dz.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 828 行 · 第 1/2 页

/*
 * dz.c: Serial port driver for DECStations equiped 
 *       with the DZ chipset.
 *
 * Copyright (C) 1998 Olivier A. D. Lebaillif 
 *             
 * Email: [e-mail]
 *
 * [31-AUG-98] triemer
 * Changed IRQ to use Harald's dec internals interrupts.h
 * removed base_addr code - moving address assignment to setup.c
 * Changed name of dz_init to rs_init to be consistent with tc code
 * [13-NOV-98] triemer fixed code to receive characters
 *    after patches by harald to irq code.  
 * [09-JAN-99] triemer minor fix for schedule - due to removal of timeout
 *            field from "current" - somewhere between 2.1.121 and 2.1.131
 Qua Jun 27 15:02:26 BRT 2001
 * [27-JUN-2001] Arnaldo Carvalho de Melo <[e-mail]> - cleanups
 *  
 * Parts (C) 1999 David Airlie, [e-mail] 
 * [07-SEP-99] Bugfixes 
 *
 * [06-Jan-2002] Russell King <[e-mail]>
 * Converted to new serial core
 */

#undef DEBUG_DZ

#include <linux/config.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/serial.h>
#include <linux/serial_core.h>

#include <asm/bootinfo.h>
#include <asm/dec/interrupts.h>
#include <asm/dec/kn01.h>
#include <asm/dec/kn02.h>
#include <asm/dec/machtype.h>
#include <asm/dec/prom.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/uaccess.h>

#define CONSOLE_LINE (3)	/* for definition of struct console */

#include "dz.h"

#define DZ_INTR_DEBUG 1

static char *dz_name = "DECstation DZ serial driver version ";
static char *dz_version = "1.02";

struct dz_port {
	struct uart_port	port;
	unsigned int		cflag;
};

static struct dz_port dz_ports[DZ_NB_PORT];

#ifdef DEBUG_DZ
/*
 * debugging code to send out chars via prom 
 */
static void debug_console(const char *s, int count)
{
	unsigned i;

	for (i = 0; i < count; i++) {
		if (*s == 10)
			prom_printf("%c", 13);
		prom_printf("%c", *s++);
	}
}
#endif

/*
 * ------------------------------------------------------------
 * dz_in () and dz_out ()
 *
 * These routines are used to access the registers of the DZ 
 * chip, hiding relocation differences between implementation.
 * ------------------------------------------------------------
 */

static inline unsigned short dz_in(struct dz_port *dport, unsigned offset)
{
	volatile unsigned short *addr =
		(volatile unsigned short *) (dport->port.membase + offset);
	return *addr;
}

static inline void dz_out(struct dz_port *dport, unsigned offset,
                          unsigned short value)
{
	volatile unsigned short *addr =
		(volatile unsigned short *) (dport->port.membase + offset);
	*addr = value;
}

/*
 * ------------------------------------------------------------
 * rs_stop () and rs_start ()
 *
 * These routines are called before setting or resetting 
 * tty->stopped. They enable or disable transmitter interrupts, 
 * as necessary.
 * ------------------------------------------------------------
 */

static void dz_stop_tx(struct uart_port *uport, unsigned int tty_stop)
{
	struct dz_port *dport = (struct dz_port *)uport;
	unsigned short tmp, mask = 1 << dport->port.line;
	unsigned long flags;

	spin_lock_irqsave(&dport->port.lock, flags);
	tmp = dz_in(dport, DZ_TCR);	/* read the TX flag */
	tmp &= ~mask;			/* clear the TX flag */
	dz_out(dport, DZ_TCR, tmp);
	spin_unlock_irqrestore(&dport->port.lock, flags);
}

static void dz_start_tx(struct uart_port *uport, unsigned int tty_start)
{
	struct dz_port *dport = (struct dz_port *)uport;
	unsigned short tmp, mask = 1 << dport->port.line;
	unsigned long flags;

	spin_lock_irqsave(&dport->port.lock, flags);
	tmp = dz_in(dport, DZ_TCR);	/* read the TX flag */
	tmp |= mask;			/* set the TX flag */
	dz_out(dport, DZ_TCR, tmp);
	spin_unlock_irqrestore(&dport->port.lock, flags);
}

static void dz_stop_rx(struct uart_port *uport)
{
	struct dz_port *dport = (struct dz_port *)uport;
	unsigned long flags;

	spin_lock_irqsave(&dport->port.lock, flags);
	dport->cflag &= ~DZ_CREAD;
	dz_out(dport, DZ_LPR, dport->cflag);
	spin_unlock_irqrestore(&dport->port.lock, flags);
}

static void dz_enable_ms(struct uart_port *port)
{
	/* nothing to do */
}

/*
 * ------------------------------------------------------------
 * Here starts the interrupt handling routines.  All of the 
 * following subroutines are declared as inline and are folded 
 * into dz_interrupt.  They were separated out for readability's 
 * sake. 
 *
 * Note: rs_interrupt() is a "fast" interrupt, which means that it
 * runs with interrupts turned off.  People who may want to modify
 * rs_interrupt() should try to keep the interrupt handler as fast as
 * possible.  After you are done making modifications, it is not a bad
 * idea to do:
 * 
 *	make drivers/serial/dz.s
 *
 * and look at the resulting assemble code in dz.s.
 *
 * ------------------------------------------------------------
 */

/*
 * ------------------------------------------------------------
 * receive_char ()
 *
 * This routine deals with inputs from any lines.
 * ------------------------------------------------------------
 */
static inline void dz_receive_chars(struct dz_port *dport)
{
	struct tty_struct *tty = NULL;
	struct uart_icount *icount;
	int ignore = 0;
	unsigned short status, tmp;
	unsigned char ch;

	/* this code is going to be a problem...
	   the call to tty_flip_buffer is going to need
	   to be rethought...
	 */
	do {
		status = dz_in(dport, DZ_RBUF);

		/* punt so we don't get duplicate characters */
		if (!(status & DZ_DVAL))
			goto ignore_char;


		ch = UCHAR(status);	/* grab the char */

#if 0
		if (info->is_console) {
			if (ch == 0)
				return;		/* it's a break ... */
		}
#endif

		tty = dport->port.info->tty;/* now tty points to the proper dev */
		icount = &dport->port.icount;

		if (!tty)
			break;
		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
			break;

		*tty->flip.char_buf_ptr = ch;
		*tty->flip.flag_buf_ptr = 0;
		icount->rx++;

		/* keep track of the statistics */
		if (status & (DZ_OERR | DZ_FERR | DZ_PERR)) {
			if (status & DZ_PERR)	/* parity error */
				icount->parity++;
			else if (status & DZ_FERR)	/* frame error */
				icount->frame++;
			if (status & DZ_OERR)	/* overrun error */
				icount->overrun++;

			/*  check to see if we should ignore the character
			   and mask off conditions that should be ignored
			 */

			if (status & dport->port.ignore_status_mask) {
				if (++ignore > 100)
					break;
				goto ignore_char;
			}
			/* mask off the error conditions we want to ignore */
			tmp = status & dport->port.read_status_mask;

			if (tmp & DZ_PERR) {
				*tty->flip.flag_buf_ptr = TTY_PARITY;
#ifdef DEBUG_DZ
				debug_console("PERR\n", 5);
#endif
			} else if (tmp & DZ_FERR) {
				*tty->flip.flag_buf_ptr = TTY_FRAME;
#ifdef DEBUG_DZ
				debug_console("FERR\n", 5);
#endif
			}
			if (tmp & DZ_OERR) {
#ifdef DEBUG_DZ
				debug_console("OERR\n", 5);
#endif
				if (tty->flip.count < TTY_FLIPBUF_SIZE) {
					tty->flip.count++;
					tty->flip.flag_buf_ptr++;
					tty->flip.char_buf_ptr++;
					*tty->flip.flag_buf_ptr = TTY_OVERRUN;
				}
			}
		}
		tty->flip.flag_buf_ptr++;
		tty->flip.char_buf_ptr++;
		tty->flip.count++;
	      ignore_char:
	} while (status & DZ_DVAL);

	if (tty)
		tty_flip_buffer_push(tty);
}

/*
 * ------------------------------------------------------------
 * transmit_char ()
 *
 * This routine deals with outputs to any lines.
 * ------------------------------------------------------------
 */
static inline void dz_transmit_chars(struct dz_port *dport)
{
	struct circ_buf *xmit = &dport->port.info->xmit;
	unsigned char tmp;

	if (dport->port.x_char) {	/* XON/XOFF chars */
		dz_out(dport, DZ_TDR, dport->port.x_char);
		dport->port.icount.tx++;
		dport->port.x_char = 0;
		return;
	}
	/* if nothing to do or stopped or hardware stopped */
	if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) {
		dz_stop_tx(&dport->port, 0);
		return;
	}

	/*
	 * if something to do ... (rember the dz has no output fifo so we go
	 * one char at a time :-<
	 */
	tmp = xmit->buf[xmit->tail];
	xmit->tail = (xmit->tail + 1) & (DZ_XMIT_SIZE - 1);
	dz_out(dport, DZ_TDR, tmp);
	dport->port.icount.tx++;

	if (uart_circ_chars_pending(xmit) < DZ_WAKEUP_CHARS)
		uart_write_wakeup(&dport->port);

	/* Are we done */
	if (uart_circ_empty(xmit))
		dz_stop_tx(&dport->port, 0);
}

/*
 * ------------------------------------------------------------
 * check_modem_status ()
 *
 * Only valid for the MODEM line duh !
 * ------------------------------------------------------------
 */
static inline void check_modem_status(struct dz_port *dport)
{
	unsigned short status;

	/* if not ne modem line just return */
	if (dport->port.line != DZ_MODEM)
		return;

	status = dz_in(dport, DZ_MSR);

	/* it's easy, since DSR2 is the only bit in the register */
	if (status)
		dport->port.icount.dsr++;
}

/*
 * ------------------------------------------------------------
 * dz_interrupt ()
 *
 * this is the main interrupt routine for the DZ chip.
 * It deals with the multiple ports.
 * ------------------------------------------------------------
 */
static irqreturn_t dz_interrupt(int irq, void *dev, struct pt_regs *regs)
{
	struct dz_port *dport;
	unsigned short status;

	/* get the reason why we just got an irq */
	status = dz_in((struct dz_port *)dev, DZ_CSR);
	dport = &dz_ports[LINE(status)];

	if (status & DZ_RDONE)
		dz_receive_chars(dport);

	if (status & DZ_TRDY)
		dz_transmit_chars(dport);

	/* FIXME: what about check modem status??? --rmk */

	return IRQ_HANDLED;
}

/*
 * -------------------------------------------------------------------
 * Here ends the DZ interrupt routines.
 * -------------------------------------------------------------------
 */

static unsigned int dz_get_mctrl(struct uart_port *uport)
{
	struct dz_port *dport = (struct dz_port *)uport;
	unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;

	if (dport->port.line == DZ_MODEM) {
		/*
		 * CHECKME: This is a guess from the other code... --rmk
		 */
		if (dz_in(dport, DZ_MSR) & DZ_MODEM_DSR)
			mctrl &= ~TIOCM_DSR;
	}

	return mctrl;
}

static void dz_set_mctrl(struct uart_port *uport, unsigned int mctrl)
{
	struct dz_port *dport = (struct dz_port *)uport;
	unsigned short tmp;

	if (dport->port.line == DZ_MODEM) {
		tmp = dz_in(dport, DZ_TCR);
		if (mctrl & TIOCM_DTR)
			tmp &= ~DZ_MODEM_DTR;
		else
			tmp |= DZ_MODEM_DTR;
		dz_out(dport, DZ_TCR, tmp);
	}
}

/*
 * -------------------------------------------------------------------
 * startup ()
 *
 * various initialization tasks
 * ------------------------------------------------------------------- 
 */
static int dz_startup(struct uart_port *uport)
{