dz.c

linux和2410结合开发 用他可以生成2410所需的zImage文件

/*
 * 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 
 */

/* #define DEBUG_DZ 1 */

#include <linux/version.h>
#include <linux/module.h>

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/init.h> 
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/major.h>
#include <linux/param.h>
#include <linux/tqueue.h>
#include <linux/interrupt.h>
#include <linux/serial.h>
#include <linux/serialP.h>
#include <asm-mips/wbflush.h>
#include <asm/dec/interrupts.h>			/* for definition of SERIAL */

/* for definition of struct console */
#ifdef CONFIG_SERIAL_CONSOLE
#define CONSOLE_LINE (3)
#endif /* ifdef CONFIG_SERIAL_CONSOLE */
#if defined(CONFIG_SERIAL_CONSOLE) || defined(DEBUG_DZ)
#include <linux/console.h>
#endif /* if defined(CONFIG_SERIAL_CONSOLE) || defined(DEBUG_DZ) */

#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>

#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/dec/machtype.h>
#include <asm/dec/kn01.h>
#include <asm/dec/kn02.h>

#ifdef DEBUG_DZ
#include <linux/ptrace.h>
#include <linux/fs.h>
#include <asm/bootinfo.h>

extern int (*prom_printf) (char *,...);
#endif



#include "dz.h"

#define DZ_INTR_DEBUG 1

DECLARE_TASK_QUEUE(tq_serial);

extern wait_queue_head_t keypress_wait; 
static struct dz_serial *lines[4];
static unsigned char tmp_buffer[256];



#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_serial *info, unsigned offset)
{
	volatile u16 *addr = (volatile u16 *)(info->port + offset);

	return *addr;
}

static inline void dz_out (struct dz_serial *info, unsigned offset,
                           unsigned short value)
{
	volatile u16 *addr = (volatile u16 *)(info->port + 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 (struct tty_struct *tty)
{
	struct dz_serial *info; 
	unsigned short mask, tmp;

	if (!tty) 
		return; 
 
	info = (struct dz_serial *)tty->driver_data; 

	mask = 1 << info->line;
	tmp = dz_in (info, DZ_TCR);       /* read the TX flag */

	tmp &= ~mask;                   /* clear the TX flag */
	dz_out (info, DZ_TCR, tmp);
}

static void dz_start (struct tty_struct *tty)
{
	struct dz_serial *info = (struct dz_serial *)tty->driver_data;
	unsigned short mask, tmp;

	mask = 1 << info->line;
	tmp = dz_in (info, DZ_TCR);      /* read the TX flag */

	tmp |= mask;                   /* set the TX flag */
	dz_out (info, DZ_TCR, tmp);
}

/*
 * ------------------------------------------------------------
 * 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:
 * 
 * gcc -S -DKERNEL -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer dz.c
 *
 * and look at the resulting assemble code in serial.s.
 *
 * ------------------------------------------------------------
 */

/*
 * ------------------------------------------------------------
 * dz_sched_event ()
 *
 * This routine is used by the interrupt handler to schedule
 * processing in the software interrupt portion of the driver.
 * ------------------------------------------------------------
 */
static inline void dz_sched_event (struct dz_serial *info, int event)
{
	info->event |= 1 << event;
	queue_task(&info->tqueue, &tq_serial);
	mark_bh(SERIAL_BH);
}

/*
 * ------------------------------------------------------------
 * receive_char ()
 *
 * This routine deals with inputs from any lines.
 * ------------------------------------------------------------
 */
static inline void receive_chars (struct dz_serial *info_in)
{
	struct dz_serial *info;
	struct tty_struct *tty = 0;
	struct async_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 (info_in, DZ_RBUF);
		info = lines[LINE(status)];

		/* 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 ... */

			wake_up (&keypress_wait);       /* It is a 'keyboard interrupt' ;-) */
		}
#endif

		tty = info->tty;	/* now tty points to the proper dev */
		icount = &info->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 & info->ignore_status_mask) {
				if (++ignore > 100)
					break;
				goto ignore_char;
			}

			/* mask off the error conditions we want to ignore */
			tmp = status & info->read_status_mask;

			if (tmp & DZ_PERR) {
				*tty->flip.flag_buf_ptr = TTY_PARITY;
#ifdef DEBUG_DZ
				debug_console("PERR\n",5);
#endif /* DEBUG_DZ */
			} else if (tmp & DZ_FERR) {
				*tty->flip.flag_buf_ptr = TTY_FRAME;
#ifdef DEBUG_DZ
				debug_console("FERR\n",5);
#endif /* DEBUG_DZ */
			} if (tmp & DZ_OERR) { 
#ifdef DEBUG_DZ
				debug_console("OERR\n",5);
#endif /* DEBUG_DZ */
				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 transmit_chars (struct dz_serial *info)
{
	unsigned char tmp;

	if (info->x_char) {           /* XON/XOFF chars */
		dz_out(info, DZ_TDR, info->x_char);
		info->icount.tx++;
		info->x_char = 0;
		return;
	}

	/* if nothing to do or stopped or hardware stopped */
	if ((info->xmit_cnt <= 0) || info->tty->stopped ||
	    info->tty->hw_stopped) {
		dz_stop(info->tty);
		return;
	}

	/*
	 * If something to do ... (rember the dz has no output fifo so we go
	 * one char at a time :-<
	 */
	tmp = (unsigned short) info->xmit_buf[info->xmit_tail++];
	dz_out(info, DZ_TDR, tmp);
	info->xmit_tail = info->xmit_tail & (DZ_XMIT_SIZE - 1);
	info->icount.tx++;

	if (--info->xmit_cnt < WAKEUP_CHARS)
	dz_sched_event(info, DZ_EVENT_WRITE_WAKEUP);

	/* Are we done */
	if (info->xmit_cnt <= 0)
		dz_stop(info->tty);
}

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

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

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

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

	 /* get the reason why we just got an irq */
	status = dz_in((struct dz_serial *)dev, DZ_CSR);
	info = lines[LINE(status)];     /* re-arrange info the proper port */

	if (status & DZ_RDONE) 
		receive_chars(info);	/* the receive function */

	if (status & DZ_TRDY) 
		transmit_chars (info);
}

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

/*
 * This routine is used to handle the "bottom half" processing for the
 * serial driver, known also the "software interrupt" processing.
 * This processing is done at the kernel interrupt level, after the
 * rs_interrupt() has returned, BUT WITH INTERRUPTS TURNED ON.  This
 * is where time-consuming activities which can not be done in the
 * interrupt driver proper are done; the interrupt driver schedules
 * them using rs_sched_event(), and they get done here.
 */
static void do_serial_bh (void)
{
	run_task_queue (&tq_serial);
}

static void do_softint (void *private_data)
{
	struct dz_serial *info = (struct dz_serial *) private_data;
	struct tty_struct *tty = info->tty;

	if (!tty)
		return;

	if (test_and_clear_bit(DZ_EVENT_WRITE_WAKEUP, &info->event)) {
		if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
		    tty->ldisc.write_wakeup)
			(tty->ldisc.write_wakeup) (tty);
		wake_up_interruptible (&tty->write_wait);
	}
}

/*
 * -------------------------------------------------------------------
 * This routine is called from the scheduler tqueue when the interrupt
 * routine has signalled that a hangup has occurred.  The path of
 * hangup processing is:
 *
 *      serial interrupt routine -> (scheduler tqueue) ->
 *      do_serial_hangup() -> tty->hangup() -> rs_hangup()
 * ------------------------------------------------------------------- 
 */
static void do_serial_hangup (void *private_data)
{
	struct dz_serial *info = (struct dz_serial *) private_data;
	struct tty_struct *tty = info->tty;;
        
	if (!tty)
		return;

	tty_hangup(tty);
}

/*
 * -------------------------------------------------------------------
 * startup ()
 *
 * various initialization tasks
 * ------------------------------------------------------------------- 
 */
static int startup (struct dz_serial *info)
{
	unsigned long page, flags;
	unsigned short tmp;

	if (info->is_initialized)
		return 0;
  
	save_and_cli(flags);

	if (!info->port) {
		if (info->tty) set_bit(TTY_IO_ERROR, &info->tty->flags);
		restore_flags(flags);
		return -ENODEV;
	}

	if (!info->xmit_buf) {
		page = get_free_page(GFP_KERNEL);
		if (!page) {
			restore_flags (flags);
		return -ENOMEM;
		}
		info->xmit_buf = (unsigned char *)page;
	}

	if (info->tty)
		clear_bit(TTY_IO_ERROR, &info->tty->flags);

	/* enable the interrupt and the scanning */
	tmp = dz_in(info, DZ_CSR);
	tmp |= (DZ_RIE | DZ_TIE | DZ_MSE);
	dz_out(info, DZ_CSR, tmp);

	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;

	change_speed(info);			/* set up the speed */

	/*
	 * Clear the line transmitter buffer I can't figure out why I need to
	 * do this - but its necessary - in order for the console portion and
	 * the interrupt portion to live happily side by side.
	 */

	info->is_initialized = 1;

	restore_flags(flags);

	return 0;
}

/* 
 * -------------------------------------------------------------------
 * shutdown ()
 *
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 * ------------------------------------------------------------------- 
 */
static void shutdown (struct dz_serial *info)
{
	unsigned long flags;
	unsigned short tmp;

	if (!info->is_initialized)
		return;

	save_and_cli(flags);

	dz_stop (info->tty);

	info->cflags &= ~DZ_CREAD;	/* turn off receive enable flag */
	dz_out(info, DZ_LPR, info->cflags);

	if (info->xmit_buf) {               /* free Tx buffer */
		free_page((unsigned long)info->xmit_buf);
		info->xmit_buf = 0;
	}

	if (!info->tty || (info->tty->termios->c_cflag & HUPCL)) {
		tmp = dz_in(info, DZ_TCR);
		if (tmp & DZ_MODEM_DTR) {
			tmp &= ~DZ_MODEM_DTR;
			dz_out(info, DZ_TCR, tmp);
		}
	}

	if (info->tty)
		set_bit (TTY_IO_ERROR, &info->tty->flags);

	info->is_initialized = 0;