ppa.c

GNU Mach 微内核源代码, 基于美国卡内基美隆大学的 Mach 研究项目

	"	outb %%al,(%%dx)\n" \
	"	subl $2,%%edx\n"

static inline 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! */
}

#define NIBBLE_IN(reg) \
	"	incl %%edx\n" \
	"	movb $0x04,%%al\n" \
	"	outb %%al,(%%dx)\n" \
	"	decl %%edx\n" \
	"	inb (%%dx),%%al\n" \
	"	andb $0xf0,%%al\n" \
	"	movb %%al," #reg "\n" \
	"	incl %%edx\n" \
	"	movb $0x06,%%al\n" \
	"	outb %%al,(%%dx)\n" \
	"	decl %%edx\n" \
	"	inb (%%dx),%%al\n" \
	"	shrb $4,%%al\n" \
	"	orb %%al," #reg "\n"

static inline int ppa_nibble_in(unsigned short str_p, 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! */
}
#else				/* Old style C routines */

static inline int ppa_byte_out(unsigned short base, const char *buffer, int len)
{
    unsigned short ctr_p = base + 2;
    int i;

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

static inline int ppa_byte_in(unsigned short base, char *buffer, int len)
{
    unsigned short ctr_p = base + 2;
    int i;

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

static inline int ppa_nibble_in(unsigned short str_p, char *buffer, int len)
{
    unsigned short ctr_p = str_p + 1;
    unsigned char h, l;
    int i;

    for (i = len; i; i--) {
	outb(0x4, ctr_p);
	h = inb(str_p);
	outb(0x6, ctr_p);
	l = inb(str_p);
	*buffer++ = (h & 0xf0) | ((l & 0xf0) >> 4);
    }
    return 1;			/* All went well - we hope! */
  }
  #endif
  
static inline int ppa_epp_out(unsigned short epp_p, unsigned short str_p, const char *buffer, int len)
{
    int i;
    for (i = len; i; i--) {
	outb(*buffer++, epp_p);
#ifdef CONFIG_SCSI_PPA_HAVE_PEDANTIC
	if (inb(str_p) & 0x01)
	    return 0;
  #endif
    }
    return 1;
  }
  
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_PPA_HAVE_PEDANTIC
	r = ppa_epp_out(ppb + 4, ppb + 1, buffer, len);
#else
	if (!(((long) buffer | len) & 0x03))
	    outsl(ppb + 4, buffer, len >> 2);
	else
	    outsb(ppb + 4, buffer, len);
	w_ctr(ppb, 0xc);
	r = !(r_str(ppb) & 0x01);
#endif
	w_ctr(ppb, 0xc);
	ecp_sync(ppb);
	break;

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

static inline int ppa_epp_in(int epp_p, int str_p, char *buffer, int len)
{
    int i;
    for (i = len; i; i--) {
	*buffer++ = inb(epp_p);
#ifdef CONFIG_SCSI_PPA_HAVE_PEDANTIC
	if (inb(str_p) & 0x01)
	    return 0;
#endif
    }
    return 1;
  }
  
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 + 1, 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_PPA_HAVE_PEDANTIC
	r = ppa_epp_in(ppb + 4, ppb + 1, buffer, len);
  #else
	if (!(((long) buffer | len) & 0x03))
	    insl(ppb + 4, buffer, len >> 2);
	else
	    insb(ppb + 4, buffer, len);
	w_ctr(ppb, 0x2c);
	r = !(r_str(ppb) & 0x01);
#endif
	w_ctr(ppb, 0x2c);
	ecp_sync(ppb);
	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--;
    } 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--;
    }
    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(int host_no)
{
    int retv;
    unsigned short ppb = PPA_BASE(host_no);

    ppa_disconnect(host_no);
    ppa_connect(host_no, 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--;

    /* This is a SCSI BUS reset signal */
    if (!retv) {
	w_dtr(ppb, 0x40);
	w_ctr(ppb, 0x08);
	udelay(30);
	w_ctr(ppb, 0x0c);
	udelay(1000);		/* Allow devices to settle down */
    }
    ppa_disconnect(host_no);
    udelay(1000);		/* Another delay to allow devices to settle */

    if (!retv)
	retv = device_check(host_no);

    return retv;
}

static inline int ppa_send_command(Scsi_Cmnd * cmd)
{
    int host_no = cmd->host->unique_id;
    int k;

    w_ctr(PPA_BASE(host_no), 0x0c);

    for (k = 0; k < cmd->cmd_len; k++)
	if (!ppa_out(host_no, &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(Scsi_Cmnd * cmd)
{
    /* Return codes:
     * -1     Error
     *  0     Told to schedule
     *  1     Finished data transfer
     */
    int host_no = cmd->host->unique_id;
    unsigned short ppb = PPA_BASE(host_no);
    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 (jiffies > start_jiffies + 1)
	    return 0;

	if (((r & 0xc0) != 0xc0) || (cmd->SCp.this_residual <= 0)) {
	    ppa_fail(host_no, DID_ERROR);
	    return -1;		/* ERROR_RETURN */
	}
	/* determine if we should use burst I/O */ fast = (bulk && (cmd->SCp.this_residual >= PPA_BURST_SIZE))
	    ? PPA_BURST_SIZE : 1;

	if (r == (unsigned char) 0xc0)
	    status = ppa_out(host_no, cmd->SCp.ptr, fast);
	else
	    status = ppa_in(host_no, cmd->SCp.ptr, fast);

	cmd->SCp.ptr += fast;
	cmd->SCp.this_residual -= fast;

	if (!status) {
	    ppa_fail(host_no, DID_BUS_BUSY);
	    return -1;		/* ERROR_RETURN */
	}
	if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
	    /* if scatter/gather, advance to the next segment */
	    if (cmd->SCp.buffers_residual--) {
		cmd->SCp.buffer++;
		cmd->SCp.this_residual = cmd->SCp.buffer->length;
		cmd->SCp.ptr = cmd->SCp.buffer->address;
	    }
	}
	/* Now check to see if the drive is ready to comunicate */
	r = (r_str(ppb) & 0xf0);
	/* If not, drop back down to the scheduler and wait a timer tick */
	if (!(r & 0x80))
	    return 0;
    }
    return 1;			/* FINISH_RETURN */
}

/*
 * Since the PPA itself doesn't generate interrupts, we use
 * the scheduler's task queue to generate a stream of call-backs and
 * complete the request when the drive is ready.
 */
static void ppa_interrupt(void *data)
{
    ppa_struct *tmp = (ppa_struct *) data;
    Scsi_Cmnd *cmd = tmp->cur_cmd;

    if (!cmd) {
	printk("PPA: bug in ppa_interrupt\n");
	return;
    }
    if (ppa_engine(tmp, cmd)) {
	tmp->ppa_tq.data = (void *) tmp;
	tmp->ppa_tq.sync = 0;
	queue_task(&tmp->ppa_tq, &tq_timer);
	return;
    }
    /* Command must of completed hence it is safe to let go... */
#if PPA_DEBUG > 0
    switch ((cmd->result >> 16) & 0xff) {
    case DID_OK:
	break;
    case DID_NO_CONNECT:
	printk("ppa: no device at SCSI ID %i\n", cmd->target);
	break;
    case DID_BUS_BUSY:
	printk("ppa: BUS BUSY - EPP timeout detected\n");
	break;
    case DID_TIME_OUT:
	printk("ppa: unknown timeout\n");
	break;
    case DID_ABORT:
	printk("ppa: told to abort\n");
	break;
    case DID_PARITY:
	printk("ppa: parity error (???)\n");
	break;
    case DID_ERROR:
	printk("ppa: internal driver error\n");
	break;
    case DID_RESET:
	printk("ppa: told to reset device\n");
	break;
    case DID_BAD_INTR:
	printk("ppa: bad interrupt (???)\n");
	break;
    default:
	printk("ppa: bad return code (%02x)\n", (cmd->result >> 16) & 0xff);
    }
  #endif
  
    if (cmd->SCp.phase > 1)
	ppa_disconnect(cmd->host->unique_id);

    tmp->cur_cmd = 0;
    cmd->scsi_done(cmd);
    return;
}

static int ppa_engine(ppa_struct * tmp, Scsi_Cmnd * cmd)
{
    int host_no = cmd->host->unique_id;
    unsigned short ppb = PPA_BASE(host_no);