ppa.c

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/* 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 Public License.
 * 
 * Current Maintainer: David Campbell (Perth, Western Australia, GMT+0800)
 *                     [e-mail]
 */

#include <linux/config.h>

/* The following #define is to avoid a clash with hosts.c */
#define PPA_CODE 1

#include <linux/blk.h>
#include <asm/io.h>
#include <linux/parport.h>
#include "sd.h"
#include "hosts.h"
int ppa_release(struct Scsi_Host *);
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                */
    int host;			/* Host number (for proc)       */
    Scsi_Cmnd *cur_cmd;		/* Current queued command       */
    struct tq_struct ppa_tq;	/* Polling interupt 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 int p_busy:1;	/* Parport sharing busy flag    */
} ppa_struct;

#define PPA_EMPTY	\
{	dev:		NULL,		\
	base:		-1,		\
	mode:		PPA_AUTODETECT,	\
	host:		-1,		\
	cur_cmd:	NULL,		\
	ppa_tq:		{ routine: ppa_interrupt },	\
	jstart:		0,		\
	recon_tmo:      PPA_RECON_TMO,	\
	failed:		0,		\
	p_busy:		0		\
}

#include  "ppa.h"

#define NO_HOSTS 4
static ppa_struct ppa_hosts[NO_HOSTS] =
{PPA_EMPTY, PPA_EMPTY, PPA_EMPTY, PPA_EMPTY};

#define PPA_BASE(x)	ppa_hosts[(x)].base

void ppa_wakeup(void *ref)
{
    ppa_struct *ppa_dev = (ppa_struct *) ref;

    if (!ppa_dev->p_busy)
	return;

    if (parport_claim(ppa_dev->dev)) {
	printk("ppa: bug in ppa_wakeup\n");
	return;
    }
    ppa_dev->p_busy = 0;
    ppa_dev->base = ppa_dev->dev->port->base;
    if (ppa_dev->cur_cmd)
	ppa_dev->cur_cmd->SCp.phase++;
    return;
}

int ppa_release(struct Scsi_Host *host)
{
    int host_no = host->unique_id;

    printk("Releasing ppa%i\n", host_no);
    parport_unregister_device(ppa_hosts[host_no].dev);
    return 0;
}

static int ppa_pb_claim(int host_no)
{
    if (parport_claim(ppa_hosts[host_no].dev)) {
	ppa_hosts[host_no].p_busy = 1;
	return 1;
    }
    if (ppa_hosts[host_no].cur_cmd)
	ppa_hosts[host_no].cur_cmd->SCp.phase++;
    return 0;
}

#define ppa_pb_release(x) parport_release(ppa_hosts[(x)].dev)

/***************************************************************************
 *                   Parallel port probing routines                        *
 ***************************************************************************/

static Scsi_Host_Template driver_template = PPA;
#include  "scsi_module.c"

/*
 * Start of Chipset kludges
 */

int ppa_detect(Scsi_Host_Template * host)
{
    struct Scsi_Host *hreg;
    int ports;
    int i, nhosts, try_again;
    struct parport *pb;

    /*
     * unlock to allow the lowlevel parport driver to probe
     * the irqs
     */
    spin_unlock_irq(&io_request_lock);
    pb = parport_enumerate();

    printk("ppa: Version %s\n", PPA_VERSION);
    nhosts = 0;
    try_again = 0;

    if (!pb) {
	printk("ppa: parport reports no devices.\n");
	spin_lock_irq(&io_request_lock);
	return 0;
    }
  retry_entry:
    for (i = 0; pb; i++, pb = pb->next) {
	int modes, ppb, ppb_hi;

	ppa_hosts[i].dev =
	    parport_register_device(pb, "ppa", NULL, ppa_wakeup,
				    NULL, 0, (void *) &ppa_hosts[i]);

	if (!ppa_hosts[i].dev)
	    continue;

	/* Claim the bus so it remembers what we do to the control
	 * registers. [ CTR and ECP ]
	 */
	if (ppa_pb_claim(i)) {
	    unsigned long now = jiffies;
	    while (ppa_hosts[i].p_busy) {
		schedule();	/* We are safe to schedule here */
		if (time_after(jiffies, now + 3 * HZ)) {
		    printk(KERN_ERR "ppa%d: failed to claim parport because a "
		      "pardevice is owning the port for too longtime!\n",
			   i);
		    spin_lock_irq(&io_request_lock);
		    return 0;
		}
	    }
	}
	ppb = PPA_BASE(i) = ppa_hosts[i].dev->port->base;
	ppb_hi =  ppa_hosts[i].dev->port->base_hi;
	w_ctr(ppb, 0x0c);
	modes = ppa_hosts[i].dev->port->modes;

	/* Mode detection works up the chain of speed
	 * This avoids a nasty if-then-else-if-... tree
	 */
	ppa_hosts[i].mode = PPA_NIBBLE;

	if (modes & PARPORT_MODE_TRISTATE)
	    ppa_hosts[i].mode = PPA_PS2;

	if (modes & PARPORT_MODE_ECP) {
	    w_ecr(ppb_hi, 0x20);
	    ppa_hosts[i].mode = PPA_PS2;
	}
	if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))
	    w_ecr(ppb_hi, 0x80);

	/* Done configuration */
	ppa_pb_release(i);

	if (ppa_init(i)) {
	    parport_unregister_device(ppa_hosts[i].dev);
	    continue;
	}
	/* now the glue ... */
	switch (ppa_hosts[i].mode) {
	case PPA_NIBBLE:
	    ports = 3;
	    break;
	case PPA_PS2:
	    ports = 3;
	    break;
	case PPA_EPP_8:
	case PPA_EPP_16:
	case PPA_EPP_32:
	    ports = 8;
	    break;
	default:		/* Never gets here */
	    continue;
	}

	host->can_queue = PPA_CAN_QUEUE;
	host->sg_tablesize = ppa_sg;
	hreg = scsi_register(host, 0);
	if(hreg == NULL)
		continue;
	hreg->io_port = pb->base;
	hreg->n_io_port = ports;
	hreg->dma_channel = -1;
	hreg->unique_id = i;
	ppa_hosts[i].host = hreg->host_no;
	nhosts++;
    }
    if (nhosts == 0) {
	if (try_again == 1) {
	    printk("WARNING - no ppa compatible devices found.\n");
	    printk("  As of 31/Aug/1998 Iomega started shipping parallel\n");
	    printk("  port ZIP drives with a different interface which is\n");
	    printk("  supported by the imm (ZIP Plus) driver. If the\n");
	    printk("  cable is marked with \"AutoDetect\", this is what has\n");
	    printk("  happened.\n");
	    return 0;
	    spin_lock_irq(&io_request_lock);
	}
	try_again = 1;
	goto retry_entry;
    } else {
	spin_lock_irq(&io_request_lock);
	return 1;		/* return number of hosts detected */
    }
}

/* 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(int hostno, char *buffer, int length)
{
    unsigned long x;

    if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
	x = simple_strtoul(buffer + 5, NULL, 0);
	ppa_hosts[hostno].mode = x;
	return length;
    }
    if ((length > 10) && (strncmp(buffer, "recon_tmo=", 10) == 0)) {
	x = simple_strtoul(buffer + 10, NULL, 0);
	ppa_hosts[hostno].recon_tmo = x;
        printk("ppa: recon_tmo set to %ld\n", x);
	return length;
    }
    printk("ppa /proc: invalid variable\n");
    return (-EINVAL);
}

int ppa_proc_info(char *buffer, char **start, off_t offset,
		  int length, int hostno, int inout)
{
    int i;
    int len = 0;

    for (i = 0; i < 4; i++)
	if (ppa_hosts[i].host == hostno)
	    break;

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

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

#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(int host_no, int error_code)
#else
static inline void ppa_fail(int host_no, int error_code)
#endif
{
    /* If we fail a device then we trash status / message bytes */
    if (ppa_hosts[host_no].cur_cmd) {
	ppa_hosts[host_no].cur_cmd->result = error_code << 16;
	ppa_hosts[host_no].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(int host_no)
{
    int k;
    unsigned short ppb = PPA_BASE(host_no);
    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(host_no, 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(unsigned short hostno)
{
    int i, ppb_hi=ppa_hosts[hostno].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(int host_no, char *buffer, int len)
{
    int r;
    unsigned short ppb = PPA_BASE(host_no);

    r = ppa_wait(host_no);

    if ((r & 0x50) != 0x40) {
	ppa_fail(host_no, DID_ERROR);
	return 0;
    }
    switch (ppa_hosts[host_no].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(host_no);
	break;

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

static int ppa_in(int host_no, char *buffer, int len)
{
    int r;
    unsigned short ppb = PPA_BASE(host_no);

    r = ppa_wait(host_no);

    if ((r & 0x50) != 0x50) {
	ppa_fail(host_no, DID_ERROR);
	return 0;
    }
    switch (ppa_hosts[host_no].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(host_no);
	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(int host_no)
{
    unsigned short ppb = PPA_BASE(host_no);

    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(int host_no, int flag)
{
    unsigned short ppb = PPA_BASE(host_no);

    ppa_c_pulse(ppb, 0);
    ppa_c_pulse(ppb, 0x3c);
    ppa_c_pulse(ppb, 0x20);
    if ((flag == CONNECT_EPP_MAYBE) &&
	IN_EPP_MODE(ppa_hosts[host_no].mode))
	ppa_c_pulse(ppb, 0xcf);
    else
	ppa_c_pulse(ppb, 0x8f);
}

static int ppa_select(int host_no, int target)
{
    int k;
    unsigned short ppb = PPA_BASE(host_no);

    /*
     * 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;