path: root/drivers/serial/bfin_5xx.c

/*
 * File:         drivers/serial/bfin_5xx.c
 * Based on:     Based on drivers/serial/sa1100.c
 * Author:       Aubrey Li <aubrey.li@analog.com>
 *
 * Created:
 * Description:  Driver for blackfin 5xx serial ports
 *
 * Modified:
 *               Copyright 2006 Analog Devices Inc.
 *
 * Bugs:         Enter bugs at http://blackfin.uclinux.org/
 *
 * 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, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#if defined(CONFIG_SERIAL_BFIN_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 <asm/gpio.h>
#include <asm/mach/bfin_serial_5xx.h>

#ifdef CONFIG_SERIAL_BFIN_DMA
#include <linux/dma-mapping.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/cacheflush.h>
#endif

/* UART name and device definitions */
#define BFIN_SERIAL_NAME	"ttyBF"
#define BFIN_SERIAL_MAJOR	204
#define BFIN_SERIAL_MINOR	64

/*
 * Setup for console. Argument comes from the menuconfig
 */
#define DMA_RX_XCOUNT		512
#define DMA_RX_YCOUNT		(PAGE_SIZE / DMA_RX_XCOUNT)

#define DMA_RX_FLUSH_JIFFIES	5

#ifdef CONFIG_SERIAL_BFIN_DMA
static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart);
#else
static void bfin_serial_do_work(struct work_struct *work);
static void bfin_serial_tx_chars(struct bfin_serial_port *uart);
static void local_put_char(struct bfin_serial_port *uart, char ch);
#endif

static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);

/*
 * interrupts are disabled on entry
 */
static void bfin_serial_stop_tx(struct uart_port *port)
{
	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;

#ifdef CONFIG_SERIAL_BFIN_DMA
	disable_dma(uart->tx_dma_channel);
#else
	unsigned short ier;

	ier = UART_GET_IER(uart);
	ier &= ~ETBEI;
	UART_PUT_IER(uart, ier);
#endif
}

/*
 * port is locked and interrupts are disabled
 */
static void bfin_serial_start_tx(struct uart_port *port)
{
	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;

#ifdef CONFIG_SERIAL_BFIN_DMA
	bfin_serial_dma_tx_chars(uart);
#else
	unsigned short ier;
	ier = UART_GET_IER(uart);
	ier |= ETBEI;
	UART_PUT_IER(uart, ier);
	bfin_serial_tx_chars(uart);
#endif
}

/*
 * Interrupts are enabled
 */
static void bfin_serial_stop_rx(struct uart_port *port)
{
	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
	unsigned short ier;

	ier = UART_GET_IER(uart);
	ier &= ~ERBFI;
	UART_PUT_IER(uart, ier);
}

/*
 * Set the modem control timer to fire immediately.
 */
static void bfin_serial_enable_ms(struct uart_port *port)
{
}

#ifdef CONFIG_SERIAL_BFIN_PIO
static void local_put_char(struct bfin_serial_port *uart, char ch)
{
	unsigned short status;
	int flags = 0;

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

	do {
		status = UART_GET_LSR(uart);
	} while (!(status & THRE));

	UART_PUT_CHAR(uart, ch);
	SSYNC();

	spin_unlock_irqrestore(&uart->port.lock, flags);
}

static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
{
	struct tty_struct *tty = uart->port.info->tty;
	unsigned int status, ch, flg;
#ifdef BF533_FAMILY
	static int in_break = 0;
#endif

	status = UART_GET_LSR(uart);
 	ch = UART_GET_CHAR(uart);
 	uart->port.icount.rx++;

#ifdef BF533_FAMILY
	/* The BF533 family of processors have a nice misbehavior where
	 * they continuously generate characters for a "single" break.
	 * We have to basically ignore this flood until the "next" valid
	 * character comes across.  All other Blackfin families operate
	 * properly though.
	 */
	if (in_break) {
		if (ch != 0) {
			in_break = 0;
			ch = UART_GET_CHAR(uart);
			if (bfin_revid() < 5)
				return;
		} else
			return;
	}
#endif

	if (status & BI) {
#ifdef BF533_FAMILY
		in_break = 1;
#endif
		uart->port.icount.brk++;
		if (uart_handle_break(&uart->port))
			goto ignore_char;
	}
	if (status<