bfin_5xx.c

linux 内核源代码

/*
 * File:         drivers/serial/bfin_5xx.c
 * Based on:     Based on drivers/serial/sa1100.c
 * Author:       Aubrey Li <[e-mail]>
 *
 * 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>

#ifdef CONFIG_KGDB_UART
#include <linux/kgdb.h>
#include <asm/irq_regs.h>
#endif

#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;

	while (!(UART_GET_LSR(uart) & TEMT))
		continue;

#ifdef CONFIG_SERIAL_BFIN_DMA
	disable_dma(uart->tx_dma_channel);
#else
#ifdef CONFIG_BF54x
	/* Waiting for Transmission Finished */
	while (!(UART_GET_LSR(uart) & TFI))
		continue;
	/* Clear TFI bit */
	UART_PUT_LSR(uart, TFI);
	UART_CLEAR_IER(uart, ETBEI);
#else
	unsigned short ier;

	ier = UART_GET_IER(uart);
	ier &= ~ETBEI;
	UART_PUT_IER(uart, ier);
#endif
#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
#ifdef CONFIG_BF54x
	UART_SET_IER(uart, ETBEI);
#else
	unsigned short ier;
	ier = UART_GET_IER(uart);
	ier |= ETBEI;
	UART_PUT_IER(uart, ier);
#endif
	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;
#ifdef	CONFIG_KGDB_UART
	if (uart->port.line != CONFIG_KGDB_UART_PORT) {
#endif
#ifdef CONFIG_BF54x
	UART_CLEAR_IER(uart, ERBFI);
#else
	unsigned short ier;

	ier = UART_GET_IER(uart);
	ier &= ~ERBFI;
	UART_PUT_IER(uart, ier);
#endif
#ifdef	CONFIG_KGDB_UART
	}
#endif
}

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

#ifdef CONFIG_KGDB_UART
static int kgdb_entry_state;

void kgdb_put_debug_char(int chr)
{
	struct bfin_serial_port *uart;
	
	if (CONFIG_KGDB_UART_PORT<0 || CONFIG_KGDB_UART_PORT>=NR_PORTS)
		uart = &bfin_serial_ports[0];
	else
		uart = &bfin_serial_ports[CONFIG_KGDB_UART_PORT];
	
	while (!(UART_GET_LSR(uart) & THRE)) {
		SSYNC();
	}

#ifndef CONFIG_BF54x
	UART_PUT_LCR(uart, UART_GET_LCR(uart)&(~DLAB));
	SSYNC();
#endif
	UART_PUT_CHAR(uart, (unsigned char)chr);
	SSYNC();
}

int kgdb_get_debug_char(void)
{
	struct bfin_serial_port *uart;
	unsigned char chr;

	if (CONFIG_KGDB_UART_PORT<0 || CONFIG_KGDB_UART_PORT>=NR_PORTS)
		uart = &bfin_serial_ports[0];
	else
		uart = &bfin_serial_ports[CONFIG_KGDB_UART_PORT];
	
	while(!(UART_GET_LSR(uart) & DR)) {
		SSYNC();
	}
#ifndef CONFIG_BF54x
	UART_PUT_LCR(uart, UART_GET_LCR(uart)&(~DLAB));
	SSYNC();
#endif
	chr = UART_GET_CHAR(uart);
	SSYNC();

	return chr;
}
#endif

#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;
	static int in_break = 0;
#ifdef CONFIG_KGDB_UART
	struct pt_regs *regs = get_irq_regs();
#endif

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

#ifdef CONFIG_KGDB_UART
	if (uart->port.line == CONFIG_KGDB_UART_PORT) {
		if (uart->port.cons->index == CONFIG_KGDB_UART_PORT && ch == 0x1) { /* Ctrl + A */
			kgdb_breakkey_pressed(regs);
			return;
		} else if (kgdb_entry_state == 0 && ch == '$') {/* connection from KGDB */
			kgdb_entry_state = 1;
		} else if (kgdb_entry_state == 1 && ch == 'q') {
			kgdb_entry_state = 0;
			kgdb_breakkey_pressed(regs);
			return;
		} else if (ch == 0x3) {/* Ctrl + C */
			kgdb_entry_state = 0;
			kgdb_breakkey_pressed(regs);
			return;
		} else {
			kgdb_entry_state = 0;
		}
	}
#endif

	if (ANOMALY_05000230) {
		/* 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.
		 * Note: While Anomaly 05000230 does not directly address this,
		 *       the changes that went in for it also fixed this issue.
		 */
		if (in_break) {
			if (ch != 0) {
				in_break = 0;
				ch = UART_GET_CHAR(uart);
				if (bfin_revid() < 5)
					return;
			} else
				return;
		}
	}

	if (status & BI) {
		if (ANOMALY_05000230)
			in_break = 1;
		uart->port.icount.brk++;
		if (uart_handle_break(&uart->port))
			goto ignore_char;
		status &= ~(PE | FE);
	}
	if (status & PE)
		uart->port.icount.parity++;
	if (status & OE)
		uart->port.icount.overrun++;
	if (status & FE)
		uart->port.icount.frame++;

	status &= uart->port.read_status_mask;

	if (status & BI)
		flg = TTY_BREAK;
	else if (status & PE)
		flg = TTY_PARITY;
	else if (status & FE)
		flg = TTY_FRAME;
	else
		flg = TTY_NORMAL;

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

	uart_insert_char(&uart->port, status, OE, ch, flg);

 ignore_char:
	tty_flip_buffer_push(tty);
}

static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
{
	struct circ_buf *xmit = &uart->port.info->xmit;

	if (uart->port.x_char) {
		UART_PUT_CHAR(uart, uart->port.x_char);
		uart->port.icount.tx++;
		uart->port.x_char = 0;
		return;
	}
	/*
	 * Check the modem control lines before
	 * transmitting anything.
	 */
	bfin_serial_mctrl_check(uart);

	if (uart_circ_empty(xmit) || uart_tx_stopped(&uart->port)) {
		bfin_serial_stop_tx(&uart->port);
		return;
	}

	local_put_char(uart, xmit->buf[xmit->tail]);
	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
	uart->port.icount.tx++;

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

	if (uart_circ_empty(xmit))
		bfin_serial_stop_tx(&uart->port);
}

static irqreturn_t bfin_serial_rx_int(int irq, void *dev_id)
{
	struct bfin_serial_port *uart = dev_id;

#ifdef CONFIG_BF54x
	unsigned short status;
	spin_lock(&uart->port.lock);
	status = UART_GET_LSR(uart);
	while ((UART_GET_IER(uart) & ERBFI) && (status & DR)) {
		bfin_serial_rx_chars(uart);
		status = UART_GET_LSR(uart);
	}
	spin_unlock(&uart->port.lock);
#else
	spin_lock(&uart->port.lock);
	while ((UART_GET_IIR(uart) & IIR_STATUS) == IIR_RX_READY)
		bfin_serial_rx_chars(uart);
	spin_unlock(&uart->port.lock);
#endif
	return IRQ_HANDLED;
}

static irqreturn_t bfin_serial_tx_int(int irq, void *dev_id)
{
	struct bfin_serial_port *uart = dev_id;

#ifdef CONFIG_BF54x
	unsigned short status;
	spin_lock(&uart->port.lock);
	status = UART_GET_LSR(uart);
	while ((UART_GET_IER(uart) & ETBEI) && (status & THRE)) {
		bfin_serial_tx_chars(uart);
		status = UART_GET_LSR(uart);
	}
	spin_unlock(&uart->port.lock);
#else
	spin_lock(&uart->port.lock);
	while ((UART_GET_IIR(uart) & IIR_STATUS) == IIR_TX_READY)
		bfin_serial_tx_chars(uart);
	spin_unlock(&uart->port.lock);
#endif
	return IRQ_HANDLED;
}


static void bfin_serial_do_work(struct work_struct *work)
{
	struct bfin_serial_port *uart = container_of(work, struct bfin_serial_port, cts_workqueue);

	bfin_serial_mctrl_check(uart);
}
#endif

#ifdef CONFIG_SERIAL_BFIN_DMA
static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
{
	struct circ_buf *xmit = &uart->port.info->xmit;
	unsigned short ier;
	int flags = 0;

	if (!uart->tx_done)
		return;

	uart->tx_done = 0;

	if (uart->port.x_char) {
		UART_PUT_CHAR(uart, uart->port.x_char);
		uart->port.icount.tx++;
		uart->port.x_char = 0;
		uart->tx_done = 1;
		return;
	}
	/*
	 * Check the modem control lines before
	 * transmitting anything.
	 */
	bfin_serial_mctrl_check(uart);

	if (uart_circ_empty(xmit) || uart_tx_stopped(&uart->port)) {
		bfin_serial_stop_tx(&uart->port);
		uart->tx_done = 1;
		return;
	}

	spin_lock_irqsave(&uart->port.lock, flags);
	uart->tx_count = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE);
	if (uart->tx_count > (UART_XMIT_SIZE - xmit->tail))