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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/drivers/serial/serial_core.c

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62 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/serial_core.h>
#include <linux/smp_lock.h>
#include <linux/device.h>
#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
#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)
#define uart_users(state) ((state)->count + (state)->info.port.blocked_open)
#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_info *info = port->info;
/*
* This means you called this function _after_ the port was
* closed. No cookie for you.
*/
BUG_ON(!info);
tasklet_schedule(&info->tlet);
}
static void uart_stop(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->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->port;
if (!uart_circ_empty(&state->info.xmit) && state->info.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->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->info.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_info *info = &state->info;
struct uart_port *port = state->port;
unsigned long page;
int retval = 0;
if (info->flags & UIF_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, &info->port.tty->flags);
if (port->type == PORT_UNKNOWN)
return 0;
/*
* Initialise and allocate the transmit and temporary
* buffer.
*/
if (!info->xmit.buf) {
/* This is protected by the per port mutex */
page = get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
info->xmit.buf = (unsigned char *) page;
uart_circ_clear(&info->xmit);
}
retval = port->ops->startup(port);
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 (info->port.tty->termios->c_cflag & CBAUD)
uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
}
if (info->flags & UIF_CTS_FLOW) {
spin_lock_irq(&port->lock);
if (!(port->ops->get_mctrl(port) & TIOCM_CTS))
info->port.tty->hw_stopped = 1;
spin_unlock_irq(&port->lock);
}
info->flags |= UIF_INITIALIZED;
clear_bit(TTY_IO_ERROR, &info->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_info *info = &state->info;
struct uart_port *port = state->port;
struct tty_struct *tty = info->port.tty;
/*
* Set the TTY IO error marker
*/
if (tty)
set_bit(TTY_IO_ERROR, &tty->flags);
if (info->flags & UIF_INITIALIZED) {
info->flags &= ~UIF_INITIALIZED;
/*
* Turn off DTR and RTS early.
*/
if (!tty || (tty->termios->c_cflag & HUPCL))
uart_clear_mctrl(port, 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(&info->delta_msr_wait);
/*
* Free the IRQ and disable the port.
*/
port->ops->shutdown(port);
/*
* Ensure that the IRQ handler isn't running on another CPU.
*/
synchronize_irq(port->irq);
}
/*
* kill off our tasklet
*/
tasklet_kill(&info->tlet);
/*
* Free the transmit buffer page.
*/
if (info->xmit.buf) {
free_page((unsigned long)info->xmit.buf);
info->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;
if (flags == UPF_SPD_VHI)
altbaud = 115200;
if (flags == UPF_SPD_SHI)
altbaud = 230400;
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 quotient is zero,
* default to 9600 bps
*/
if (!hung_up)
tty_termios_encode_baud_rate(termios, 9600, 9600);
}
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_struct *tty = state->info.port.tty;
struct uart_port *port = state->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 || port->type == PORT_UNKNOWN)
return;
termios = tty->termios;
/*
* Set flags based on termios cflag
*/
if (termios->c_cflag & CRTSCTS)
state->info.flags |= UIF_CTS_FLOW;
else
state->info.flags &= ~UIF_CTS_FLOW;
if (termios->c_cflag & CLOCAL)
state->info.flags &= ~UIF_CHECK_CD;
else
state->info.flags |= UIF_CHECK_CD;
port->ops->set_termios(port, 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->port, &state->info.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->port;
circ = &state->info.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->port->lock, flags);
ret = uart_circ_chars_free(&state->info.xmit);
spin_unlock_irqrestore(&state->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->port->lock, flags);
ret = uart_circ_chars_pending(&state->info.xmit);
spin_unlock_irqrestore(&state->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->port;
pr_debug("uart_flush_buffer(%d) called\n", tty->index);
spin_lock_irqsave(&port->lock, flags);
uart_circ_clear(&state->info.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->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->port, TIOCM_RTS);
}
static void uart_unthrottle(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->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 *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(&state->mutex);
tmp.type = port->type;
tmp.line = port->line;
tmp.port = port->iobase;
if (HIGH_BITS_OFFSET)
tmp.port_high = (long) port->iobase >> HIGH_BITS_OFFSET;
tmp.irq = port->irq;
tmp.flags = port->flags;
tmp.xmit_fifo_size = port->fifosize;
tmp.baud_base = port->uartclk / 16;
tmp.close_delay = state->close_delay / 10;
tmp.closing_wait = state->closing_wait == USF_CLOSING_WAIT_NONE ?
ASYNC_CLOSING_WAIT_NONE :
state->closing_wait / 10;
tmp.custom_divisor = port->custom_divisor;
tmp.hub6 = port->hub6;
tmp.io_type = port->iotype;
tmp.iomem_reg_shift = port->regshift;
tmp.iomem_base = (void *)(unsigned long)port->mapbase;
mutex_unlock(&state->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 *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 ?
USF_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
/*
* This semaphore protects state->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(&state->mutex);
change_irq = !(port->flags & UPF_FIXED_PORT)
&& new_serial.irq != port->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 = !(port->flags & UPF_FIXED_PORT)
&& (new_port != port->iobase ||
(unsigned long)new_serial.iomem_base != port->mapbase ||
new_serial.hub6 != port->hub6 ||
new_serial.io_type != port->iotype ||
new_serial.iomem_reg_shift != port->regshift ||
new_serial.type != port->type);
old_flags = port->flags;
new_flags = new_serial.flags;
old_custom_divisor = port->custom_divisor;
if (!capable(CAP_SYS_ADMIN)) {
retval = -EPERM;
if (change_irq || change_port ||
(new_serial.baud_base != port->uartclk / 16) ||
(close_delay != state->close_delay) ||
(closing_wait != state->closing_wait) ||
(new_serial.xmit_fifo_size &&
new_serial.xmit_fifo_size != port->fifosize) ||
(((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
goto exit;
port->flags = ((port->flags & ~UPF_USR_MASK) |
(new_flags & UPF_USR_MASK));
port->custom_divisor = new_serial.custom_divisor;
goto check_and_exit;
}
/*
* Ask the low level driver to verify the settings.
*/
if (port->ops->verify_port)
retval = port->ops->verify_port(port, &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 (uart_users(state) > 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 = port->iobase;
old_mapbase = port->mapbase;
old_type = port->type;
old_hub6 = port->hub6;
old_iotype = port->iotype;
old_shift = port->regshift;
/*
* Free and release old regions
*/
if (old_type != PORT_UNKNOWN)
port->ops->release_port(port);
port->iobase = new_port;
port->type = new_serial.type;
port->hub6 = new_serial.hub6;
port->iotype = new_serial.io_type;
port->regshift = new_serial.iomem_reg_shift;
port->mapbase = (unsigned long)new_serial.iomem_base;
/*
* Claim and map the new regions
*/
if (port->type != PORT_UNKNOWN) {
retval = port->ops->request_port(port);
} 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) {
port->iobase = old_iobase;
port->type = old_type;
port->hub6 = old_hub6;
port->iotype = old_iotype;
port->regshift = old_shift;
port->mapbase = old_mapbase;
retval = port->ops->request_port(port);
/*
* If we failed to restore the old settings,
* we fail like this.
*/
if (retval)
port->type = PORT_UNKNOWN;
/*
* We failed anyway.
*/
retval = -EBUSY;
/* Added to return the correct error -Ram Gupta */
goto exit;
}
}
if (change_irq)
port->irq = new_serial.irq;
if (!(port->flags & UPF_FIXED_PORT))
port->uartclk = new_serial.baud_base * 16;
port->flags = (port->flags & ~UPF_CHANGE_MASK) |
(new_flags & UPF_CHANGE_MASK);
port->custom_divisor = new_serial.custom_divisor;
state->close_delay = close_delay;
state->closing_wait = closing_wait;
if (new_serial.xmit_fifo_size)
port->fifosize = new_serial.xmit_fifo_size;
if (state->info.port.tty)
state->info.port.tty->low_latency =
(port->flags & UPF_LOW_LATENCY) ? 1 : 0;
check_and_exit:
retval = 0;
if (port->type == PORT_UNKNOWN)
goto exit;
if (state->info.flags & UIF_INITIALIZED) {
if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||
old_custom_divisor != port->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 (port->flags & UPF_SPD_MASK) {
char buf[64];
printk(KERN_NOTICE
"%s sets custom speed on %s. This "
"is deprecated.\n", current->comm,
tty_name(state->info.port.tty, buf));
}
uart_change_speed(state, NULL);
}
} else
retval = uart_startup(state, 1);
exit:
mutex_unlock(&state->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 *port = state->port;
unsigned int result;
result = port->ops->tx_empty(port);
/*
* 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 (port->x_char ||
((uart_circ_chars_pending(&state->info.xmit) > 0) &&
!state->info.port.tty->stopped && !state->info.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 uart_port *port = state->port;
int result = -EIO;
mutex_lock(&state->mutex);
if ((!file || !tty_hung_up_p(file)) &&
!(tty->flags & (1 << TTY_IO_ERROR))) {
result = port->mctrl;
spin_lock_irq(&port->lock);
result |= port->ops->get_mctrl(port);
spin_unlock_irq(&port->lock);
}
mutex_unlock(&state->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 *port = state->port;
int ret = -EIO;
mutex_lock(&state->mutex);
if ((!file || !tty_hung_up_p(file)) &&
!(tty->flags & (1 << TTY_IO_ERROR))) {
uart_update_mctrl(port, set, clear);
ret = 0;
}
mutex_unlock(&state->mutex);
return ret;
}
static int uart_break_ctl(struct tty_struct *tty, int break_state)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->port;
mutex_lock(&state->mutex);
if (port->type != PORT_UNKNOWN)
port->ops->break_ctl(port, break_state);
mutex_unlock(&state->mutex);
return 0;
}
static int uart_do_autoconfig(struct uart_state *state)
{
struct uart_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(&state->mutex))
return -ERESTARTSYS;
ret = -EBUSY;
if (uart_users(state) == 1) {
uart_shutdown(state);
/*
* If we already have a port type configured,
* we must release its resources.
*/
if (port->type != PORT_UNKNOWN)
port->ops->release_port(port);
flags = UART_CONFIG_TYPE;
if (port->flags & UPF_AUTO_IRQ)
flags |= UART_CONFIG_IRQ;
/*
* This will claim the ports resources if
* a port is found.
*/
port->ops->config_port(port, flags);
ret = uart_startup(state, 1);
}
mutex_unlock(&state->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
*/
static int
uart_wait_modem_status(struct uart_state *state, unsigned long arg)
{
struct uart_port *port = state->port;
DECLARE_WAITQUEUE(wait, current);
struct uart_icount cprev, cnow;
int ret;
/*
* note the counters on entry
*/
spin_lock_irq(&port->lock);
memcpy(&cprev, &port->icount, sizeof(struct uart_icount));
/*
* Force modem status interrupts on
*/
port->ops->enable_ms(port);
spin_unlock_irq(&port->lock);
add_wait_queue(&state->info.delta_msr_wait, &wait);
for (;;) {
spin_lock_irq(&port->lock);
memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
spin_unlock_irq(&port->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(&state->info.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 *port = state->port;
spin_lock_irq(&port->lock);
memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
spin_unlock_irq(&port->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;
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(&state->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 *port = state->port;
if (port->ops->ioctl)
ret = port->ops->ioctl(port, cmd, arg);
break;
}
}
out_up:
mutex_unlock(&state->mutex);
out:
return ret;
}
static void uart_set_ldisc(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->port;
if (port->ops->set_ldisc)
port->ops->set_ldisc(port);
}
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->port, TIOCM_RTS | TIOCM_DTR);
/* Handle transition away from B0 status */
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->port, mask);
}
/* Handle turning off CRTSCTS */
if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
spin_lock_irqsave(&state->port->lock, flags);
tty->hw_stopped = 0;
__uart_start(tty);
spin_unlock_irqrestore(&state->port->lock, flags);
}
/* Handle turning on CRTSCTS */
if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
spin_lock_irqsave(&state->port->lock, flags);
if (!(state->port->ops->get_mctrl(state->port) & TIOCM_CTS)) {
tty->hw_stopped = 1;
state->port->ops->stop_tx(state->port);
}
spin_unlock_irqrestore(&state->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(&info->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 uart_port *port;
BUG_ON(!kernel_locked());
if (!state || !state->port)
return;
port = state->port;
pr_debug("uart_close(%d) called\n", port->line);
mutex_lock(&state->mutex);
if (tty_hung_up_p(filp))
goto done;
if ((tty->count == 1) && (state->count != 1)) {
/*
* Uh, oh. tty->count is 1, which means that the tty
* structure will be freed. state->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, "
"state->count is %d\n", state->count);
state->count = 1;
}
if (--state->count < 0) {
printk(KERN_ERR "uart_close: bad serial port count for %s: %d\n",
tty->name, state->count);
state->count = 0;
}
if (state->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 (state->closing_wait != USF_CLOSING_WAIT_NONE)
tty_wait_until_sent(tty, msecs_to_jiffies(state->closing_wait));
/*
* At this point, we stop accepting input. To do this, we
* disable the receive line status interrupts.
*/
if (state->info.flags & UIF_INITIALIZED) {
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
port->ops->stop_rx(port);
spin_unlock_irqrestore(&port->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, port->timeout);
}
uart_shutdown(state);
uart_flush_buffer(tty);
tty_ldisc_flush(tty);
tty->closing = 0;
state->info.port.tty = NULL;
if (state->info.port.blocked_open) {
if (state->close_delay)
msleep_interruptible(state->close_delay);
} else if (!uart_console(port)) {
uart_change_pm(state, 3);
}
/*
* Wake up anyone trying to open this port.
*/
state->info.flags &= ~UIF_NORMAL_ACTIVE;
wake_up_interruptible(&state->info.port.open_wait);
done:
mutex_unlock(&state->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->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 uart_info *info = &state->info;
BUG_ON(!kernel_locked());
pr_debug("uart_hangup(%d)\n", state->port->line);
mutex_lock(&state->mutex);
if (info->flags & UIF_NORMAL_ACTIVE) {
uart_flush_buffer(tty);
uart_shutdown(state);
state->count = 0;
info->flags &= ~UIF_NORMAL_ACTIVE;
info->port.tty = NULL;
wake_up_interruptible(&info->port.open_wait);
wake_up_interruptible(&info->delta_msr_wait);
}
mutex_unlock(&state->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->info.port.tty;
struct uart_port *port = state->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_info *info = &state->info;
struct uart_port *port = state->port;
unsigned int mctrl;
info->port.blocked_open++;
state->count--;
add_wait_queue(&info->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) || info->port.tty == NULL)
break;
/*
* If the port has been closed, tell userspace/restart open.
*/
if (!(info->flags & UIF_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) ||
(info->port.tty->termios->c_cflag & CLOCAL) ||
(info->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 (info->port.tty->termios->c_cflag & CBAUD)
uart_set_mctrl(port, TIOCM_DTR);
/*
* and wait for the carrier to indicate that the
* modem is ready for us.
*/
spin_lock_irq(&port->lock);
port->ops->enable_ms(port);
mctrl = port->ops->get_mctrl(port);
spin_unlock_irq(&port->lock);
if (mctrl & TIOCM_CAR)
break;
mutex_unlock(&state->mutex);
schedule();
mutex_lock(&state->mutex);
if (signal_pending(current))
break;
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&info->port.open_wait, &wait);
state->count++;
info->port.blocked_open--;
if (signal_pending(current))
return -ERESTARTSYS;
if (!info->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;
int ret = 0;
state = drv->state + line;
if (mutex_lock_interruptible(&state->mutex)) {
ret = -ERESTARTSYS;
goto err;
}
state->count++;
if (!state->port || state->port->flags & UPF_DEAD) {
ret = -ENXIO;
goto err_unlock;
}
return state;
err_unlock:
state->count--;
mutex_unlock(&state->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;
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 info 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 info->port.tty will always contain something reasonable.
*/
state = uart_get(drv, line);
if (IS_ERR(state)) {
retval = PTR_ERR(state);
goto fail;
}
/*
* 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->port->info = &state->info;
tty->low_latency = (state->port->flags & UPF_LOW_LATENCY) ? 1 : 0;
tty->alt_speed = 0;
state->info.port.tty = tty;
/*
* If the port is in the middle of closing, bail out now.
*/
if (tty_hung_up_p(filp)) {
retval = -EAGAIN;
state->count--;
mutex_unlock(&state->mutex);
goto fail;
}
/*
* Make sure the device is in D0 state.
*/
if (state->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(&state->mutex);
/*
* If this is the first open to succeed, adjust things to suit.
*/
if (retval == 0 && !(state->info.flags & UIF_NORMAL_ACTIVE)) {
state->info.flags |= UIF_NORMAL_ACTIVE;
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;
int pm_state;
struct uart_port *port = state->port;
char stat_buf[32];
unsigned int status;
int mmio;
if (!port)
return;
mmio = port->iotype >= UPIO_MEM;
seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
port->line, uart_type(port),
mmio ? "mmio:0x" : "port:",
mmio ? (unsigned long long)port->mapbase
: (unsigned long long) port->iobase,
port->irq);
if (port->type == PORT_UNKNOWN) {
seq_putc(m, '\n');
return;
}
if (capable(CAP_SYS_ADMIN)) {
mutex_lock(&state->mutex);
pm_state = state->pm_state;
if (pm_state)
uart_change_pm(state, 0);
spin_lock_irq(&port->lock);
status = port->ops->get_mctrl(port);
spin_unlock_irq(&port->lock);
if (pm_state)
uart_change_pm(state, pm_state);
mutex_unlock(&state->mutex);
seq_printf(m, " tx:%d rx:%d",
port->icount.tx, port->icount.rx);
if (port->icount.frame)
seq_printf(m, " fe:%d",
port->icount.frame);
if (port->icount.parity)
seq_printf(m, " pe:%d",
port->icount.parity);
if (port->icount.brk)
seq_printf(m, " brk:%d",
port->icount.brk);
if (port->icount.overrun)
seq_printf(m, " oe:%d",
port->icount.overrun);
#define INFOBIT(bit, str) \
if (port->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->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 *port)
{
struct uart_state *state = drv->state + port->line;
struct device *tty_dev;
struct uart_match match = {port, drv};
mutex_lock(&state->mutex);
if (!console_suspend_enabled && uart_console(port)) {
/* we're going to avoid suspending serial console */
mutex_unlock(&state->mutex);
return 0;
}
tty_dev = device_find_child(port->dev, &match, serial_match_port);
if (device_may_wakeup(tty_dev)) {
enable_irq_wake(port->irq);
put_device(tty_dev);
mutex_unlock(&state->mutex);
return 0;
}
port->suspended = 1;
if (state->info.flags & UIF_INITIALIZED) {
const struct uart_ops *ops = port->ops;
int tries;
state->info.flags = (state->info.flags & ~UIF_INITIALIZED)
| UIF_SUSPENDED;
spin_lock_irq(&port->lock);
ops->stop_tx(port);
ops->set_mctrl(port, 0);
ops->stop_rx(port);
spin_unlock_irq(&port->lock);
/*
* Wait for the transmitter to empty.
*/
for (tries = 3; !ops->tx_empty(port) && tries; tries--)
msleep(10);
if (!tries)
printk(KERN_ERR "%s%s%s%d: Unable to drain "
"transmitter\n",
port->dev ? dev_name(port->dev) : "",
port->dev ? ": " : "",
drv->dev_name,
drv->tty_driver->name_base + port->line);
ops->shutdown(port);
}
/*
* Disable the console device before suspending.
*/
if (uart_console(port))
console_stop(port->cons);
uart_change_pm(state, 3);
mutex_unlock(&state->mutex);
return 0;
}
int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
{
struct uart_state *state = drv->state + port->line;
struct device *tty_dev;
struct uart_match match = {port, drv};
mutex_lock(&state->mutex);
if (!console_suspend_enabled && uart_console(port)) {
/* no need to resume serial console, it wasn't suspended */
mutex_unlock(&state->mutex);
return 0;
}
tty_dev = device_find_child(port->dev, &match, serial_match_port);
if (!port->suspended && device_may_wakeup(tty_dev)) {
disable_irq_wake(port->irq);
mutex_unlock(&state->mutex);
return 0;
}
port->suspended = 0;
/*
* Re-enable the console device after suspending.
*/
if (uart_console(port)) {
struct ktermios termios;
/*
* First try to use the console cflag setting.
*/
memset(&termios, 0, sizeof(struct ktermios));
termios.c_cflag = port->cons->cflag;
/*
* If that's unset, use the tty termios setting.
*/
if (state->info.port.tty && termios.c_cflag == 0)
termios = *state->info.port.tty->termios;
uart_change_pm(state, 0);
port->ops->set_termios(port, &termios, NULL);
console_start(port->cons);
}
if (state->info.flags & UIF_SUSPENDED) {
const struct uart_ops *ops = port->ops;
int ret;
uart_change_pm(state, 0);
spin_lock_irq(&port->lock);
ops->set_mctrl(port, 0);
spin_unlock_irq(&port->lock);
ret = ops->startup(port);
if (ret == 0) {
uart_change_speed(state, NULL);
spin_lock_irq(&port->lock);
ops->set_mctrl(port, port->mctrl);
ops->start_tx(port);
spin_unlock_irq(&port->lock);
state->info.flags |= UIF_INITIALIZED;
} 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);
}
state->info.flags &= ~UIF_SUSPENDED;
}
mutex_unlock(&state->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->port)
return -1;
port = state->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->port)
return -1;
port = state->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->port)
return;
port = state->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 = NULL;
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);
retval = -ENOMEM;
if (!drv->state)
goto out;
normal = alloc_tty_driver(drv->nr);
if (!normal)
goto out;
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;
state->close_delay = 500; /* .5 seconds */
state->closing_wait = 30000; /* 30 seconds */
mutex_init(&state->mutex);
tty_port_init(&state->info.port);
init_waitqueue_head(&state->info.delta_msr_wait);
tasklet_init(&state->info.tlet, uart_tasklet_action,
(unsigned long)state);
}
retval = tty_register_driver(normal);
out:
if (retval < 0) {
put_tty_driver(normal);
kfree(drv->state);
}
return retval;
}
/**
* 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
* @port: 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 *port)
{
struct uart_state *state;
int ret = 0;
struct device *tty_dev;
BUG_ON(in_interrupt());
if (port->line >= drv->nr)
return -EINVAL;
state = drv->state + port->line;
mutex_lock(&port_mutex);
mutex_lock(&state->mutex);
if (state->port) {
ret = -EINVAL;
goto out;
}
state->port = port;
state->pm_state = -1;
port->cons = drv->cons;
port->info = &state->info;
/*
* If this port is a console, then the spinlock is already
* initialised.
*/
if (!(uart_console(port) && (port->cons->flags & CON_ENABLED))) {
spin_lock_init(&port->lock);
lockdep_set_class(&port->lock, &port_lock_key);
}
uart_configure_port(drv, state, port);
/*
* 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, port->line, port->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",
port->line);
/*
* Ensure UPF_DEAD is not set.
*/
port->flags &= ~UPF_DEAD;
out:
mutex_unlock(&state->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
* @port: 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 *port)
{
struct uart_state *state = drv->state + port->line;
struct uart_info *info;
BUG_ON(in_interrupt());
if (state->port != port)
printk(KERN_ALERT "Removing wrong port: %p != %p\n",
state->port, port);
mutex_lock(&port_mutex);
/*
* Mark the port "dead" - this prevents any opens from
* succeeding while we shut down the port.
*/
mutex_lock(&state->mutex);
port->flags |= UPF_DEAD;
mutex_unlock(&state->mutex);
/*
* Remove the devices from the tty layer
*/
tty_unregister_device(drv->tty_driver, port->line);
info = &state->info;
if (info && info->port.tty)
tty_vhangup(info->port.tty);
/*
* Free the port IO and memory resources, if any.
*/
if (port->type != PORT_UNKNOWN)
port->ops->release_port(port);
/*
* Indicate that there isn't a port here anymore.
*/
port->type = PORT_UNKNOWN;
/*
* Kill the tasklet, and free resources.
*/
if (info)
tasklet_kill(&info->tlet);
state->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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