ppa.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,151 行 · 第 1/2 页

/* ppa.c   --  low level driver for the IOMEGA PPA3 
 * parallel port SCSI host adapter.
 * 
 * (The PPA3 is the embedded controller in the ZIP drive.)
 * 
 * (c) 1995,1996 Grant R. Guenther, [e-mail],
 * under the terms of the GNU General Public License.
 * 
 * Current Maintainer: David Campbell (Perth, Western Australia, GMT+0800)
 *                     [e-mail]
 */

#include <linux/config.h>
#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 <asm/io.h>

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


static void ppa_reset_pulse(unsigned int base);

typedef struct {
	struct pardevice *dev;	/* Parport device entry         */
	int base;		/* Actual port address          */
	int mode;		/* Transfer mode                */
	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
	struct work_struct ppa_tq;	/* Polling interrupt stuff       */
	unsigned long jstart;	/* Jiffies at start             */
	unsigned long recon_tmo;	/* How many usecs to wait for reconnection (6th bit) */
	unsigned int failed:1;	/* Failure flag                 */
	unsigned wanted:1;	/* Parport sharing busy flag    */
	wait_queue_head_t *waiting;
	struct Scsi_Host *host;
	struct list_head list;
} ppa_struct;

#include  "ppa.h"

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

static spinlock_t arbitration_lock = SPIN_LOCK_UNLOCKED;

static void got_it(ppa_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 ppa_wakeup(void *ref)
{
	ppa_struct *dev = (ppa_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);
	return;
}

static int ppa_pb_claim(ppa_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 ppa_pb_dismiss(ppa_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 ppa_pb_release(ppa_struct *dev)
{
	parport_release(dev->dev);
}

/*
 * Start of Chipset kludges
 */

/* This is to give the ppa driver a way to modify the timings (and other
 * parameters) by writing to the /proc/scsi/ppa/0 file.
 * Very simple method really... (To 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 ppa_proc_write(ppa_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;
	}
	if ((length > 10) && (strncmp(buffer, "recon_tmo=", 10) == 0)) {
		x = simple_strtoul(buffer + 10, NULL, 0);
		dev->recon_tmo = x;
		printk("ppa: recon_tmo set to %ld\n", x);
		return length;
	}
	printk("ppa /proc: invalid variable\n");
	return (-EINVAL);
}

static int ppa_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset, int length, int inout)
{
	int len = 0;
	ppa_struct *dev = ppa_dev(host);

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

	len += sprintf(buffer + len, "Version : %s\n", PPA_VERSION);
	len +=
	    sprintf(buffer + len, "Parport : %s\n",
		    dev->dev->port->name);
	len +=
	    sprintf(buffer + len, "Mode    : %s\n",
		    PPA_MODE_STRING[dev->mode]);
#if PPA_DEBUG > 0
	len +=
	    sprintf(buffer + len, "recon_tmo : %lu\n", dev->recon_tmo);
#endif

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

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

static int device_check(ppa_struct *dev);

#if PPA_DEBUG > 0
#define ppa_fail(x,y) printk("ppa: ppa_fail(%i) from %s at line %d\n",\
	   y, __FUNCTION__, __LINE__); ppa_fail_func(x,y);
static inline void ppa_fail_func(ppa_struct *dev, int error_code)
#else
static inline void ppa_fail(ppa_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 ppa_wait(ppa_struct *dev)
{
	int k;
	unsigned short ppb = dev->base;
	unsigned char r;

	k = PPA_SPIN_TMO;
	/* Wait for bit 6 and 7 - PJC */
	for (r = r_str(ppb); ((r & 0xc0) != 0xc0) && (k); k--) {
		udelay(1);
		r = r_str(ppb);
	}

	/*
	 * return some status information.
	 * Semantics: 0xc0 = ZIP wants more data
	 *            0xd0 = ZIP wants to send more data
	 *            0xe0 = ZIP is expecting SCSI command data
	 *            0xf0 = end of transfer, ZIP is sending status
	 */
	if (k)
		return (r & 0xf0);

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

/*
 * 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(ppa_struct *dev)
{
	int i, ppb_hi = dev->dev->port->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("ppa: ECP sync failed as data still present in FIFO.\n");
	}
}

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

	for (i = len; i; i--) {
		w_dtr(base, *buffer++);
		w_ctr(base, 0xe);
		w_ctr(base, 0xc);
	}
	return 1;		/* All went well - we hope! */
}

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

	for (i = len; i; i--) {
		*buffer++ = r_dtr(base);
		w_ctr(base, 0x27);
		w_ctr(base, 0x25);
	}
	return 1;		/* All went well - we hope! */
}

static int ppa_nibble_in(unsigned short base, char *buffer, int len)
{
	for (; len; len--) {
		unsigned char h;

		w_ctr(base, 0x4);
		h = r_str(base) & 0xf0;
		w_ctr(base, 0x6);
		*buffer++ = h | ((r_str(base) & 0xf0) >> 4);
	}
	return 1;		/* All went well - we hope! */
}

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

	r = ppa_wait(dev);

	if ((r & 0x50) != 0x40) {
		ppa_fail(dev, DID_ERROR);
		return 0;
	}
	switch (dev->mode) {
	case PPA_NIBBLE:
	case PPA_PS2:
		/* 8 bit output, with a loop */
		r = ppa_byte_out(ppb, buffer, len);
		break;

	case PPA_EPP_32:
	case PPA_EPP_16:
	case PPA_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;

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

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

	r = ppa_wait(dev);

	if ((r & 0x50) != 0x50) {
		ppa_fail(dev, DID_ERROR);
		return 0;
	}
	switch (dev->mode) {
	case PPA_NIBBLE:
		/* 4 bit input, with a loop */
		r = ppa_nibble_in(ppb, buffer, len);
		w_ctr(ppb, 0xc);
		break;

	case PPA_PS2:
		/* 8 bit input, with a loop */
		w_ctr(ppb, 0x25);
		r = ppa_byte_in(ppb, buffer, len);
		w_ctr(ppb, 0x4);
		w_ctr(ppb, 0xc);
		break;

	case PPA_EPP_32:
	case PPA_EPP_16:
	case PPA_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("PPA: bug in ppa_ins()\n");
		r = 0;
		break;
	}
	return r;
}

/* end of ppa_io.h */
static inline void ppa_d_pulse(unsigned short ppb, unsigned char b)
{
	w_dtr(ppb, b);
	w_ctr(ppb, 0xc);
	w_ctr(ppb, 0xe);
	w_ctr(ppb, 0xc);
	w_ctr(ppb, 0x4);
	w_ctr(ppb, 0xc);
}

static void ppa_disconnect(ppa_struct *dev)
{
	unsigned short ppb = dev->base;

	ppa_d_pulse(ppb, 0);
	ppa_d_pulse(ppb, 0x3c);
	ppa_d_pulse(ppb, 0x20);
	ppa_d_pulse(ppb, 0xf);
}

static inline void ppa_c_pulse(unsigned short ppb, unsigned char b)
{
	w_dtr(ppb, b);
	w_ctr(ppb, 0x4);
	w_ctr(ppb, 0x6);
	w_ctr(ppb, 0x4);
	w_ctr(ppb, 0xc);
}

static inline void ppa_connect(ppa_struct *dev, int flag)
{
	unsigned short ppb = dev->base;

	ppa_c_pulse(ppb, 0);
	ppa_c_pulse(ppb, 0x3c);
	ppa_c_pulse(ppb, 0x20);
	if ((flag == CONNECT_EPP_MAYBE) && IN_EPP_MODE(dev->mode))
		ppa_c_pulse(ppb, 0xcf);
	else
		ppa_c_pulse(ppb, 0x8f);
}

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

	/*
	 * Bit 6 (0x40) is the device selected bit.
	 * First we must wait till the current device goes off line...
	 */
	k = PPA_SELECT_TMO;
	do {
		k--;
		udelay(1);
	} while ((r_str(ppb) & 0x40) && (k));
	if (!k)
		return 0;

	w_dtr(ppb, (1 << target));
	w_ctr(ppb, 0xe);
	w_ctr(ppb, 0xc);
	w_dtr(ppb, 0x80);	/* This is NOT the initator */
	w_ctr(ppb, 0x8);

	k = PPA_SELECT_TMO;
	do {
		k--;
		udelay(1);
	}
	while (!(r_str(ppb) & 0x40) && (k));
	if (!k)
		return 0;

	return 1;
}

/* 
 * This is based on a trace of what the Iomega DOS 'guest' driver does.
 * I've tried several different kinds of parallel ports with guest and
 * coded this to react in the same ways that it does.
 * 
 * The return value from this function is just a hint about where the
 * handshaking failed.
 * 
 */
static int ppa_init(ppa_struct *dev)
{
	int retv;
	unsigned short ppb = dev->base;

	ppa_disconnect(dev);
	ppa_connect(dev, CONNECT_NORMAL);

	retv = 2;		/* Failed */

	w_ctr(ppb, 0xe);
	if ((r_str(ppb) & 0x08) == 0x08)
		retv--;

	w_ctr(ppb, 0xc);
	if ((r_str(ppb) & 0x08) == 0x00)
		retv--;

	if (!retv)
		ppa_reset_pulse(ppb);
	udelay(1000);		/* Allow devices to settle down */
	ppa_disconnect(dev);
	udelay(1000);		/* Another delay to allow devices to settle */

	if (retv)
		return -EIO;

	return device_check(dev);
}

static inline int ppa_send_command(struct scsi_cmnd *cmd)
{
	ppa_struct *dev = ppa_dev(cmd->device->host);
	int k;

	w_ctr(dev->base, 0x0c);

	for (k = 0; k < cmd->cmd_len; k++)
		if (!ppa_out(dev, &cmd->cmnd[k], 1))
			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 ppa_completion(struct scsi_cmnd *cmd)
{
	/* Return codes:
	 * -1     Error
	 *  0     Told to schedule
	 *  1     Finished data transfer
	 */
	ppa_struct *dev = ppa_dev(cmd->device->host);
	unsigned short ppb = dev->base;
	unsigned long start_jiffies = jiffies;

	unsigned char r, v;
	int fast, bulk, status;

	v = cmd->cmnd[0];
	bulk = ((v == READ_6) ||
		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));

	/*
	 * We only get here if the drive is ready to comunicate,
	 * hence no need for a full ppa_wait.
	 */
	r = (r_str(ppb) & 0xf0);

	while (r != (unsigned char) 0xf0) {
		/*
		 * If we have been running for more than a full timer tick
		 * then take a rest.
		 */
		if (time_after(jiffies, start_jiffies + 1))
			return 0;

		if ((cmd->SCp.this_residual <= 0)) {
			ppa_fail(dev, DID_ERROR);
			return -1;	/* ERROR_RETURN */
		}

		/* On some hardware we have SCSI disconnected (6th bit low)
		 * for about 100usecs. It is too expensive to wait a 
		 * tick on every loop so we busy wait for no more than
		 * 500usecs to give the drive a chance first. We do not 
		 * change things for "normal" hardware since generally 
		 * the 6th bit is always high.
		 * This makes the CPU load higher on some hardware 
		 * but otherwise we can not get more than 50K/secs 
		 * on this problem hardware.
		 */