esp.c

linux 内核源代码

/*
 *  esp.c - driver for Hayes ESP serial cards
 *
 *  --- Notices from serial.c, upon which this driver is based ---
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Extensively rewritten by Theodore Ts'o, 8/16/92 -- 9/14/92.  Now
 *  much more extensible to support other serial cards based on the
 *  16450/16550A UART's.  Added support for the AST FourPort and the
 *  Accent Async board.  
 *
 *  set_serial_info fixed to set the flags, custom divisor, and uart
 * 	type fields.  Fix suggested by Michael K. Johnson 12/12/92.
 *
 *  11/95: TIOCMIWAIT, TIOCGICOUNT by Angelo Haritsis <[e-mail]>
 *
 *  03/96: Modularised by Angelo Haritsis <[e-mail]>
 *
 *  rs_set_termios fixed to look also for changes of the input
 *      flags INPCK, BRKINT, PARMRK, IGNPAR and IGNBRK.
 *                                            Bernd Anhäupl 05/17/96.
 *
 * --- End of notices from serial.c ---
 *
 * Support for the ESP serial card by Andrew J. Robinson
 *     <[e-mail]> (Card detection routine taken from a patch
 *     by Dennis J. Boylan).  Patches to allow use with 2.1.x contributed
 *     by Chris Faylor.
 *
 * Most recent changes: (Andrew J. Robinson)
 *   Support for PIO mode.  This allows the driver to work properly with
 *     multiport cards.
 *
 * Arnaldo Carvalho de Melo <[e-mail]> -
 * several cleanups, use module_init/module_exit, etc
 *
 * This module exports the following rs232 io functions:
 *
 *	int espserial_init(void);
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serialP.h>
#include <linux/serial_reg.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/bitops.h>

#include <asm/system.h>
#include <asm/io.h>

#include <asm/dma.h>
#include <linux/slab.h>
#include <asm/uaccess.h>

#include <linux/hayesesp.h>

#define NR_PORTS 64	/* maximum number of ports */
#define NR_PRIMARY 8	/* maximum number of primary ports */
#define REGION_SIZE 8   /* size of io region to request */

/* The following variables can be set by giving module options */
static int irq[NR_PRIMARY];	/* IRQ for each base port */
static unsigned int divisor[NR_PRIMARY]; /* custom divisor for each port */
static unsigned int dma = ESP_DMA_CHANNEL; /* DMA channel */
static unsigned int rx_trigger = ESP_RX_TRIGGER;
static unsigned int tx_trigger = ESP_TX_TRIGGER;
static unsigned int flow_off = ESP_FLOW_OFF;
static unsigned int flow_on = ESP_FLOW_ON;
static unsigned int rx_timeout = ESP_RX_TMOUT;
static unsigned int pio_threshold = ESP_PIO_THRESHOLD;

MODULE_LICENSE("GPL");

module_param_array(irq, int, NULL, 0);
module_param_array(divisor, uint, NULL, 0);
module_param(dma, uint, 0);
module_param(rx_trigger, uint, 0);
module_param(tx_trigger, uint, 0);
module_param(flow_off, uint, 0);
module_param(flow_on, uint, 0);
module_param(rx_timeout, uint, 0);
module_param(pio_threshold, uint, 0);

/* END */

static char *dma_buffer;
static int dma_bytes;
static struct esp_pio_buffer *free_pio_buf;

#define DMA_BUFFER_SZ 1024

#define WAKEUP_CHARS 1024

static char serial_name[] __initdata = "ESP serial driver";
static char serial_version[] __initdata = "2.2";

static struct tty_driver *esp_driver;

/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL	1

/*
 * Serial driver configuration section.  Here are the various options:
 *
 * SERIAL_PARANOIA_CHECK
 * 		Check the magic number for the esp_structure where
 * 		ever possible.
 */

#undef SERIAL_PARANOIA_CHECK
#define SERIAL_DO_RESTART

#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW

#if defined(MODULE) && defined(SERIAL_DEBUG_MCOUNT)
#define DBG_CNT(s) printk("(%s): [%x] refc=%d, serc=%d, ttyc=%d -> %s\n", \
 tty->name, (info->flags), serial_driver.refcount,info->count,tty->count,s)
#else
#define DBG_CNT(s)
#endif

static struct esp_struct *ports;

static void change_speed(struct esp_struct *info);
static void rs_wait_until_sent(struct tty_struct *, int);

/*
 * The ESP card has a clock rate of 14.7456 MHz (that is, 2**ESPC_SCALE
 * times the normal 1.8432 Mhz clock of most serial boards).
 */
#define BASE_BAUD ((1843200 / 16) * (1 << ESPC_SCALE))

/* Standard COM flags (except for COM4, because of the 8514 problem) */
#define STD_COM_FLAGS (ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST)

static inline int serial_paranoia_check(struct esp_struct *info,
					char *name, const char *routine)
{
#ifdef SERIAL_PARANOIA_CHECK
	static const char badmagic[] = KERN_WARNING
		"Warning: bad magic number for serial struct (%s) in %s\n";
	static const char badinfo[] = KERN_WARNING
		"Warning: null esp_struct for (%s) in %s\n";

	if (!info) {
		printk(badinfo, name, routine);
		return 1;
	}
	if (info->magic != ESP_MAGIC) {
		printk(badmagic, name, routine);
		return 1;
	}
#endif
	return 0;
}

static inline unsigned int serial_in(struct esp_struct *info, int offset)
{
	return inb(info->port + offset);
}

static inline void serial_out(struct esp_struct *info, int offset,
			      unsigned char value)
{
	outb(value, info->port+offset);
}

/*
 * ------------------------------------------------------------
 * rs_stop() and rs_start()
 *
 * This routines are called before setting or resetting tty->stopped.
 * They enable or disable transmitter interrupts, as necessary.
 * ------------------------------------------------------------
 */
static void rs_stop(struct tty_struct *tty)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
	unsigned long flags;

	if (serial_paranoia_check(info, tty->name, "rs_stop"))
		return;

	spin_lock_irqsave(&info->lock, flags);
	if (info->IER & UART_IER_THRI) {
		info->IER &= ~UART_IER_THRI;
		serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
		serial_out(info, UART_ESI_CMD2, info->IER);
	}
	spin_unlock_irqrestore(&info->lock, flags);
}

static void rs_start(struct tty_struct *tty)
{
	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
	unsigned long flags;
	
	if (serial_paranoia_check(info, tty->name, "rs_start"))
		return;
	
	spin_lock_irqsave(&info->lock, flags);
	if (info->xmit_cnt && info->xmit_buf && !(info->IER & UART_IER_THRI)) {
		info->IER |= UART_IER_THRI;
		serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
		serial_out(info, UART_ESI_CMD2, info->IER);
	}
	spin_unlock_irqrestore(&info->lock, flags);
}

/*
 * ----------------------------------------------------------------------
 *
 * Here starts the interrupt handling routines.  All of the following
 * subroutines are declared as inline and are folded into
 * rs_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 serial.c
 *
 * and look at the resulting assemble code in serial.s.
 *
 * 				- Ted Ts'o ([e-mail]), 7-Mar-93
 * -----------------------------------------------------------------------
 */

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

static DEFINE_SPINLOCK(pio_lock);

static inline struct esp_pio_buffer *get_pio_buffer(void)
{
	struct esp_pio_buffer *buf;
	unsigned long flags;

	spin_lock_irqsave(&pio_lock, flags);
	if (free_pio_buf) {
		buf = free_pio_buf;
		free_pio_buf = buf->next;
	} else {
		buf = kmalloc(sizeof(struct esp_pio_buffer), GFP_ATOMIC);
	}
	spin_unlock_irqrestore(&pio_lock, flags);
	return buf;
}

static inline void release_pio_buffer(struct esp_pio_buffer *buf)
{
	unsigned long flags;
	spin_lock_irqsave(&pio_lock, flags);
	buf->next = free_pio_buf;
	free_pio_buf = buf;
	spin_unlock_irqrestore(&pio_lock, flags);
}

static inline void receive_chars_pio(struct esp_struct *info, int num_bytes)
{
	struct tty_struct *tty = info->tty;
	int i;
	struct esp_pio_buffer *pio_buf;
	struct esp_pio_buffer *err_buf;
	unsigned char status_mask;

	pio_buf = get_pio_buffer();

	if (!pio_buf)
		return;

	err_buf = get_pio_buffer();

	if (!err_buf) {
		release_pio_buffer(pio_buf);
		return;
	}

	status_mask = (info->read_status_mask >> 2) & 0x07;
		
	for (i = 0; i < num_bytes - 1; i += 2) {
		*((unsigned short *)(pio_buf->data + i)) =
			inw(info->port + UART_ESI_RX);
		err_buf->data[i] = serial_in(info, UART_ESI_RWS);
		err_buf->data[i + 1] = (err_buf->data[i] >> 3) & status_mask;
		err_buf->data[i] &= status_mask;
	}

	if (num_bytes & 0x0001) {
		pio_buf->data[num_bytes - 1] = serial_in(info, UART_ESI_RX);
		err_buf->data[num_bytes - 1] =
			(serial_in(info, UART_ESI_RWS) >> 3) & status_mask;
	}

	/* make sure everything is still ok since interrupts were enabled */
	tty = info->tty;

	if (!tty) {
		release_pio_buffer(pio_buf);
		release_pio_buffer(err_buf);
		info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
		return;
	}

	status_mask = (info->ignore_status_mask >> 2) & 0x07;

	for (i = 0; i < num_bytes; i++) {
		if (!(err_buf->data[i] & status_mask)) {
			int flag = 0;

			if (err_buf->data[i] & 0x04) {
				flag = TTY_BREAK;
				if (info->flags & ASYNC_SAK)
					do_SAK(tty);
			}
			else if (err_buf->data[i] & 0x02)
				flag = TTY_FRAME;
			else if (err_buf->data[i] & 0x01)
				flag = TTY_PARITY;
			tty_insert_flip_char(tty, pio_buf->data[i], flag);
		}
	}

	tty_schedule_flip(tty);

	info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
	release_pio_buffer(pio_buf);
	release_pio_buffer(err_buf);
}

static inline void receive_chars_dma(struct esp_struct *info, int num_bytes)
{
	unsigned long flags;
	info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
	dma_bytes = num_bytes;
	info->stat_flags |= ESP_STAT_DMA_RX;
	
	flags=claim_dma_lock();
        disable_dma(dma);
        clear_dma_ff(dma);
        set_dma_mode(dma, DMA_MODE_READ);
        set_dma_addr(dma, isa_virt_to_bus(dma_buffer));
        set_dma_count(dma, dma_bytes);
        enable_dma(dma);
        release_dma_lock(flags);
        
        serial_out(info, UART_ESI_CMD1, ESI_START_DMA_RX);
}

static inline void receive_chars_dma_done(struct esp_struct *info,
					    int status)
{
	struct tty_struct *tty = info->tty;
	int num_bytes;
	unsigned long flags;
	
	flags=claim_dma_lock();
	disable_dma(dma);
	clear_dma_ff(dma);

	info->stat_flags &= ~ESP_STAT_DMA_RX;
	num_bytes = dma_bytes - get_dma_residue(dma);
	release_dma_lock(flags);
	
	info->icount.rx += num_bytes;

	if (num_bytes > 0) {
		tty_insert_flip_string(tty, dma_buffer, num_bytes - 1);

		status &= (0x1c & info->read_status_mask);
		
		/* Is the status significant or do we throw the last byte ? */
		if (!(status & info->ignore_status_mask)) {
			int statflag = 0;

			if (status & 0x10) {
				statflag = TTY_BREAK;
				(info->icount.brk)++;
				if (info->flags & ASYNC_SAK)
					do_SAK(tty);
			} else if (status & 0x08) {
				statflag = TTY_FRAME;
				(info->icount.frame)++;
			}
			else if (status & 0x04) {
				statflag = TTY_PARITY;
				(info->icount.parity)++;
			}
			tty_insert_flip_char(tty, dma_buffer[num_bytes - 1], statflag);
		}
		tty_schedule_flip(tty);
	}

	if (dma_bytes != num_bytes) {
		num_bytes = dma_bytes - num_bytes;
		dma_bytes = 0;
		receive_chars_dma(info, num_bytes);
	} else
		dma_bytes = 0;
}

/* Caller must hold info->lock */

static inline void transmit_chars_pio(struct esp_struct *info,
					int space_avail)
{
	int i;
	struct esp_pio_buffer *pio_buf;

	pio_buf = get_pio_buffer();

	if (!pio_buf)
		return;

	while (space_avail && info->xmit_cnt) {
		if (info->xmit_tail + space_avail <= ESP_XMIT_SIZE) {
			memcpy(pio_buf->data,
			       &(info->xmit_buf[info->xmit_tail]),
			       space_avail);
		} else {
			i = ESP_XMIT_SIZE - info->xmit_tail;
			memcpy(pio_buf->data,
			       &(info->xmit_buf[info->xmit_tail]), i);
			memcpy(&(pio_buf->data[i]), info->xmit_buf,
			       space_avail - i);
		}

		info->xmit_cnt -= space_avail;
		info->xmit_tail = (info->xmit_tail + space_avail) &
			(ESP_XMIT_SIZE - 1);

		for (i = 0; i < space_avail - 1; i += 2) {
			outw(*((unsigned short *)(pio_buf->data + i)),
			     info->port + UART_ESI_TX);
		}

		if (space_avail & 0x0001)
			serial_out(info, UART_ESI_TX,
				   pio_buf->data[space_avail - 1]);

		if (info->xmit_cnt) {
			serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
			serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
			space_avail = serial_in(info, UART_ESI_STAT1) << 8;
			space_avail |= serial_in(info, UART_ESI_STAT2);

			if (space_avail > info->xmit_cnt)
				space_avail = info->xmit_cnt;
		}
	}

	if (info->xmit_cnt < WAKEUP_CHARS) {
		rs_sched_event(info, ESP_EVENT_WRITE_WAKEUP);

#ifdef SERIAL_DEBUG_INTR
		printk("THRE...");
#endif

		if (info->xmit_cnt <= 0) {
			info->IER &= ~UART_IER_THRI;
			serial_out(info, UART_ESI_CMD1,