rxtrig(port, bytes);
if (ret < 0)
return ret;
return count;
}
static DEVICE_ATTR_RW(rx_trig_bytes);
static struct attribute *serial8250_dev_attrs[] = {
&dev_attr_rx_trig_bytes.attr,
NULL
};
static struct attribute_group serial8250_dev_attr_group = {
.attrs = serial8250_dev_attrs,
};
static void register_dev_spec_attr_grp(struct uart_8250_port *up)
{
const struct serial8250_config *conf_type = &uart_config[up->port.type];
if (conf_type->rxtrig_bytes[0])
up->port.attr_group = &serial8250_dev_attr_group;
}
static void serial8250_config_port(struct uart_port *port, int flags)
{
struct uart_8250_port *up = up_to_u8250p(port);
int ret;
/*
* Find the region that we can probe for. This in turn
* tells us whether we can probe for the type of port.
*/
ret = serial8250_request_std_resource(up);
if (ret < 0)
return;
if (port->iotype != up->cur_iotype)
set_io_from_upio(port);
if (flags & UART_CONFIG_TYPE)
autoconfig(up);
/* if access method is AU, it is a 16550 with a quirk */
if (port->type == PORT_16550A && port->iotype == UPIO_AU)
up->bugs |= UART_BUG_NOMSR;
/* HW bugs may trigger IRQ while IIR == NO_INT */
if (port->type == PORT_TEGRA)
up->bugs |= UART_BUG_NOMSR;
if (port->type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ)
autoconfig_irq(up);
if (port->type == PORT_UNKNOWN)
serial8250_release_std_resource(up);
register_dev_spec_attr_grp(up);
up->fcr = uart_config[up->port.type].fcr;
}
static int
serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
{
if (ser->irq >= nr_irqs || ser->irq < 0 ||
ser->baud_base < 9600 || ser->type < PORT_UNKNOWN ||
ser->type >= ARRAY_SIZE(uart_config) || ser->type == PORT_CIRRUS ||
ser->type == PORT_STARTECH)
return -EINVAL;
return 0;
}
static const char *serial8250_type(struct uart_port *port)
{
int type = port->type;
if (type >= ARRAY_SIZE(uart_config))
type = 0;
return uart_config[type].name;
}
static const struct uart_ops serial8250_pops = {
.tx_empty = serial8250_tx_empty,
.set_mctrl = serial8250_set_mctrl,
.get_mctrl = serial8250_get_mctrl,
.stop_tx = serial8250_stop_tx,
.start_tx = serial8250_start_tx,
.throttle = serial8250_throttle,
.unthrottle = serial8250_unthrottle,
.stop_rx = serial8250_stop_rx,
.enable_ms = serial8250_enable_ms,
.break_ctl = serial8250_break_ctl,
.startup = serial8250_startup,
.shutdown = serial8250_shutdown,
.set_termios = serial8250_set_termios,
.set_ldisc = serial8250_set_ldisc,
.pm = serial8250_pm,
.type = serial8250_type,
.release_port = serial8250_release_port,
.request_port = serial8250_request_port,
.config_port = serial8250_config_port,
.verify_port = serial8250_verify_port,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = serial8250_get_poll_char,
.poll_put_char = serial8250_put_poll_char,
#endif
};
void serial8250_init_port(struct uart_8250_port *up)
{
struct uart_port *port = &up->port;
spin_lock_init(&port->lock);
port->ops = &serial8250_pops;
port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
up->cur_iotype = 0xFF;
}
EXPORT_SYMBOL_GPL(serial8250_init_port);
void serial8250_set_defaults(struct uart_8250_port *up)
{
struct uart_port *port = &up->port;
if (up->port.flags & UPF_FIXED_TYPE) {
unsigned int type = up->port.type;
if (!up->port.fifosize)
up->port.fifosize = uart_config[type].fifo_size;
if (!up->tx_loadsz)
up->tx_loadsz = uart_config[type].tx_loadsz;
if (!up->capabilities)
up->capabilities = uart_config[type].flags;
}
set_io_from_upio(port);
/* default dma handlers */
if (up->dma) {
if (!up->dma->tx_dma)
up->dma->tx_dma = serial8250_tx_dma;
if (!up->dma->rx_dma)
up->dma->rx_dma = serial8250_rx_dma;
}
}
EXPORT_SYMBOL_GPL(serial8250_set_defaults);
#ifdef CONFIG_SERIAL_8250_CONSOLE
static void serial8250_console_putchar(struct uart_port *port, unsigned char ch)
{
struct uart_8250_port *up = up_to_u8250p(port);
wait_for_xmitr(up, UART_LSR_THRE);
serial_port_out(port, UART_TX, ch);
}
/*
* Restore serial console when h/w power-off detected
*/
static void serial8250_console_restore(struct uart_8250_port *up)
{
struct uart_port *port = &up->port;
struct ktermios termios;
unsigned int baud, quot, frac = 0;
termios.c_cflag = port->cons->cflag;
termios.c_ispeed = port->cons->ispeed;
termios.c_ospeed = port->cons->ospeed;
if (port->state->port.tty && termios.c_cflag == 0) {
termios.c_cflag = port->state->port.tty->termios.c_cflag;
termios.c_ispeed = port->state->port.tty->termios.c_ispeed;
termios.c_ospeed = port->state->port.tty->termios.c_ospeed;
}
baud = serial8250_get_baud_rate(port, &termios, NULL);
quot = serial8250_get_divisor(port, baud, &frac);
serial8250_set_divisor(port, baud, quot, frac);
serial_port_out(port, UART_LCR, up->lcr);
serial8250_out_MCR(up, up->mcr | UART_MCR_DTR | UART_MCR_RTS);
}
/*
* Print a string to the serial port using the device FIFO
*
* It sends fifosize bytes and then waits for the fifo
* to get empty.
*/
static void serial8250_console_fifo_write(struct uart_8250_port *up,
const char *s, unsigned int count)
{
int i;
const char *end = s + count;
unsigned int fifosize = up->tx_loadsz;
bool cr_sent = false;
while (s != end) {
wait_for_lsr(up, UART_LSR_THRE);
for (i = 0; i < fifosize && s != end; ++i) {
if (*s == '\n' && !cr_sent) {
serial_out(up, UART_TX, '\r');
cr_sent = true;
} else {
serial_out(up, UART_TX, *s++);
cr_sent = false;
}
}
}
}
/*
* Print a string to the serial port trying not to disturb
* any possible real use of the port...
*
* The console_lock must be held when we get here.
*
* Doing runtime PM is really a bad idea for the kernel console.
* Thus, we assume the function is called when device is powered up.
*/
void serial8250_console_write(struct uart_8250_port *up, const char *s,
unsigned int count)
{
struct uart_8250_em485 *em485 = up->em485;
struct uart_port *port = &up->port;
unsigned long flags;
unsigned int ier, use_fifo;
int locked = 1;
touch_nmi_watchdog();
if (oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
else
spin_lock_irqsave(&port->lock, flags);
/*
* First save the IER then disable the interrupts
*/
ier = serial_port_in(port, UART_IER);
serial8250_clear_IER(up);
/* check scratch reg to see if port powered off during system sleep */
if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) {
serial8250_console_restore(up);
up->canary = 0;
}
if (em485) {
if (em485->tx_stopped)
up->rs485_start_tx(up);
mdelay(port->rs485.delay_rts_before_send);
}
use_fifo = (up->capabilities & UART_CAP_FIFO) &&
/*
* BCM283x requires to check the fifo
* after each byte.
*/
!(up->capabilities & UART_CAP_MINI) &&
/*
* tx_loadsz contains the transmit fifo size
*/
up->tx_loadsz > 1 &&
(up->fcr & UART_FCR_ENABLE_FIFO) &&
port->state &&
test_bit(TTY_PORT_INITIALIZED, &port->state->port.iflags) &&
/*
* After we put a data in the fifo, the controller will send
* it regardless of the CTS state. Therefore, only use fifo
* if we don't use control flow.
*/
!(up->port.flags & UPF_CONS_FLOW);
if (likely(use_fifo))
serial8250_console_fifo_write(up, s, count);
else
uart_console_write(port, s, count, serial8250_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the IER
*/
wait_for_xmitr(up, UART_LSR_BOTH_EMPTY);
if (em485) {
mdelay(port->rs485.delay_rts_after_send);
if (em485->tx_stopped)
up->rs485_stop_tx(up);
}
serial_port_out(port, UART_IER, ier);
/*
* The receive handling will happen properly because the
* receive ready bit will still be set; it is not cleared
* on read. However, modem control will not, we must
* call it if we have saved something in the saved flags
* while processing with interrupts off.
*/
if (up->msr_saved_flags)
serial8250_modem_status(up);
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
}
static unsigned int probe_baud(struct uart_port *port)
{
unsigned char lcr, dll, dlm;
unsigned int quot;
lcr = serial_port_in(port, UART_LCR);
serial_port_out(port, UART_LCR, lcr | UART_LCR_DLAB);
dll = serial_port_in(port, UART_DLL);
dlm = serial_port_in(port, UART_DLM);
serial_port_out(port, UART_LCR, lcr);
quot = (dlm << 8) | dll;
return (port->uartclk / 16) / quot;
}
int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
{
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
int ret;
if (!port->iobase && !port->membase)
return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else if (probe)
baud = probe_baud(port);
ret = uart_set_options(port, port->cons, baud, parity, bits, flow);
if (ret)
return ret;
if (port->dev)
pm_runtime_get_sync(port->dev);
return 0;
}
int serial8250_console_exit(struct uart_port *port)
{
if (port->dev)
pm_runtime_put_sync(port->dev);
return 0;
}
#endif /* CONFIG_SERIAL_8250_CONSOLE */
MODULE_LICENSE("GPL");