amba-pl010.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 827 行 · 第 1/2 页

/*
 *  linux/drivers/char/amba.c
 *
 *  Driver for AMBA 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: amba.c,v 1.41 2002/07/28 10:03:27 rmk Exp $
 *
 * This is a generic driver for ARM AMBA-type serial ports.  They
 * have a lot of 16550-like features, but are not register compatible.
 * Note that although they do have CTS, DCD and DSR inputs, they do
 * not have an RI input, nor do they have DTR or RTS outputs.  If
 * required, these have to be supplied via some other means (eg, GPIO)
 * and hooked into this driver.
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/device.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware/amba.h>

#if defined(CONFIG_SERIAL_AMBA_PL010_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>

#include <asm/hardware/amba_serial.h>

#define UART_NR		2

#define SERIAL_AMBA_MAJOR	204
#define SERIAL_AMBA_MINOR	16
#define SERIAL_AMBA_NR		UART_NR

#define AMBA_ISR_PASS_LIMIT	256

/*
 * Access macros for the AMBA UARTs
 */
#define UART_GET_INT_STATUS(p)	readb((p)->membase + UART010_IIR)
#define UART_PUT_ICR(p, c)	writel((c), (p)->membase + UART010_ICR)
#define UART_GET_FR(p)		readb((p)->membase + UART01x_FR)
#define UART_GET_CHAR(p)	readb((p)->membase + UART01x_DR)
#define UART_PUT_CHAR(p, c)	writel((c), (p)->membase + UART01x_DR)
#define UART_GET_RSR(p)		readb((p)->membase + UART01x_RSR)
#define UART_GET_CR(p)		readb((p)->membase + UART010_CR)
#define UART_PUT_CR(p,c)	writel((c), (p)->membase + UART010_CR)
#define UART_GET_LCRL(p)	readb((p)->membase + UART010_LCRL)
#define UART_PUT_LCRL(p,c)	writel((c), (p)->membase + UART010_LCRL)
#define UART_GET_LCRM(p)	readb((p)->membase + UART010_LCRM)
#define UART_PUT_LCRM(p,c)	writel((c), (p)->membase + UART010_LCRM)
#define UART_GET_LCRH(p)	readb((p)->membase + UART010_LCRH)
#define UART_PUT_LCRH(p,c)	writel((c), (p)->membase + UART010_LCRH)
#define UART_RX_DATA(s)		(((s) & UART01x_FR_RXFE) == 0)
#define UART_TX_READY(s)	(((s) & UART01x_FR_TXFF) == 0)
#define UART_TX_EMPTY(p)	((UART_GET_FR(p) & UART01x_FR_TMSK) == 0)

#define UART_DUMMY_RSR_RX	/*256*/0
#define UART_PORT_SIZE		64

/*
 * On the Integrator platform, the port RTS and DTR are provided by
 * bits in the following SC_CTRLS register bits:
 *        RTS  DTR
 *  UART0  7    6
 *  UART1  5    4
 */
#define SC_CTRLC	(IO_ADDRESS(INTEGRATOR_SC_BASE) + INTEGRATOR_SC_CTRLC_OFFSET)
#define SC_CTRLS	(IO_ADDRESS(INTEGRATOR_SC_BASE) + INTEGRATOR_SC_CTRLS_OFFSET)

/*
 * We wrap our port structure around the generic uart_port.
 */
struct uart_amba_port {
	struct uart_port	port;
	unsigned int		dtr_mask;
	unsigned int		rts_mask;
	unsigned int		old_status;
};

static void pl010_stop_tx(struct uart_port *port, unsigned int tty_stop)
{
	unsigned int cr;

	cr = UART_GET_CR(port);
	cr &= ~UART010_CR_TIE;
	UART_PUT_CR(port, cr);
}

static void pl010_start_tx(struct uart_port *port, unsigned int tty_start)
{
	unsigned int cr;

	cr = UART_GET_CR(port);
	cr |= UART010_CR_TIE;
	UART_PUT_CR(port, cr);
}

static void pl010_stop_rx(struct uart_port *port)
{
	unsigned int cr;

	cr = UART_GET_CR(port);
	cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
	UART_PUT_CR(port, cr);
}

static void pl010_enable_ms(struct uart_port *port)
{
	unsigned int cr;

	cr = UART_GET_CR(port);
	cr |= UART010_CR_MSIE;
	UART_PUT_CR(port, cr);
}

static void
#ifdef SUPPORT_SYSRQ
pl010_rx_chars(struct uart_port *port, struct pt_regs *regs)
#else
pl010_rx_chars(struct uart_port *port)
#endif
{
	struct tty_struct *tty = port->info->tty;
	unsigned int status, ch, rsr, max_count = 256;

	status = UART_GET_FR(port);
	while (UART_RX_DATA(status) && max_count--) {
		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
			tty->flip.work.func((void *)tty);
			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
				printk(KERN_WARNING "TTY_DONT_FLIP set\n");
				return;
			}
		}

		ch = UART_GET_CHAR(port);

		*tty->flip.char_buf_ptr = ch;
		*tty->flip.flag_buf_ptr = TTY_NORMAL;
		port->icount.rx++;

		/*
		 * Note that the error handling code is
		 * out of the main execution path
		 */
		rsr = UART_GET_RSR(port) | UART_DUMMY_RSR_RX;
		if (rsr & UART01x_RSR_ANY) {
			if (rsr & UART01x_RSR_BE) {
				rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
				port->icount.brk++;
				if (uart_handle_break(port))
					goto ignore_char;
			} else if (rsr & UART01x_RSR_PE)
				port->icount.parity++;
			else if (rsr & UART01x_RSR_FE)
				port->icount.frame++;
			if (rsr & UART01x_RSR_OE)
				port->icount.overrun++;

			rsr &= port->read_status_mask;

			if (rsr & UART01x_RSR_BE)
				*tty->flip.flag_buf_ptr = TTY_BREAK;
			else if (rsr & UART01x_RSR_PE)
				*tty->flip.flag_buf_ptr = TTY_PARITY;
			else if (rsr & UART01x_RSR_FE)
				*tty->flip.flag_buf_ptr = TTY_FRAME;
		}

		if (uart_handle_sysrq_char(port, ch, regs))
			goto ignore_char;

		if ((rsr & port->ignore_status_mask) == 0) {
			tty->flip.flag_buf_ptr++;
			tty->flip.char_buf_ptr++;
			tty->flip.count++;
		}
		if ((rsr & UART01x_RSR_OE) &&
		    tty->flip.count < TTY_FLIPBUF_SIZE) {
			/*
			 * Overrun is special, since it's reported
			 * immediately, and doesn't affect the current
			 * character
			 */
			*tty->flip.char_buf_ptr++ = 0;
			*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
			tty->flip.count++;
		}
	ignore_char:
		status = UART_GET_FR(port);
	}
	tty_flip_buffer_push(tty);
	return;
}

static void pl010_tx_chars(struct uart_port *port)
{
	struct circ_buf *xmit = &port->info->xmit;
	int count;

	if (port->x_char) {
		UART_PUT_CHAR(port, port->x_char);
		port->icount.tx++;
		port->x_char = 0;
		return;
	}
	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
		pl010_stop_tx(port, 0);
		return;
	}

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

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);

	if (uart_circ_empty(xmit))
		pl010_stop_tx(port, 0);
}

static void pl010_modem_status(struct uart_port *port)
{
	struct uart_amba_port *uap = (struct uart_amba_port *)port;
	unsigned int status, delta;

	UART_PUT_ICR(&uap->port, 0);

	status = UART_GET_FR(&uap->port) & UART01x_FR_MODEM_ANY;

	delta = status ^ uap->old_status;
	uap->old_status = status;

	if (!delta)
		return;

	if (delta & UART01x_FR_DCD)
		uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);

	if (delta & UART01x_FR_DSR)
		uap->port.icount.dsr++;

	if (delta & UART01x_FR_CTS)
		uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);

	wake_up_interruptible(&uap->port.info->delta_msr_wait);
}

static irqreturn_t pl010_int(int irq, void *dev_id, struct pt_regs *regs)
{
	struct uart_port *port = dev_id;
	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
	int handled = 0;

	spin_lock(&port->lock);

	status = UART_GET_INT_STATUS(port);
	if (status) {
		do {
			if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
#ifdef SUPPORT_SYSRQ
				pl010_rx_chars(port, regs);
#else
				pl010_rx_chars(port);
#endif
			if (status & UART010_IIR_MIS)
				pl010_modem_status(port);
			if (status & UART010_IIR_TIS)
				pl010_tx_chars(port);

			if (pass_counter-- == 0)
				break;

			status = UART_GET_INT_STATUS(port);
		} while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
				   UART010_IIR_TIS));
		handled = 1;
	}

	spin_unlock(&port->lock);

	return IRQ_RETVAL(handled);
}

static unsigned int pl010_tx_empty(struct uart_port *port)
{
	return UART_GET_FR(port) & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
}

static unsigned int pl010_get_mctrl(struct uart_port *port)
{
	unsigned int result = 0;
	unsigned int status;

	status = UART_GET_FR(port);
	if (status & UART01x_FR_DCD)
		result |= TIOCM_CAR;
	if (status & UART01x_FR_DSR)
		result |= TIOCM_DSR;
	if (status & UART01x_FR_CTS)
		result |= TIOCM_CTS;

	return result;
}

static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	struct uart_amba_port *uap = (struct uart_amba_port *)port;
	unsigned int ctrls = 0, ctrlc = 0;

	if (mctrl & TIOCM_RTS)
		ctrlc |= uap->rts_mask;
	else
		ctrls |= uap->rts_mask;

	if (mctrl & TIOCM_DTR)
		ctrlc |= uap->dtr_mask;
	else
		ctrls |= uap->dtr_mask;

	__raw_writel(ctrls, SC_CTRLS);
	__raw_writel(ctrlc, SC_CTRLC);
}

static void pl010_break_ctl(struct uart_port *port, int break_state)
{
	unsigned long flags;
	unsigned int lcr_h;

	spin_lock_irqsave(&port->lock, flags);
	lcr_h = UART_GET_LCRH(port);
	if (break_state == -1)
		lcr_h |= UART01x_LCRH_BRK;
	else
		lcr_h &= ~UART01x_LCRH_BRK;
	UART_PUT_LCRH(port, lcr_h);
	spin_unlock_irqrestore(&port->lock, flags);
}

static int pl010_startup(struct uart_port *port)
{
	struct uart_amba_port *uap = (struct uart_amba_port *)port;
	int retval;

	/*
	 * Allocate the IRQ
	 */
	retval = request_irq(port->irq, pl010_int, 0, "uart-pl010", port);
	if (retval)
		return retval;

	/*
	 * initialise the old status of the modem signals
	 */
	uap->old_status = UART_GET_FR(port) & UART01x_FR_MODEM_ANY;

	/*
	 * Finally, enable interrupts
	 */
	UART_PUT_CR(port, UART01x_CR_UARTEN | UART010_CR_RIE |
			  UART010_CR_RTIE);

	return 0;
}

static void pl010_shutdown(struct uart_port *port)
{
	/*
	 * Free the interrupt
	 */
	free_irq(port->irq, port);

	/*
	 * disable all interrupts, disable the port
	 */
	UART_PUT_CR(port, 0);

	/* disable break condition and fifos */
	UART_PUT_LCRH(port, UART_GET_LCRH(port) &
		~(UART01x_LCRH_BRK | UART01x_LCRH_FEN));