serial_clps711x.c

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/*
 *  linux/drivers/char/serial_clps711x.c
 *
 *  Driver for CLPS711x serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
 *  Copyright 1999 ARM Limited
 *  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: serial_clps711x.c,v 1.12.2.1 2001/11/27 17:35:39 rmk Exp $
 *
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/circ_buf.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>

#include <asm/bitops.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/uaccess.h>

#include <linux/serial_core.h>

#include <asm/hardware/clps7111.h>

#define UART_NR		2

#define SERIAL_CLPS711X_NAME	"ttyAM"
#define SERIAL_CLPS711X_MAJOR	204
#define SERIAL_CLPS711X_MINOR	16
#define SERIAL_CLPS711X_NR	UART_NR

#define CALLOUT_CLPS711X_NAME	"cuaam"
#define CALLOUT_CLPS711X_MAJOR	205
#define CALLOUT_CLPS711X_MINOR	16
#define CALLOUT_CLPS711X_NR	UART_NR

static struct tty_driver normal, callout;
static struct tty_struct *clps711x_table[UART_NR];
static struct termios *clps711x_termios[UART_NR], *clps711x_termios_locked[UART_NR];

/*
 * We use the relevant SYSCON register as a base address for these ports.
 */
#define UBRLCR(port)		((port)->iobase + UBRLCR1 - SYSCON1)
#define UARTDR(port)		((port)->iobase + UARTDR1 - SYSCON1)
#define SYSFLG(port)		((port)->iobase + SYSFLG1 - SYSCON1)
#define SYSCON(port)		((port)->iobase + SYSCON1 - SYSCON1)

#define TX_IRQ(port)		((port)->irq)
#define RX_IRQ(port)		((port)->irq + 1)

#define UART_ANY_ERR		(UARTDR_FRMERR | UARTDR_PARERR | UARTDR_OVERR)

static void clps711xuart_stop_tx(struct uart_port *port, u_int from_tty)
{
	disable_irq(TX_IRQ(port));
}

static void clps711xuart_start_tx(struct uart_port *port, u_int nonempty, u_int from_tty)
{
	if (nonempty)
		enable_irq(TX_IRQ(port));
}

static void clps711xuart_stop_rx(struct uart_port *port)
{
	disable_irq(RX_IRQ(port));
}

static void clps711xuart_enable_ms(struct uart_port *port)
{
}

#if 0
static void ambauart_modem_status(struct uart_info *info)
{
	unsigned int status, delta;
	struct uart_icount *icount = &info->port->icount;

	UART_PUT_ICR(info->port, 0);

	status = UART_GET_FR(info->port) & AMBA_UARTFR_MODEM_ANY;

	delta = status ^ info->port->old_status;
	info->port->old_status = status;

	if (!delta)
		return;

	if (delta & AMBA_UARTFR_DCD)
		uart_handle_dcd_change(info, status & AMBA_UARTFR_DCD);

	if (delta & AMBA_UARTFR_DSR)
		icount->dsr++;

	if (delta & AMBA_UARTFR_CTS)
		uart_handle_cts_change(info, status & AMBA_UARTFR_CTS);

	wake_up_interruptible(&info->delta_msr_wait);
}
#endif

static void clps711xuart_int_rx(int irq, void *dev_id, struct pt_regs *regs)
{
	struct uart_info *info = dev_id;
	struct tty_struct *tty = info->tty;
	unsigned int status, ch, flg, ignored = 0;
	struct uart_port *port = info->port;

	status = clps_readl(SYSFLG(port));
	while (!(status & SYSFLG_URXFE)) {
		ch = clps_readl(UARTDR(port));

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

		flg = TTY_NORMAL;

		/*
		 * Note that the error handling code is
		 * out of the main execution path
		 */
		if (ch & UART_ANY_ERR)
			goto handle_error;

		if (uart_handle_sysrq_char(info, 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 = clps_readl(SYSFLG(port));
	}
out:
	tty_flip_buffer_push(tty);
	return;

handle_error:
	if (ch & UARTDR_PARERR)
		port->icount.parity++;
	else if (ch & UARTDR_FRMERR)
		port->icount.frame++;
	if (ch & UARTDR_OVERR)
		port->icount.overrun++;

	if (ch & port->ignore_status_mask) {
		if (++ignored > 100)
			goto out;
		goto ignore_char;
	}
	ch &= port->read_status_mask;

	if (ch & UARTDR_PARERR)
		flg = TTY_PARITY;
	else if (ch & UARTDR_FRMERR)
		flg = TTY_FRAME;

	if (ch & UARTDR_OVERR) {
		/*
		 * CHECK: does overrun affect the current character?
		 * ASSUMPTION: it does not.
		 */
		*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
	info->sysrq = 0;
#endif
	goto error_return;
}

static void clps711xuart_int_tx(int irq, void *dev_id, struct pt_regs *regs)
{
	struct uart_info *info = dev_id;
	struct uart_port *port = info->port;
	int count;

	if (port->x_char) {
		clps_writel(port->x_char, UARTDR(port));
		port->icount.tx++;
		port->x_char = 0;
		return;
	}
	if (info->xmit.head == info->xmit.tail
	    || info->tty->stopped
	    || info->tty->hw_stopped) {
		clps711xuart_stop_tx(info->port, 0);
		return;
	}

	count = port->fifosize >> 1;
	do {
		clps_writel(info->xmit.buf[info->xmit.tail], UARTDR(port));
		info->xmit.tail = (info->xmit.tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;
		if (info->xmit.head == info->xmit.tail)
			break;
	} while (--count > 0);

	if (CIRC_CNT(info->xmit.head,
		     info->xmit.tail,
		     UART_XMIT_SIZE) < WAKEUP_CHARS)
		uart_event(info, EVT_WRITE_WAKEUP);

	if (info->xmit.head == info->xmit.tail)
		clps711xuart_stop_tx(info->port, 0);
}

static u_int clps711xuart_tx_empty(struct uart_port *port)
{
	u_int status = clps_readl(SYSFLG(port));
	return status & SYSFLG_UBUSY ? 0 : TIOCSER_TEMT;
}

static u_int clps711xuart_get_mctrl(struct uart_port *port)
{
	unsigned int port_addr;
	unsigned int result = 0;
	unsigned int status;

	port_addr = SYSFLG(port);
	if (port_addr == SYSFLG1) {
		status = clps_readl(SYSFLG1);
		if (status & SYSFLG1_DCD)
			result |= TIOCM_CAR;
		if (status & SYSFLG1_DSR)
			result |= TIOCM_DSR;
		if (status & SYSFLG1_CTS)
			result |= TIOCM_CTS;
	}

	return result;
}

static void clps711xuart_set_mctrl_null(struct uart_port *port, u_int mctrl)
{
}

static void clps711xuart_break_ctl(struct uart_port *port, int break_state)
{
	unsigned int ubrlcr;

	ubrlcr = clps_readl(UBRLCR(port));
	if (break_state == -1)
		ubrlcr |= UBRLCR_BREAK;
	else
		ubrlcr &= ~UBRLCR_BREAK;
	clps_writel(ubrlcr, UBRLCR(port));
}

static int clps711xuart_startup(struct uart_port *port, struct uart_info *info)
{
	u_int syscon;
	int retval;

	/*
	 * Allocate the IRQs
	 */
	retval = request_irq(TX_IRQ(port), clps711xuart_int_tx, 0,
			     "clps711xuart_tx", info);
	if (retval)
		return retval;

	retval = request_irq(RX_IRQ(port), clps711xuart_int_rx, 0,
			     "clps711xuart_rx", info);
	if (retval) {
		free_irq(TX_IRQ(port), info);
		return retval;
	}

	port->ops->set_mctrl(port, info->mctrl);

	/*
	 * enable the port
	 */
	syscon = clps_readl(SYSCON(port));
	syscon |= SYSCON_UARTEN;
	clps_writel(syscon, SYSCON(port));

	return 0;
}

static void clps711xuart_shutdown(struct uart_port *port, struct uart_info *info)
{
	u_int ubrlcr, syscon;

	/*
	 * Free the interrupt
	 */
	free_irq(TX_IRQ(port), info);	/* TX interrupt */
	free_irq(RX_IRQ(port), info);	/* RX interrupt */

	/*
	 * disable the port
	 */
	syscon = clps_readl(SYSCON(port));
	syscon &= ~SYSCON_UARTEN;
	clps_writel(syscon, SYSCON(port));

	/*
	 * disable break condition and fifos
	 */
	ubrlcr = clps_readl(UBRLCR(port));
	ubrlcr &= ~(UBRLCR_FIFOEN | UBRLCR_BREAK);