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linux-next/drivers/tty/serial/mvebu-uart.c
Thomas Petazzoni c2c1659b4f serial: mvebu-uart: free the IRQ in ->shutdown() 
As suggested by the serial port infrastructure documentation, the IRQ is
requested in ->startup(). However, it is never freed in the ->shutdown()
hook.

With simple systems that open the serial port once for all and always
have at least one process that keep the serial port opened, there was no
problem. But with a more complicated system (*cough* systemd *cough*),
the serial port is opened/closed many times, which at some point no
processes having the serial port open at all. Due to this ->startup()
gets called again, tries to request_irq() again, which fails.

Fixes: 30530791a7 ("serial: mvebu-uart: initial support for Armada-3700 serial port")
Cc: <stable@vger.kernel.org>
Cc: Ofer Heifetz <oferh@marvell.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25 14:00:06 -07:00

630 lines
15 KiB
C
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/*
* ***************************************************************************
* Marvell Armada-3700 Serial Driver
* Author: Wilson Ding <dingwei@marvell.com>
* Copyright (C) 2015 Marvell International Ltd.
* ***************************************************************************
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation, either version 2 of the License, or any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
* ***************************************************************************
*/
#include <linux/clk.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
/* Register Map */
#define UART_RBR 0x00
#define RBR_BRK_DET BIT(15)
#define RBR_FRM_ERR_DET BIT(14)
#define RBR_PAR_ERR_DET BIT(13)
#define RBR_OVR_ERR_DET BIT(12)
#define UART_TSH 0x04
#define UART_CTRL 0x08
#define CTRL_SOFT_RST BIT(31)
#define CTRL_TXFIFO_RST BIT(15)
#define CTRL_RXFIFO_RST BIT(14)
#define CTRL_ST_MIRR_EN BIT(13)
#define CTRL_LPBK_EN BIT(12)
#define CTRL_SND_BRK_SEQ BIT(11)
#define CTRL_PAR_EN BIT(10)
#define CTRL_TWO_STOP BIT(9)
#define CTRL_TX_HFL_INT BIT(8)
#define CTRL_RX_HFL_INT BIT(7)
#define CTRL_TX_EMP_INT BIT(6)
#define CTRL_TX_RDY_INT BIT(5)
#define CTRL_RX_RDY_INT BIT(4)
#define CTRL_BRK_DET_INT BIT(3)
#define CTRL_FRM_ERR_INT BIT(2)
#define CTRL_PAR_ERR_INT BIT(1)
#define CTRL_OVR_ERR_INT BIT(0)
#define CTRL_RX_INT (CTRL_RX_RDY_INT | CTRL_BRK_DET_INT |\
CTRL_FRM_ERR_INT | CTRL_PAR_ERR_INT | CTRL_OVR_ERR_INT)
#define UART_STAT 0x0c
#define STAT_TX_FIFO_EMP BIT(13)
#define STAT_RX_FIFO_EMP BIT(12)
#define STAT_TX_FIFO_FUL BIT(11)
#define STAT_TX_FIFO_HFL BIT(10)
#define STAT_RX_TOGL BIT(9)
#define STAT_RX_FIFO_FUL BIT(8)
#define STAT_RX_FIFO_HFL BIT(7)
#define STAT_TX_EMP BIT(6)
#define STAT_TX_RDY BIT(5)
#define STAT_RX_RDY BIT(4)
#define STAT_BRK_DET BIT(3)
#define STAT_FRM_ERR BIT(2)
#define STAT_PAR_ERR BIT(1)
#define STAT_OVR_ERR BIT(0)
#define STAT_BRK_ERR (STAT_BRK_DET | STAT_FRM_ERR | STAT_FRM_ERR\
| STAT_PAR_ERR | STAT_OVR_ERR)
#define UART_BRDV 0x10
#define MVEBU_NR_UARTS 1
#define MVEBU_UART_TYPE "mvebu-uart"
static struct uart_port mvebu_uart_ports[MVEBU_NR_UARTS];
struct mvebu_uart_data {
struct uart_port *port;
struct clk *clk;
};
/* Core UART Driver Operations */
static unsigned int mvebu_uart_tx_empty(struct uart_port *port)
{
unsigned long flags;
unsigned int st;
spin_lock_irqsave(&port->lock, flags);
st = readl(port->membase + UART_STAT);
spin_unlock_irqrestore(&port->lock, flags);
return (st & STAT_TX_FIFO_EMP) ? TIOCSER_TEMT : 0;
}
static unsigned int mvebu_uart_get_mctrl(struct uart_port *port)
{
return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}
static void mvebu_uart_set_mctrl(struct uart_port *port,
unsigned int mctrl)
{
/*
* Even if we do not support configuring the modem control lines, this
* function must be proided to the serial core
*/
}
static void mvebu_uart_stop_tx(struct uart_port *port)
{
unsigned int ctl = readl(port->membase + UART_CTRL);
ctl &= ~CTRL_TX_RDY_INT;
writel(ctl, port->membase + UART_CTRL);
}
static void mvebu_uart_start_tx(struct uart_port *port)
{
unsigned int ctl = readl(port->membase + UART_CTRL);
ctl |= CTRL_TX_RDY_INT;
writel(ctl, port->membase + UART_CTRL);
}
static void mvebu_uart_stop_rx(struct uart_port *port)
{
unsigned int ctl = readl(port->membase + UART_CTRL);
ctl &= ~CTRL_RX_INT;
writel(ctl, port->membase + UART_CTRL);
}
static void mvebu_uart_break_ctl(struct uart_port *port, int brk)
{
unsigned int ctl;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
ctl = readl(port->membase + UART_CTRL);
if (brk == -1)
ctl |= CTRL_SND_BRK_SEQ;
else
ctl &= ~CTRL_SND_BRK_SEQ;
writel(ctl, port->membase + UART_CTRL);
spin_unlock_irqrestore(&port->lock, flags);
}
static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status)
{
struct tty_port *tport = &port->state->port;
unsigned char ch = 0;
char flag = 0;
do {
if (status & STAT_RX_RDY) {
ch = readl(port->membase + UART_RBR);
ch &= 0xff;
flag = TTY_NORMAL;
port->icount.rx++;
if (status & STAT_PAR_ERR)
port->icount.parity++;
}
if (status & STAT_BRK_DET) {
port->icount.brk++;
status &= ~(STAT_FRM_ERR | STAT_PAR_ERR);
if (uart_handle_break(port))
goto ignore_char;
}
if (status & STAT_OVR_ERR)
port->icount.overrun++;
if (status & STAT_FRM_ERR)
port->icount.frame++;
if (uart_handle_sysrq_char(port, ch))
goto ignore_char;
if (status & port->ignore_status_mask & STAT_PAR_ERR)
status &= ~STAT_RX_RDY;
status &= port->read_status_mask;
if (status & STAT_PAR_ERR)
flag = TTY_PARITY;
status &= ~port->ignore_status_mask;
if (status & STAT_RX_RDY)
tty_insert_flip_char(tport, ch, flag);
if (status & STAT_BRK_DET)
tty_insert_flip_char(tport, 0, TTY_BREAK);
if (status & STAT_FRM_ERR)
tty_insert_flip_char(tport, 0, TTY_FRAME);
if (status & STAT_OVR_ERR)
tty_insert_flip_char(tport, 0, TTY_OVERRUN);
ignore_char:
status = readl(port->membase + UART_STAT);
} while (status & (STAT_RX_RDY | STAT_BRK_DET));
tty_flip_buffer_push(tport);
}
static void mvebu_uart_tx_chars(struct uart_port *port, unsigned int status)
{
struct circ_buf *xmit = &port->state->xmit;
unsigned int count;
unsigned int st;
if (port->x_char) {
writel(port->x_char, port->membase + UART_TSH);
port->icount.tx++;
port->x_char = 0;
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
mvebu_uart_stop_tx(port);
return;
}
for (count = 0; count < port->fifosize; count++) {
writel(xmit->buf[xmit->tail], port->membase + UART_TSH);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (uart_circ_empty(xmit))
break;
st = readl(port->membase + UART_STAT);
if (st & STAT_TX_FIFO_FUL)
break;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (uart_circ_empty(xmit))
mvebu_uart_stop_tx(port);
}
static irqreturn_t mvebu_uart_isr(int irq, void *dev_id)
{
struct uart_port *port = (struct uart_port *)dev_id;
unsigned int st = readl(port->membase + UART_STAT);
if (st & (STAT_RX_RDY | STAT_OVR_ERR | STAT_FRM_ERR | STAT_BRK_DET))
mvebu_uart_rx_chars(port, st);
if (st & STAT_TX_RDY)
mvebu_uart_tx_chars(port, st);
return IRQ_HANDLED;
}
static int mvebu_uart_startup(struct uart_port *port)
{
int ret;
writel(CTRL_TXFIFO_RST | CTRL_RXFIFO_RST,
port->membase + UART_CTRL);
udelay(1);
writel(CTRL_RX_INT, port->membase + UART_CTRL);
ret = request_irq(port->irq, mvebu_uart_isr, port->irqflags, "serial",
port);
if (ret) {
dev_err(port->dev, "failed to request irq\n");
return ret;
}
return 0;
}
static void mvebu_uart_shutdown(struct uart_port *port)
{
writel(0, port->membase + UART_CTRL);
free_irq(port->irq, port);
}
static void mvebu_uart_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old)
{
unsigned long flags;
unsigned int baud;
spin_lock_irqsave(&port->lock, flags);
port->read_status_mask = STAT_RX_RDY | STAT_OVR_ERR |
STAT_TX_RDY | STAT_TX_FIFO_FUL;
if (termios->c_iflag & INPCK)
port->read_status_mask |= STAT_FRM_ERR | STAT_PAR_ERR;
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |=
STAT_FRM_ERR | STAT_PAR_ERR | STAT_OVR_ERR;
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= STAT_RX_RDY | STAT_BRK_ERR;
if (old)
tty_termios_copy_hw(termios, old);
baud = uart_get_baud_rate(port, termios, old, 0, 460800);
uart_update_timeout(port, termios->c_cflag, baud);
spin_unlock_irqrestore(&port->lock, flags);
}
static const char *mvebu_uart_type(struct uart_port *port)
{
return MVEBU_UART_TYPE;
}
static void mvebu_uart_release_port(struct uart_port *port)
{
/* Nothing to do here */
}
static int mvebu_uart_request_port(struct uart_port *port)
{
return 0;
}
#ifdef CONFIG_CONSOLE_POLL
static int mvebu_uart_get_poll_char(struct uart_port *port)
{
unsigned int st = readl(port->membase + UART_STAT);
if (!(st & STAT_RX_RDY))
return NO_POLL_CHAR;
return readl(port->membase + UART_RBR);
}
static void mvebu_uart_put_poll_char(struct uart_port *port, unsigned char c)
{
unsigned int st;
for (;;) {
st = readl(port->membase + UART_STAT);
if (!(st & STAT_TX_FIFO_FUL))
break;
udelay(1);
}
writel(c, port->membase + UART_TSH);
}
#endif
static const struct uart_ops mvebu_uart_ops = {
.tx_empty = mvebu_uart_tx_empty,
.set_mctrl = mvebu_uart_set_mctrl,
.get_mctrl = mvebu_uart_get_mctrl,
.stop_tx = mvebu_uart_stop_tx,
.start_tx = mvebu_uart_start_tx,
.stop_rx = mvebu_uart_stop_rx,
.break_ctl = mvebu_uart_break_ctl,
.startup = mvebu_uart_startup,
.shutdown = mvebu_uart_shutdown,
.set_termios = mvebu_uart_set_termios,
.type = mvebu_uart_type,
.release_port = mvebu_uart_release_port,
.request_port = mvebu_uart_request_port,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = mvebu_uart_get_poll_char,
.poll_put_char = mvebu_uart_put_poll_char,
#endif
};
/* Console Driver Operations */
#ifdef CONFIG_SERIAL_MVEBU_CONSOLE
/* Early Console */
static void mvebu_uart_putc(struct uart_port *port, int c)
{
unsigned int st;
for (;;) {
st = readl(port->membase + UART_STAT);
if (!(st & STAT_TX_FIFO_FUL))
break;
}
writel(c, port->membase + UART_TSH);
for (;;) {
st = readl(port->membase + UART_STAT);
if (st & STAT_TX_FIFO_EMP)
break;
}
}
static void mvebu_uart_putc_early_write(struct console *con,
const char *s,
unsigned n)
{
struct earlycon_device *dev = con->data;
uart_console_write(&dev->port, s, n, mvebu_uart_putc);
}
static int __init
mvebu_uart_early_console_setup(struct earlycon_device *device,
const char *opt)
{
if (!device->port.membase)
return -ENODEV;
device->con->write = mvebu_uart_putc_early_write;
return 0;
}
EARLYCON_DECLARE(ar3700_uart, mvebu_uart_early_console_setup);
OF_EARLYCON_DECLARE(ar3700_uart, "marvell,armada-3700-uart",
mvebu_uart_early_console_setup);
static void wait_for_xmitr(struct uart_port *port)
{
u32 val;
readl_poll_timeout_atomic(port->membase + UART_STAT, val,
(val & STAT_TX_EMP), 1, 10000);
}
static void mvebu_uart_console_putchar(struct uart_port *port, int ch)
{
wait_for_xmitr(port);
writel(ch, port->membase + UART_TSH);
}
static void mvebu_uart_console_write(struct console *co, const char *s,
unsigned int count)
{
struct uart_port *port = &mvebu_uart_ports[co->index];
unsigned long flags;
unsigned int ier;
int locked = 1;
if (oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
else
spin_lock_irqsave(&port->lock, flags);
ier = readl(port->membase + UART_CTRL) &
(CTRL_RX_INT | CTRL_TX_RDY_INT);
writel(0, port->membase + UART_CTRL);
uart_console_write(port, s, count, mvebu_uart_console_putchar);
wait_for_xmitr(port);
if (ier)
writel(ier, port->membase + UART_CTRL);
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
}
static int mvebu_uart_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (co->index < 0 || co->index >= MVEBU_NR_UARTS)
return -EINVAL;
port = &mvebu_uart_ports[co->index];
if (!port->mapbase || !port->membase) {
pr_debug("console on ttyMV%i not present\n", co->index);
return -ENODEV;
}
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver mvebu_uart_driver;
static struct console mvebu_uart_console = {
.name = "ttyMV",
.write = mvebu_uart_console_write,
.device = uart_console_device,
.setup = mvebu_uart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &mvebu_uart_driver,
};
static int __init mvebu_uart_console_init(void)
{
register_console(&mvebu_uart_console);
return 0;
}
console_initcall(mvebu_uart_console_init);
#endif /* CONFIG_SERIAL_MVEBU_CONSOLE */
static struct uart_driver mvebu_uart_driver = {
.owner = THIS_MODULE,
.driver_name = "mvebu_serial",
.dev_name = "ttyMV",
.nr = MVEBU_NR_UARTS,
#ifdef CONFIG_SERIAL_MVEBU_CONSOLE
.cons = &mvebu_uart_console,
#endif
};
static int mvebu_uart_probe(struct platform_device *pdev)
{
struct resource *reg = platform_get_resource(pdev, IORESOURCE_MEM, 0);
struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
struct uart_port *port;
struct mvebu_uart_data *data;
int ret;
if (!reg || !irq) {
dev_err(&pdev->dev, "no registers/irq defined\n");
return -EINVAL;
}
port = &mvebu_uart_ports[0];
spin_lock_init(&port->lock);
port->dev = &pdev->dev;
port->type = PORT_MVEBU;
port->ops = &mvebu_uart_ops;
port->regshift = 0;
port->fifosize = 32;
port->iotype = UPIO_MEM32;
port->flags = UPF_FIXED_PORT;
port->line = 0; /* single port: force line number to 0 */
port->irq = irq->start;
port->irqflags = 0;
port->mapbase = reg->start;
port->membase = devm_ioremap_resource(&pdev->dev, reg);
if (IS_ERR(port->membase))
return -PTR_ERR(port->membase);
data = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_uart_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
data->port = port;
port->private_data = data;
platform_set_drvdata(pdev, data);
ret = uart_add_one_port(&mvebu_uart_driver, port);
if (ret)
return ret;
return 0;
}
/* Match table for of_platform binding */
static const struct of_device_id mvebu_uart_of_match[] = {
{ .compatible = "marvell,armada-3700-uart", },
{}
};
static struct platform_driver mvebu_uart_platform_driver = {
.probe = mvebu_uart_probe,
.driver = {
.name = "mvebu-uart",
.of_match_table = of_match_ptr(mvebu_uart_of_match),
.suppress_bind_attrs = true,
},
};
static int __init mvebu_uart_init(void)
{
int ret;
ret = uart_register_driver(&mvebu_uart_driver);
if (ret)
return ret;
ret = platform_driver_register(&mvebu_uart_platform_driver);
if (ret)
uart_unregister_driver(&mvebu_uart_driver);
return ret;
}
arch_initcall(mvebu_uart_init);
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