path: root/drivers/tty/serial/msm_serial.c

/*
 * Driver for msm7k serial device and console
 *
 * Copyright (C) 2007 Google, Inc.
 * Author: Robert Love <rlove@google.com>
 * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 */

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

#include <linux/hrtimer.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/delay.h>

#include "msm_serial.h"

struct msm_port {
	struct uart_port	uart;
	char			name[16];
	struct clk		*clk;
	struct clk		*pclk;
	unsigned int		imr;
	unsigned int            *gsbi_base;
	int			is_uartdm;
	unsigned int		old_snap_state;
};

static inline void wait_for_xmitr(struct uart_port *port, int bits)
{
	if (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY))
		while ((msm_read(port, UART_ISR) & bits) != bits)
			cpu_relax();
}

static void msm_stop_tx(struct uart_port *port)
{
	struct msm_port *msm_port = UART_TO_MSM(port);

	msm_port->imr &= ~UART_IMR_TXLEV;
	msm_write(port, msm_port->imr, UART_IMR);
}

static void msm_start_tx(struct uart_port *port)
{
	struct msm_port *msm_port = UART_TO_MSM(port);

	msm_port->imr |= UART_IMR_TXLEV;
	msm_write(port, msm_port->imr, UART_IMR);
}

static void msm_stop_rx(struct uart_port *port)
{
	struct msm_port *msm_port = UART_TO_MSM(port);

	msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
	msm_write(port, msm_port->imr, UART_IMR);
}

static void msm_enable_ms(struct uart_port *port)
{
	struct msm_port *msm_port = UART_TO_MSM(port);

	msm_port->imr |= UART_IMR_DELTA_CTS;
	msm_write(port, msm_port->imr, UART_IMR);
}

static void handle_rx_dm(struct uart_port *port, unsigned int misr)
{
	struct tty_struct *tty = port->state->port.tty;
	unsigned int sr;
	int count = 0;
	struct msm_port *msm_port = UART_TO_MSM(port);

	if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
		port->icount.overrun++;
		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
		msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
	}

	if (misr & UART_IMR_RXSTALE) {
		count = msm_read(port, UARTDM_RX_TOTAL_SNAP) -
			msm_port->old_snap_state;
		msm_port->old_snap_state = 0;
	} else {
		count = 4 * (msm_read(port, UART_RFWR));
		msm_port->old_snap_state += count;
	}

	/* TODO: Precise error reporting */

	port->icount.rx += count;

	while (count > 0) {
		unsigned int c;

		sr = msm_read(port, UART_SR);
		if ((sr & UART_SR_RX_READY) == 0) {
			msm_port->old_snap_state -= count;
			break;
		}
		c = msm_read(port, UARTDM_RF);
		if (sr & UART_SR_RX_BREAK) {
			port->icount.brk++;
			if (uart_handle_break(port))
				continue;
		} else if (sr & UART_SR_PAR_FRAME_ERR)
			port->icount.frame++;

		/* TODO: handle sysrq */
		tty_insert_flip_string(tty, (char *) &c,
				       (count > 4) ? 4 : count);
		count -= 4;
	}

	tty_flip_buffer_push(tty);
	if (misr & (UART_IMR_RXSTALE))
		msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
	msm_write(port, 0xFFFFFF, UARTDM_DMRX);
	msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
}

static void handle_rx(struct uart_port *port)
{
	struct tty_struct *tty = port->state->port.tty;
	unsigned int sr;

	/*
	 * Handle overr