path: root/drivers/serial/imx.c

/*
 *  linux/drivers/serial/imx.c
 *
 *  Driver for Motorola IMX serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
 *  Author: Sascha Hauer <sascha@saschahauer.de>
 *  Copyright (C) 2004 Pengutronix
 *
 * 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
 *
 * [29-Mar-2005] Mike Lee
 * Added hardware handshake
 */
#include <linux/config.h>

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

#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/arch/imx-uart.h>

/* We've been assigned a range on the "Low-density serial ports" major */
#define SERIAL_IMX_MAJOR	204
#define MINOR_START		41

#define NR_PORTS		2

#define IMX_ISR_PASS_LIMIT	256

/*
 * This is the size of our serial port register set.
 */
#define UART_PORT_SIZE	0x100

/*
 * 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)

#define DRIVER_NAME "IMX-uart"

struct imx_port {
	struct uart_port	port;
	struct timer_list	timer;
	unsigned int		old_status;
	int			txirq,rxirq,rtsirq;
	int			have_rtscts:1;
};

/*
 * Handle any change of modem status signal since we were last called.
 */
static void imx_mctrl_check(struct imx_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 imx_timeout(unsigned long data)
{
	struct imx_port *sport = (struct imx_port *)data;
	unsigned long flags;

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

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

/*
 * interrupts disabled on entry
 */
static void imx_stop_tx(struct uart_port *port)
{
	struct imx_port *sport = (struct imx_port *)port;
	UCR1((u32)sport->port.membase) &= ~UCR1_TXMPTYEN;
}

/*
 * interrupts disabled on entry
 */
static void imx_stop_rx(struct uart_port *port)
{
	struct imx_port *sport = (struct imx_port *)port;
	UCR2((u32)sport->port.membase) &= ~UCR2_RXEN;
}

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

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

static inline void imx_transmit_buffer(struct imx_port *sport)
{
	struct circ_buf *xmit = &sport->port.info->xmit;

	do {
		/* send xmit->buf[xmit->tail]
		 * out the port here */
		URTX0((u32)sport->port.membase) = xmit->buf[xmit->tail];
		xmit->tail = (xmit->tail + 1) &
		         (UART_XMIT_SIZE - 1);
		sport->port.icount.tx++;
		if (uart_circ_empty(xmit))
			break;
	} while (!(UTS((u32)sport->port.membase) & UTS_TXFULL));

	if (uart_circ_empty(xmit))
		imx_stop_tx(&sport->port);
}

/*
 * interrupts disabled on entry
 */
static void imx_start_tx(struct uart_port *port)
{
	struct imx_port *sport = (struct imx_port *)port;

	UCR1((u32)sport->port.membase) |= UCR1_TXMPTYEN;

	if(UTS((u32)sport->port.membase) & UTS_TXEMPTY)
		imx_transmit_buffer(sport);
}

static irqreturn_