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linux/drivers/tty/serial/serial_core.c
Ilpo Järvinen 31f6bd7fad serial: Store character timing information to uart_port 
Struct uart_port currently stores FIFO timeout. Having character timing
information readily available is useful. Even serial core itself
determines char_time from port->timeout using inverse calculation.

Store frame_time directly into uart_port. Character time is stored in
nanoseconds to have reasonable precision with high rates. To avoid
overflow, 64-bit math is necessary.

It might be possible to determine timeout from frame_time by
multiplying it with fifosize as needed but only part of the users seem
to be protected by a lock. Thus, this patch does not pursue storing
only frame_time in uart_port.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220425143410.12703-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-26 13:28:32 +02:00

3326 lines
82 KiB
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// SPDX-License-Identifier: GPL-2.0+
/*
* 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.
*/
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
#include <linux/serial_core.h>
#include <linux/sysrq.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/math64.h>
#include <linux/security.h>
#include <linux/irq.h>
#include <linux/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)
/*
* Max time with active RTS before/after data is sent.
*/
#define RS485_MAX_RTS_DELAY 100 /* msecs */
static void uart_change_speed(struct tty_struct *tty, 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,
enum uart_pm_state pm_state);
static void uart_port_shutdown(struct tty_port *port);
static int uart_dcd_enabled(struct uart_port *uport)
{
return !!(uport->status & UPSTAT_DCD_ENABLE);
}
static inline struct uart_port *uart_port_ref(struct uart_state *state)
{
if (atomic_add_unless(&state->refcount, 1, 0))
return state->uart_port;
return NULL;
}
static inline void uart_port_deref(struct uart_port *uport)
{
if (atomic_dec_and_test(&uport->state->refcount))
wake_up(&uport->state->remove_wait);
}
#define uart_port_lock(state, flags) \
({ \
struct uart_port *__uport = uart_port_ref(state); \
if (__uport) \
spin_lock_irqsave(&__uport->lock, flags); \
__uport; \
})
#define uart_port_unlock(uport, flags) \
({ \
struct uart_port *__uport = uport; \
if (__uport) { \
spin_unlock_irqrestore(&__uport->lock, flags); \
uart_port_deref(__uport); \
} \
})
static inline struct uart_port *uart_port_check(struct uart_state *state)
{
lockdep_assert_held(&state->port.mutex);
return state->uart_port;
}
/*
* 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);
tty_port_tty_wakeup(&state->port);
}
EXPORT_SYMBOL(uart_write_wakeup);
static void uart_stop(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
unsigned long flags;
port = uart_port_lock(state, flags);
if (port)
port->ops->stop_tx(port);
uart_port_unlock(port, flags);
}
static void __uart_start(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->uart_port;
if (port && !uart_tx_stopped(port))
port->ops->start_tx(port);
}
static void uart_start(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
unsigned long flags;
port = uart_port_lock(state, flags);
__uart_start(tty);
uart_port_unlock(port, flags);
}
static void
uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
{
unsigned long flags;
unsigned int old;
if (port->rs485.flags & SER_RS485_ENABLED) {
set &= ~TIOCM_RTS;
clear &= ~TIOCM_RTS;
}
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)
static void uart_port_dtr_rts(struct uart_port *uport, int raise)
{
if (raise)
uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
else
uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
}
/*
* Startup the port. This will be called once per open. All calls
* will be serialised by the per-port mutex.
*/
static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
int init_hw)
{
struct uart_port *uport = uart_port_check(state);
unsigned long flags;
unsigned long page;
int retval = 0;
if (uport->type == PORT_UNKNOWN)
return 1;
/*
* Make sure the device is in D0 state.
*/
uart_change_pm(state, UART_PM_STATE_ON);
/*
* Initialise and allocate the transmit and temporary
* buffer.
*/
page = get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
uart_port_lock(state, flags);
if (!state->xmit.buf) {
state->xmit.buf = (unsigned char *) page;
uart_circ_clear(&state->xmit);
uart_port_unlock(uport, flags);
} else {
uart_port_unlock(uport, flags);
/*
* Do not free() the page under the port lock, see
* uart_shutdown().
*/
free_page(page);
}
retval = uport->ops->startup(uport);
if (retval == 0) {
if (uart_console(uport) && uport->cons->cflag) {
tty->termios.c_cflag = uport->cons->cflag;
tty->termios.c_ispeed = uport->cons->ispeed;
tty->termios.c_ospeed = uport->cons->ospeed;
uport->cons->cflag = 0;
uport->cons->ispeed = 0;
uport->cons->ospeed = 0;
}
/*
* Initialise the hardware port settings.
*/
uart_change_speed(tty, state, NULL);
/*
* Setup the RTS and DTR signals once the
* port is open and ready to respond.
*/
if (init_hw && C_BAUD(tty))
uart_port_dtr_rts(uport, 1);
}
/*
* This is to allow setserial on this port. People may want to set
* port/irq/type and then reconfigure the port properly if it failed
* now.
*/
if (retval && capable(CAP_SYS_ADMIN))
return 1;
return retval;
}
static int uart_startup(struct tty_struct *tty, struct uart_state *state,
int init_hw)
{
struct tty_port *port = &state->port;
int retval;
if (tty_port_initialized(port))
return 0;
retval = uart_port_startup(tty, state, init_hw);
if (retval)
set_bit(TTY_IO_ERROR, &tty->flags);
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.
*
* uport == NULL if uart_port has already been removed
*/
static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
{
struct uart_port *uport = uart_port_check(state);
struct tty_port *port = &state->port;
unsigned long flags;
char *xmit_buf = NULL;
/*
* Set the TTY IO error marker
*/
if (tty)
set_bit(TTY_IO_ERROR, &tty->flags);
if (tty_port_initialized(port)) {
tty_port_set_initialized(port, 0);
/*
* Turn off DTR and RTS early.
*/
if (uport && uart_console(uport) && tty) {
uport->cons->cflag = tty->termios.c_cflag;
uport->cons->ispeed = tty->termios.c_ispeed;
uport->cons->ospeed = tty->termios.c_ospeed;
}
if (!tty || C_HUPCL(tty))
uart_port_dtr_rts(uport, 0);
uart_port_shutdown(port);
}
/*
* It's possible for shutdown to be called after suspend if we get
* a DCD drop (hangup) at just the right time. Clear suspended bit so
* we don't try to resume a port that has been shutdown.
*/
tty_port_set_suspended(port, 0);
/*
* Do not free() the transmit buffer page under the port lock since
* this can create various circular locking scenarios. For instance,
* console driver may need to allocate/free a debug object, which
* can endup in printk() recursion.
*/
uart_port_lock(state, flags);
xmit_buf = state->xmit.buf;
state->xmit.buf = NULL;
uart_port_unlock(uport, flags);
free_page((unsigned long)xmit_buf);
}
/**
* 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 size = tty_get_frame_size(cflag);
u64 frame_time;
frame_time = (u64)size * NSEC_PER_SEC;
size *= port->fifosize;
/*
* Figure the timeout to send the above number of bits.
* Add .02 seconds of slop
*/
port->timeout = (HZ * size) / baud + HZ/50;
port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
}
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;
unsigned int baud;
unsigned int altbaud;
int hung_up = 0;
upf_t flags = port->flags & UPF_SPD_MASK;
switch (flags) {
case UPF_SPD_HI:
altbaud = 57600;
break;
case UPF_SPD_VHI:
altbaud = 115200;
break;
case UPF_SPD_SHI:
altbaud = 230400;
break;
case UPF_SPD_WARP:
altbaud = 460800;
break;
default:
altbaud = 38400;
break;
}
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 (try == 0 && 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 = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
return quot;
}
EXPORT_SYMBOL(uart_get_divisor);
/* Caller holds port mutex */
static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
struct ktermios *old_termios)
{
struct uart_port *uport = uart_port_check(state);
struct ktermios *termios;
int hw_stopped;
/*
* If we have no tty, termios, or the port does not exist,
* then we can't set the parameters for this port.
*/
if (!tty || uport->type == PORT_UNKNOWN)
return;
termios = &tty->termios;
uport->ops->set_termios(uport, termios, old_termios);
/*
* Set modem status enables based on termios cflag
*/
spin_lock_irq(&uport->lock);
if (termios->c_cflag & CRTSCTS)
uport->status |= UPSTAT_CTS_ENABLE;
else
uport->status &= ~UPSTAT_CTS_ENABLE;
if (termios->c_cflag & CLOCAL)
uport->status &= ~UPSTAT_DCD_ENABLE;
else
uport->status |= UPSTAT_DCD_ENABLE;
/* reset sw-assisted CTS flow control based on (possibly) new mode */
hw_stopped = uport->hw_stopped;
uport->hw_stopped = uart_softcts_mode(uport) &&
!(uport->ops->get_mctrl(uport) & TIOCM_CTS);
if (uport->hw_stopped) {
if (!hw_stopped)
uport->ops->stop_tx(uport);
} else {
if (hw_stopped)
__uart_start(tty);
}
spin_unlock_irq(&uport->lock);
}
static int uart_put_char(struct tty_struct *tty, unsigned char c)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
struct circ_buf *circ;
unsigned long flags;
int ret = 0;
circ = &state->xmit;
port = uart_port_lock(state, flags);
if (!circ->buf) {
uart_port_unlock(port, flags);
return 0;
}
if (port && uart_circ_chars_free(circ) != 0) {
circ->buf[circ->head] = c;
circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
ret = 1;
}
uart_port_unlock(port, flags);
return ret;
}
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 = uart_port_lock(state, flags);
circ = &state->xmit;
if (!circ->buf) {
uart_port_unlock(port, flags);
return 0;
}
while (port) {
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;
}
__uart_start(tty);
uart_port_unlock(port, flags);
return ret;
}
static unsigned int uart_write_room(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
unsigned long flags;
unsigned int ret;
port = uart_port_lock(state, flags);
ret = uart_circ_chars_free(&state->xmit);
uart_port_unlock(port, flags);
return ret;
}
static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
unsigned long flags;
unsigned int ret;
port = uart_port_lock(state, flags);
ret = uart_circ_chars_pending(&state->xmit);
uart_port_unlock(port, 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;
}
pr_debug("uart_flush_buffer(%d) called\n", tty->index);
port = uart_port_lock(state, flags);
if (!port)
return;
uart_circ_clear(&state->xmit);
if (port->ops->flush_buffer)
port->ops->flush_buffer(port);
uart_port_unlock(port, flags);
tty_port_tty_wakeup(&state->port);
}
/*
* This function performs low-level write of high-priority XON/XOFF
* character and accounting for it.
*
* Requires uart_port to implement .serial_out().
*/
void uart_xchar_out(struct uart_port *uport, int offset)
{
serial_port_out(uport, offset, uport->x_char);
uport->icount.tx++;
uport->x_char = 0;
}
EXPORT_SYMBOL_GPL(uart_xchar_out);
/*
* 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;
unsigned long flags;
port = uart_port_ref(state);
if (!port)
return;
if (port->ops->send_xchar)
port->ops->send_xchar(port, ch);
else {
spin_lock_irqsave(&port->lock, flags);
port->x_char = ch;
if (ch)
port->ops->start_tx(port);
spin_unlock_irqrestore(&port->lock, flags);
}
uart_port_deref(port);
}
static void uart_throttle(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
upstat_t mask = UPSTAT_SYNC_FIFO;
struct uart_port *port;
port = uart_port_ref(state);
if (!port)
return;
if (I_IXOFF(tty))
mask |= UPSTAT_AUTOXOFF;
if (C_CRTSCTS(tty))
mask |= UPSTAT_AUTORTS;
if (port->status & mask) {
port->ops->throttle(port);
mask &= ~port->status;
}
if (mask & UPSTAT_AUTORTS)
uart_clear_mctrl(port, TIOCM_RTS);
if (mask & UPSTAT_AUTOXOFF)
uart_send_xchar(tty, STOP_CHAR(tty));
uart_port_deref(port);
}
static void uart_unthrottle(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
upstat_t mask = UPSTAT_SYNC_FIFO;
struct uart_port *port;
port = uart_port_ref(state);
if (!port)
return;
if (I_IXOFF(tty))
mask |= UPSTAT_AUTOXOFF;
if (C_CRTSCTS(tty))
mask |= UPSTAT_AUTORTS;
if (port->status & mask) {
port->ops->unthrottle(port);
mask &= ~port->status;
}
if (mask & UPSTAT_AUTORTS)
uart_set_mctrl(port, TIOCM_RTS);
if (mask & UPSTAT_AUTOXOFF)
uart_send_xchar(tty, START_CHAR(tty));
uart_port_deref(port);
}
static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport;
int ret = -ENODEV;
/*
* Ensure the state we copy is consistent and no hardware changes
* occur as we go
*/
mutex_lock(&port->mutex);
uport = uart_port_check(state);
if (!uport)
goto out;
retinfo->type = uport->type;
retinfo->line = uport->line;
retinfo->port = uport->iobase;
if (HIGH_BITS_OFFSET)
retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
retinfo->irq = uport->irq;
retinfo->flags = (__force int)uport->flags;
retinfo->xmit_fifo_size = uport->fifosize;
retinfo->baud_base = uport->uartclk / 16;
retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
ASYNC_CLOSING_WAIT_NONE :
jiffies_to_msecs(port->closing_wait) / 10;
retinfo->custom_divisor = uport->custom_divisor;
retinfo->hub6 = uport->hub6;
retinfo->io_type = uport->iotype;
retinfo->iomem_reg_shift = uport->regshift;
retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
ret = 0;
out:
mutex_unlock(&port->mutex);
return ret;
}
static int uart_get_info_user(struct tty_struct *tty,
struct serial_struct *ss)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
return uart_get_info(port, ss) < 0 ? -EIO : 0;
}
static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
struct uart_state *state,
struct serial_struct *new_info)
{
struct uart_port *uport = uart_port_check(state);
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 (!uport)
return -EIO;
new_port = new_info->port;
if (HIGH_BITS_OFFSET)
new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
new_info->irq = irq_canonicalize(new_info->irq);
close_delay = msecs_to_jiffies(new_info->close_delay * 10);
closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
ASYNC_CLOSING_WAIT_NONE :
msecs_to_jiffies(new_info->closing_wait * 10);
change_irq = !(uport->flags & UPF_FIXED_PORT)
&& new_info->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_info->iomem_base != uport->mapbase ||
new_info->hub6 != uport->hub6 ||
new_info->io_type != uport->iotype ||
new_info->iomem_reg_shift != uport->regshift ||
new_info->type != uport->type);
old_flags = uport->flags;
new_flags = (__force upf_t)new_info->flags;
old_custom_divisor = uport->custom_divisor;
if (!capable(CAP_SYS_ADMIN)) {
retval = -EPERM;
if (change_irq || change_port ||
(new_info->baud_base != uport->uartclk / 16) ||
(close_delay != port->close_delay) ||
(closing_wait != port->closing_wait) ||
(new_info->xmit_fifo_size &&
new_info->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_info->custom_divisor;
goto check_and_exit;
}
if (change_irq || change_port) {
retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
if (retval)
goto exit;
}
/*
* Ask the low level driver to verify the settings.
*/
if (uport->ops->verify_port)
retval = uport->ops->verify_port(uport, new_info);
if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
(new_info->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(tty, 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->ops->release_port(uport);
uport->iobase = new_port;
uport->type = new_info->type;
uport->hub6 = new_info->hub6;
uport->iotype = new_info->io_type;
uport->regshift = new_info->iomem_reg_shift;
uport->mapbase = (unsigned long)new_info->iomem_base;
/*
* Claim and map the new regions
*/
if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
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) {
uport->iobase = old_iobase;
uport->type = old_type;
uport->hub6 = old_hub6;
uport->iotype = old_iotype;
uport->regshift = old_shift;
uport->mapbase = old_mapbase;
if (old_type != PORT_UNKNOWN) {
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_info->irq;
if (!(uport->flags & UPF_FIXED_PORT))
uport->uartclk = new_info->baud_base * 16;
uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
(new_flags & UPF_CHANGE_MASK);
uport->custom_divisor = new_info->custom_divisor;
port->close_delay = close_delay;
port->closing_wait = closing_wait;
if (new_info->xmit_fifo_size)
uport->fifosize = new_info->xmit_fifo_size;
check_and_exit:
retval = 0;
if (uport->type == PORT_UNKNOWN)
goto exit;
if (tty_port_initialized(port)) {
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.
*/
if (uport->flags & UPF_SPD_MASK) {
dev_notice_ratelimited(uport->dev,
"%s sets custom speed on %s. This is deprecated.\n",
current->comm,
tty_name(port->tty));
}
uart_change_speed(tty, state, NULL);
}
} else {
retval = uart_startup(tty, state, 1);
if (retval == 0)
tty_port_set_initialized(port, true);
if (retval > 0)
retval = 0;
}
exit:
return retval;
}
static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
int retval;
down_write(&tty->termios_rwsem);
/*
* 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);
retval = uart_set_info(tty, port, state, ss);
mutex_unlock(&port->mutex);
up_write(&tty->termios_rwsem);
return retval;
}
/**
* uart_get_lsr_info - get line status register info
* @tty: tty associated with the UART
* @state: UART being queried
* @value: returned modem value
*/
static int uart_get_lsr_info(struct tty_struct *tty,
struct uart_state *state, unsigned int __user *value)
{
struct uart_port *uport = uart_port_check(state);
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) &&
!uart_tx_stopped(uport)))
result &= ~TIOCSER_TEMT;
return put_user(result, value);
}
static int uart_tiocmget(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
struct uart_port *uport;
int result = -EIO;
mutex_lock(&port->mutex);
uport = uart_port_check(state);
if (!uport)
goto out;
if (!tty_io_error(tty)) {
result = uport->mctrl;
spin_lock_irq(&uport->lock);
result |= uport->ops->get_mctrl(uport);
spin_unlock_irq(&uport->lock);
}
out:
mutex_unlock(&port->mutex);
return result;
}
static int
uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
struct uart_port *uport;
int ret = -EIO;
mutex_lock(&port->mutex);
uport = uart_port_check(state);
if (!uport)
goto out;
if (!tty_io_error(tty)) {
uart_update_mctrl(uport, set, clear);
ret = 0;
}
out:
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;
int ret = -EIO;
mutex_lock(&port->mutex);
uport = uart_port_check(state);
if (!uport)
goto out;
if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
uport->ops->break_ctl(uport, break_state);
ret = 0;
out:
mutex_unlock(&port->mutex);
return ret;
}
static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
{
struct tty_port *port = &state->port;
struct uart_port *uport;
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;
uport = uart_port_check(state);
if (!uport) {
ret = -EIO;
goto out;
}
ret = -EBUSY;
if (tty_port_users(port) == 1) {
uart_shutdown(tty, state);
/*
* If we already have a port type configured,
* we must release its resources.
*/
if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
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(tty, state, 1);
if (ret == 0)
tty_port_set_initialized(port, true);
if (ret > 0)
ret = 0;
}
out:
mutex_unlock(&port->mutex);
return ret;
}
static void uart_enable_ms(struct uart_port *uport)
{
/*
* Force modem status interrupts on
*/
if (uport->ops->enable_ms)
uport->ops->enable_ms(uport);
}
/*
* 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;
struct tty_port *port = &state->port;
DECLARE_WAITQUEUE(wait, current);
struct uart_icount cprev, cnow;
int ret;
/*
* note the counters on entry
*/
uport = uart_port_ref(state);
if (!uport)
return -EIO;
spin_lock_irq(&uport->lock);
memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
uart_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;
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(&port->delta_msr_wait, &wait);
uart_port_deref(uport);
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_icount(struct tty_struct *tty,
struct serial_icounter_struct *icount)
{
struct uart_state *state = tty->driver_data;
struct uart_icount cnow;
struct uart_port *uport;
uport = uart_port_ref(state);
if (!uport)
return -EIO;
spin_lock_irq(&uport->lock);
memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
spin_unlock_irq(&uport->lock);
uart_port_deref(uport);
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 0;
}
static int uart_get_rs485_config(struct uart_port *port,
struct serial_rs485 __user *rs485)
{
unsigned long flags;
struct serial_rs485 aux;
spin_lock_irqsave(&port->lock, flags);
aux = port->rs485;
spin_unlock_irqrestore(&port->lock, flags);
if (copy_to_user(rs485, &aux, sizeof(aux)))
return -EFAULT;
return 0;
}
static int uart_set_rs485_config(struct uart_port *port,
struct serial_rs485 __user *rs485_user)
{
struct serial_rs485 rs485;
int ret;
unsigned long flags;
if (!port->rs485_config)
return -ENOTTY;
if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
return -EFAULT;
/* pick sane settings if the user hasn't */
if (!(rs485.flags & SER_RS485_RTS_ON_SEND) ==
!(rs485.flags & SER_RS485_RTS_AFTER_SEND)) {
dev_warn_ratelimited(port->dev,
"%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
port->name, port->line);
rs485.flags |= SER_RS485_RTS_ON_SEND;
rs485.flags &= ~SER_RS485_RTS_AFTER_SEND;
}
if (rs485.delay_rts_before_send > RS485_MAX_RTS_DELAY) {
rs485.delay_rts_before_send = RS485_MAX_RTS_DELAY;
dev_warn_ratelimited(port->dev,
"%s (%d): RTS delay before sending clamped to %u ms\n",
port->name, port->line, rs485.delay_rts_before_send);
}
if (rs485.delay_rts_after_send > RS485_MAX_RTS_DELAY) {
rs485.delay_rts_after_send = RS485_MAX_RTS_DELAY;
dev_warn_ratelimited(port->dev,
"%s (%d): RTS delay after sending clamped to %u ms\n",
port->name, port->line, rs485.delay_rts_after_send);
}
/* Return clean padding area to userspace */
memset(rs485.padding, 0, sizeof(rs485.padding));
spin_lock_irqsave(&port->lock, flags);
ret = port->rs485_config(port, &rs485);
if (!ret)
port->rs485 = rs485;
spin_unlock_irqrestore(&port->lock, flags);
if (ret)
return ret;
if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
return -EFAULT;
return 0;
}
static int uart_get_iso7816_config(struct uart_port *port,
struct serial_iso7816 __user *iso7816)
{
unsigned long flags;
struct serial_iso7816 aux;
if (!port->iso7816_config)
return -ENOTTY;
spin_lock_irqsave(&port->lock, flags);
aux = port->iso7816;
spin_unlock_irqrestore(&port->lock, flags);
if (copy_to_user(iso7816, &aux, sizeof(aux)))
return -EFAULT;
return 0;
}
static int uart_set_iso7816_config(struct uart_port *port,
struct serial_iso7816 __user *iso7816_user)
{
struct serial_iso7816 iso7816;
int i, ret;
unsigned long flags;
if (!port->iso7816_config)
return -ENOTTY;
if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
return -EFAULT;
/*
* There are 5 words reserved for future use. Check that userspace
* doesn't put stuff in there to prevent breakages in the future.
*/
for (i = 0; i < 5; i++)
if (iso7816.reserved[i])
return -EINVAL;
spin_lock_irqsave(&port->lock, flags);
ret = port->iso7816_config(port, &iso7816);
spin_unlock_irqrestore(&port->lock, flags);
if (ret)
return ret;
if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
return -EFAULT;
return 0;
}
/*
* Called via sys_ioctl. We can use spin_lock_irq() here.
*/
static int
uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
struct uart_port *uport;
void __user *uarg = (void __user *)arg;
int ret = -ENOIOCTLCMD;
/*
* These ioctls don't rely on the hardware to be present.
*/
switch (cmd) {
case TIOCSERCONFIG:
down_write(&tty->termios_rwsem);
ret = uart_do_autoconfig(tty, state);
up_write(&tty->termios_rwsem);
break;
}
if (ret != -ENOIOCTLCMD)
goto out;
if (tty_io_error(tty)) {
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;
}
if (ret != -ENOIOCTLCMD)
goto out;
mutex_lock(&port->mutex);
uport = uart_port_check(state);
if (!uport || tty_io_error(tty)) {
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(tty, state, uarg);
break;
case TIOCGRS485:
ret = uart_get_rs485_config(uport, uarg);
break;
case TIOCSRS485:
ret = uart_set_rs485_config(uport, uarg);
break;
case TIOCSISO7816:
ret = uart_set_iso7816_config(state->uart_port, uarg);
break;
case TIOCGISO7816:
ret = uart_get_iso7816_config(state->uart_port, uarg);
break;
default:
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;
struct tty_port *port = &state->port;
if (!tty_port_initialized(port))
return;
mutex_lock(&state->port.mutex);
uport = uart_port_check(state);
if (uport && uport->ops->set_ldisc)
uport->ops->set_ldisc(uport, &tty->termios);
mutex_unlock(&state->port.mutex);
}
static void uart_set_termios(struct tty_struct *tty,
struct ktermios *old_termios)
{
struct uart_state *state = tty->driver_data;
struct uart_port *uport;
unsigned int cflag = tty->termios.c_cflag;
unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
bool sw_changed = false;
mutex_lock(&state->port.mutex);
uport = uart_port_check(state);
if (!uport)
goto out;
/*
* Drivers doing software flow control also need to know
* about changes to these input settings.
*/
if (uport->flags & UPF_SOFT_FLOW) {
iflag_mask |= IXANY|IXON|IXOFF;
sw_changed =
tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
}
/*
* 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
*/
if ((cflag ^ old_termios->c_cflag) == 0 &&
tty->termios.c_ospeed == old_termios->c_ospeed &&
tty->termios.c_ispeed == old_termios->c_ispeed &&
((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
!sw_changed) {
goto out;
}
uart_change_speed(tty, state, old_termios);
/* reload cflag from termios; port driver may have overridden flags */
cflag = tty->termios.c_cflag;
/* Handle transition to B0 status */
if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
uart_clear_mctrl(uport, 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) || !tty_throttled(tty))
mask |= TIOCM_RTS;
uart_set_mctrl(uport, mask);
}
out:
mutex_unlock(&state->port.mutex);
}
/*
* Calls to uart_close() are serialised via the tty_lock in
* drivers/tty/tty_io.c:tty_release()
* drivers/tty/tty_io.c:do_tty_hangup()
*/
static void uart_close(struct tty_struct *tty, struct file *filp)
{
struct uart_state *state = tty->driver_data;
if (!state) {
struct uart_driver *drv = tty->driver->driver_state;
struct tty_port *port;
state = drv->state + tty->index;
port = &state->port;
spin_lock_irq(&port->lock);
--port->count;
spin_unlock_irq(&port->lock);
return;
}
pr_debug("uart_close(%d) called\n", tty->index);
tty_port_close(tty->port, tty, filp);
}
static void uart_tty_port_shutdown(struct tty_port *port)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport = uart_port_check(state);
char *buf;
/*
* At this point, we stop accepting input. To do this, we
* disable the receive line status interrupts.
*/
if (WARN(!uport, "detached port still initialized!\n"))
return;
spin_lock_irq(&uport->lock);
uport->ops->stop_rx(uport);
spin_unlock_irq(&uport->lock);
uart_port_shutdown(port);
/*
* It's possible for shutdown to be called after suspend if we get
* a DCD drop (hangup) at just the right time. Clear suspended bit so
* we don't try to resume a port that has been shutdown.
*/
tty_port_set_suspended(port, 0);
/*
* Free the transmit buffer.
*/
spin_lock_irq(&uport->lock);
buf = state->xmit.buf;
state->xmit.buf = NULL;
spin_unlock_irq(&uport->lock);
free_page((unsigned long)buf);
uart_change_pm(state, UART_PM_STATE_OFF);
}
static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
{
struct uart_state *state = tty->driver_data;
struct uart_port *port;
unsigned long char_time, expire;
port = uart_port_ref(state);
if (!port)
return;
if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
uart_port_deref(port);
return;
}
/*
* 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 = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
if (timeout && timeout < char_time)
char_time = timeout;
if (!uart_cts_enabled(port)) {
/*
* 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 (timeout && time_after(jiffies, expire))
break;
}
uart_port_deref(port);
}
/*
* Calls to uart_hangup() are serialised by the tty_lock in
* drivers/tty/tty_io.c:do_tty_hangup()
* This runs from a workqueue and 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;
struct uart_port *uport;
unsigned long flags;
pr_debug("uart_hangup(%d)\n", tty->index);
mutex_lock(&port->mutex);
uport = uart_port_check(state);
WARN(!uport, "hangup of detached port!\n");
if (tty_port_active(port)) {
uart_flush_buffer(tty);
uart_shutdown(tty, state);
spin_lock_irqsave(&port->lock, flags);
port->count = 0;
spin_unlock_irqrestore(&port->lock, flags);
tty_port_set_active(port, 0);
tty_port_tty_set(port, NULL);
if (uport && !uart_console(uport))
uart_change_pm(state, UART_PM_STATE_OFF);
wake_up_interruptible(&port->open_wait);
wake_up_interruptible(&port->delta_msr_wait);
}
mutex_unlock(&port->mutex);
}
/* uport == NULL if uart_port has already been removed */
static void uart_port_shutdown(struct tty_port *port)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport = uart_port_check(state);
/*
* 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);
if (uport) {
/* 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);
}
}
static int uart_carrier_raised(struct tty_port *port)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport;
int mctrl;
uport = uart_port_ref(state);
/*
* Should never observe uport == NULL since checks for hangup should
* abort the tty_port_block_til_ready() loop before checking for carrier
* raised -- but report carrier raised if it does anyway so open will
* continue and not sleep
*/
if (WARN_ON(!uport))
return 1;
spin_lock_irq(&uport->lock);
uart_enable_ms(uport);
mctrl = uport->ops->get_mctrl(uport);
spin_unlock_irq(&uport->lock);
uart_port_deref(uport);
if (mctrl & TIOCM_CAR)
return 1;
return 0;
}
static void uart_dtr_rts(struct tty_port *port, int raise)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport;
uport = uart_port_ref(state);
if (!uport)
return;
uart_port_dtr_rts(uport, raise);
uart_port_deref(uport);
}
static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
{
struct uart_driver *drv = driver->driver_state;
struct uart_state *state = drv->state + tty->index;
tty->driver_data = state;
return tty_standard_install(driver, tty);
}
/*
* Calls to uart_open are serialised by the tty_lock in
* drivers/tty/tty_io.c:tty_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_state *state = tty->driver_data;
int retval;
retval = tty_port_open(&state->port, tty, filp);
if (retval > 0)
retval = 0;
return retval;
}
static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport;
int ret;
uport = uart_port_check(state);
if (!uport || uport->flags & UPF_DEAD)
return -ENXIO;
/*
* Start up the serial port.
*/
ret = uart_startup(tty, state, 0);
if (ret > 0)
tty_port_set_active(port, 1);
return ret;
}
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;
enum uart_pm_state pm_state;
struct uart_port *uport;
char stat_buf[32];
unsigned int status;
int mmio;
mutex_lock(&port->mutex);
uport = uart_port_check(state);
if (!uport)
goto out;
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');
goto out;
}
if (capable(CAP_SYS_ADMIN)) {
pm_state = state->pm_state;
if (pm_state != UART_PM_STATE_ON)
uart_change_pm(state, UART_PM_STATE_ON);
spin_lock_irq(&uport->lock);
status = uport->ops->get_mctrl(uport);
spin_unlock_irq(&uport->lock);
if (pm_state != UART_PM_STATE_ON)
uart_change_pm(state, pm_state);
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);
if (uport->icount.buf_overrun)
seq_printf(m, " bo:%d", uport->icount.buf_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
out:
mutex_unlock(&port->mutex);
}
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;
}
#endif
static inline bool uart_console_enabled(struct uart_port *port)
{
return uart_console(port) && (port->cons->flags & CON_ENABLED);
}
static void uart_port_spin_lock_init(struct uart_port *port)
{
spin_lock_init(&port->lock);
lockdep_set_class(&port->lock, &port_lock_key);
}
#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
* @putchar: 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 *, unsigned char))
{
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_earlycon - Parse earlycon options
* @p: ptr to 2nd field (ie., just beyond '<name>,')
* @iotype: ptr for decoded iotype (out)
* @addr: ptr for decoded mapbase/iobase (out)
* @options: ptr for <options> field; NULL if not present (out)
*
* Decodes earlycon kernel command line parameters of the form
* earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
* console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
*
* The optional form
*
* earlycon=<name>,0x<addr>,<options>
* console=<name>,0x<addr>,<options>
*
* is also accepted; the returned @iotype will be UPIO_MEM.
*
* Returns 0 on success or -EINVAL on failure
*/
int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
char **options)
{
if (strncmp(p, "mmio,", 5) == 0) {
*iotype = UPIO_MEM;
p += 5;
} else if (strncmp(p, "mmio16,", 7) == 0) {
*iotype = UPIO_MEM16;
p += 7;
} else if (strncmp(p, "mmio32,", 7) == 0) {
*iotype = UPIO_MEM32;
p += 7;
} else if (strncmp(p, "mmio32be,", 9) == 0) {
*iotype = UPIO_MEM32BE;
p += 9;
} else if (strncmp(p, "mmio32native,", 13) == 0) {
*iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
UPIO_MEM32BE : UPIO_MEM32;
p += 13;
} else if (strncmp(p, "io,", 3) == 0) {
*iotype = UPIO_PORT;
p += 3;
} else if (strncmp(p, "0x", 2) == 0) {
*iotype = UPIO_MEM;
} else {
return -EINVAL;
}
/*
* Before you replace it with kstrtoull(), think about options separator
* (',') it will not tolerate
*/
*addr = simple_strtoull(p, NULL, 0);
p = strchr(p, ',');
if (p)
p++;
*options = p;
return 0;
}
EXPORT_SYMBOL_GPL(uart_parse_earlycon);
/**
* uart_parse_options - Parse serial port baud/parity/bits/flow control.
* @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(const char *options, int *baud, int *parity,
int *bits, int *flow)
{
const 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);
/**
* 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;
/*
* Ensure that the serial-console lock is initialised early.
*
* Note that the console-enabled check is needed because of kgdboc,
* which can end up calling uart_set_options() for an already enabled
* console via tty_find_polling_driver() and uart_poll_init().
*/
if (!uart_console_enabled(port) && !port->console_reinit)
uart_port_spin_lock_init(port);
memset(&termios, 0, sizeof(struct ktermios));
termios.c_cflag |= CREAD | HUPCL | CLOCAL;
tty_termios_encode_baud_rate(&termios, baud, baud);
if (bits == 7)
termios.c_cflag |= CS7;
else
termios.c_cflag |= CS8;
switch (parity) {
case 'o': case 'O':
termios.c_cflag |= PARODD;
fallthrough;
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;
co->ispeed = termios.c_ispeed;
co->ospeed = termios.c_ospeed;
}
return 0;
}
EXPORT_SYMBOL_GPL(uart_set_options);
#endif /* CONFIG_SERIAL_CORE_CONSOLE */
/**
* uart_change_pm - set power state of the port
*
* @state: port descriptor
* @pm_state: new state
*
* Locking: port->mutex has to be held
*/
static void uart_change_pm(struct uart_state *state,
enum uart_pm_state pm_state)
{
struct uart_port *port = uart_port_check(state);
if (state->pm_state != pm_state) {
if (port && 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 (tty_dev && device_may_wakeup(tty_dev)) {
enable_irq_wake(uport->irq);
put_device(tty_dev);
mutex_unlock(&port->mutex);
return 0;
}
put_device(tty_dev);
/* Nothing to do if the console is not suspending */
if (!console_suspend_enabled && uart_console(uport))
goto unlock;
uport->suspended = 1;
if (tty_port_initialized(port)) {
const struct uart_ops *ops = uport->ops;
int tries;
unsigned int mctrl;
tty_port_set_suspended(port, 1);
tty_port_set_initialized(port, 0);
spin_lock_irq(&uport->lock);
ops->stop_tx(uport);
ops->set_mctrl(uport, 0);
/* save mctrl so it can be restored on resume */
mctrl = uport->mctrl;
uport->mctrl = 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)
dev_err(uport->dev, "%s: Unable to drain transmitter\n",
uport->name);
ops->shutdown(uport);
uport->mctrl = mctrl;
}
/*
* Disable the console device before suspending.
*/
if (uart_console(uport))
console_stop(uport->cons);
uart_change_pm(state, UART_PM_STATE_OFF);
unlock:
mutex_unlock(&port->mutex);
return 0;
}
EXPORT_SYMBOL(uart_suspend_port);
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)) {
if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
disable_irq_wake(uport->irq);
put_device(tty_dev);
mutex_unlock(&port->mutex);
return 0;
}
put_device(tty_dev);
uport->suspended = 0;
/*
* Re-enable the console device after suspending.
*/
if (uart_console(uport)) {
/*
* First try to use the console cflag setting.
*/
memset(&termios, 0, sizeof(struct ktermios));
termios.c_cflag = uport->cons->cflag;
termios.c_ispeed = uport->cons->ispeed;
termios.c_ospeed = uport->cons->ospeed;
/*
* If that's unset, use the tty termios setting.
*/
if (port->tty && termios.c_cflag == 0)
termios = port->tty->termios;
if (console_suspend_enabled)
uart_change_pm(state, UART_PM_STATE_ON);
uport->ops->set_termios(uport, &termios, NULL);
if (console_suspend_enabled)
console_start(uport->cons);
}
if (tty_port_suspended(port)) {
const struct uart_ops *ops = uport->ops;
int ret;
uart_change_pm(state, UART_PM_STATE_ON);
spin_lock_irq(&uport->lock);
ops->set_mctrl(uport, 0);
spin_unlock_irq(&uport->lock);
if (console_suspend_enabled || !uart_console(uport)) {
/* Protected by port mutex for now */
struct tty_struct *tty = port->tty;
ret = ops->startup(uport);
if (ret == 0) {
if (tty)
uart_change_speed(tty, state, NULL);
spin_lock_irq(&uport->lock);
ops->set_mctrl(uport, uport->mctrl);
ops->start_tx(uport);
spin_unlock_irq(&uport->lock);
tty_port_set_initialized(port, 1);
} 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(tty, state);
}
}
tty_port_set_suspended(port, 0);
}
mutex_unlock(&port->mutex);
return 0;
}
EXPORT_SYMBOL(uart_resume_port);
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_MEM16:
case UPIO_MEM32:
case UPIO_MEM32BE:
case UPIO_AU:
case UPIO_TSI:
snprintf(address, sizeof(address),
"MMIO 0x%llx", (unsigned long long)port->mapbase);
break;
default:
strlcpy(address, "*unknown*", sizeof(address));
break;
}
pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
port->dev ? dev_name(port->dev) : "",
port->dev ? ": " : "",
port->name,
address, port->irq, port->uartclk / 16, uart_type(port));
/* The magic multiplier feature is a bit obscure, so report it too. */
if (port->flags & UPF_MAGIC_MULTIPLIER)
pr_info("%s%s%s extra baud rates supported: %d, %d",
port->dev ? dev_name(port->dev) : "",
port->dev ? ": " : "",
port->name,
port->uartclk / 8, port->uartclk / 4);
}
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, UART_PM_STATE_ON);
/*
* 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->mctrl &= TIOCM_DTR;
if (port->rs485.flags & SER_RS485_ENABLED &&
!(port->rs485.flags & SER_RS485_RTS_AFTER_SEND))
port->mctrl |= TIOCM_RTS;
port->ops->set_mctrl(port, port->mctrl);
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, UART_PM_STATE_OFF);
}
}
#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 tty_port *tport;
struct uart_port *port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
int ret = 0;
tport = &state->port;
mutex_lock(&tport->mutex);
port = uart_port_check(state);
if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
ret = -1;
goto out;
}
if (port->ops->poll_init) {
/*
* We don't set initialized as we only initialized the hw,
* e.g. state->xmit is still uninitialized.
*/
if (!tty_port_initialized(tport))
ret = port->ops->poll_init(port);
}
if (!ret && options) {
uart_parse_options(options, &baud, &parity, &bits, &flow);
ret = uart_set_options(port, NULL, baud, parity, bits, flow);
}
out:
mutex_unlock(&tport->mutex);
return ret;
}
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;
int ret = -1;
port = uart_port_ref(state);
if (port) {
ret = port->ops->poll_get_char(port);
uart_port_deref(port);
}
return ret;
}
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;
port = uart_port_ref(state);
if (!port)
return;
if (ch == '\n')
port->ops->poll_put_char(port, '\r');
port->ops->poll_put_char(port, ch);
uart_port_deref(port);
}
#endif
static const struct tty_operations uart_ops = {
.install = uart_install,
.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_show = uart_proc_show,
#endif
.tiocmget = uart_tiocmget,
.tiocmset = uart_tiocmset,
.set_serial = uart_set_info_user,
.get_serial = uart_get_info_user,
.get_icount = uart_get_icount,
#ifdef CONFIG_CONSOLE_POLL
.poll_init = uart_poll_init,
.poll_get_char = uart_poll_get_char,
.poll_put_char = uart_poll_put_char,
#endif
};
static const struct tty_port_operations uart_port_ops = {
.carrier_raised = uart_carrier_raised,
.dtr_rts = uart_dtr_rts,
.activate = uart_port_activate,
.shutdown = uart_tty_port_shutdown,
};
/**
* 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 = -ENOMEM;
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 = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
if (!drv->state)
goto out;
normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
TTY_DRIVER_DYNAMIC_DEV);
if (IS_ERR(normal)) {
retval = PTR_ERR(normal);
goto out_kfree;
}
drv->tty_driver = normal;
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->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->ops = &uart_port_ops;
}
retval = tty_register_driver(normal);
if (retval >= 0)
return retval;
for (i = 0; i < drv->nr; i++)
tty_port_destroy(&drv->state[i].port);
tty_driver_kref_put(normal);
out_kfree:
kfree(drv->state);
out:
return retval;
}
EXPORT_SYMBOL(uart_register_driver);
/**
* 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;
unsigned int i;
tty_unregister_driver(p);
tty_driver_kref_put(p);
for (i = 0; i < drv->nr; i++)
tty_port_destroy(&drv->state[i].port);
kfree(drv->state);
drv->state = NULL;
drv->tty_driver = NULL;
}
EXPORT_SYMBOL(uart_unregister_driver);
struct tty_driver *uart_console_device(struct console *co, int *index)
{
struct uart_driver *p = co->data;
*index = co->index;
return p->tty_driver;
}
EXPORT_SYMBOL_GPL(uart_console_device);
static ssize_t uartclk_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.baud_base * 16);
}
static ssize_t type_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.type);
}
static ssize_t line_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.line);
}
static ssize_t port_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
unsigned long ioaddr;
uart_get_info(port, &tmp);
ioaddr = tmp.port;
if (HIGH_BITS_OFFSET)
ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
return sprintf(buf, "0x%lX\n", ioaddr);
}
static ssize_t irq_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.irq);
}
static ssize_t flags_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "0x%X\n", tmp.flags);
}
static ssize_t xmit_fifo_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
}
static ssize_t close_delay_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.close_delay);
}
static ssize_t closing_wait_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.closing_wait);
}
static ssize_t custom_divisor_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.custom_divisor);
}
static ssize_t io_type_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.io_type);
}
static ssize_t iomem_base_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
}
static ssize_t iomem_reg_shift_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct serial_struct tmp;
struct tty_port *port = dev_get_drvdata(dev);
uart_get_info(port, &tmp);
return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
}
static ssize_t console_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct tty_port *port = dev_get_drvdata(dev);
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport;
bool console = false;
mutex_lock(&port->mutex);
uport = uart_port_check(state);
if (uport)
console = uart_console_enabled(uport);
mutex_unlock(&port->mutex);
return sprintf(buf, "%c\n", console ? 'Y' : 'N');
}
static ssize_t console_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct tty_port *port = dev_get_drvdata(dev);
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport;
bool oldconsole, newconsole;
int ret;
ret = kstrtobool(buf, &newconsole);
if (ret)
return ret;
mutex_lock(&port->mutex);
uport = uart_port_check(state);
if (uport) {
oldconsole = uart_console_enabled(uport);
if (oldconsole && !newconsole) {
ret = unregister_console(uport->cons);
} else if (!oldconsole && newconsole) {
if (uart_console(uport)) {
uport->console_reinit = 1;
register_console(uport->cons);
} else {
ret = -ENOENT;
}
}
} else {
ret = -ENXIO;
}
mutex_unlock(&port->mutex);
return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RO(uartclk);
static DEVICE_ATTR_RO(type);
static DEVICE_ATTR_RO(line);
static DEVICE_ATTR_RO(port);
static DEVICE_ATTR_RO(irq);
static DEVICE_ATTR_RO(flags);
static DEVICE_ATTR_RO(xmit_fifo_size);
static DEVICE_ATTR_RO(close_delay);
static DEVICE_ATTR_RO(closing_wait);
static DEVICE_ATTR_RO(custom_divisor);
static DEVICE_ATTR_RO(io_type);
static DEVICE_ATTR_RO(iomem_base);
static DEVICE_ATTR_RO(iomem_reg_shift);
static DEVICE_ATTR_RW(console);
static struct attribute *tty_dev_attrs[] = {
&dev_attr_uartclk.attr,
&dev_attr_type.attr,
&dev_attr_line.attr,
&dev_attr_port.attr,
&dev_attr_irq.attr,
&dev_attr_flags.attr,
&dev_attr_xmit_fifo_size.attr,
&dev_attr_close_delay.attr,
&dev_attr_closing_wait.attr,
&dev_attr_custom_divisor.attr,
&dev_attr_io_type.attr,
&dev_attr_iomem_base.attr,
&dev_attr_iomem_reg_shift.attr,
&dev_attr_console.attr,
NULL
};
static const struct attribute_group tty_dev_attr_group = {
.attrs = tty_dev_attrs,
};
/**
* 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.
*
* Context: task context, might sleep
*
* 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;
int num_groups;
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;
}
/* Link the port to the driver state table and vice versa */
atomic_set(&state->refcount, 1);
init_waitqueue_head(&state->remove_wait);
state->uart_port = uport;
uport->state = state;
state->pm_state = UART_PM_STATE_UNDEFINED;
uport->cons = drv->cons;
uport->minor = drv->tty_driver->minor_start + uport->line;
uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
drv->tty_driver->name_base + uport->line);
if (!uport->name) {
ret = -ENOMEM;
goto out;
}
/*
* If this port is in use as a console then the spinlock is already
* initialised.
*/
if (!uart_console_enabled(uport))
uart_port_spin_lock_init(uport);
if (uport->cons && uport->dev)
of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
tty_port_link_device(port, drv->tty_driver, uport->line);
uart_configure_port(drv, state, uport);
port->console = uart_console(uport);
num_groups = 2;
if (uport->attr_group)
num_groups++;
uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
GFP_KERNEL);
if (!uport->tty_groups) {
ret = -ENOMEM;
goto out;
}
uport->tty_groups[0] = &tty_dev_attr_group;
if (uport->attr_group)
uport->tty_groups[1] = uport->attr_group;
/*
* Register the port whether it's detected or not. This allows
* setserial to be used to alter this port's parameters.
*/
tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
uport->line, uport->dev, port, uport->tty_groups);
if (!IS_ERR(tty_dev)) {
device_set_wakeup_capable(tty_dev, 1);
} else {
dev_err(uport->dev, "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;
}
EXPORT_SYMBOL(uart_add_one_port);
/**
* 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
*
* Context: task context, might sleep
*
* 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;
struct uart_port *uart_port;
struct tty_struct *tty;
int ret = 0;
mutex_lock(&port_mutex);
/*
* Mark the port "dead" - this prevents any opens from
* succeeding while we shut down the port.
*/
mutex_lock(&port->mutex);
uart_port = uart_port_check(state);
if (uart_port != uport)
dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
uart_port, uport);
if (!uart_port) {
mutex_unlock(&port->mutex);
ret = -EINVAL;
goto out;
}
uport->flags |= UPF_DEAD;
mutex_unlock(&port->mutex);
/*
* Remove the devices from the tty layer
*/
tty_port_unregister_device(port, drv->tty_driver, uport->line);
tty = tty_port_tty_get(port);
if (tty) {
tty_vhangup(port->tty);
tty_kref_put(tty);
}
/*
* If the port is used as a console, unregister it
*/
if (uart_console(uport))
unregister_console(uport->cons);
/*
* Free the port IO and memory resources, if any.
*/
if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
uport->ops->release_port(uport);
kfree(uport->tty_groups);
kfree(uport->name);
/*
* Indicate that there isn't a port here anymore.
*/
uport->type = PORT_UNKNOWN;
mutex_lock(&port->mutex);
WARN_ON(atomic_dec_return(&state->refcount) < 0);
wait_event(state->remove_wait, !atomic_read(&state->refcount));
state->uart_port = NULL;
mutex_unlock(&port->mutex);
out:
mutex_unlock(&port_mutex);
return ret;
}
EXPORT_SYMBOL(uart_remove_one_port);
/*
* Are the two ports equivalent?
*/
bool uart_match_port(const struct uart_port *port1,
const struct uart_port *port2)
{
if (port1->iotype != port2->iotype)
return false;
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_MEM16:
case UPIO_MEM32:
case UPIO_MEM32BE:
case UPIO_AU:
case UPIO_TSI:
return port1->mapbase == port2->mapbase;
}
return false;
}
EXPORT_SYMBOL(uart_match_port);
/**
* uart_handle_dcd_change - handle a change of carrier detect state
* @uport: uart_port structure for the open port
* @status: new carrier detect status, nonzero if active
*
* Caller must hold uport->lock
*/
void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
{
struct tty_port *port = &uport->state->port;
struct tty_struct *tty = port->tty;
struct tty_ldisc *ld;
lockdep_assert_held_once(&uport->lock);
if (tty) {
ld = tty_ldisc_ref(tty);
if (ld) {
if (ld->ops->dcd_change)
ld->ops->dcd_change(tty, status);
tty_ldisc_deref(ld);
}
}
uport->icount.dcd++;
if (uart_dcd_enabled(uport)) {
if (status)
wake_up_interruptible(&port->open_wait);
else if (tty)
tty_hangup(tty);
}
}
EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
/**
* uart_handle_cts_change - handle a change of clear-to-send state
* @uport: uart_port structure for the open port
* @status: new clear to send status, nonzero if active
*
* Caller must hold uport->lock
*/
void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
{
lockdep_assert_held_once(&uport->lock);
uport->icount.cts++;
if (uart_softcts_mode(uport)) {
if (uport->hw_stopped) {
if (status) {
uport->hw_stopped = 0;
uport->ops->start_tx(uport);
uart_write_wakeup(uport);
}
} else {
if (!status) {
uport->hw_stopped = 1;
uport->ops->stop_tx(uport);
}
}
}
}
EXPORT_SYMBOL_GPL(uart_handle_cts_change);
/**
* uart_insert_char - push a char to the uart layer
*
* User is responsible to call tty_flip_buffer_push when they are done with
* insertion.
*
* @port: corresponding port
* @status: state of the serial port RX buffer (LSR for 8250)
* @overrun: mask of overrun bits in @status
* @ch: character to push
* @flag: flag for the character (see TTY_NORMAL and friends)
*/
void uart_insert_char(struct uart_port *port, unsigned int status,
unsigned int overrun, unsigned int ch, unsigned int flag)
{
struct tty_port *tport = &port->state->port;
if ((status & port->ignore_status_mask & ~overrun) == 0)
if (tty_insert_flip_char(tport, ch, flag) == 0)
++port->icount.buf_overrun;
/*
* Overrun is special. Since it's reported immediately,
* it doesn't affect the current character.
*/
if (status & ~port->ignore_status_mask & overrun)
if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
++port->icount.buf_overrun;
}
EXPORT_SYMBOL_GPL(uart_insert_char);
#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
static void uart_sysrq_on(struct work_struct *w)
{
int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
sysrq_toggle_support(1);
pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
sysrq_toggle_seq_len, sysrq_toggle_seq);
}
static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
/**
* uart_try_toggle_sysrq - Enables SysRq from serial line
* @port: uart_port structure where char(s) after BREAK met
* @ch: new character in the sequence after received BREAK
*
* Enables magic SysRq when the required sequence is met on port
* (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
*
* Returns false if @ch is out of enabling sequence and should be
* handled some other way, true if @ch was consumed.
*/
bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
{
int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
if (!sysrq_toggle_seq_len)
return false;
BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
port->sysrq_seq = 0;
return false;
}
if (++port->sysrq_seq < sysrq_toggle_seq_len) {
port->sysrq = jiffies + SYSRQ_TIMEOUT;
return true;
}
schedule_work(&sysrq_enable_work);
port->sysrq = 0;
return true;
}
EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
#endif
/**
* uart_get_rs485_mode() - retrieve rs485 properties for given uart
* @port: uart device's target port
*
* This function implements the device tree binding described in
* Documentation/devicetree/bindings/serial/rs485.txt.
*/
int uart_get_rs485_mode(struct uart_port *port)
{
struct serial_rs485 *rs485conf = &port->rs485;
struct device *dev = port->dev;
u32 rs485_delay[2];
int ret;
ret = device_property_read_u32_array(dev, "rs485-rts-delay",
rs485_delay, 2);
if (!ret) {
rs485conf->delay_rts_before_send = rs485_delay[0];
rs485conf->delay_rts_after_send = rs485_delay[1];
} else {
rs485conf->delay_rts_before_send = 0;
rs485conf->delay_rts_after_send = 0;
}
/*
* Clear full-duplex and enabled flags, set RTS polarity to active high
* to get to a defined state with the following properties:
*/
rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
SER_RS485_TERMINATE_BUS |
SER_RS485_RTS_AFTER_SEND);
rs485conf->flags |= SER_RS485_RTS_ON_SEND;
if (device_property_read_bool(dev, "rs485-rx-during-tx"))
rs485conf->flags |= SER_RS485_RX_DURING_TX;
if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
rs485conf->flags |= SER_RS485_ENABLED;
if (device_property_read_bool(dev, "rs485-rts-active-low")) {
rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
}
/*
* Disabling termination by default is the safe choice: Else if many
* bus participants enable it, no communication is possible at all.
* Works fine for short cables and users may enable for longer cables.
*/
port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
GPIOD_OUT_LOW);
if (IS_ERR(port->rs485_term_gpio)) {
ret = PTR_ERR(port->rs485_term_gpio);
port->rs485_term_gpio = NULL;
return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
}
return 0;
}
EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
MODULE_DESCRIPTION("Serial driver core");
MODULE_LICENSE("GPL");
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