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linux/drivers/serial/serial_core.c
Alan Cox 16ae2a877b serial: Fix crash if the minimum rate of the device is > 9600 baud 
In that situation if the old rate is invalid and the new rate is invalid
and the chip cannot do 9600 baud we report zero, which makes all the
drivers explode.

Instead force the rate based on min/max

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-01-20 15:03:29 -08:00

2580 lines
63 KiB
C
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/*
* linux/drivers/char/core.c
*
* Driver core for serial ports
*
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*
* Copyright 1999 ARM Limited
* Copyright (C) 2000-2001 Deep Blue Solutions 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
* (at your option) 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/smp_lock.h>
#include <linux/device.h>
#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
#include <linux/serial_core.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
/*
* This is used to lock changes in serial line configuration.
*/
static DEFINE_MUTEX(port_mutex);
/*
* lockdep: port->lock is initialized in two places, but we
* want only one lock-class:
*/
static struct lock_class_key port_lock_key;
#define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
#ifdef CONFIG_SERIAL_CORE_CONSOLE
#define uart_console(port) ((port)->cons && (port)->cons->index == (port)->line)
#else
#define uart_console(port) (0)
#endif
static void uart_change_speed(struct uart_state *state,
struct ktermios *old_termios);
static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
static void uart_change_pm(struct uart_state *state, int pm_state);
/*
* This routine is used by the interrupt handler to schedule processing in
* the software interrupt portion of the driver.
*/
void uart_write_wakeup(struct uart_port *port)
{
struct uart_state *state = port->state;
/*
* This means you called this function _after_ the port was
* closed. No cookie for you.
*/
BUG_ON(!state);
tasklet_schedule(&state->tlet);
}
static void uart_stop(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->uart_port;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
port->ops->stop_tx(port);
spin_unlock_irqrestore(&port->lock, flags);
}
static void __uart_start(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->uart_port;
if (!uart_circ_empty(&state->xmit) && state->xmit.buf &&
!tty->stopped && !tty->hw_stopped)
port->ops->start_tx(port);
}
static void uart_start(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->uart_port;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
__uart_start(tty);
spin_unlock_irqrestore(&port->lock, flags);
}
static void uart_tasklet_action(unsigned long data)
{
struct uart_state *state = (struct uart_state *)data;
tty_wakeup(state->port.tty);
}
static inline void
uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
{
unsigned long flags;
unsigned int old;
spin_lock_irqsave(&port->lock, flags);
old = port->mctrl;
port->mctrl = (old & ~clear) | set;
if (old != port->mctrl)
port->ops->set_mctrl(port, port->mctrl);
spin_unlock_irqrestore(&port->lock, flags);
}
#define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
#define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
/*
* Startup the port. This will be called once per open. All calls
* will be serialised by the per-port mutex.
*/
static int uart_startup(struct uart_state *state, int init_hw)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
unsigned long page;
int retval = 0;
if (port->flags & ASYNC_INITIALIZED)
return 0;
/*
* Set the TTY IO error marker - we will only clear this
* once we have successfully opened the port. Also set
* up the tty->alt_speed kludge
*/
set_bit(TTY_IO_ERROR, &port->tty->flags);
if (uport->type == PORT_UNKNOWN)
return 0;
/*
* Initialise and allocate the transmit and temporary
* buffer.
*/
if (!state->xmit.buf) {
/* This is protected by the per port mutex */
page = get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
state->xmit.buf = (unsigned char *) page;
uart_circ_clear(&state->xmit);
}
retval = uport->ops->startup(uport);
if (retval == 0) {
if (init_hw) {
/*
* Initialise the hardware port settings.
*/
uart_change_speed(state, NULL);
/*
* Setup the RTS and DTR signals once the
* port is open and ready to respond.
*/
if (port->tty->termios->c_cflag & CBAUD)
uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
}
if (port->flags & ASYNC_CTS_FLOW) {
spin_lock_irq(&uport->lock);
if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS))
port->tty->hw_stopped = 1;
spin_unlock_irq(&uport->lock);
}
set_bit(ASYNCB_INITIALIZED, &port->flags);
clear_bit(TTY_IO_ERROR, &port->tty->flags);
}
if (retval && capable(CAP_SYS_ADMIN))
retval = 0;
return retval;
}
/*
* This routine will shutdown a serial port; interrupts are disabled, and
* DTR is dropped if the hangup on close termio flag is on. Calls to
* uart_shutdown are serialised by the per-port semaphore.
*/
static void uart_shutdown(struct uart_state *state)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
struct tty_struct *tty = port->tty;
/*
* Set the TTY IO error marker
*/
if (tty)
set_bit(TTY_IO_ERROR, &tty->flags);
if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) {
/*
* Turn off DTR and RTS early.
*/
if (!tty || (tty->termios->c_cflag & HUPCL))
uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
/*
* clear delta_msr_wait queue to avoid mem leaks: we may free
* the irq here so the queue might never be woken up. Note
* that we won't end up waiting on delta_msr_wait again since
* any outstanding file descriptors should be pointing at
* hung_up_tty_fops now.
*/
wake_up_interruptible(&port->delta_msr_wait);
/*
* Free the IRQ and disable the port.
*/
uport->ops->shutdown(uport);
/*
* Ensure that the IRQ handler isn't running on another CPU.
*/
synchronize_irq(uport->irq);
}
/*
* kill off our tasklet
*/
tasklet_kill(&state->tlet);
/*
* Free the transmit buffer page.
*/
if (state->xmit.buf) {
free_page((unsigned long)state->xmit.buf);
state->xmit.buf = NULL;
}
}
/**
* uart_update_timeout - update per-port FIFO timeout.
* @port: uart_port structure describing the port
* @cflag: termios cflag value
* @baud: speed of the port
*
* Set the port FIFO timeout value. The @cflag value should
* reflect the actual hardware settings.
*/
void
uart_update_timeout(struct uart_port *port, unsigned int cflag,
unsigned int baud)
{
unsigned int bits;
/* byte size and parity */
switch (cflag & CSIZE) {
case CS5:
bits = 7;
break;
case CS6:
bits = 8;
break;
case CS7:
bits = 9;
break;
default:
bits = 10;
break; /* CS8 */
}
if (cflag & CSTOPB)
bits++;
if (cflag & PARENB)
bits++;
/*
* The total number of bits to be transmitted in the fifo.
*/
bits = bits * port->fifosize;
/*
* Figure the timeout to send the above number of bits.
* Add .02 seconds of slop
*/
port->timeout = (HZ * bits) / baud + HZ/50;
}
EXPORT_SYMBOL(uart_update_timeout);
/**
* uart_get_baud_rate - return baud rate for a particular port
* @port: uart_port structure describing the port in question.
* @termios: desired termios settings.
* @old: old termios (or NULL)
* @min: minimum acceptable baud rate
* @max: maximum acceptable baud rate
*
* Decode the termios structure into a numeric baud rate,
* taking account of the magic 38400 baud rate (with spd_*
* flags), and mapping the %B0 rate to 9600 baud.
*
* If the new baud rate is invalid, try the old termios setting.
* If it's still invalid, we try 9600 baud.
*
* Update the @termios structure to reflect the baud rate
* we're actually going to be using. Don't do this for the case
* where B0 is requested ("hang up").
*/
unsigned int
uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
struct ktermios *old, unsigned int min, unsigned int max)
{
unsigned int try, baud, altbaud = 38400;
int hung_up = 0;
upf_t flags = port->flags & UPF_SPD_MASK;
if (flags == UPF_SPD_HI)
altbaud = 57600;
else if (flags == UPF_SPD_VHI)
altbaud = 115200;
else if (flags == UPF_SPD_SHI)
altbaud = 230400;
else if (flags == UPF_SPD_WARP)
altbaud = 460800;
for (try = 0; try < 2; try++) {
baud = tty_termios_baud_rate(termios);
/*
* The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
* Die! Die! Die!
*/
if (baud == 38400)
baud = altbaud;
/*
* Special case: B0 rate.
*/
if (baud == 0) {
hung_up = 1;
baud = 9600;
}
if (baud >= min && baud <= max)
return baud;
/*
* Oops, the quotient was zero. Try again with
* the old baud rate if possible.
*/
termios->c_cflag &= ~CBAUD;
if (old) {
baud = tty_termios_baud_rate(old);
if (!hung_up)
tty_termios_encode_baud_rate(termios,
baud, baud);
old = NULL;
continue;
}
/*
* As a last resort, if the range cannot be met then clip to
* the nearest chip supported rate.
*/
if (!hung_up) {
if (baud <= min)
tty_termios_encode_baud_rate(termios,
min + 1, min + 1);
else
tty_termios_encode_baud_rate(termios,
max - 1, max - 1);
}
}
/* Should never happen */
WARN_ON(1);
return 0;
}
EXPORT_SYMBOL(uart_get_baud_rate);
/**
* uart_get_divisor - return uart clock divisor
* @port: uart_port structure describing the port.
* @baud: desired baud rate
*
* Calculate the uart clock divisor for the port.
*/
unsigned int
uart_get_divisor(struct uart_port *port, unsigned int baud)
{
unsigned int quot;
/*
* Old custom speed handling.
*/
if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
quot = port->custom_divisor;
else
quot = (port->uartclk + (8 * baud)) / (16 * baud);
return quot;
}
EXPORT_SYMBOL(uart_get_divisor);
/* FIXME: Consistent locking policy */
static void
uart_change_speed(struct uart_state *state, struct ktermios *old_termios)
{
struct tty_port *port = &state->port;
struct tty_struct *tty = port->tty;
struct uart_port *uport = state->uart_port;
struct ktermios *termios;
/*
* If we have no tty, termios, or the port does not exist,
* then we can't set the parameters for this port.
*/
if (!tty || !tty->termios || uport->type == PORT_UNKNOWN)
return;
termios = tty->termios;
/*
* Set flags based on termios cflag
*/
if (termios->c_cflag & CRTSCTS)
set_bit(ASYNCB_CTS_FLOW, &port->flags);
else
clear_bit(ASYNCB_CTS_FLOW, &port->flags);
if (termios->c_cflag & CLOCAL)
clear_bit(ASYNCB_CHECK_CD, &port->flags);
else
set_bit(ASYNCB_CHECK_CD, &port->flags);
uport->ops->set_termios(uport, termios, old_termios);
}
static inline int
__uart_put_char(struct uart_port *port, struct circ_buf *circ, unsigned char c)
{
unsigned long flags;
int ret = 0;
if (!circ->buf)
return 0;
spin_lock_irqsave(&port->lock, flags);
if (uart_circ_chars_free(circ) != 0) {
circ->buf[circ->head] = c;
circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
ret = 1;
}
spin_unlock_irqrestore(&port->lock, flags);
return ret;
}
static int uart_put_char(struct tty_struct *tty, unsigned char ch)
{
struct uart_state *state = tty->driver_data;
return __uart_put_char(state->uart_port, &state->xmit, ch);
}
static void uart_flush_chars(struct tty_struct *tty)
{
uart_start(tty);
}
static int
uart_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
struct circ_buf *circ;
unsigned long flags;
int c, ret = 0;
/*
* This means you called this function _after_ the port was
* closed. No cookie for you.
*/
if (!state) {
WARN_ON(1);
return -EL3HLT;
}
port = state->uart_port;
circ = &state->xmit;
if (!circ->buf)
return 0;
spin_lock_irqsave(&port->lock, flags);
while (1) {
c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
if (count < c)
c = count;
if (c <= 0)
break;
memcpy(circ->buf + circ->head, buf, c);
circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
buf += c;
count -= c;
ret += c;
}
spin_unlock_irqrestore(&port->lock, flags);
uart_start(tty);
return ret;
}
static int uart_write_room(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
unsigned long flags;
int ret;
spin_lock_irqsave(&state->uart_port->lock, flags);
ret = uart_circ_chars_free(&state->xmit);
spin_unlock_irqrestore(&state->uart_port->lock, flags);
return ret;
}
static int uart_chars_in_buffer(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
unsigned long flags;
int ret;
spin_lock_irqsave(&state->uart_port->lock, flags);
ret = uart_circ_chars_pending(&state->xmit);
spin_unlock_irqrestore(&state->uart_port->lock, flags);
return ret;
}
static void uart_flush_buffer(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
unsigned long flags;
/*
* This means you called this function _after_ the port was
* closed. No cookie for you.
*/
if (!state) {
WARN_ON(1);
return;
}
port = state->uart_port;
pr_debug("uart_flush_buffer(%d) called\n", tty->index);
spin_lock_irqsave(&port->lock, flags);
uart_circ_clear(&state->xmit);
if (port->ops->flush_buffer)
port->ops->flush_buffer(port);
spin_unlock_irqrestore(&port->lock, flags);
tty_wakeup(tty);
}
/*
* This function is used to send a high-priority XON/XOFF character to
* the device
*/
static void uart_send_xchar(struct tty_struct *tty, char ch)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->uart_port;
unsigned long flags;
if (port->ops->send_xchar)
port->ops->send_xchar(port, ch);
else {
port->x_char = ch;
if (ch) {
spin_lock_irqsave(&port->lock, flags);
port->ops->start_tx(port);
spin_unlock_irqrestore(&port->lock, flags);
}
}
}
static void uart_throttle(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
if (I_IXOFF(tty))
uart_send_xchar(tty, STOP_CHAR(tty));
if (tty->termios->c_cflag & CRTSCTS)
uart_clear_mctrl(state->uart_port, TIOCM_RTS);
}
static void uart_unthrottle(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->uart_port;
if (I_IXOFF(tty)) {
if (port->x_char)
port->x_char = 0;
else
uart_send_xchar(tty, START_CHAR(tty));
}
if (tty->termios->c_cflag & CRTSCTS)
uart_set_mctrl(port, TIOCM_RTS);
}
static int uart_get_info(struct uart_state *state,
struct serial_struct __user *retinfo)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
struct serial_struct tmp;
memset(&tmp, 0, sizeof(tmp));
/* Ensure the state we copy is consistent and no hardware changes
occur as we go */
mutex_lock(&port->mutex);
tmp.type = uport->type;
tmp.line = uport->line;
tmp.port = uport->iobase;
if (HIGH_BITS_OFFSET)
tmp.port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
tmp.irq = uport->irq;
tmp.flags = uport->flags;
tmp.xmit_fifo_size = uport->fifosize;
tmp.baud_base = uport->uartclk / 16;
tmp.close_delay = port->close_delay / 10;
tmp.closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
ASYNC_CLOSING_WAIT_NONE :
port->closing_wait / 10;
tmp.custom_divisor = uport->custom_divisor;
tmp.hub6 = uport->hub6;
tmp.io_type = uport->iotype;
tmp.iomem_reg_shift = uport->regshift;
tmp.iomem_base = (void *)(unsigned long)uport->mapbase;
mutex_unlock(&port->mutex);
if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
return -EFAULT;
return 0;
}
static int uart_set_info(struct uart_state *state,
struct serial_struct __user *newinfo)
{
struct serial_struct new_serial;
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
unsigned long new_port;
unsigned int change_irq, change_port, closing_wait;
unsigned int old_custom_divisor, close_delay;
upf_t old_flags, new_flags;
int retval = 0;
if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
return -EFAULT;
new_port = new_serial.port;
if (HIGH_BITS_OFFSET)
new_port += (unsigned long) new_serial.port_high << HIGH_BITS_OFFSET;
new_serial.irq = irq_canonicalize(new_serial.irq);
close_delay = new_serial.close_delay * 10;
closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
/*
* This semaphore protects port->count. It is also
* very useful to prevent opens. Also, take the
* port configuration semaphore to make sure that a
* module insertion/removal doesn't change anything
* under us.
*/
mutex_lock(&port->mutex);
change_irq = !(uport->flags & UPF_FIXED_PORT)
&& new_serial.irq != uport->irq;
/*
* Since changing the 'type' of the port changes its resource
* allocations, we should treat type changes the same as
* IO port changes.
*/
change_port = !(uport->flags & UPF_FIXED_PORT)
&& (new_port != uport->iobase ||
(unsigned long)new_serial.iomem_base != uport->mapbase ||
new_serial.hub6 != uport->hub6 ||
new_serial.io_type != uport->iotype ||
new_serial.iomem_reg_shift != uport->regshift ||
new_serial.type != uport->type);
old_flags = uport->flags;
new_flags = new_serial.flags;
old_custom_divisor = uport->custom_divisor;
if (!capable(CAP_SYS_ADMIN)) {
retval = -EPERM;
if (change_irq || change_port ||
(new_serial.baud_base != uport->uartclk / 16) ||
(close_delay != port->close_delay) ||
(closing_wait != port->closing_wait) ||
(new_serial.xmit_fifo_size &&
new_serial.xmit_fifo_size != uport->fifosize) ||
(((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
goto exit;
uport->flags = ((uport->flags & ~UPF_USR_MASK) |
(new_flags & UPF_USR_MASK));
uport->custom_divisor = new_serial.custom_divisor;
goto check_and_exit;
}
/*
* Ask the low level driver to verify the settings.
*/
if (uport->ops->verify_port)
retval = uport->ops->verify_port(uport, &new_serial);
if ((new_serial.irq >= nr_irqs) || (new_serial.irq < 0) ||
(new_serial.baud_base < 9600))
retval = -EINVAL;
if (retval)
goto exit;
if (change_port || change_irq) {
retval = -EBUSY;
/*
* Make sure that we are the sole user of this port.
*/
if (tty_port_users(port) > 1)
goto exit;
/*
* We need to shutdown the serial port at the old
* port/type/irq combination.
*/
uart_shutdown(state);
}
if (change_port) {
unsigned long old_iobase, old_mapbase;
unsigned int old_type, old_iotype, old_hub6, old_shift;
old_iobase = uport->iobase;
old_mapbase = uport->mapbase;
old_type = uport->type;
old_hub6 = uport->hub6;
old_iotype = uport->iotype;
old_shift = uport->regshift;
/*
* Free and release old regions
*/
if (old_type != PORT_UNKNOWN)
uport->ops->release_port(uport);
uport->iobase = new_port;
uport->type = new_serial.type;
uport->hub6 = new_serial.hub6;
uport->iotype = new_serial.io_type;
uport->regshift = new_serial.iomem_reg_shift;
uport->mapbase = (unsigned long)new_serial.iomem_base;
/*
* Claim and map the new regions
*/
if (uport->type != PORT_UNKNOWN) {
retval = uport->ops->request_port(uport);
} else {
/* Always success - Jean II */
retval = 0;
}
/*
* If we fail to request resources for the
* new port, try to restore the old settings.
*/
if (retval && old_type != PORT_UNKNOWN) {
uport->iobase = old_iobase;
uport->type = old_type;
uport->hub6 = old_hub6;
uport->iotype = old_iotype;
uport->regshift = old_shift;
uport->mapbase = old_mapbase;
retval = uport->ops->request_port(uport);
/*
* If we failed to restore the old settings,
* we fail like this.
*/
if (retval)
uport->type = PORT_UNKNOWN;
/*
* We failed anyway.
*/
retval = -EBUSY;
/* Added to return the correct error -Ram Gupta */
goto exit;
}
}
if (change_irq)
uport->irq = new_serial.irq;
if (!(uport->flags & UPF_FIXED_PORT))
uport->uartclk = new_serial.baud_base * 16;
uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
(new_flags & UPF_CHANGE_MASK);
uport->custom_divisor = new_serial.custom_divisor;
port->close_delay = close_delay;
port->closing_wait = closing_wait;
if (new_serial.xmit_fifo_size)
uport->fifosize = new_serial.xmit_fifo_size;
if (port->tty)
port->tty->low_latency =
(uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
check_and_exit:
retval = 0;
if (uport->type == PORT_UNKNOWN)
goto exit;
if (port->flags & ASYNC_INITIALIZED) {
if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
old_custom_divisor != uport->custom_divisor) {
/*
* If they're setting up a custom divisor or speed,
* instead of clearing it, then bitch about it. No
* need to rate-limit; it's CAP_SYS_ADMIN only.
*/
if (uport->flags & UPF_SPD_MASK) {
char buf[64];
printk(KERN_NOTICE
"%s sets custom speed on %s. This "
"is deprecated.\n", current->comm,
tty_name(port->tty, buf));
}
uart_change_speed(state, NULL);
}
} else
retval = uart_startup(state, 1);
exit:
mutex_unlock(&port->mutex);
return retval;
}
/*
* uart_get_lsr_info - get line status register info.
* Note: uart_ioctl protects us against hangups.
*/
static int uart_get_lsr_info(struct uart_state *state,
unsigned int __user *value)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
unsigned int result;
result = uport->ops->tx_empty(uport);
/*
* If we're about to load something into the transmit
* register, we'll pretend the transmitter isn't empty to
* avoid a race condition (depending on when the transmit
* interrupt happens).
*/
if (uport->x_char ||
((uart_circ_chars_pending(&state->xmit) > 0) &&
!port->tty->stopped && !port->tty->hw_stopped))
result &= ~TIOCSER_TEMT;
return put_user(result, value);
}
static int uart_tiocmget(struct tty_struct *tty, struct file *file)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
struct uart_port *uport = state->uart_port;
int result = -EIO;
mutex_lock(&port->mutex);
if ((!file || !tty_hung_up_p(file)) &&
!(tty->flags & (1 << TTY_IO_ERROR))) {
result = uport->mctrl;
spin_lock_irq(&uport->lock);
result |= uport->ops->get_mctrl(uport);
spin_unlock_irq(&uport->lock);
}
mutex_unlock(&port->mutex);
return result;
}
static int
uart_tiocmset(struct tty_struct *tty, struct file *file,
unsigned int set, unsigned int clear)
{
struct uart_state *state = tty->driver_data;
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
int ret = -EIO;
mutex_lock(&port->mutex);
if ((!file || !tty_hung_up_p(file)) &&
!(tty->flags & (1 << TTY_IO_ERROR))) {
uart_update_mctrl(uport, set, clear);
ret = 0;
}
mutex_unlock(&port->mutex);
return ret;
}
static int uart_break_ctl(struct tty_struct *tty, int break_state)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
struct uart_port *uport = state->uart_port;
mutex_lock(&port->mutex);
if (uport->type != PORT_UNKNOWN)
uport->ops->break_ctl(uport, break_state);
mutex_unlock(&port->mutex);
return 0;
}
static int uart_do_autoconfig(struct uart_state *state)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
int flags, ret;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/*
* Take the per-port semaphore. This prevents count from
* changing, and hence any extra opens of the port while
* we're auto-configuring.
*/
if (mutex_lock_interruptible(&port->mutex))
return -ERESTARTSYS;
ret = -EBUSY;
if (tty_port_users(port) == 1) {
uart_shutdown(state);
/*
* If we already have a port type configured,
* we must release its resources.
*/
if (uport->type != PORT_UNKNOWN)
uport->ops->release_port(uport);
flags = UART_CONFIG_TYPE;
if (uport->flags & UPF_AUTO_IRQ)
flags |= UART_CONFIG_IRQ;
/*
* This will claim the ports resources if
* a port is found.
*/
uport->ops->config_port(uport, flags);
ret = uart_startup(state, 1);
}
mutex_unlock(&port->mutex);
return ret;
}
/*
* Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
* - mask passed in arg for lines of interest
* (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
* Caller should use TIOCGICOUNT to see which one it was
*
* FIXME: This wants extracting into a common all driver implementation
* of TIOCMWAIT using tty_port.
*/
static int
uart_wait_modem_status(struct uart_state *state, unsigned long arg)
{
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
DECLARE_WAITQUEUE(wait, current);
struct uart_icount cprev, cnow;
int ret;
/*
* note the counters on entry
*/
spin_lock_irq(&uport->lock);
memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
/*
* Force modem status interrupts on
*/
uport->ops->enable_ms(uport);
spin_unlock_irq(&uport->lock);
add_wait_queue(&port->delta_msr_wait, &wait);
for (;;) {
spin_lock_irq(&uport->lock);
memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
spin_unlock_irq(&uport->lock);
set_current_state(TASK_INTERRUPTIBLE);
if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
ret = 0;
break;
}
schedule();
/* see if a signal did it */
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
cprev = cnow;
}
current->state = TASK_RUNNING;
remove_wait_queue(&port->delta_msr_wait, &wait);
return ret;
}
/*
* Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
* Return: write counters to the user passed counter struct
* NB: both 1->0 and 0->1 transitions are counted except for
* RI where only 0->1 is counted.
*/
static int uart_get_count(struct uart_state *state,
struct serial_icounter_struct __user *icnt)
{
struct serial_icounter_struct icount;
struct uart_icount cnow;
struct uart_port *uport = state->uart_port;
spin_lock_irq(&uport->lock);
memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
spin_unlock_irq(&uport->lock);
icount.cts = cnow.cts;
icount.dsr = cnow.dsr;
icount.rng = cnow.rng;
icount.dcd = cnow.dcd;
icount.rx = cnow.rx;
icount.tx = cnow.tx;
icount.frame = cnow.frame;
icount.overrun = cnow.overrun;
icount.parity = cnow.parity;
icount.brk = cnow.brk;
icount.buf_overrun = cnow.buf_overrun;
return copy_to_user(icnt, &icount, sizeof(icount)) ? -EFAULT : 0;
}
/*
* Called via sys_ioctl. We can use spin_lock_irq() here.
*/
static int
uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
unsigned long arg)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
void __user *uarg = (void __user *)arg;
int ret = -ENOIOCTLCMD;
/*
* These ioctls don't rely on the hardware to be present.
*/
switch (cmd) {
case TIOCGSERIAL:
ret = uart_get_info(state, uarg);
break;
case TIOCSSERIAL:
ret = uart_set_info(state, uarg);
break;
case TIOCSERCONFIG:
ret = uart_do_autoconfig(state);
break;
case TIOCSERGWILD: /* obsolete */
case TIOCSERSWILD: /* obsolete */
ret = 0;
break;
}
if (ret != -ENOIOCTLCMD)
goto out;
if (tty->flags & (1 << TTY_IO_ERROR)) {
ret = -EIO;
goto out;
}
/*
* The following should only be used when hardware is present.
*/
switch (cmd) {
case TIOCMIWAIT:
ret = uart_wait_modem_status(state, arg);
break;
case TIOCGICOUNT:
ret = uart_get_count(state, uarg);
break;
}
if (ret != -ENOIOCTLCMD)
goto out;
mutex_lock(&port->mutex);
if (tty_hung_up_p(filp)) {
ret = -EIO;
goto out_up;
}
/*
* All these rely on hardware being present and need to be
* protected against the tty being hung up.
*/
switch (cmd) {
case TIOCSERGETLSR: /* Get line status register */
ret = uart_get_lsr_info(state, uarg);
break;
default: {
struct uart_port *uport = state->uart_port;
if (uport->ops->ioctl)
ret = uport->ops->ioctl(uport, cmd, arg);
break;
}
}
out_up:
mutex_unlock(&port->mutex);
out:
return ret;
}
static void uart_set_ldisc(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *uport = state->uart_port;
if (uport->ops->set_ldisc)
uport->ops->set_ldisc(uport);
}
static void uart_set_termios(struct tty_struct *tty,
struct ktermios *old_termios)
{
struct uart_state *state = tty->driver_data;
unsigned long flags;
unsigned int cflag = tty->termios->c_cflag;
/*
* These are the bits that are used to setup various
* flags in the low level driver. We can ignore the Bfoo
* bits in c_cflag; c_[io]speed will always be set
* appropriately by set_termios() in tty_ioctl.c
*/
#define RELEVANT_IFLAG(iflag) ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
if ((cflag ^ old_termios->c_cflag) == 0 &&
tty->termios->c_ospeed == old_termios->c_ospeed &&
tty->termios->c_ispeed == old_termios->c_ispeed &&
RELEVANT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0) {
return;
}
uart_change_speed(state, old_termios);
/* Handle transition to B0 status */
if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
uart_clear_mctrl(state->uart_port, TIOCM_RTS | TIOCM_DTR);
/* Handle transition away from B0 status */
else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
unsigned int mask = TIOCM_DTR;
if (!(cflag & CRTSCTS) ||
!test_bit(TTY_THROTTLED, &tty->flags))
mask |= TIOCM_RTS;
uart_set_mctrl(state->uart_port, mask);
}
/* Handle turning off CRTSCTS */
if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
spin_lock_irqsave(&state->uart_port->lock, flags);
tty->hw_stopped = 0;
__uart_start(tty);
spin_unlock_irqrestore(&state->uart_port->lock, flags);
}
/* Handle turning on CRTSCTS */
else if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
spin_lock_irqsave(&state->uart_port->lock, flags);
if (!(state->uart_port->ops->get_mctrl(state->uart_port) & TIOCM_CTS)) {
tty->hw_stopped = 1;
state->uart_port->ops->stop_tx(state->uart_port);
}
spin_unlock_irqrestore(&state->uart_port->lock, flags);
}
#if 0
/*
* No need to wake up processes in open wait, since they
* sample the CLOCAL flag once, and don't recheck it.
* XXX It's not clear whether the current behavior is correct
* or not. Hence, this may change.....
*/
if (!(old_termios->c_cflag & CLOCAL) &&
(tty->termios->c_cflag & CLOCAL))
wake_up_interruptible(&state->uart_port.open_wait);
#endif
}
/*
* In 2.4.5, calls to this will be serialized via the BKL in
* linux/drivers/char/tty_io.c:tty_release()
* linux/drivers/char/tty_io.c:do_tty_handup()
*/
static void uart_close(struct tty_struct *tty, struct file *filp)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port;
struct uart_port *uport;
BUG_ON(!kernel_locked());
if (!state)
return;
uport = state->uart_port;
port = &state->port;
pr_debug("uart_close(%d) called\n", uport->line);
mutex_lock(&port->mutex);
if (tty_hung_up_p(filp))
goto done;
if ((tty->count == 1) && (port->count != 1)) {
/*
* Uh, oh. tty->count is 1, which means that the tty
* structure will be freed. port->count should always
* be one in these conditions. If it's greater than
* one, we've got real problems, since it means the
* serial port won't be shutdown.
*/
printk(KERN_ERR "uart_close: bad serial port count; tty->count is 1, "
"port->count is %d\n", port->count);
port->count = 1;
}
if (--port->count < 0) {
printk(KERN_ERR "uart_close: bad serial port count for %s: %d\n",
tty->name, port->count);
port->count = 0;
}
if (port->count)
goto done;
/*
* Now we wait for the transmit buffer to clear; and we notify
* the line discipline to only process XON/XOFF characters by
* setting tty->closing.
*/
tty->closing = 1;
if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
tty_wait_until_sent(tty, msecs_to_jiffies(port->closing_wait));
/*
* At this point, we stop accepting input. To do this, we
* disable the receive line status interrupts.
*/
if (port->flags & ASYNC_INITIALIZED) {
unsigned long flags;
spin_lock_irqsave(&uport->lock, flags);
uport->ops->stop_rx(uport);
spin_unlock_irqrestore(&uport->lock, flags);
/*
* Before we drop DTR, make sure the UART transmitter
* has completely drained; this is especially
* important if there is a transmit FIFO!
*/
uart_wait_until_sent(tty, uport->timeout);
}
uart_shutdown(state);
uart_flush_buffer(tty);
tty_ldisc_flush(tty);
tty->closing = 0;
tty_port_tty_set(port, NULL);
if (port->blocked_open) {
if (port->close_delay)
msleep_interruptible(port->close_delay);
} else if (!uart_console(uport)) {
uart_change_pm(state, 3);
}
/*
* Wake up anyone trying to open this port.
*/
clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
wake_up_interruptible(&port->open_wait);
done:
mutex_unlock(&port->mutex);
}
static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->uart_port;
unsigned long char_time, expire;
if (port->type == PORT_UNKNOWN || port->fifosize == 0)
return;
lock_kernel();
/*
* Set the check interval to be 1/5 of the estimated time to
* send a single character, and make it at least 1. The check
* interval should also be less than the timeout.
*
* Note: we have to use pretty tight timings here to satisfy
* the NIST-PCTS.
*/
char_time = (port->timeout - HZ/50) / port->fifosize;
char_time = char_time / 5;
if (char_time == 0)
char_time = 1;
if (timeout && timeout < char_time)
char_time = timeout;
/*
* If the transmitter hasn't cleared in twice the approximate
* amount of time to send the entire FIFO, it probably won't
* ever clear. This assumes the UART isn't doing flow
* control, which is currently the case. Hence, if it ever
* takes longer than port->timeout, this is probably due to a
* UART bug of some kind. So, we clamp the timeout parameter at
* 2*port->timeout.
*/
if (timeout == 0 || timeout > 2 * port->timeout)
timeout = 2 * port->timeout;
expire = jiffies + timeout;
pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
port->line, jiffies, expire);
/*
* Check whether the transmitter is empty every 'char_time'.
* 'timeout' / 'expire' give us the maximum amount of time
* we wait.
*/
while (!port->ops->tx_empty(port)) {
msleep_interruptible(jiffies_to_msecs(char_time));
if (signal_pending(current))
break;
if (time_after(jiffies, expire))
break;
}
set_current_state(TASK_RUNNING); /* might not be needed */
unlock_kernel();
}
/*
* This is called with the BKL held in
* linux/drivers/char/tty_io.c:do_tty_hangup()
* We're called from the eventd thread, so we can sleep for
* a _short_ time only.
*/
static void uart_hangup(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
BUG_ON(!kernel_locked());
pr_debug("uart_hangup(%d)\n", state->uart_port->line);
mutex_lock(&port->mutex);
if (port->flags & ASYNC_NORMAL_ACTIVE) {
uart_flush_buffer(tty);
uart_shutdown(state);
port->count = 0;
clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
tty_port_tty_set(port, NULL);
wake_up_interruptible(&port->open_wait);
wake_up_interruptible(&port->delta_msr_wait);
}
mutex_unlock(&port->mutex);
}
/*
* Copy across the serial console cflag setting into the termios settings
* for the initial open of the port. This allows continuity between the
* kernel settings, and the settings init adopts when it opens the port
* for the first time.
*/
static void uart_update_termios(struct uart_state *state)
{
struct tty_struct *tty = state->port.tty;
struct uart_port *port = state->uart_port;
if (uart_console(port) && port->cons->cflag) {
tty->termios->c_cflag = port->cons->cflag;
port->cons->cflag = 0;
}
/*
* If the device failed to grab its irq resources,
* or some other error occurred, don't try to talk
* to the port hardware.
*/
if (!(tty->flags & (1 << TTY_IO_ERROR))) {
/*
* Make termios settings take effect.
*/
uart_change_speed(state, NULL);
/*
* And finally enable the RTS and DTR signals.
*/
if (tty->termios->c_cflag & CBAUD)
uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
}
}
/*
* Block the open until the port is ready. We must be called with
* the per-port semaphore held.
*/
static int
uart_block_til_ready(struct file *filp, struct uart_state *state)
{
DECLARE_WAITQUEUE(wait, current);
struct uart_port *uport = state->uart_port;
struct tty_port *port = &state->port;
unsigned int mctrl;
port->blocked_open++;
port->count--;
add_wait_queue(&port->open_wait, &wait);
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
/*
* If we have been hung up, tell userspace/restart open.
*/
if (tty_hung_up_p(filp) || port->tty == NULL)
break;
/*
* If the port has been closed, tell userspace/restart open.
*/
if (!(port->flags & ASYNC_INITIALIZED))
break;
/*
* If non-blocking mode is set, or CLOCAL mode is set,
* we don't want to wait for the modem status lines to
* indicate that the port is ready.
*
* Also, if the port is not enabled/configured, we want
* to allow the open to succeed here. Note that we will
* have set TTY_IO_ERROR for a non-existant port.
*/
if ((filp->f_flags & O_NONBLOCK) ||
(port->tty->termios->c_cflag & CLOCAL) ||
(port->tty->flags & (1 << TTY_IO_ERROR)))
break;
/*
* Set DTR to allow modem to know we're waiting. Do
* not set RTS here - we want to make sure we catch
* the data from the modem.
*/
if (port->tty->termios->c_cflag & CBAUD)
uart_set_mctrl(uport, TIOCM_DTR);
/*
* and wait for the carrier to indicate that the
* modem is ready for us.
*/
spin_lock_irq(&uport->lock);
uport->ops->enable_ms(uport);
mctrl = uport->ops->get_mctrl(uport);
spin_unlock_irq(&uport->lock);
if (mctrl & TIOCM_CAR)
break;
mutex_unlock(&port->mutex);
schedule();
mutex_lock(&port->mutex);
if (signal_pending(current))
break;
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
port->count++;
port->blocked_open--;
if (signal_pending(current))
return -ERESTARTSYS;
if (!port->tty || tty_hung_up_p(filp))
return -EAGAIN;
return 0;
}
static struct uart_state *uart_get(struct uart_driver *drv, int line)
{
struct uart_state *state;
struct tty_port *port;
int ret = 0;
state = drv->state + line;
port = &state->port;
if (mutex_lock_interruptible(&port->mutex)) {
ret = -ERESTARTSYS;
goto err;
}
port->count++;
if (!state->uart_port || state->uart_port->flags & UPF_DEAD) {
ret = -ENXIO;
goto err_unlock;
}
return state;
err_unlock:
port->count--;
mutex_unlock(&port->mutex);
err:
return ERR_PTR(ret);
}
/*
* calls to uart_open are serialised by the BKL in
* fs/char_dev.c:chrdev_open()
* Note that if this fails, then uart_close() _will_ be called.
*
* In time, we want to scrap the "opening nonpresent ports"
* behaviour and implement an alternative way for setserial
* to set base addresses/ports/types. This will allow us to
* get rid of a certain amount of extra tests.
*/
static int uart_open(struct tty_struct *tty, struct file *filp)
{
struct uart_driver *drv = (struct uart_driver *)tty->driver->driver_state;
struct uart_state *state;
struct tty_port *port;
int retval, line = tty->index;
BUG_ON(!kernel_locked());
pr_debug("uart_open(%d) called\n", line);
/*
* tty->driver->num won't change, so we won't fail here with
* tty->driver_data set to something non-NULL (and therefore
* we won't get caught by uart_close()).
*/
retval = -ENODEV;
if (line >= tty->driver->num)
goto fail;
/*
* We take the semaphore inside uart_get to guarantee that we won't
* be re-entered while allocating the state structure, or while we
* request any IRQs that the driver may need. This also has the nice
* side-effect that it delays the action of uart_hangup, so we can
* guarantee that state->port.tty will always contain something
* reasonable.
*/
state = uart_get(drv, line);
if (IS_ERR(state)) {
retval = PTR_ERR(state);
goto fail;
}
port = &state->port;
/*
* Once we set tty->driver_data here, we are guaranteed that
* uart_close() will decrement the driver module use count.
* Any failures from here onwards should not touch the count.
*/
tty->driver_data = state;
state->uart_port->state = state;
tty->low_latency = (state->uart_port->flags & UPF_LOW_LATENCY) ? 1 : 0;
tty->alt_speed = 0;
tty_port_tty_set(port, tty);
/*
* If the port is in the middle of closing, bail out now.
*/
if (tty_hung_up_p(filp)) {
retval = -EAGAIN;
port->count--;
mutex_unlock(&port->mutex);
goto fail;
}
/*
* Make sure the device is in D0 state.
*/
if (port->count == 1)
uart_change_pm(state, 0);
/*
* Start up the serial port.
*/
retval = uart_startup(state, 0);
/*
* If we succeeded, wait until the port is ready.
*/
if (retval == 0)
retval = uart_block_til_ready(filp, state);
mutex_unlock(&port->mutex);
/*
* If this is the first open to succeed, adjust things to suit.
*/
if (retval == 0 && !(port->flags & ASYNC_NORMAL_ACTIVE)) {
set_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
uart_update_termios(state);
}
fail:
return retval;
}
static const char *uart_type(struct uart_port *port)
{
const char *str = NULL;
if (port->ops->type)
str = port->ops->type(port);
if (!str)
str = "unknown";
return str;
}
#ifdef CONFIG_PROC_FS
static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
{
struct uart_state *state = drv->state + i;
struct tty_port *port = &state->port;
int pm_state;
struct uart_port *uport = state->uart_port;
char stat_buf[32];
unsigned int status;
int mmio;
if (!uport)
return;
mmio = uport->iotype >= UPIO_MEM;
seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
uport->line, uart_type(uport),
mmio ? "mmio:0x" : "port:",
mmio ? (unsigned long long)uport->mapbase
: (unsigned long long)uport->iobase,
uport->irq);
if (uport->type == PORT_UNKNOWN) {
seq_putc(m, '\n');
return;
}
if (capable(CAP_SYS_ADMIN)) {
mutex_lock(&port->mutex);
pm_state = state->pm_state;
if (pm_state)
uart_change_pm(state, 0);
spin_lock_irq(&uport->lock);
status = uport->ops->get_mctrl(uport);
spin_unlock_irq(&uport->lock);
if (pm_state)
uart_change_pm(state, pm_state);
mutex_unlock(&port->mutex);
seq_printf(m, " tx:%d rx:%d",
uport->icount.tx, uport->icount.rx);
if (uport->icount.frame)
seq_printf(m, " fe:%d",
uport->icount.frame);
if (uport->icount.parity)
seq_printf(m, " pe:%d",
uport->icount.parity);
if (uport->icount.brk)
seq_printf(m, " brk:%d",
uport->icount.brk);
if (uport->icount.overrun)
seq_printf(m, " oe:%d",
uport->icount.overrun);
#define INFOBIT(bit, str) \
if (uport->mctrl & (bit)) \
strncat(stat_buf, (str), sizeof(stat_buf) - \
strlen(stat_buf) - 2)
#define STATBIT(bit, str) \
if (status & (bit)) \
strncat(stat_buf, (str), sizeof(stat_buf) - \
strlen(stat_buf) - 2)
stat_buf[0] = '\0';
stat_buf[1] = '\0';
INFOBIT(TIOCM_RTS, "|RTS");
STATBIT(TIOCM_CTS, "|CTS");
INFOBIT(TIOCM_DTR, "|DTR");
STATBIT(TIOCM_DSR, "|DSR");
STATBIT(TIOCM_CAR, "|CD");
STATBIT(TIOCM_RNG, "|RI");
if (stat_buf[0])
stat_buf[0] = ' ';
seq_puts(m, stat_buf);
}
seq_putc(m, '\n');
#undef STATBIT
#undef INFOBIT
}
static int uart_proc_show(struct seq_file *m, void *v)
{
struct tty_driver *ttydrv = m->private;
struct uart_driver *drv = ttydrv->driver_state;
int i;
seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n",
"", "", "");
for (i = 0; i < drv->nr; i++)
uart_line_info(m, drv, i);
return 0;
}
static int uart_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, uart_proc_show, PDE(inode)->data);
}
static const struct file_operations uart_proc_fops = {
.owner = THIS_MODULE,
.open = uart_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
#endif
#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
/*
* uart_console_write - write a console message to a serial port
* @port: the port to write the message
* @s: array of characters
* @count: number of characters in string to write
* @write: function to write character to port
*/
void uart_console_write(struct uart_port *port, const char *s,
unsigned int count,
void (*putchar)(struct uart_port *, int))
{
unsigned int i;
for (i = 0; i < count; i++, s++) {
if (*s == '\n')
putchar(port, '\r');
putchar(port, *s);
}
}
EXPORT_SYMBOL_GPL(uart_console_write);
/*
* Check whether an invalid uart number has been specified, and
* if so, search for the first available port that does have
* console support.
*/
struct uart_port * __init
uart_get_console(struct uart_port *ports, int nr, struct console *co)
{
int idx = co->index;
if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
ports[idx].membase == NULL))
for (idx = 0; idx < nr; idx++)
if (ports[idx].iobase != 0 ||
ports[idx].membase != NULL)
break;
co->index = idx;
return ports + idx;
}
/**
* uart_parse_options - Parse serial port baud/parity/bits/flow contro.
* @options: pointer to option string
* @baud: pointer to an 'int' variable for the baud rate.
* @parity: pointer to an 'int' variable for the parity.
* @bits: pointer to an 'int' variable for the number of data bits.
* @flow: pointer to an 'int' variable for the flow control character.
*
* uart_parse_options decodes a string containing the serial console
* options. The format of the string is <baud><parity><bits><flow>,
* eg: 115200n8r
*/
void
uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
{
char *s = options;
*baud = simple_strtoul(s, NULL, 10);
while (*s >= '0' && *s <= '9')
s++;
if (*s)
*parity = *s++;
if (*s)
*bits = *s++ - '0';
if (*s)
*flow = *s;
}
EXPORT_SYMBOL_GPL(uart_parse_options);
struct baud_rates {
unsigned int rate;
unsigned int cflag;
};
static const struct baud_rates baud_rates[] = {
{ 921600, B921600 },
{ 460800, B460800 },
{ 230400, B230400 },
{ 115200, B115200 },
{ 57600, B57600 },
{ 38400, B38400 },
{ 19200, B19200 },
{ 9600, B9600 },
{ 4800, B4800 },
{ 2400, B2400 },
{ 1200, B1200 },
{ 0, B38400 }
};
/**
* uart_set_options - setup the serial console parameters
* @port: pointer to the serial ports uart_port structure
* @co: console pointer
* @baud: baud rate
* @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
* @bits: number of data bits
* @flow: flow control character - 'r' (rts)
*/
int
uart_set_options(struct uart_port *port, struct console *co,
int baud, int parity, int bits, int flow)
{
struct ktermios termios;
static struct ktermios dummy;
int i;
/*
* Ensure that the serial console lock is initialised
* early.
*/
spin_lock_init(&port->lock);
lockdep_set_class(&port->lock, &port_lock_key);
memset(&termios, 0, sizeof(struct ktermios));
termios.c_cflag = CREAD | HUPCL | CLOCAL;
/*
* Construct a cflag setting.
*/
for (i = 0; baud_rates[i].rate; i++)
if (baud_rates[i].rate <= baud)
break;
termios.c_cflag |= baud_rates[i].cflag;
if (bits == 7)
termios.c_cflag |= CS7;
else
termios.c_cflag |= CS8;
switch (parity) {
case 'o': case 'O':
termios.c_cflag |= PARODD;
/*fall through*/
case 'e': case 'E':
termios.c_cflag |= PARENB;
break;
}
if (flow == 'r')
termios.c_cflag |= CRTSCTS;
/*
* some uarts on other side don't support no flow control.
* So we set * DTR in host uart to make them happy
*/
port->mctrl |= TIOCM_DTR;
port->ops->set_termios(port, &termios, &dummy);
/*
* Allow the setting of the UART parameters with a NULL console
* too:
*/
if (co)
co->cflag = termios.c_cflag;
return 0;
}
EXPORT_SYMBOL_GPL(uart_set_options);
#endif /* CONFIG_SERIAL_CORE_CONSOLE */
static void uart_change_pm(struct uart_state *state, int pm_state)
{
struct uart_port *port = state->uart_port;
if (state->pm_state != pm_state) {
if (port->ops->pm)
port->ops->pm(port, pm_state, state->pm_state);
state->pm_state = pm_state;
}
}
struct uart_match {
struct uart_port *port;
struct uart_driver *driver;
};
static int serial_match_port(struct device *dev, void *data)
{
struct uart_match *match = data;
struct tty_driver *tty_drv = match->driver->tty_driver;
dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
match->port->line;
return dev->devt == devt; /* Actually, only one tty per port */
}
int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
{
struct uart_state *state = drv->state + uport->line;
struct tty_port *port = &state->port;
struct device *tty_dev;
struct uart_match match = {uport, drv};
mutex_lock(&port->mutex);
tty_dev = device_find_child(uport->dev, &match, serial_match_port);
if (device_may_wakeup(tty_dev)) {
enable_irq_wake(uport->irq);
put_device(tty_dev);
mutex_unlock(&port->mutex);
return 0;
}
if (console_suspend_enabled || !uart_console(uport))
uport->suspended = 1;
if (port->flags & ASYNC_INITIALIZED) {
const struct uart_ops *ops = uport->ops;
int tries;
if (console_suspend_enabled || !uart_console(uport)) {
set_bit(ASYNCB_SUSPENDED, &port->flags);
clear_bit(ASYNCB_INITIALIZED, &port->flags);
spin_lock_irq(&uport->lock);
ops->stop_tx(uport);
ops->set_mctrl(uport, 0);
ops->stop_rx(uport);
spin_unlock_irq(&uport->lock);
}
/*
* Wait for the transmitter to empty.
*/
for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
msleep(10);
if (!tries)
printk(KERN_ERR "%s%s%s%d: Unable to drain "
"transmitter\n",
uport->dev ? dev_name(uport->dev) : "",
uport->dev ? ": " : "",
drv->dev_name,
drv->tty_driver->name_base + uport->line);
if (console_suspend_enabled || !uart_console(uport))
ops->shutdown(uport);
}
/*
* Disable the console device before suspending.
*/
if (console_suspend_enabled && uart_console(uport))
console_stop(uport->cons);
if (console_suspend_enabled || !uart_console(uport))
uart_change_pm(state, 3);
mutex_unlock(&port->mutex);
return 0;
}
int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
{
struct uart_state *state = drv->state + uport->line;
struct tty_port *port = &state->port;
struct device *tty_dev;
struct uart_match match = {uport, drv};
struct ktermios termios;
mutex_lock(&port->mutex);
tty_dev = device_find_child(uport->dev, &match, serial_match_port);
if (!uport->suspended && device_may_wakeup(tty_dev)) {
disable_irq_wake(uport->irq);
mutex_unlock(&port->mutex);
return 0;
}
uport->suspended = 0;
/*
* Re-enable the console device after suspending.
*/
if (uart_console(uport)) {
uart_change_pm(state, 0);
uport->ops->set_termios(uport, &termios, NULL);
console_start(uport->cons);
}
if (port->flags & ASYNC_SUSPENDED) {
const struct uart_ops *ops = uport->ops;
int ret;
uart_change_pm(state, 0);
spin_lock_irq(&uport->lock);
ops->set_mctrl(uport, 0);
spin_unlock_irq(&uport->lock);
if (console_suspend_enabled || !uart_console(uport)) {
ret = ops->startup(uport);
if (ret == 0) {
uart_change_speed(state, NULL);
spin_lock_irq(&uport->lock);
ops->set_mctrl(uport, uport->mctrl);
ops->start_tx(uport);
spin_unlock_irq(&uport->lock);
set_bit(ASYNCB_INITIALIZED, &port->flags);
} else {
/*
* Failed to resume - maybe hardware went away?
* Clear the "initialized" flag so we won't try
* to call the low level drivers shutdown method.
*/
uart_shutdown(state);
}
}
clear_bit(ASYNCB_SUSPENDED, &port->flags);
}
mutex_unlock(&port->mutex);
return 0;
}
static inline void
uart_report_port(struct uart_driver *drv, struct uart_port *port)
{
char address[64];
switch (port->iotype) {
case UPIO_PORT:
snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
break;
case UPIO_HUB6:
snprintf(address, sizeof(address),
"I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
break;
case UPIO_MEM:
case UPIO_MEM32:
case UPIO_AU:
case UPIO_TSI:
case UPIO_DWAPB:
snprintf(address, sizeof(address),
"MMIO 0x%llx", (unsigned long long)port->mapbase);
break;
default:
strlcpy(address, "*unknown*", sizeof(address));
break;
}
printk(KERN_INFO "%s%s%s%d at %s (irq = %d) is a %s\n",
port->dev ? dev_name(port->dev) : "",
port->dev ? ": " : "",
drv->dev_name,
drv->tty_driver->name_base + port->line,
address, port->irq, uart_type(port));
}
static void
uart_configure_port(struct uart_driver *drv, struct uart_state *state,
struct uart_port *port)
{
unsigned int flags;
/*
* If there isn't a port here, don't do anything further.
*/
if (!port->iobase && !port->mapbase && !port->membase)
return;
/*
* Now do the auto configuration stuff. Note that config_port
* is expected to claim the resources and map the port for us.
*/
flags = 0;
if (port->flags & UPF_AUTO_IRQ)
flags |= UART_CONFIG_IRQ;
if (port->flags & UPF_BOOT_AUTOCONF) {
if (!(port->flags & UPF_FIXED_TYPE)) {
port->type = PORT_UNKNOWN;
flags |= UART_CONFIG_TYPE;
}
port->ops->config_port(port, flags);
}
if (port->type != PORT_UNKNOWN) {
unsigned long flags;
uart_report_port(drv, port);
/* Power up port for set_mctrl() */
uart_change_pm(state, 0);
/*
* Ensure that the modem control lines are de-activated.
* keep the DTR setting that is set in uart_set_options()
* We probably don't need a spinlock around this, but
*/
spin_lock_irqsave(&port->lock, flags);
port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
spin_unlock_irqrestore(&port->lock, flags);
/*
* If this driver supports console, and it hasn't been
* successfully registered yet, try to re-register it.
* It may be that the port was not available.
*/
if (port->cons && !(port->cons->flags & CON_ENABLED))
register_console(port->cons);
/*
* Power down all ports by default, except the
* console if we have one.
*/
if (!uart_console(port))
uart_change_pm(state, 3);
}
}
#ifdef CONFIG_CONSOLE_POLL
static int uart_poll_init(struct tty_driver *driver, int line, char *options)
{
struct uart_driver *drv = driver->driver_state;
struct uart_state *state = drv->state + line;
struct uart_port *port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (!state || !state->uart_port)
return -1;
port = state->uart_port;
if (!(port->ops->poll_get_char && port->ops->poll_put_char))
return -1;
if (options) {
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, NULL, baud, parity, bits, flow);
}
return 0;
}
static int uart_poll_get_char(struct tty_driver *driver, int line)
{
struct uart_driver *drv = driver->driver_state;
struct uart_state *state = drv->state + line;
struct uart_port *port;
if (!state || !state->uart_port)
return -1;
port = state->uart_port;
return port->ops->poll_get_char(port);
}
static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
{
struct uart_driver *drv = driver->driver_state;
struct uart_state *state = drv->state + line;
struct uart_port *port;
if (!state || !state->uart_port)
return;
port = state->uart_port;
port->ops->poll_put_char(port, ch);
}
#endif
static const struct tty_operations uart_ops = {
.open = uart_open,
.close = uart_close,
.write = uart_write,
.put_char = uart_put_char,
.flush_chars = uart_flush_chars,
.write_room = uart_write_room,
.chars_in_buffer= uart_chars_in_buffer,
.flush_buffer = uart_flush_buffer,
.ioctl = uart_ioctl,
.throttle = uart_throttle,
.unthrottle = uart_unthrottle,
.send_xchar = uart_send_xchar,
.set_termios = uart_set_termios,
.set_ldisc = uart_set_ldisc,
.stop = uart_stop,
.start = uart_start,
.hangup = uart_hangup,
.break_ctl = uart_break_ctl,
.wait_until_sent= uart_wait_until_sent,
#ifdef CONFIG_PROC_FS
.proc_fops = &uart_proc_fops,
#endif
.tiocmget = uart_tiocmget,
.tiocmset = uart_tiocmset,
#ifdef CONFIG_CONSOLE_POLL
.poll_init = uart_poll_init,
.poll_get_char = uart_poll_get_char,
.poll_put_char = uart_poll_put_char,
#endif
};
/**
* uart_register_driver - register a driver with the uart core layer
* @drv: low level driver structure
*
* Register a uart driver with the core driver. We in turn register
* with the tty layer, and initialise the core driver per-port state.
*
* We have a proc file in /proc/tty/driver which is named after the
* normal driver.
*
* drv->port should be NULL, and the per-port structures should be
* registered using uart_add_one_port after this call has succeeded.
*/
int uart_register_driver(struct uart_driver *drv)
{
struct tty_driver *normal;
int i, retval;
BUG_ON(drv->state);
/*
* Maybe we should be using a slab cache for this, especially if
* we have a large number of ports to handle.
*/
drv->state = kzalloc(sizeof(struct uart_state) * drv->nr, GFP_KERNEL);
if (!drv->state)
goto out;
normal = alloc_tty_driver(drv->nr);
if (!normal)
goto out_kfree;
drv->tty_driver = normal;
normal->owner = drv->owner;
normal->driver_name = drv->driver_name;
normal->name = drv->dev_name;
normal->major = drv->major;
normal->minor_start = drv->minor;
normal->type = TTY_DRIVER_TYPE_SERIAL;
normal->subtype = SERIAL_TYPE_NORMAL;
normal->init_termios = tty_std_termios;
normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
normal->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
normal->driver_state = drv;
tty_set_operations(normal, &uart_ops);
/*
* Initialise the UART state(s).
*/
for (i = 0; i < drv->nr; i++) {
struct uart_state *state = drv->state + i;
struct tty_port *port = &state->port;
tty_port_init(port);
port->close_delay = 500; /* .5 seconds */
port->closing_wait = 30000; /* 30 seconds */
tasklet_init(&state->tlet, uart_tasklet_action,
(unsigned long)state);
}
retval = tty_register_driver(normal);
if (retval >= 0)
return retval;
put_tty_driver(normal);
out_kfree:
kfree(drv->state);
out:
return -ENOMEM;
}
/**
* uart_unregister_driver - remove a driver from the uart core layer
* @drv: low level driver structure
*
* Remove all references to a driver from the core driver. The low
* level driver must have removed all its ports via the
* uart_remove_one_port() if it registered them with uart_add_one_port().
* (ie, drv->port == NULL)
*/
void uart_unregister_driver(struct uart_driver *drv)
{
struct tty_driver *p = drv->tty_driver;
tty_unregister_driver(p);
put_tty_driver(p);
kfree(drv->state);
drv->tty_driver = NULL;
}
struct tty_driver *uart_console_device(struct console *co, int *index)
{
struct uart_driver *p = co->data;
*index = co->index;
return p->tty_driver;
}
/**
* uart_add_one_port - attach a driver-defined port structure
* @drv: pointer to the uart low level driver structure for this port
* @uport: uart port structure to use for this port.
*
* This allows the driver to register its own uart_port structure
* with the core driver. The main purpose is to allow the low
* level uart drivers to expand uart_port, rather than having yet
* more levels of structures.
*/
int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
{
struct uart_state *state;
struct tty_port *port;
int ret = 0;
struct device *tty_dev;
BUG_ON(in_interrupt());
if (uport->line >= drv->nr)
return -EINVAL;
state = drv->state + uport->line;
port = &state->port;
mutex_lock(&port_mutex);
mutex_lock(&port->mutex);
if (state->uart_port) {
ret = -EINVAL;
goto out;
}
state->uart_port = uport;
state->pm_state = -1;
uport->cons = drv->cons;
uport->state = state;
/*
* If this port is a console, then the spinlock is already
* initialised.
*/
if (!(uart_console(uport) && (uport->cons->flags & CON_ENABLED))) {
spin_lock_init(&uport->lock);
lockdep_set_class(&uport->lock, &port_lock_key);
}
uart_configure_port(drv, state, uport);
/*
* Register the port whether it's detected or not. This allows
* setserial to be used to alter this ports parameters.
*/
tty_dev = tty_register_device(drv->tty_driver, uport->line, uport->dev);
if (likely(!IS_ERR(tty_dev))) {
device_init_wakeup(tty_dev, 1);
device_set_wakeup_enable(tty_dev, 0);
} else
printk(KERN_ERR "Cannot register tty device on line %d\n",
uport->line);
/*
* Ensure UPF_DEAD is not set.
*/
uport->flags &= ~UPF_DEAD;
out:
mutex_unlock(&port->mutex);
mutex_unlock(&port_mutex);
return ret;
}
/**
* uart_remove_one_port - detach a driver defined port structure
* @drv: pointer to the uart low level driver structure for this port
* @uport: uart port structure for this port
*
* This unhooks (and hangs up) the specified port structure from the
* core driver. No further calls will be made to the low-level code
* for this port.
*/
int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
{
struct uart_state *state = drv->state + uport->line;
struct tty_port *port = &state->port;
BUG_ON(in_interrupt());
if (state->uart_port != uport)
printk(KERN_ALERT "Removing wrong port: %p != %p\n",
state->uart_port, uport);
mutex_lock(&port_mutex);
/*
* Mark the port "dead" - this prevents any opens from
* succeeding while we shut down the port.
*/
mutex_lock(&port->mutex);
uport->flags |= UPF_DEAD;
mutex_unlock(&port->mutex);
/*
* Remove the devices from the tty layer
*/
tty_unregister_device(drv->tty_driver, uport->line);
if (port->tty)
tty_vhangup(port->tty);
/*
* Free the port IO and memory resources, if any.
*/
if (uport->type != PORT_UNKNOWN)
uport->ops->release_port(uport);
/*
* Indicate that there isn't a port here anymore.
*/
uport->type = PORT_UNKNOWN;
/*
* Kill the tasklet, and free resources.
*/
tasklet_kill(&state->tlet);
state->uart_port = NULL;
mutex_unlock(&port_mutex);
return 0;
}
/*
* Are the two ports equivalent?
*/
int uart_match_port(struct uart_port *port1, struct uart_port *port2)
{
if (port1->iotype != port2->iotype)
return 0;
switch (port1->iotype) {
case UPIO_PORT:
return (port1->iobase == port2->iobase);
case UPIO_HUB6:
return (port1->iobase == port2->iobase) &&
(port1->hub6 == port2->hub6);
case UPIO_MEM:
case UPIO_MEM32:
case UPIO_AU:
case UPIO_TSI:
case UPIO_DWAPB:
return (port1->mapbase == port2->mapbase);
}
return 0;
}
EXPORT_SYMBOL(uart_match_port);
EXPORT_SYMBOL(uart_write_wakeup);
EXPORT_SYMBOL(uart_register_driver);
EXPORT_SYMBOL(uart_unregister_driver);
EXPORT_SYMBOL(uart_suspend_port);
EXPORT_SYMBOL(uart_resume_port);
EXPORT_SYMBOL(uart_add_one_port);
EXPORT_SYMBOL(uart_remove_one_port);
MODULE_DESCRIPTION("Serial driver core");
MODULE_LICENSE("GPL");
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