diff options
Diffstat (limited to 'drivers/serial/serial_core.c')
| -rw-r--r-- | drivers/serial/serial_core.c | 2395 |
1 files changed, 2395 insertions, 0 deletions
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c new file mode 100644 index 00000000000..36b1ae083fb --- /dev/null +++ b/drivers/serial/serial_core.c @@ -0,0 +1,2395 @@ +/* + * 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/config.h> +#include <linux/module.h> +#include <linux/tty.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/console.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 <asm/irq.h> +#include <asm/uaccess.h> + +#undef DEBUG +#ifdef DEBUG +#define DPRINTK(x...) printk(x) +#else +#define DPRINTK(x...) do { } while (0) +#endif + +/* + * This is used to lock changes in serial line configuration. + */ +static DECLARE_MUTEX(port_sem); + +#define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8) + +#define uart_users(state) ((state)->count + ((state)->info ? (state)->info->blocked_open : 0)) + +#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 termios *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; + 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, 1); + 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, 1); +} + +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->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 semaphore. + */ +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 + */ + if (info->tty) + set_bit(TTY_IO_ERROR, &info->tty->flags); + + if (port->type == PORT_UNKNOWN) + return 0; + + /* + * Initialise and allocate the transmit and temporary + * buffer. + */ + if (!info->xmit.buf) { + 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->tty->termios->c_cflag & CBAUD) + uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR); + } + + info->flags |= UIF_INITIALIZED; + + clear_bit(TTY_IO_ERROR, &info->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; + + if (!(info->flags & UIF_INITIALIZED)) + return; + + /* + * Turn off DTR and RTS early. + */ + if (!info->tty || (info->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); + + /* + * Free the transmit buffer page. + */ + if (info->xmit.buf) { + free_page((unsigned long)info->xmit.buf); + info->xmit.buf = NULL; + } + + /* + * kill off our tasklet + */ + tasklet_kill(&info->tlet); + if (info->tty) + set_bit(TTY_IO_ERROR, &info->tty->flags); + + info->flags &= ~UIF_INITIALIZED; +} + +/** + * 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. + */ +unsigned int +uart_get_baud_rate(struct uart_port *port, struct termios *termios, + struct termios *old, unsigned int min, unsigned int max) +{ + unsigned int try, baud, altbaud = 38400; + unsigned int 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) + 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) { + termios->c_cflag |= old->c_cflag & CBAUD; + old = NULL; + continue; + } + + /* + * As a last resort, if the quotient is zero, + * default to 9600 bps + */ + termios->c_cflag |= B9600; + } + + 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); + +static void +uart_change_speed(struct uart_state *state, struct termios *old_termios) +{ + struct tty_struct *tty = state->info->tty; + struct uart_port *port = state->port; + struct termios *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 void +__uart_put_char(struct uart_port *port, struct circ_buf *circ, unsigned char c) +{ + unsigned long flags; + + if (!circ->buf) + return; + + 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); + } + spin_unlock_irqrestore(&port->lock, flags); +} + +static void uart_put_char(struct tty_struct *tty, unsigned char ch) +{ + struct uart_state *state = tty->driver_data; + + __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 = state->port; + struct circ_buf *circ = &state->info->xmit; + unsigned long flags; + int c, ret = 0; + + 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; + + return uart_circ_chars_free(&state->info->xmit); +} + +static int uart_chars_in_buffer(struct tty_struct *tty) +{ + struct uart_state *state = tty->driver_data; + + return uart_circ_chars_pending(&state->info->xmit); +} + +static void uart_flush_buffer(struct tty_struct *tty) +{ + struct uart_state *state = tty->driver_data; + struct uart_port *port = state->port; + unsigned long flags; + + DPRINTK("uart_flush_buffer(%d) called\n", tty->index); + + spin_lock_irqsave(&port->lock, flags); + uart_circ_clear(&state->info->xmit); + 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, 0); + 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)); + 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 *)port->mapbase; + + 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, old_flags, closing_wait; + unsigned int old_custom_divisor, close_delay; + 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. + */ + down(&state->sem); + + change_irq = 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 = 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; + 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 != port->fifosize) || + (((new_serial.flags ^ old_flags) & ~UPF_USR_MASK) != 0)) + goto exit; + port->flags = ((port->flags & ~UPF_USR_MASK) | + (new_serial.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; + } + } + + port->irq = new_serial.irq; + port->uartclk = new_serial.baud_base * 16; + port->flags = (port->flags & ~UPF_CHANGE_MASK) | + (new_serial.flags & UPF_CHANGE_MASK); + port->custom_divisor = new_serial.custom_divisor; + state->close_delay = close_delay; + state->closing_wait = closing_wait; + port->fifosize = new_serial.xmit_fifo_size; + if (state->info->tty) + state->info->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->tty, buf)); + } + uart_change_speed(state, NULL); + } + } else + retval = uart_startup(state, 1); + exit: + up(&state->sem); + 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->tty->stopped && !state->info->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; + + down(&state->sem); + if ((!file || !tty_hung_up_p(file)) && + !(tty->flags & (1 << TTY_IO_ERROR))) { + result = port->mctrl; + result |= port->ops->get_mctrl(port); + } + up(&state->sem); + + 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; + + down(&state->sem); + if ((!file || !tty_hung_up_p(file)) && + !(tty->flags & (1 << TTY_IO_ERROR))) { + uart_update_mctrl(port, set, clear); + ret = 0; + } + up(&state->sem); + return ret; +} + +static void uart_break_ctl(struct tty_struct *tty, int break_state) +{ + struct uart_state *state = tty->driver_data; + struct uart_port *port = state->port; + + BUG_ON(!kernel_locked()); + + down(&state->sem); + + if (port->type != PORT_UNKNOWN) + port->ops->break_ctl(port, break_state); + + up(&state->sem); +} + +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 (down_interruptible(&state->sem)) + 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); + } + up(&state->sem); + 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 under the BKL. 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; + + BUG_ON(!kernel_locked()); + + /* + * 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; + + down(&state->sem); + + 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: + up(&state->sem); + out: + return ret; +} + +static void uart_set_termios(struct tty_struct *tty, struct termios *old_termios) +{ + struct uart_state *state = tty->driver_data; + unsigned long flags; + unsigned int cflag = tty->termios->c_cflag; + + BUG_ON(!kernel_locked()); + + /* + * These are the bits that are used to setup various + * flags in the low level driver. + */ +#define RELEVANT_IFLAG(iflag) ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK)) + + if ((cflag ^ old_termios->c_cflag) == 0 && + 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); + } + +#if 0 + /* + * No need to wake up processes in open wait, since they + * sample the CLOCAL flag once, and don't recheck it. + * XXX It's not clear whether the current behavior is correct + * or not. Hence, this may change..... + */ + if (!(old_termios->c_cflag & CLOCAL) && + (tty->termios->c_cflag & CLOCAL)) + wake_up_interruptible(&state->info->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; + + DPRINTK("uart_close(%d) called\n", port->line); + + down(&state->sem); + + 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! + */ |