imm.c

linux 内核源代码

/* imm.c   --  low level driver for the IOMEGA MatchMaker
 * parallel port SCSI host adapter.
 * 
 * (The IMM is the embedded controller in the ZIP Plus drive.)
 * 
 * My unoffical company acronym list is 21 pages long:
 *      FLA:    Four letter acronym with built in facility for
 *              future expansion to five letters.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/parport.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <asm/io.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

/* The following #define is to avoid a clash with hosts.c */
#define IMM_PROBE_SPP   0x0001
#define IMM_PROBE_PS2   0x0002
#define IMM_PROBE_ECR   0x0010
#define IMM_PROBE_EPP17 0x0100
#define IMM_PROBE_EPP19 0x0200


typedef struct {
	struct pardevice *dev;	/* Parport device entry         */
	int base;		/* Actual port address          */
	int base_hi;		/* Hi Base address for ECP-ISA chipset */
	int mode;		/* Transfer mode                */
	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
	struct delayed_work imm_tq;	/* Polling interrupt stuff       */
	unsigned long jstart;	/* Jiffies at start             */
	unsigned failed:1;	/* Failure flag                 */
	unsigned dp:1;		/* Data phase present           */
	unsigned rd:1;		/* Read data in data phase      */
	unsigned wanted:1;	/* Parport sharing busy flag    */
	wait_queue_head_t *waiting;
	struct Scsi_Host *host;
	struct list_head list;
} imm_struct;

static void imm_reset_pulse(unsigned int base);
static int device_check(imm_struct *dev);

#include "imm.h"

static inline imm_struct *imm_dev(struct Scsi_Host *host)
{
	return *(imm_struct **)&host->hostdata;
}

static DEFINE_SPINLOCK(arbitration_lock);

static void got_it(imm_struct *dev)
{
	dev->base = dev->dev->port->base;
	if (dev->cur_cmd)
		dev->cur_cmd->SCp.phase = 1;
	else
		wake_up(dev->waiting);
}

static void imm_wakeup(void *ref)
{
	imm_struct *dev = (imm_struct *) ref;
	unsigned long flags;

	spin_lock_irqsave(&arbitration_lock, flags);
	if (dev->wanted) {
		parport_claim(dev->dev);
		got_it(dev);
		dev->wanted = 0;
	}
	spin_unlock_irqrestore(&arbitration_lock, flags);
}

static int imm_pb_claim(imm_struct *dev)
{
	unsigned long flags;
	int res = 1;
	spin_lock_irqsave(&arbitration_lock, flags);
	if (parport_claim(dev->dev) == 0) {
		got_it(dev);
		res = 0;
	}
	dev->wanted = res;
	spin_unlock_irqrestore(&arbitration_lock, flags);
	return res;
}

static void imm_pb_dismiss(imm_struct *dev)
{
	unsigned long flags;
	int wanted;
	spin_lock_irqsave(&arbitration_lock, flags);
	wanted = dev->wanted;
	dev->wanted = 0;
	spin_unlock_irqrestore(&arbitration_lock, flags);
	if (!wanted)
		parport_release(dev->dev);
}

static inline void imm_pb_release(imm_struct *dev)
{
	parport_release(dev->dev);
}

/* This is to give the imm driver a way to modify the timings (and other
 * parameters) by writing to the /proc/scsi/imm/0 file.
 * Very simple method really... (Too simple, no error checking :( )
 * Reason: Kernel hackers HATE having to unload and reload modules for
 * testing...
 * Also gives a method to use a script to obtain optimum timings (TODO)
 */
static inline int imm_proc_write(imm_struct *dev, char *buffer, int length)
{
	unsigned long x;

	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
		x = simple_strtoul(buffer + 5, NULL, 0);
		dev->mode = x;
		return length;
	}
	printk("imm /proc: invalid variable\n");
	return (-EINVAL);
}

static int imm_proc_info(struct Scsi_Host *host, char *buffer, char **start,
			off_t offset, int length, int inout)
{
	imm_struct *dev = imm_dev(host);
	int len = 0;

	if (inout)
		return imm_proc_write(dev, buffer, length);

	len += sprintf(buffer + len, "Version : %s\n", IMM_VERSION);
	len +=
	    sprintf(buffer + len, "Parport : %s\n",
		    dev->dev->port->name);
	len +=
	    sprintf(buffer + len, "Mode    : %s\n",
		    IMM_MODE_STRING[dev->mode]);

	/* Request for beyond end of buffer */
	if (offset > len)
		return 0;

	*start = buffer + offset;
	len -= offset;
	if (len > length)
		len = length;
	return len;
}

#if IMM_DEBUG > 0
#define imm_fail(x,y) printk("imm: imm_fail(%i) from %s at line %d\n",\
	   y, __FUNCTION__, __LINE__); imm_fail_func(x,y);
static inline void
imm_fail_func(imm_struct *dev, int error_code)
#else
static inline void
imm_fail(imm_struct *dev, int error_code)
#endif
{
	/* If we fail a device then we trash status / message bytes */
	if (dev->cur_cmd) {
		dev->cur_cmd->result = error_code << 16;
		dev->failed = 1;
	}
}

/*
 * Wait for the high bit to be set.
 * 
 * In principle, this could be tied to an interrupt, but the adapter
 * doesn't appear to be designed to support interrupts.  We spin on
 * the 0x80 ready bit. 
 */
static unsigned char imm_wait(imm_struct *dev)
{
	int k;
	unsigned short ppb = dev->base;
	unsigned char r;

	w_ctr(ppb, 0x0c);

	k = IMM_SPIN_TMO;
	do {
		r = r_str(ppb);
		k--;
		udelay(1);
	}
	while (!(r & 0x80) && (k));

	/*
	 * STR register (LPT base+1) to SCSI mapping:
	 *
	 * STR      imm     imm
	 * ===================================
	 * 0x80     S_REQ   S_REQ
	 * 0x40     !S_BSY  (????)
	 * 0x20     !S_CD   !S_CD
	 * 0x10     !S_IO   !S_IO
	 * 0x08     (????)  !S_BSY
	 *
	 * imm      imm     meaning
	 * ==================================
	 * 0xf0     0xb8    Bit mask
	 * 0xc0     0x88    ZIP wants more data
	 * 0xd0     0x98    ZIP wants to send more data
	 * 0xe0     0xa8    ZIP is expecting SCSI command data
	 * 0xf0     0xb8    end of transfer, ZIP is sending status
	 */
	w_ctr(ppb, 0x04);
	if (k)
		return (r & 0xb8);

	/* Counter expired - Time out occurred */
	imm_fail(dev, DID_TIME_OUT);
	printk("imm timeout in imm_wait\n");
	return 0;		/* command timed out */
}

static int imm_negotiate(imm_struct * tmp)
{
	/*
	 * The following is supposedly the IEEE 1284-1994 negotiate
	 * sequence. I have yet to obtain a copy of the above standard
	 * so this is a bit of a guess...
	 *
	 * A fair chunk of this is based on the Linux parport implementation
	 * of IEEE 1284.
	 *
	 * Return 0 if data available
	 *        1 if no data available
	 */

	unsigned short base = tmp->base;
	unsigned char a, mode;

	switch (tmp->mode) {
	case IMM_NIBBLE:
		mode = 0x00;
		break;
	case IMM_PS2:
		mode = 0x01;
		break;
	default:
		return 0;
	}

	w_ctr(base, 0x04);
	udelay(5);
	w_dtr(base, mode);
	udelay(100);
	w_ctr(base, 0x06);
	udelay(5);
	a = (r_str(base) & 0x20) ? 0 : 1;
	udelay(5);
	w_ctr(base, 0x07);
	udelay(5);
	w_ctr(base, 0x06);

	if (a) {
		printk
		    ("IMM: IEEE1284 negotiate indicates no data available.\n");
		imm_fail(tmp, DID_ERROR);
	}
	return a;
}

/* 
 * Clear EPP timeout bit. 
 */
static inline void epp_reset(unsigned short ppb)
{
	int i;

	i = r_str(ppb);
	w_str(ppb, i);
	w_str(ppb, i & 0xfe);
}

/* 
 * Wait for empty ECP fifo (if we are in ECP fifo mode only)
 */
static inline void ecp_sync(imm_struct *dev)
{
	int i, ppb_hi = dev->base_hi;

	if (ppb_hi == 0)
		return;

	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
		for (i = 0; i < 100; i++) {
			if (r_ecr(ppb_hi) & 0x01)
				return;
			udelay(5);
		}
		printk("imm: ECP sync failed as data still present in FIFO.\n");
	}
}

static int imm_byte_out(unsigned short base, const char *buffer, int len)
{
	int i;

	w_ctr(base, 0x4);	/* apparently a sane mode */
	for (i = len >> 1; i; i--) {
		w_dtr(base, *buffer++);
		w_ctr(base, 0x5);	/* Drop STROBE low */
		w_dtr(base, *buffer++);
		w_ctr(base, 0x0);	/* STROBE high + INIT low */
	}
	w_ctr(base, 0x4);	/* apparently a sane mode */
	return 1;		/* All went well - we hope! */
}

static int imm_nibble_in(unsigned short base, char *buffer, int len)
{
	unsigned char l;
	int i;

	/*
	 * The following is based on documented timing signals
	 */
	w_ctr(base, 0x4);
	for (i = len; i; i--) {
		w_ctr(base, 0x6);
		l = (r_str(base) & 0xf0) >> 4;
		w_ctr(base, 0x5);
		*buffer++ = (r_str(base) & 0xf0) | l;
		w_ctr(base, 0x4);
	}
	return 1;		/* All went well - we hope! */
}

static int imm_byte_in(unsigned short base, char *buffer, int len)
{
	int i;

	/*
	 * The following is based on documented timing signals
	 */
	w_ctr(base, 0x4);
	for (i = len; i; i--) {
		w_ctr(base, 0x26);
		*buffer++ = r_dtr(base);
		w_ctr(base, 0x25);
	}
	return 1;		/* All went well - we hope! */
}

static int imm_out(imm_struct *dev, char *buffer, int len)
{
	unsigned short ppb = dev->base;
	int r = imm_wait(dev);

	/*
	 * Make sure that:
	 * a) the SCSI bus is BUSY (device still listening)
	 * b) the device is listening
	 */
	if ((r & 0x18) != 0x08) {
		imm_fail(dev, DID_ERROR);
		printk("IMM: returned SCSI status %2x\n", r);
		return 0;
	}
	switch (dev->mode) {
	case IMM_EPP_32:
	case IMM_EPP_16:
	case IMM_EPP_8:
		epp_reset(ppb);
		w_ctr(ppb, 0x4);
#ifdef CONFIG_SCSI_IZIP_EPP16
		if (!(((long) buffer | len) & 0x01))
			outsw(ppb + 4, buffer, len >> 1);
#else
		if (!(((long) buffer | len) & 0x03))
			outsl(ppb + 4, buffer, len >> 2);
#endif
		else
			outsb(ppb + 4, buffer, len);
		w_ctr(ppb, 0xc);
		r = !(r_str(ppb) & 0x01);
		w_ctr(ppb, 0xc);
		ecp_sync(dev);
		break;

	case IMM_NIBBLE:
	case IMM_PS2:
		/* 8 bit output, with a loop */
		r = imm_byte_out(ppb, buffer, len);
		break;

	default:
		printk("IMM: bug in imm_out()\n");
		r = 0;
	}
	return r;
}

static int imm_in(imm_struct *dev, char *buffer, int len)
{
	unsigned short ppb = dev->base;
	int r = imm_wait(dev);

	/*
	 * Make sure that:
	 * a) the SCSI bus is BUSY (device still listening)
	 * b) the device is sending data
	 */
	if ((r & 0x18) != 0x18) {
		imm_fail(dev, DID_ERROR);
		return 0;
	}
	switch (dev->mode) {
	case IMM_NIBBLE:
		/* 4 bit input, with a loop */
		r = imm_nibble_in(ppb, buffer, len);
		w_ctr(ppb, 0xc);
		break;

	case IMM_PS2:
		/* 8 bit input, with a loop */
		r = imm_byte_in(ppb, buffer, len);
		w_ctr(ppb, 0xc);
		break;

	case IMM_EPP_32:
	case IMM_EPP_16:
	case IMM_EPP_8:
		epp_reset(ppb);
		w_ctr(ppb, 0x24);
#ifdef CONFIG_SCSI_IZIP_EPP16
		if (!(((long) buffer | len) & 0x01))
			insw(ppb + 4, buffer, len >> 1);
#else
		if (!(((long) buffer | len) & 0x03))
			insl(ppb + 4, buffer, len >> 2);
#endif
		else
			insb(ppb + 4, buffer, len);
		w_ctr(ppb, 0x2c);
		r = !(r_str(ppb) & 0x01);
		w_ctr(ppb, 0x2c);
		ecp_sync(dev);
		break;

	default:
		printk("IMM: bug in imm_ins()\n");
		r = 0;
		break;
	}
	return r;
}

static int imm_cpp(unsigned short ppb, unsigned char b)
{
	/*
	 * Comments on udelay values refer to the
	 * Command Packet Protocol (CPP) timing diagram.
	 */

	unsigned char s1, s2, s3;
	w_ctr(ppb, 0x0c);
	udelay(2);		/* 1 usec - infinite */
	w_dtr(ppb, 0xaa);
	udelay(10);		/* 7 usec - infinite */
	w_dtr(ppb, 0x55);
	udelay(10);		/* 7 usec - infinite */
	w_dtr(ppb, 0x00);
	udelay(10);		/* 7 usec - infinite */
	w_dtr(ppb, 0xff);
	udelay(10);		/* 7 usec - infinite */
	s1 = r_str(ppb) & 0xb8;
	w_dtr(ppb, 0x87);
	udelay(10);		/* 7 usec - infinite */
	s2 = r_str(ppb) & 0xb8;
	w_dtr(ppb, 0x78);
	udelay(10);		/* 7 usec - infinite */
	s3 = r_str(ppb) & 0x38;
	/*
	 * Values for b are:
	 * 0000 00aa    Assign address aa to current device
	 * 0010 00aa    Select device aa in EPP Winbond mode
	 * 0010 10aa    Select device aa in EPP mode
	 * 0011 xxxx    Deselect all devices
	 * 0110 00aa    Test device aa
	 * 1101 00aa    Select device aa in ECP mode
	 * 1110 00aa    Select device aa in Compatible mode
	 */
	w_dtr(ppb, b);
	udelay(2);		/* 1 usec - infinite */
	w_ctr(ppb, 0x0c);
	udelay(10);		/* 7 usec - infinite */
	w_ctr(ppb, 0x0d);
	udelay(2);		/* 1 usec - infinite */
	w_ctr(ppb, 0x0c);
	udelay(10);		/* 7 usec - infinite */
	w_dtr(ppb, 0xff);
	udelay(10);		/* 7 usec - infinite */

	/*
	 * The following table is electrical pin values.
	 * (BSY is inverted at the CTR register)
	 *
	 *       BSY  ACK  POut SEL  Fault
	 * S1    0    X    1    1    1
	 * S2    1    X    0    1    1
	 * S3    L    X    1    1    S
	 *
	 * L => Last device in chain
	 * S => Selected
	 *
	 * Observered values for S1,S2,S3 are:
	 * Disconnect => f8/58/78
	 * Connect    => f8/58/70
	 */
	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x30))
		return 1;	/* Connected */
	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x38))
		return 0;	/* Disconnected */

	return -1;		/* No device present */
}

static inline int imm_connect(imm_struct *dev, int flag)
{
	unsigned short ppb = dev->base;

	imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
	imm_cpp(ppb, 0x30);	/* Disconnect all devices */

	if ((dev->mode == IMM_EPP_8) ||
	    (dev->mode == IMM_EPP_16) ||
	    (dev->mode == IMM_EPP_32))
		return imm_cpp(ppb, 0x28);	/* Select device 0 in EPP mode */
	return imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
}

static void imm_disconnect(imm_struct *dev)
{
	imm_cpp(dev->base, 0x30);	/* Disconnect all devices */
}

static int imm_select(imm_struct *dev, int target)
{
	int k;
	unsigned short ppb = dev->base;

	/*
	 * Firstly we want to make sure there is nothing
	 * holding onto the SCSI bus.
	 */
	w_ctr(ppb, 0xc);

	k = IMM_SELECT_TMO;
	do {
		k--;
	} while ((r_str(ppb) & 0x08) && (k));

	if (!k)
		return 0;

	/*
	 * Now assert the SCSI ID (HOST and TARGET) on the data bus
	 */
	w_ctr(ppb, 0x4);
	w_dtr(ppb, 0x80 | (1 << target));
	udelay(1);

	/*
	 * Deassert SELIN first followed by STROBE
	 */
	w_ctr(ppb, 0xc);
	w_ctr(ppb, 0xd);

	/*
	 * ACK should drop low while SELIN is deasserted.
	 * FAULT should drop low when the SCSI device latches the bus.
	 */
	k = IMM_SELECT_TMO;
	do {
		k--;
	}
	while (!(r_str(ppb) & 0x08) && (k));

	/*
	 * Place the interface back into a sane state (status mode)
	 */
	w_ctr(ppb, 0xc);
	return (k) ? 1 : 0;
}

static int imm_init(imm_struct *dev)
{
	if (imm_connect(dev, 0) != 1)
		return -EIO;
	imm_reset_pulse(dev->base);
	mdelay(1);	/* Delay to allow devices to settle */
	imm_disconnect(dev);
	mdelay(1);	/* Another delay to allow devices to settle */
	return device_check(dev);
}

static inline int imm_send_command(struct scsi_cmnd *cmd)
{
	imm_struct *dev = imm_dev(cmd->device->host);
	int k;

	/* NOTE: IMM uses byte pairs */
	for (k = 0; k < cmd->cmd_len; k += 2)
		if (!imm_out(dev, &cmd->cmnd[k], 2))
			return 0;
	return 1;
}

/*
 * The bulk flag enables some optimisations in the data transfer loops,
 * it should be true for any command that transfers data in integral
 * numbers of sectors.
 * 
 * The driver appears to remain stable if we speed up the parallel port
 * i/o in this function, but not elsewhere.
 */
static int imm_completion(struct scsi_cmnd *cmd)
{
	/* Return codes:
	 * -1     Error
	 *  0     Told to schedule
	 *  1     Finished data transfer
	 */
	imm_struct *dev = imm_dev(cmd->device->host);
	unsigned short ppb = dev->base;