imm.c

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/* 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.)
 * 
 * Current Maintainer: David Campbell (Perth, Western Australia)
 *                     [e-mail]
 *
 * 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/config.h>

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

void imm_reset_pulse(unsigned int base);
static int device_check(int host_no);

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

#define IMM_EMPTY \
{	dev:		NULL,		\
	base:		-1,		\
	base_hi:	0,		\
	mode:		IMM_AUTODETECT,	\
	host:		-1,		\
	cur_cmd:	NULL,		\
	imm_tq:		{ routine: imm_interrupt },    \
	jstart:		0,		\
	failed:		0,		\
	dp:		0,		\
	rd:		0,		\
	p_busy:		0		\
}

#include "imm.h"
#define NO_HOSTS 4
static imm_struct imm_hosts[NO_HOSTS] =
{IMM_EMPTY, IMM_EMPTY, IMM_EMPTY, IMM_EMPTY};

#define IMM_BASE(x)	imm_hosts[(x)].base
#define IMM_BASE_HI(x)     imm_hosts[(x)].base_hi

int parbus_base[NO_HOSTS] =
{0x03bc, 0x0378, 0x0278, 0x0000};

void imm_wakeup(void *ref)
{
    imm_struct *imm_dev = (imm_struct *) ref;

    if (!imm_dev->p_busy)
	return;

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

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

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

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

#define imm_pb_release(x) parport_release(imm_hosts[(x)].dev)

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

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

int imm_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("imm: Version %s\n", IMM_VERSION);
    nhosts = 0;
    try_again = 0;

    if (!pb) {
	printk("imm: 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;

	imm_hosts[i].dev =
	    parport_register_device(pb, "imm", NULL, imm_wakeup,
				    NULL, 0, (void *) &imm_hosts[i]);

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

	/* Claim the bus so it remembers what we do to the control
	 * registers. [ CTR and ECP ]
	 */
	if (imm_pb_claim(i)) {
	    unsigned long now = jiffies;
	    while (imm_hosts[i].p_busy) {
		schedule();	/* We are safe to schedule here */
		if (time_after(jiffies, now + 3 * HZ)) {
		    printk(KERN_ERR "imm%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 = IMM_BASE(i) = imm_hosts[i].dev->port->base;
	IMM_BASE_HI(i) = imm_hosts[i].dev->port->base_hi;
	w_ctr(ppb, 0x0c);
	modes = imm_hosts[i].dev->port->modes;

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

	if (modes & PARPORT_MODE_TRISTATE)
	    imm_hosts[i].mode = IMM_PS2;

	/* Done configuration */
	imm_pb_release(i);

	if (imm_init(i)) {
	    parport_unregister_device(imm_hosts[i].dev);
	    continue;
	}
	/* now the glue ... */
	switch (imm_hosts[i].mode) {
	case IMM_NIBBLE:
	    ports = 3;
	    break;
	case IMM_PS2:
	    ports = 3;
	    break;
	case IMM_EPP_8:
	case IMM_EPP_16:
	case IMM_EPP_32:
	    ports = 8;
	    break;
	default:		/* Never gets here */
	    continue;
	}

	host->can_queue = IMM_CAN_QUEUE;
	host->sg_tablesize = imm_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;
	imm_hosts[i].host = hreg->host_no;
	nhosts++;
    }
    if (nhosts == 0) {
	if (try_again == 1) {
	    spin_lock_irq(&io_request_lock);
	    return 0;
	}
	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 imm driver a way to modify the timings (and other
 * parameters) by writing to the /proc/scsi/imm/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 imm_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);
	imm_hosts[hostno].mode = x;
	return length;
    }
    printk("imm /proc: invalid variable\n");
    return (-EINVAL);
}

int imm_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 (imm_hosts[i].host == hostno)
	    break;

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

    len += sprintf(buffer + len, "Version : %s\n", IMM_VERSION);
    len += sprintf(buffer + len, "Parport : %s\n", imm_hosts[i].dev->port->name);
    len += sprintf(buffer + len, "Mode    : %s\n", IMM_MODE_STRING[imm_hosts[i].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(int host_no, int error_code)
#else
static inline void imm_fail(int host_no, int error_code)
#endif
{
    /* If we fail a device then we trash status / message bytes */
    if (imm_hosts[host_no].cur_cmd) {
	imm_hosts[host_no].cur_cmd->result = error_code << 16;
	imm_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 imm_wait(int host_no)
{
    int k;
    unsigned short ppb = IMM_BASE(host_no);
    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(host_no, 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->host, 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(unsigned short hostno)
{
    int i, ppb_hi=IMM_BASE_HI(hostno);

    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");
    }
}