linux/drivers/tty/serial/ar933x_uart.c
Johan Hovold 80d43febac serial: ar933x: drop low-latency workaround
Commit b16c8e3eed ("tty: serial: ar933x: drop uart_port->lock before
calling tty_flip_buffer_push()") claimed to address a locking
issue but only provided a dubious lockdep splat from an unrelated
driver, which in the end turned out to be due a broken local change
carried by the author.

Unfortunately these patches were merged before the issue had been
analysed properly so the commit messages makes no sense whatsoever.

The real issue was first seen on RT which at the time effectively always
set the low_latency flag for all serial drivers by patching
tty_flip_buffer_push(). This in turn revealed that many drivers did not
handle the infamous low_latency behaviour which meant that data was
pushed immediately to the line discipline instead of being deferred to a
work queue.

Since commit a9c3f68f3c ("tty: Fix low_latency BUG"),
tty_flip_buffer_push() always schedules a work item to push data to the
line discipline and there's no need to keep any low_latency hacks
around.

Link: https://lore.kernel.org/linux-serial/cover.1376923198.git.viresh.kumar@linaro.org/
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210421095509.3024-8-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-22 12:09:25 +02:00

887 lines
21 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Atheros AR933X SoC built-in UART driver
*
* Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
*
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*/
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/clk.h>
#include <asm/div64.h>
#include <asm/mach-ath79/ar933x_uart.h>
#include "serial_mctrl_gpio.h"
#define DRIVER_NAME "ar933x-uart"
#define AR933X_UART_MAX_SCALE 0xff
#define AR933X_UART_MAX_STEP 0xffff
#define AR933X_UART_MIN_BAUD 300
#define AR933X_UART_MAX_BAUD 3000000
#define AR933X_DUMMY_STATUS_RD 0x01
static struct uart_driver ar933x_uart_driver;
struct ar933x_uart_port {
struct uart_port port;
unsigned int ier; /* shadow Interrupt Enable Register */
unsigned int min_baud;
unsigned int max_baud;
struct clk *clk;
struct mctrl_gpios *gpios;
struct gpio_desc *rts_gpiod;
};
static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
int offset)
{
return readl(up->port.membase + offset);
}
static inline void ar933x_uart_write(struct ar933x_uart_port *up,
int offset, unsigned int value)
{
writel(value, up->port.membase + offset);
}
static inline void ar933x_uart_rmw(struct ar933x_uart_port *up,
unsigned int offset,
unsigned int mask,
unsigned int val)
{
unsigned int t;
t = ar933x_uart_read(up, offset);
t &= ~mask;
t |= val;
ar933x_uart_write(up, offset, t);
}
static inline void ar933x_uart_rmw_set(struct ar933x_uart_port *up,
unsigned int offset,
unsigned int val)
{
ar933x_uart_rmw(up, offset, 0, val);
}
static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up,
unsigned int offset,
unsigned int val)
{
ar933x_uart_rmw(up, offset, val, 0);
}
static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up)
{
up->ier |= AR933X_UART_INT_TX_EMPTY;
ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
}
static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up)
{
up->ier &= ~AR933X_UART_INT_TX_EMPTY;
ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
}
static inline void ar933x_uart_start_rx_interrupt(struct ar933x_uart_port *up)
{
up->ier |= AR933X_UART_INT_RX_VALID;
ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
}
static inline void ar933x_uart_stop_rx_interrupt(struct ar933x_uart_port *up)
{
up->ier &= ~AR933X_UART_INT_RX_VALID;
ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
}
static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
{
unsigned int rdata;
rdata = ch & AR933X_UART_DATA_TX_RX_MASK;
rdata |= AR933X_UART_DATA_TX_CSR;
ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
}
static unsigned int ar933x_uart_tx_empty(struct uart_port *port)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
unsigned long flags;
unsigned int rdata;
spin_lock_irqsave(&up->port.lock, flags);
rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
spin_unlock_irqrestore(&up->port.lock, flags);
return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
}
static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
int ret = TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
mctrl_gpio_get(up->gpios, &ret);
return ret;
}
static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
mctrl_gpio_set(up->gpios, mctrl);
}
static void ar933x_uart_start_tx(struct uart_port *port)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
ar933x_uart_start_tx_interrupt(up);
}
static void ar933x_uart_wait_tx_complete(struct ar933x_uart_port *up)
{
unsigned int status;
unsigned int timeout = 60000;
/* Wait up to 60ms for the character(s) to be sent. */
do {
status = ar933x_uart_read(up, AR933X_UART_CS_REG);
if (--timeout == 0)
break;
udelay(1);
} while (status & AR933X_UART_CS_TX_BUSY);
if (timeout == 0)
dev_err(up->port.dev, "waiting for TX timed out\n");
}
static void ar933x_uart_rx_flush(struct ar933x_uart_port *up)
{
unsigned int status;
/* clear RX_VALID interrupt */
ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_RX_VALID);
/* remove characters from the RX FIFO */
do {
ar933x_uart_write(up, AR933X_UART_DATA_REG, AR933X_UART_DATA_RX_CSR);
status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
} while (status & AR933X_UART_DATA_RX_CSR);
}
static void ar933x_uart_stop_tx(struct uart_port *port)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
ar933x_uart_stop_tx_interrupt(up);
}
static void ar933x_uart_stop_rx(struct uart_port *port)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
ar933x_uart_stop_rx_interrupt(up);
}
static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
unsigned long flags;
spin_lock_irqsave(&up->port.lock, flags);
if (break_state == -1)
ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
AR933X_UART_CS_TX_BREAK);
else
ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
AR933X_UART_CS_TX_BREAK);
spin_unlock_irqrestore(&up->port.lock, flags);
}
/*
* baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
*/
static unsigned long ar933x_uart_get_baud(unsigned int clk,
unsigned int scale,
unsigned int step)
{
u64 t;
u32 div;
div = (2 << 16) * (scale + 1);
t = clk;
t *= step;
t += (div / 2);
do_div(t, div);
return t;
}
static void ar933x_uart_get_scale_step(unsigned int clk,
unsigned int baud,
unsigned int *scale,
unsigned int *step)
{
unsigned int tscale;
long min_diff;
*scale = 0;
*step = 0;
min_diff = baud;
for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
u64 tstep;
int diff;
tstep = baud * (tscale + 1);
tstep *= (2 << 16);
do_div(tstep, clk);
if (tstep > AR933X_UART_MAX_STEP)
break;
diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
if (diff < min_diff) {
min_diff = diff;
*scale = tscale;
*step = tstep;
}
}
}
static void ar933x_uart_set_termios(struct uart_port *port,
struct ktermios *new,
struct ktermios *old)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
unsigned int cs;
unsigned long flags;
unsigned int baud, scale, step;
/* Only CS8 is supported */
new->c_cflag &= ~CSIZE;
new->c_cflag |= CS8;
/* Only one stop bit is supported */
new->c_cflag &= ~CSTOPB;
cs = 0;
if (new->c_cflag & PARENB) {
if (!(new->c_cflag & PARODD))
cs |= AR933X_UART_CS_PARITY_EVEN;
else
cs |= AR933X_UART_CS_PARITY_ODD;
} else {
cs |= AR933X_UART_CS_PARITY_NONE;
}
/* Mark/space parity is not supported */
new->c_cflag &= ~CMSPAR;
baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud);
ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step);
/*
* Ok, we're now changing the port state. Do it with
* interrupts disabled.
*/
spin_lock_irqsave(&up->port.lock, flags);
/* disable the UART */
ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S);
/* Update the per-port timeout. */
uart_update_timeout(port, new->c_cflag, baud);
up->port.ignore_status_mask = 0;
/* ignore all characters if CREAD is not set */
if ((new->c_cflag & CREAD) == 0)
up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
scale << AR933X_UART_CLOCK_SCALE_S | step);
/* setup configuration register */
ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
/* enable host interrupt */
ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
AR933X_UART_CS_HOST_INT_EN);
/* enable RX and TX ready overide */
ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE);
/* reenable the UART */
ar933x_uart_rmw(up, AR933X_UART_CS_REG,
AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
spin_unlock_irqrestore(&up->port.lock, flags);
if (tty_termios_baud_rate(new))
tty_termios_encode_baud_rate(new, baud, baud);
}
static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
{
struct tty_port *port = &up->port.state->port;
int max_count = 256;
do {
unsigned int rdata;
unsigned char ch;
rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
break;
/* remove the character from the FIFO */
ar933x_uart_write(up, AR933X_UART_DATA_REG,
AR933X_UART_DATA_RX_CSR);
up->port.icount.rx++;
ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
if (uart_handle_sysrq_char(&up->port, ch))
continue;
if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
tty_insert_flip_char(port, ch, TTY_NORMAL);
} while (max_count-- > 0);
tty_flip_buffer_push(port);
}
static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
{
struct circ_buf *xmit = &up->port.state->xmit;
struct serial_rs485 *rs485conf = &up->port.rs485;
int count;
bool half_duplex_send = false;
if (uart_tx_stopped(&up->port))
return;
if ((rs485conf->flags & SER_RS485_ENABLED) &&
(up->port.x_char || !uart_circ_empty(xmit))) {
ar933x_uart_stop_rx_interrupt(up);
gpiod_set_value(up->rts_gpiod, !!(rs485conf->flags & SER_RS485_RTS_ON_SEND));
half_duplex_send = true;
}
count = up->port.fifosize;
do {
unsigned int rdata;
rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
break;
if (up->port.x_char) {
ar933x_uart_putc(up, up->port.x_char);
up->port.icount.tx++;
up->port.x_char = 0;
continue;
}
if (uart_circ_empty(xmit))
break;
ar933x_uart_putc(up, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
up->port.icount.tx++;
} while (--count > 0);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&up->port);
if (!uart_circ_empty(xmit)) {
ar933x_uart_start_tx_interrupt(up);
} else if (half_duplex_send) {
ar933x_uart_wait_tx_complete(up);
ar933x_uart_rx_flush(up);
ar933x_uart_start_rx_interrupt(up);
gpiod_set_value(up->rts_gpiod, !!(rs485conf->flags & SER_RS485_RTS_AFTER_SEND));
}
}
static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
{
struct ar933x_uart_port *up = dev_id;
unsigned int status;
status = ar933x_uart_read(up, AR933X_UART_CS_REG);
if ((status & AR933X_UART_CS_HOST_INT) == 0)
return IRQ_NONE;
spin_lock(&up->port.lock);
status = ar933x_uart_read(up, AR933X_UART_INT_REG);
status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
if (status & AR933X_UART_INT_RX_VALID) {
ar933x_uart_write(up, AR933X_UART_INT_REG,
AR933X_UART_INT_RX_VALID);
ar933x_uart_rx_chars(up);
}
if (status & AR933X_UART_INT_TX_EMPTY) {
ar933x_uart_write(up, AR933X_UART_INT_REG,
AR933X_UART_INT_TX_EMPTY);
ar933x_uart_stop_tx_interrupt(up);
ar933x_uart_tx_chars(up);
}
spin_unlock(&up->port.lock);
return IRQ_HANDLED;
}
static int ar933x_uart_startup(struct uart_port *port)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
unsigned long flags;
int ret;
ret = request_irq(up->port.irq, ar933x_uart_interrupt,
up->port.irqflags, dev_name(up->port.dev), up);
if (ret)
return ret;
spin_lock_irqsave(&up->port.lock, flags);
/* Enable HOST interrupts */
ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
AR933X_UART_CS_HOST_INT_EN);
/* enable RX and TX ready overide */
ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE);
/* Enable RX interrupts */
ar933x_uart_start_rx_interrupt(up);
spin_unlock_irqrestore(&up->port.lock, flags);
return 0;
}
static void ar933x_uart_shutdown(struct uart_port *port)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
/* Disable all interrupts */
up->ier = 0;
ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
/* Disable break condition */
ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
AR933X_UART_CS_TX_BREAK);
free_irq(up->port.irq, up);
}
static const char *ar933x_uart_type(struct uart_port *port)
{
return (port->type == PORT_AR933X) ? "AR933X UART" : NULL;
}
static void ar933x_uart_release_port(struct uart_port *port)
{
/* Nothing to release ... */
}
static int ar933x_uart_request_port(struct uart_port *port)
{
/* UARTs always present */
return 0;
}
static void ar933x_uart_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_AR933X;
}
static int ar933x_uart_verify_port(struct uart_port *port,
struct serial_struct *ser)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
if (ser->type != PORT_UNKNOWN &&
ser->type != PORT_AR933X)
return -EINVAL;
if (ser->irq < 0 || ser->irq >= NR_IRQS)
return -EINVAL;
if (ser->baud_base < up->min_baud ||
ser->baud_base > up->max_baud)
return -EINVAL;
return 0;
}
static const struct uart_ops ar933x_uart_ops = {
.tx_empty = ar933x_uart_tx_empty,
.set_mctrl = ar933x_uart_set_mctrl,
.get_mctrl = ar933x_uart_get_mctrl,
.stop_tx = ar933x_uart_stop_tx,
.start_tx = ar933x_uart_start_tx,
.stop_rx = ar933x_uart_stop_rx,
.break_ctl = ar933x_uart_break_ctl,
.startup = ar933x_uart_startup,
.shutdown = ar933x_uart_shutdown,
.set_termios = ar933x_uart_set_termios,
.type = ar933x_uart_type,
.release_port = ar933x_uart_release_port,
.request_port = ar933x_uart_request_port,
.config_port = ar933x_uart_config_port,
.verify_port = ar933x_uart_verify_port,
};
static int ar933x_config_rs485(struct uart_port *port,
struct serial_rs485 *rs485conf)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
if ((rs485conf->flags & SER_RS485_ENABLED) &&
!up->rts_gpiod) {
dev_err(port->dev, "RS485 needs rts-gpio\n");
return 1;
}
port->rs485 = *rs485conf;
return 0;
}
#ifdef CONFIG_SERIAL_AR933X_CONSOLE
static struct ar933x_uart_port *
ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
{
unsigned int status;
unsigned int timeout = 60000;
/* Wait up to 60ms for the character(s) to be sent. */
do {
status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
if (--timeout == 0)
break;
udelay(1);
} while ((status & AR933X_UART_DATA_TX_CSR) == 0);
}
static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
{
struct ar933x_uart_port *up =
container_of(port, struct ar933x_uart_port, port);
ar933x_uart_wait_xmitr(up);
ar933x_uart_putc(up, ch);
}
static void ar933x_uart_console_write(struct console *co, const char *s,
unsigned int count)
{
struct ar933x_uart_port *up = ar933x_console_ports[co->index];
unsigned long flags;
unsigned int int_en;
int locked = 1;
local_irq_save(flags);
if (up->port.sysrq)
locked = 0;
else if (oops_in_progress)
locked = spin_trylock(&up->port.lock);
else
spin_lock(&up->port.lock);
/*
* First save the IER then disable the interrupts
*/
int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the IER
*/
ar933x_uart_wait_xmitr(up);
ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
if (locked)
spin_unlock(&up->port.lock);
local_irq_restore(flags);
}
static int ar933x_uart_console_setup(struct console *co, char *options)
{
struct ar933x_uart_port *up;
int baud = 115200;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS)
return -EINVAL;
up = ar933x_console_ports[co->index];
if (!up)
return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(&up->port, co, baud, parity, bits, flow);
}
static struct console ar933x_uart_console = {
.name = "ttyATH",
.write = ar933x_uart_console_write,
.device = uart_console_device,
.setup = ar933x_uart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &ar933x_uart_driver,
};
#endif /* CONFIG_SERIAL_AR933X_CONSOLE */
static struct uart_driver ar933x_uart_driver = {
.owner = THIS_MODULE,
.driver_name = DRIVER_NAME,
.dev_name = "ttyATH",
.nr = CONFIG_SERIAL_AR933X_NR_UARTS,
.cons = NULL, /* filled in runtime */
};
static int ar933x_uart_probe(struct platform_device *pdev)
{
struct ar933x_uart_port *up;
struct uart_port *port;
struct resource *mem_res;
struct resource *irq_res;
struct device_node *np;
unsigned int baud;
int id;
int ret;
np = pdev->dev.of_node;
if (IS_ENABLED(CONFIG_OF) && np) {
id = of_alias_get_id(np, "serial");
if (id < 0) {
dev_err(&pdev->dev, "unable to get alias id, err=%d\n",
id);
return id;
}
} else {
id = pdev->id;
if (id == -1)
id = 0;
}
if (id >= CONFIG_SERIAL_AR933X_NR_UARTS)
return -EINVAL;
irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!irq_res) {
dev_err(&pdev->dev, "no IRQ resource\n");
return -EINVAL;
}
up = devm_kzalloc(&pdev->dev, sizeof(struct ar933x_uart_port),
GFP_KERNEL);
if (!up)
return -ENOMEM;
up->clk = devm_clk_get(&pdev->dev, "uart");
if (IS_ERR(up->clk)) {
dev_err(&pdev->dev, "unable to get UART clock\n");
return PTR_ERR(up->clk);
}
port = &up->port;
mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
port->membase = devm_ioremap_resource(&pdev->dev, mem_res);
if (IS_ERR(port->membase))
return PTR_ERR(port->membase);
ret = clk_prepare_enable(up->clk);
if (ret)
return ret;
port->uartclk = clk_get_rate(up->clk);
if (!port->uartclk) {
ret = -EINVAL;
goto err_disable_clk;
}
port->mapbase = mem_res->start;
port->line = id;
port->irq = irq_res->start;
port->dev = &pdev->dev;
port->type = PORT_AR933X;
port->iotype = UPIO_MEM32;
port->regshift = 2;
port->fifosize = AR933X_UART_FIFO_SIZE;
port->ops = &ar933x_uart_ops;
port->rs485_config = ar933x_config_rs485;
baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
ret = uart_get_rs485_mode(port);
if (ret)
goto err_disable_clk;
up->gpios = mctrl_gpio_init(port, 0);
if (IS_ERR(up->gpios) && PTR_ERR(up->gpios) != -ENOSYS) {
ret = PTR_ERR(up->gpios);
goto err_disable_clk;
}
up->rts_gpiod = mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS);
if ((port->rs485.flags & SER_RS485_ENABLED) &&
!up->rts_gpiod) {
dev_err(&pdev->dev, "lacking rts-gpio, disabling RS485\n");
port->rs485.flags &= ~SER_RS485_ENABLED;
}
#ifdef CONFIG_SERIAL_AR933X_CONSOLE
ar933x_console_ports[up->port.line] = up;
#endif
ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
if (ret)
goto err_disable_clk;
platform_set_drvdata(pdev, up);
return 0;
err_disable_clk:
clk_disable_unprepare(up->clk);
return ret;
}
static int ar933x_uart_remove(struct platform_device *pdev)
{
struct ar933x_uart_port *up;
up = platform_get_drvdata(pdev);
if (up) {
uart_remove_one_port(&ar933x_uart_driver, &up->port);
clk_disable_unprepare(up->clk);
}
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id ar933x_uart_of_ids[] = {
{ .compatible = "qca,ar9330-uart" },
{},
};
MODULE_DEVICE_TABLE(of, ar933x_uart_of_ids);
#endif
static struct platform_driver ar933x_uart_platform_driver = {
.probe = ar933x_uart_probe,
.remove = ar933x_uart_remove,
.driver = {
.name = DRIVER_NAME,
.of_match_table = of_match_ptr(ar933x_uart_of_ids),
},
};
static int __init ar933x_uart_init(void)
{
int ret;
#ifdef CONFIG_SERIAL_AR933X_CONSOLE
ar933x_uart_driver.cons = &ar933x_uart_console;
#endif
ret = uart_register_driver(&ar933x_uart_driver);
if (ret)
goto err_out;
ret = platform_driver_register(&ar933x_uart_platform_driver);
if (ret)
goto err_unregister_uart_driver;
return 0;
err_unregister_uart_driver:
uart_unregister_driver(&ar933x_uart_driver);
err_out:
return ret;
}
static void __exit ar933x_uart_exit(void)
{
platform_driver_unregister(&ar933x_uart_platform_driver);
uart_unregister_driver(&ar933x_uart_driver);
}
module_init(ar933x_uart_init);
module_exit(ar933x_uart_exit);
MODULE_DESCRIPTION("Atheros AR933X UART driver");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);