sa1100.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 958 行 · 第 1/2 页

/*
 *  linux/drivers/char/sa1100.c
 *
 *  Driver for SA11x0 serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
 *  Copyright (C) 2000 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
 *
 *  $Id: sa1100.c,v 1.50 2002/07/29 14:41:04 rmk Exp $
 *
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/device.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/mach/serial_sa1100.h>

#if defined(CONFIG_SERIAL_SA1100_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>

/* We've been assigned a range on the "Low-density serial ports" major */
#define SERIAL_SA1100_MAJOR	204
#define MINOR_START		5

#define NR_PORTS		3

#define SA1100_ISR_PASS_LIMIT	256

/*
 * Convert from ignore_status_mask or read_status_mask to UTSR[01]
 */
#define SM_TO_UTSR0(x)	((x) & 0xff)
#define SM_TO_UTSR1(x)	((x) >> 8)
#define UTSR0_TO_SM(x)	((x))
#define UTSR1_TO_SM(x)	((x) << 8)

#define UART_GET_UTCR0(sport)	__raw_readl((sport)->port.membase + UTCR0)
#define UART_GET_UTCR1(sport)	__raw_readl((sport)->port.membase + UTCR1)
#define UART_GET_UTCR2(sport)	__raw_readl((sport)->port.membase + UTCR2)
#define UART_GET_UTCR3(sport)	__raw_readl((sport)->port.membase + UTCR3)
#define UART_GET_UTSR0(sport)	__raw_readl((sport)->port.membase + UTSR0)
#define UART_GET_UTSR1(sport)	__raw_readl((sport)->port.membase + UTSR1)
#define UART_GET_CHAR(sport)	__raw_readl((sport)->port.membase + UTDR)

#define UART_PUT_UTCR0(sport,v)	__raw_writel((v),(sport)->port.membase + UTCR0)
#define UART_PUT_UTCR1(sport,v)	__raw_writel((v),(sport)->port.membase + UTCR1)
#define UART_PUT_UTCR2(sport,v)	__raw_writel((v),(sport)->port.membase + UTCR2)
#define UART_PUT_UTCR3(sport,v)	__raw_writel((v),(sport)->port.membase + UTCR3)
#define UART_PUT_UTSR0(sport,v)	__raw_writel((v),(sport)->port.membase + UTSR0)
#define UART_PUT_UTSR1(sport,v)	__raw_writel((v),(sport)->port.membase + UTSR1)
#define UART_PUT_CHAR(sport,v)	__raw_writel((v),(sport)->port.membase + UTDR)

/*
 * This is the size of our serial port register set.
 */
#define UART_PORT_SIZE	0x24

/*
 * This determines how often we check the modem status signals
 * for any change.  They generally aren't connected to an IRQ
 * so we have to poll them.  We also check immediately before
 * filling the TX fifo incase CTS has been dropped.
 */
#define MCTRL_TIMEOUT	(250*HZ/1000)

struct sa1100_port {
	struct uart_port	port;
	struct timer_list	timer;
	unsigned int		old_status;
};

/*
 * Handle any change of modem status signal since we were last called.
 */
static void sa1100_mctrl_check(struct sa1100_port *sport)
{
	unsigned int status, changed;

	status = sport->port.ops->get_mctrl(&sport->port);
	changed = status ^ sport->old_status;

	if (changed == 0)
		return;

	sport->old_status = status;

	if (changed & TIOCM_RI)
		sport->port.icount.rng++;
	if (changed & TIOCM_DSR)
		sport->port.icount.dsr++;
	if (changed & TIOCM_CAR)
		uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
	if (changed & TIOCM_CTS)
		uart_handle_cts_change(&sport->port, status & TIOCM_CTS);

	wake_up_interruptible(&sport->port.info->delta_msr_wait);
}

/*
 * This is our per-port timeout handler, for checking the
 * modem status signals.
 */
static void sa1100_timeout(unsigned long data)
{
	struct sa1100_port *sport = (struct sa1100_port *)data;
	unsigned long flags;

	if (sport->port.info) {
		spin_lock_irqsave(&sport->port.lock, flags);
		sa1100_mctrl_check(sport);
		spin_unlock_irqrestore(&sport->port.lock, flags);

		mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
	}
}

/*
 * interrupts disabled on entry
 */
static void sa1100_stop_tx(struct uart_port *port, unsigned int tty_stop)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;
	u32 utcr3;

	utcr3 = UART_GET_UTCR3(sport);
	UART_PUT_UTCR3(sport, utcr3 & ~UTCR3_TIE);
	sport->port.read_status_mask &= ~UTSR0_TO_SM(UTSR0_TFS);
}

/*
 * interrupts may not be disabled on entry
 */
static void sa1100_start_tx(struct uart_port *port, unsigned int tty_start)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;
	unsigned long flags;
	u32 utcr3;

	spin_lock_irqsave(&sport->port.lock, flags);
	utcr3 = UART_GET_UTCR3(sport);
	sport->port.read_status_mask |= UTSR0_TO_SM(UTSR0_TFS);
	UART_PUT_UTCR3(sport, utcr3 | UTCR3_TIE);
	spin_unlock_irqrestore(&sport->port.lock, flags);
}

/*
 * Interrupts enabled
 */
static void sa1100_stop_rx(struct uart_port *port)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;
	u32 utcr3;

	utcr3 = UART_GET_UTCR3(sport);
	UART_PUT_UTCR3(sport, utcr3 & ~UTCR3_RIE);
}

/*
 * Set the modem control timer to fire immediately.
 */
static void sa1100_enable_ms(struct uart_port *port)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;

	mod_timer(&sport->timer, jiffies);
}

static void
sa1100_rx_chars(struct sa1100_port *sport, struct pt_regs *regs)
{
	struct tty_struct *tty = sport->port.info->tty;
	unsigned int status, ch, flg, ignored = 0;

	status = UTSR1_TO_SM(UART_GET_UTSR1(sport)) |
		 UTSR0_TO_SM(UART_GET_UTSR0(sport));
	while (status & UTSR1_TO_SM(UTSR1_RNE)) {
		ch = UART_GET_CHAR(sport);

		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
			goto ignore_char;
		sport->port.icount.rx++;

		flg = TTY_NORMAL;

		/*
		 * note that the error handling code is
		 * out of the main execution path
		 */
		if (status & UTSR1_TO_SM(UTSR1_PRE | UTSR1_FRE | UTSR1_ROR))
			goto handle_error;

		if (uart_handle_sysrq_char(&sport->port, ch, regs))
			goto ignore_char;

	error_return:
		*tty->flip.flag_buf_ptr++ = flg;
		*tty->flip.char_buf_ptr++ = ch;
		tty->flip.count++;
	ignore_char:
		status = UTSR1_TO_SM(UART_GET_UTSR1(sport)) |
			 UTSR0_TO_SM(UART_GET_UTSR0(sport));
	}
 out:
	tty_flip_buffer_push(tty);
	return;

 handle_error:
	if (status & UTSR1_TO_SM(UTSR1_PRE))
		sport->port.icount.parity++;
	else if (status & UTSR1_TO_SM(UTSR1_FRE))
		sport->port.icount.frame++;
	if (status & UTSR1_TO_SM(UTSR1_ROR))
		sport->port.icount.overrun++;

	if (status & sport->port.ignore_status_mask) {
		if (++ignored > 100)
			goto out;
		goto ignore_char;
	}

	status &= sport->port.read_status_mask;

	if (status & UTSR1_TO_SM(UTSR1_PRE))
		flg = TTY_PARITY;
	else if (status & UTSR1_TO_SM(UTSR1_FRE))
		flg = TTY_FRAME;

	if (status & UTSR1_TO_SM(UTSR1_ROR)) {
		/*
		 * overrun does *not* affect the character
		 * we read from the FIFO
		 */
		*tty->flip.flag_buf_ptr++ = flg;
		*tty->flip.char_buf_ptr++ = ch;
		tty->flip.count++;
		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
			goto ignore_char;
		ch = 0;
		flg = TTY_OVERRUN;
	}
#ifdef SUPPORT_SYSRQ
	sport->port.sysrq = 0;
#endif
	goto error_return;
}

static void sa1100_tx_chars(struct sa1100_port *sport)
{
	struct circ_buf *xmit = &sport->port.info->xmit;

	if (sport->port.x_char) {
		UART_PUT_CHAR(sport, sport->port.x_char);
		sport->port.icount.tx++;
		sport->port.x_char = 0;
		return;
	}

	/*
	 * Check the modem control lines before
	 * transmitting anything.
	 */
	sa1100_mctrl_check(sport);

	if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
		sa1100_stop_tx(&sport->port, 0);
		return;
	}

	/*
	 * Tried using FIFO (not checking TNF) for fifo fill:
	 * still had the '4 bytes repeated' problem.
	 */
	while (UART_GET_UTSR1(sport) & UTSR1_TNF) {
		UART_PUT_CHAR(sport, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		sport->port.icount.tx++;
		if (uart_circ_empty(xmit))
			break;
	}

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(&sport->port);

	if (uart_circ_empty(xmit))
		sa1100_stop_tx(&sport->port, 0);
}

static irqreturn_t sa1100_int(int irq, void *dev_id, struct pt_regs *regs)
{
	struct sa1100_port *sport = dev_id;
	unsigned int status, pass_counter = 0;

	spin_lock(&sport->port.lock);
	status = UART_GET_UTSR0(sport);
	status &= SM_TO_UTSR0(sport->port.read_status_mask) | ~UTSR0_TFS;
	do {
		if (status & (UTSR0_RFS | UTSR0_RID)) {
			/* Clear the receiver idle bit, if set */
			if (status & UTSR0_RID)
				UART_PUT_UTSR0(sport, UTSR0_RID);
			sa1100_rx_chars(sport, regs);
		}

		/* Clear the relevant break bits */
		if (status & (UTSR0_RBB | UTSR0_REB))
			UART_PUT_UTSR0(sport, status & (UTSR0_RBB | UTSR0_REB));

		if (status & UTSR0_RBB)
			sport->port.icount.brk++;

		if (status & UTSR0_REB)
			uart_handle_break(&sport->port);

		if (status & UTSR0_TFS)
			sa1100_tx_chars(sport);
		if (pass_counter++ > SA1100_ISR_PASS_LIMIT)
			break;
		status = UART_GET_UTSR0(sport);
		status &= SM_TO_UTSR0(sport->port.read_status_mask) |
			  ~UTSR0_TFS;
	} while (status & (UTSR0_TFS | UTSR0_RFS | UTSR0_RID));
	spin_unlock(&sport->port.lock);

	return IRQ_HANDLED;
}

/*
 * Return TIOCSER_TEMT when transmitter is not busy.
 */
static unsigned int sa1100_tx_empty(struct uart_port *port)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;

	return UART_GET_UTSR1(sport) & UTSR1_TBY ? 0 : TIOCSER_TEMT;
}

static unsigned int sa1100_get_mctrl(struct uart_port *port)
{
	return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}

static void sa1100_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}

/*
 * Interrupts always disabled.
 */
static void sa1100_break_ctl(struct uart_port *port, int break_state)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;
	unsigned long flags;
	unsigned int utcr3;

	spin_lock_irqsave(&sport->port.lock, flags);
	utcr3 = UART_GET_UTCR3(sport);
	if (break_state == -1)
		utcr3 |= UTCR3_BRK;
	else
		utcr3 &= ~UTCR3_BRK;
	UART_PUT_UTCR3(sport, utcr3);
	spin_unlock_irqrestore(&sport->port.lock, flags);
}

static int sa1100_startup(struct uart_port *port)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;
	int retval;

	/*
	 * Allocate the IRQ
	 */
	retval = request_irq(sport->port.irq, sa1100_int, 0,
			     "sa11x0-uart", sport);
	if (retval)
		return retval;

	/*
	 * Finally, clear and enable interrupts
	 */
	UART_PUT_UTSR0(sport, -1);
	UART_PUT_UTCR3(sport, UTCR3_RXE | UTCR3_TXE | UTCR3_RIE);

	/*
	 * Enable modem status interrupts
	 */
	spin_lock_irq(&sport->port.lock);
	sa1100_enable_ms(&sport->port);
	spin_unlock_irq(&sport->port.lock);

	return 0;
}

static void sa1100_shutdown(struct uart_port *port)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;

	/*
	 * Stop our timer.
	 */
	del_timer_sync(&sport->timer);

	/*
	 * Free the interrupt
	 */
	free_irq(sport->port.irq, sport);

	/*
	 * Disable all interrupts, port and break condition.
	 */
	UART_PUT_UTCR3(sport, 0);
}

static void
sa1100_set_termios(struct uart_port *port, struct termios *termios,
		   struct termios *old)
{
	struct sa1100_port *sport = (struct sa1100_port *)port;
	unsigned long flags;
	unsigned int utcr0, old_utcr3, baud, quot;
	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;

	/*
	 * We only support CS7 and CS8.
	 */
	while ((termios->c_cflag & CSIZE) != CS7 &&
	       (termios->c_cflag & CSIZE) != CS8) {
		termios->c_cflag &= ~CSIZE;
		termios->c_cflag |= old_csize;
		old_csize = CS8;
	}

	if ((termios->c_cflag & CSIZE) == CS8)
		utcr0 = UTCR0_DSS;
	else
		utcr0 = 0;

	if (termios->c_cflag & CSTOPB)
		utcr0 |= UTCR0_SBS;
	if (termios->c_cflag & PARENB) {
		utcr0 |= UTCR0_PE;
		if (!(termios->c_cflag & PARODD))
			utcr0 |= UTCR0_OES;
	}

	/*
	 * Ask the core to calculate the divisor for us.
	 */
	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16); 
	quot = uart_get_divisor(port, baud);

	spin_lock_irqsave(&sport->port.lock, flags);