ncr5380.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

    for (i = 0; signals[i].mask ; ++i) 
	if (status & signals[i].mask)
	    printk(",%s", signals[i].name);
    printk("\nBASR: %02x ", basr);
    for (i = 0; basrs[i].mask ; ++i) 
	if (basr & basrs[i].mask)
	    printk(",%s", basrs[i].name);
    printk("\nICR: %02x ", icr);
    for (i = 0; icrs[i].mask; ++i) 
	if (icr & icrs[i].mask)
	    printk(",%s", icrs[i].name);
    printk("\nMODE: %02x ", mr);
    for (i = 0; mrs[i].mask; ++i) 
	if (mr & mrs[i].mask)
	    printk(",%s", mrs[i].name);
    printk("\n");
}

static struct {
    unsigned char value;
    const char *name;
} phases[] = {
{PHASE_DATAOUT, "DATAOUT"}, {PHASE_DATAIN, "DATAIN"}, {PHASE_CMDOUT, "CMDOUT"},
{PHASE_STATIN, "STATIN"}, {PHASE_MSGOUT, "MSGOUT"}, {PHASE_MSGIN, "MSGIN"},
{PHASE_UNKNOWN, "UNKNOWN"}};

/* 
 * Function : void NCR5380_print_phase(struct Scsi_Host *instance)
 *
 * Purpose : print the current SCSI phase for debugging purposes
 *
 * Input : instance - which NCR5380
 */

static void NCR5380_print_phase(struct Scsi_Host *instance) {
    NCR5380_local_declare();
    unsigned char status;
    int i;
    NCR5380_setup(instance);

    status = NCR5380_read(STATUS_REG);
    if (!(status & SR_REQ)) 
	printk("scsi%d : REQ not asserted, phase unknown.\n", 
	    instance->host_no);
    else {
	for (i = 0; (phases[i].value != PHASE_UNKNOWN) && 
	    (phases[i].value != (status & PHASE_MASK)); ++i); 
	printk("scsi%d : phase %s\n", instance->host_no, phases[i].name);
    }
}
#endif

/*
 * We need to have our coroutine active given these constraints : 
 * 1.  The mutex flag, main_running, can only be set when the main 
 *     routine can actually process data, otherwise SCSI commands
 *     will never get issued.
 *
 * 2.  NCR5380_main() shouldn't be called before it has exited, because
 *     other drivers have had kernel stack overflows in similar
 *     situations.
 *
 * 3.  We don't want to inline NCR5380_main() because of space concerns,
 *     even though it is only called in two places.
 *
 * So, the solution is to set the mutex in an inline wrapper for the 
 * main coroutine, and have the main coroutine exit with interrupts 
 * disabled after the final search through the queues so that no race 
 * conditions are possible.
 */

static volatile int main_running = 0;

/* 
 * Function : run_main(void)
 * 
 * Purpose : insure that the coroutine is running and will process our 
 * 	request.  main_running is checked/set here (in an inline function)
 *	rather than in NCR5380_main itself to reduce the chances of stack
 *	overflow.
 *
 */

static __inline__ void run_main(void) {
    cli();
    if (!main_running) {
	main_running = 1;
	NCR5380_main();
	/* 
	 * main_running is cleared in NCR5380_main once it can't do 
	 * more work, and NCR5380_main exits with interrupts disabled.
	 */
	sti();
    } else 
	sti();
}

#ifdef USLEEP
#ifndef NCR5380_TIMER
#error "NCR5380_TIMER must be defined so that this type of NCR5380 driver gets a unique timer."
#endif

/*
 * These need tweaking, and would probably work best as per-device 
 * flags initialized differently for disk, tape, cd, etc devices.
 * People with broken devices are free to experiment as to what gives
 * the best results for them.
 *
 * USLEEP_SLEEP should be a minimum seek time.
 *
 * USLEEP_POLL should be a maximum rotational latency.
 */
#ifndef USLEEP_SLEEP
/* 20 ms (reasonable hard disk speed) */
#define USLEEP_SLEEP (20*HZ/1000)
#endif
/* 300 RPM (floppy speed) */
#ifndef USLEEP_POLL
#define USLEEP_POLL (200*HZ/1000)
#endif

static struct Scsi_Host * expires_first = NULL;

/* 
 * Function : int should_disconnect (unsigned char cmd)
 *
 * Purpose : decide weather a command would normally disconnect or 
 *	not, since if it won't disconnect we should go to sleep.
 *
 * Input : cmd - opcode of SCSI command
 *
 * Returns : DISCONNECT_LONG if we should disconnect for a really long 
 * 	time (ie always, sleep, look for REQ active, sleep), 
 *	DISCONNECT_TIME_TO_DATA if we would only disconnect for a normal
 * 	time-to-data delay, DISCONNECT_NONE if this command would return
 * 	immediately.
 *
 *      Future sleep algorithms based on time to data can exploit 
 *      something like this so they can differentiate between "normal" 
 *	(ie, read, write, seek) and unusual commands (ie, * format).
 *
 * Note : We don't deal with commands that handle an immediate disconnect,
 *        
 */

static int should_disconnect (unsigned char cmd) {
    switch (cmd) {
    case READ_6:
    case WRITE_6:
    case SEEK_6:
    case READ_10:
    case WRITE_10:
    case SEEK_10:
	return DISCONNECT_TIME_TO_DATA;
    case FORMAT_UNIT:
    case SEARCH_HIGH:
    case SEARCH_LOW:
    case SEARCH_EQUAL:
	return DISCONNECT_LONG;
    default:
	return DISCONNECT_NONE;
    }
}

/*
 * Assumes instance->time_expires has been set in higher level code.
 */

static int NCR5380_set_timer (struct Scsi_Host *instance) {
    struct Scsi_Host *tmp, **prev;
    
    cli();
    if (((struct NCR5380_hostdata *) (instance->host_data))->next_timer) {
	sti();
	return -1;
    }

    for (prev = &expires_first, tmp = expires_first; tmp; 
	prev = &(((struct NCR5380_hostdata *) tmp->host_data)->next_timer), 
	tmp = ((struct NCR5380_hostdata *) tmp->host_data)->next_timer)
	if (instance->time_expires < tmp->time_expires) 
	    break;
	   
    instance->next_timer = tmp;
    *prev = instance;
    timer_table[NCR5380_TIMER].expires = expires_first->time_expires;
    timer_active |= 1 << NCR5380_TIMER;
    sti();
    return 0;
}    

/* Doing something about unwanted reentrancy here might be useful */
void NCR5380_timer_fn(void) {
    struct Scsi_Host *instance;
    cli();
    for (; expires_first && expires_first->time_expires >= jiffies; ) {
	instance = ((NCR5380_hostdata *) expires_first->host_data)->
	    expires_next;
	((NCR5380_hostdata *) expires_first->host_data)->expires_next = 
	    NULL;
	((NCR5380_hostdata *) expires_first->host_data)->time_expires = 
	    0;
	expires_first = instance;
    }

    if (expires_first) {
	timer_table[NCR5380_TIMER].expires = ((NCR5380_hostdata *) 
	    expires_first->host_data)->time_expires;
	timer_active |= (1 << NCR5380_TIMER);
    } else {
	timer_table[NCR5380_TIMER].expires = 0;
	timer_active &= ~(1 << MCR5380_TIMER);
    }
    sti();

    run_main();
}
#endif /* def USLEEP */

static void NCR5380_all_init (void) {
    static int done = 0;
    if (!done) {
#if (NDEBUG & NDEBUG_INIT)
	printk("scsi : NCR5380_all_init()\n");
#endif
	done = 1;
#ifdef USLEEP
	timer_table[NCR5380_TIMER].expires = 0;
	timer_table[NCR5380_TIMER].fn = NCR5380_timer_fn;
#endif
    }
}

#ifdef AUTOPROBE_IRQ
/*
 * Function : int NCR5380_probe_irq (struct Scsi_Host *instance, int possible)
 * 
 * Purpose : autoprobe for the IRQ line used by the NCR5380.  
 *
 * Inputs : instance - pointer to this instance of the NCR5380 driver,
 *          possible - bitmask of permissible interrupts.
 *
 * Returns : number of the IRQ selected, IRQ_NONE if no interrupt fired.
 * 
 * XXX no effort is made to deal with spurious interrupts. 
 */


static int probe_irq;
static void probe_intr (int irq, void *dev_id, struct pt_regs * regs) {
    probe_irq = irq;
};

static int NCR5380_probe_irq (struct Scsi_Host *instance, int possible) {
    NCR5380_local_declare();
    struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *)
	 instance->hostdata;
    unsigned long timeout;
    int trying_irqs, i, mask;
    NCR5380_setup(instance);

    for (trying_irqs = i = 0, mask = 1; i < 16; ++i, mask <<= 1) 
	if ((mask & possible) &&  (request_irq(i, &probe_intr, SA_INTERRUPT, "NCR-probe", NULL) 
	    == 0)) 
	    trying_irqs |= mask;

    timeout = jiffies + 250*HZ/1000;
    probe_irq = IRQ_NONE;

/*
 * A interrupt is triggered whenever BSY = false, SEL = true
 * and a bit set in the SELECT_ENABLE_REG is asserted on the 
 * SCSI bus.
 *
 * Note that the bus is only driven when the phase control signals
 * (I/O, C/D, and MSG) match those in the TCR, so we must reset that
 * to zero.
 */

    NCR5380_write(TARGET_COMMAND_REG, 0);
    NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
    NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
    NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | 
	ICR_ASSERT_SEL);

    while (probe_irq == IRQ_NONE && jiffies < timeout)
    	barrier();

    NCR5380_write(SELECT_ENABLE_REG, 0);
    NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

    for (i = 0, mask = 1; i < 16; ++i, mask <<= 1)
	if (trying_irqs & mask) 
	    free_irq(i, NULL);

    return probe_irq;
}
#endif /* AUTOPROBE_IRQ */
 
/*
 * Function : void NCR58380_print_options (struct Scsi_Host *instance)
 *
 * Purpose : called by probe code indicating the NCR5380 driver
 *	     options that were selected.
 *
 * Inputs : instance, pointer to this instance.  Unused.
 */

static void NCR5380_print_options (struct Scsi_Host *instance) {
    printk(" generic options"
#ifdef AUTOPROBE_IRQ
    " AUTOPROBE_IRQ"
#endif
#ifdef AUTOSENSE 
    " AUTOSENSE"
#endif
#ifdef DIFFERENTIAL
    " DIFFERENTIAL"
#endif
#ifdef REAL_DMA
    " REAL DMA"
#endif
#ifdef REAL_DMA_POLL
    " REAL DMA POLL"
#endif
#ifdef PARITY
    " PARITY"
#endif
#ifdef PSEUDO_DMA
    " PSEUDO DMA"
#endif
#ifdef SCSI2
    " SCSI-2"
#endif
#ifdef UNSAFE
    " UNSAFE "
#endif
    );
#ifdef USLEEP
    printk(" USLEEP, USLEEP_POLL=%d USLEEP_SLEEP=%d", USLEEP_POLL, USLEEP_SLEEP);
#endif
    printk(" generic release=%d", NCR5380_PUBLIC_RELEASE);
    if (((struct NCR5380_hostdata *)instance->hostdata)->flags & FLAG_NCR53C400) {
	printk(" ncr53c400 release=%d", NCR53C400_PUBLIC_RELEASE);
    }
}

/*
 * Function : void NCR5380_print_status (struct Scsi_Host *instance)
 *
 * Purpose : print commands in the various queues, called from
 *	NCR5380_abort and NCR5380_debug to aid debugging.
 *
 * Inputs : instance, pointer to this instance.  
 */

static void NCR5380_print_status (struct Scsi_Host *instance) {
   static char pr_bfr[512];
   char *start;
   int len;

    printk("NCR5380 : coroutine is%s running.\n",
	main_running ? "" : "n't");
    
#ifdef NDEBUG
    NCR5380_print (instance);
    NCR5380_print_phase (instance);
#endif

   len = NCR5380_proc_info(pr_bfr, &start, 0, sizeof(pr_bfr),
			instance->host_no, 0);
   pr_bfr[len] = 0;
   printk("\n%s\n", pr_bfr);
  }

/******************************************/
/*
 * /proc/scsi/[dtc pas16 t128 generic]/[0-ASC_NUM_BOARD_SUPPORTED]
 *
 * *buffer: I/O buffer
 * **start: if inout == FALSE pointer into buffer where user read should start
 * offset: current offset
 * length: length of buffer
 * hostno: Scsi_Host host_no
 * inout: TRUE - user is writing; FALSE - user is reading
 *
 * Return the number of bytes read from or written
*/

#undef SPRINTF
#define SPRINTF(args...) do { if(pos < buffer + length-80) pos += sprintf(pos, ## args); } while(0)
static
char *lprint_Scsi_Cmnd (Scsi_Cmnd *cmd, char *pos, char *buffer, int length);
static
char *lprint_command (unsigned char *cmd, char *pos, char *buffer, int len);
static
char *lprint_opcode(int opcode, char *pos, char *buffer, int length);

#ifndef NCR5380_proc_info
static
#endif
int NCR5380_proc_info (
     char *buffer, char **start,off_t offset,
     int length,int hostno,int inout)
{
   char *pos = buffer;
   struct Scsi_Host *instance;
   struct NCR5380_hostdata *hostdata;
   Scsi_Cmnd *ptr;

   for (instance = first_instance; instance &&
        instance->host_no != hostno; instance=instance->next)
        ;
   if (!instance)
      return(-ESRCH);
   hostdata = (struct NCR5380_hostdata *)instance->hostdata;

   if (inout) { /* Has data been written to the file ? */
#ifdef DTC_PUBLIC_RELEASE
        dtc_wmaxi = dtc_maxi = 0;
#endif