53c7xx.c

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         }
      }
   for (i=0; i<MAX_SETUP_STRINGS; i++)
      setup_used[i] = 0;
}


/* check_setup_strings() returns index if key found, 0 if not
 */

static int check_setup_strings(char *key, int *flags, int *val, char *buf)
{
int x;
char *cp;

   for  (x=0; x<MAX_SETUP_STRINGS; x++) {
      if (setup_used[x])
         continue;
      if (!strncmp(setup_strings[x], key, strlen(key)))
         break;
      if (!strncmp(setup_strings[x], "next", strlen("next")))
         return 0;
      }
   if (x == MAX_SETUP_STRINGS)
      return 0;
   setup_used[x] = 1;
   cp = setup_strings[x] + strlen(key);
   *val = -1;
   if (*cp != ':')
      return ++x;
   cp++;
   if ((*cp >= '0') && (*cp <= '9')) {
      *val = simple_strtoul(cp,NULL,0);
      }
   return ++x;
}



/*
 * KNOWN BUGS :
 * - There is some sort of conflict when the PPP driver is compiled with 
 * 	support for 16 channels?
 * 
 * - On systems which predate the 1.3.x initialization order change,
 *      the NCR driver will cause Cannot get free page messages to appear.  
 *      These are harmless, but I don't know of an easy way to avoid them.
 *
 * - With OPTION_DISCONNECT, on two systems under unknown circumstances,
 *	we get a PHASE MISMATCH with DSA set to zero (suggests that we 
 *	are occurring somewhere in the reselection code) where 
 *	DSP=some value DCMD|DBC=same value.  
 * 	
 *	Closer inspection suggests that we may be trying to execute
 *	some portion of the DSA?
 * scsi0 : handling residual transfer (+ 0 bytes from DMA FIFO)
 * scsi0 : handling residual transfer (+ 0 bytes from DMA FIFO)
 * scsi0 : no current command : unexpected phase MSGIN.
 *         DSP=0x1c46cc, DCMD|DBC=0x1c46ac, DSA=0x0
 *         DSPS=0x0, TEMP=0x1c3e70, DMODE=0x80
 * scsi0 : DSP->
 * 001c46cc : 0x001c46cc 0x00000000
 * 001c46d4 : 0x001c5ea0 0x000011f8
 *
 *	Changed the print code in the phase_mismatch handler so
 *	that we call print_lots to try to diagnose this.
 *
 */

/* 
 * Possible future direction of architecture for max performance :
 *
 * We're using a single start array for the NCR chip.  This is 
 * sub-optimal, because we cannot add a command which would conflict with 
 * an executing command to this start queue, and therefore must insert the 
 * next command for a given I/T/L combination after the first has completed;
 * incurring our interrupt latency between SCSI commands.
 *
 * To allow further pipelining of the NCR and host CPU operation, we want 
 * to set things up so that immediately on termination of a command destined 
 * for a given LUN, we get that LUN busy again.  
 * 
 * To do this, we need to add a 32 bit pointer to which is jumped to 
 * on completion of a command.  If no new command is available, this 
 * would point to the usual DSA issue queue select routine.
 *
 * If one were, it would point to a per-NCR53c7x0_cmd select routine 
 * which starts execution immediately, inserting the command at the head 
 * of the start queue if the NCR chip is selected or reselected.
 *
 * We would change so that we keep a list of outstanding commands 
 * for each unit, rather than a single running_list.  We'd insert 
 * a new command into the right running list; if the NCR didn't 
 * have something running for that yet, we'd put it in the 
 * start queue as well.  Some magic needs to happen to handle the 
 * race condition between the first command terminating before the 
 * new one is written.
 *
 * Potential for profiling : 
 * Call do_gettimeofday(struct timeval *tv) to get 800ns resolution.
 */


/*
 * TODO : 
 * 1.  To support WIDE transfers, not much needs to happen.  We
 *	should do CHMOVE instructions instead of MOVEs when
 *	we have scatter/gather segments of uneven length.  When
 * 	we do this, we need to handle the case where we disconnect
 *	between segments.
 * 
 * 2.  Currently, when Icky things happen we do a FATAL().  Instead,
 *     we want to do an integrity check on the parts of the NCR hostdata
 *     structure which were initialized at boot time; FATAL() if that 
 *     fails, and otherwise try to recover.  Keep track of how many
 *     times this has happened within a single SCSI command; if it 
 *     gets excessive, then FATAL().
 *
 * 3.  Parity checking is currently disabled, and a few things should 
 *     happen here now that we support synchronous SCSI transfers :
 *     1.  On soft-reset, we shoould set the EPC (Enable Parity Checking)
 *	   and AAP (Assert SATN/ on parity error) bits in SCNTL0.
 *	
 *     2.  We should enable the parity interrupt in the SIEN0 register.
 * 
 *     3.  intr_phase_mismatch() needs to believe that message out is 
 *	   always an "acceptable" phase to have a mismatch in.  If 
 *	   the old phase was MSG_IN, we should send a MESSAGE PARITY 
 *	   error.  If the old phase was something else, we should send
 *	   a INITIATOR_DETECTED_ERROR message.  Note that this could
 *	   cause a RESTORE POINTERS message; so we should handle that 
 *	   correctly first.  Instead, we should probably do an 
 *	   initiator_abort.
 *
 * 4.  MPEE bit of CTEST4 should be set so we get interrupted if 
 *     we detect an error.
 *
 *  
 * 5.  The initial code has been tested on the NCR53c810.  I don't 
 *     have access to NCR53c700, 700-66 (Forex boards), NCR53c710
 *     (NCR Pentium systems), NCR53c720, NCR53c820, or NCR53c825 boards to 
 *     finish development on those platforms.
 *
 *     NCR53c820/825/720 - need to add wide transfer support, including WDTR 
 *     		negotiation, programming of wide transfer capabilities
 *		on reselection and table indirect selection.
 *
 *     NCR53c710 - need to add fatal interrupt or GEN code for 
 *		command completion signaling.   Need to modify all 
 *		SDID, SCID, etc. registers, and table indirect select code 
 *		since these use bit fielded (ie 1<<target) instead of 
 *		binary encoded target ids.  Need to accommodate
 *		different register mappings, probably scan through
 *		the SCRIPT code and change the non SFBR register operand
 *		of all MOVE instructions.
 *
 *		It is rather worse than this actually, the 710 corrupts
 *		both TEMP and DSA when you do a MOVE MEMORY.  This
 *		screws you up all over the place.  MOVE MEMORY 4 with a
 *		destination of DSA seems to work OK, which helps some.
 *		Richard Hirst  [e-mail]
 * 
 *     NCR53c700/700-66 - need to add code to refix addresses on 
 *		every nexus change, eliminate all table indirect code,
 *		very messy.
 *
 * 6.  The NCR53c7x0 series is very popular on other platforms that 
 *     could be running Linux - ie, some high performance AMIGA SCSI 
 *     boards use it.  
 *	
 *     So, I should include #ifdef'd code so that it is 
 *     compatible with these systems.
 *	
 *     Specifically, the little Endian assumptions I made in my 
 *     bit fields need to change, and if the NCR doesn't see memory
 *     the right way, we need to provide options to reverse words
 *     when the scripts are relocated.
 *
 * 7.  Use vremap() to access memory mapped boards.  
 */

/* 
 * Allow for simultaneous existence of multiple SCSI scripts so we 
 * can have a single driver binary for all of the family.
 *
 * - one for NCR53c700 and NCR53c700-66 chips	(not yet supported)
 * - one for rest (only the NCR53c810, 815, 820, and 825 are currently 
 *	supported)
 * 
 * So that we only need two SCSI scripts, we need to modify things so
 * that we fixup register accesses in READ/WRITE instructions, and 
 * we'll also have to accommodate the bit vs. binary encoding of IDs
 * with the 7xx chips.
 */

#define ROUNDUP(adr,type)	\
  ((void *) (((long) (adr) + sizeof(type) - 1) & ~(sizeof(type) - 1)))


/*
 * Function: issue_to_cmd
 *
 * Purpose: convert jump instruction in issue array to NCR53c7x0_cmd
 *	structure pointer.  
 *
 * Inputs; issue - pointer to start of NOP or JUMP instruction
 *	in issue array.
 *
 * Returns: pointer to command on success; 0 if opcode is NOP.
 */

static inline struct NCR53c7x0_cmd *
issue_to_cmd (struct Scsi_Host *host, struct NCR53c7x0_hostdata *hostdata,
    u32 *issue)
{
    return (issue[0] != hostdata->NOP_insn) ? 
    /* 
     * If the IF TRUE bit is set, it's a JUMP instruction.  The
     * operand is a bus pointer to the dsa_begin routine for this DSA.  The
     * dsa field of the NCR53c7x0_cmd structure starts with the 
     * DSA code template.  By converting to a virtual address,
     * subtracting the code template size, and offset of the 
     * dsa field, we end up with a pointer to the start of the 
     * structure (alternatively, we could use the 
     * dsa_cmnd field, an anachronism from when we weren't
     * sure what the relationship between the NCR structures
     * and host structures were going to be.
     */
	(struct NCR53c7x0_cmd *) ((char *) bus_to_virt (issue[1]) - 
	    (hostdata->E_dsa_code_begin - hostdata->E_dsa_code_template) -
	    offsetof(struct NCR53c7x0_cmd, dsa)) 
    /* If the IF TRUE bit is not set, it's a NOP */
	: NULL;
}


/* 
 * FIXME: we should junk these, in favor of synchronous_want and 
 * wide_want in the NCR53c7x0_hostdata structure.
 */

/* Template for "preferred" synchronous transfer parameters. */

static const unsigned char sdtr_message[] = {
#ifdef CONFIG_SCSI_NCR53C7xx_FAST
    EXTENDED_MESSAGE, 3 /* length */, EXTENDED_SDTR, 25 /* *4ns */, 8 /* off */
#else
    EXTENDED_MESSAGE, 3 /* length */, EXTENDED_SDTR, 50 /* *4ns */, 8 /* off */ 
#endif
};

/* Template to request asynchronous transfers */

static const unsigned char async_message[] = {
    EXTENDED_MESSAGE, 3 /* length */, EXTENDED_SDTR, 0, 0 /* asynchronous */
};

/* Template for "preferred" WIDE transfer parameters */

static const unsigned char wdtr_message[] = {
    EXTENDED_MESSAGE, 2 /* length */, EXTENDED_WDTR, 1 /* 2^1 bytes */
};

#if 0
/*
 * Function : struct Scsi_Host *find_host (int host)
 * 
 * Purpose : KGDB support function which translates a host number 
 * 	to a host structure. 
 *
 * Inputs : host - number of SCSI host
 *
 * Returns : NULL on failure, pointer to host structure on success.
 */

static struct Scsi_Host *
find_host (int host) {
    struct Scsi_Host *h;
    for (h = first_host; h && h->host_no != host; h = h->next);
    if (!h) {
	printk (KERN_ALERT "scsi%d not found\n", host);
	return NULL;
    } else if (h->hostt != the_template) {
	printk (KERN_ALERT "scsi%d is not a NCR board\n", host);
	return NULL;
    }
    return h;
}

#if 0
/*
 * Function : request_synchronous (int host, int target)
 * 
 * Purpose : KGDB interface which will allow us to negotiate for 
 * 	synchronous transfers.  This ill be replaced with a more 
 * 	integrated function; perhaps a new entry in the scsi_host 
 *	structure, accessible via an ioctl() or perhaps /proc/scsi.
 *
 * Inputs : host - number of SCSI host; target - number of target.
 *
 * Returns : 0 when negotiation has been setup for next SCSI command,
 *	-1 on failure.
 */

static int
request_synchronous (int host, int target) {
    struct Scsi_Host *h;
    struct NCR53c7x0_hostdata *hostdata;
    unsigned long flags;
    if (target < 0) {
	printk (KERN_ALERT "target %d is bogus\n", target);
	return -1;
    }
    if (!(h = find_host (host)))
	return -1;
    else if (h->this_id == target) {
	printk (KERN_ALERT "target %d is host ID\n", target);
	return -1;
    } 
    else if (target > h->max_id) {
	printk (KERN_ALERT "target %d exceeds maximum of %d\n", target,
	    h->max_id);
	return -1;
    }
    hostdata = (struct NCR53c7x0_hostdata *)h->hostdata[0];

    save_flags(flags);
    cli();
    if (hostdata->initiate_sdtr & (1 << target)) {
	restore_flags(flags);
	printk (KERN_ALERT "target %d already doing SDTR\n", target);
	return -1;
    } 
    hostdata->initiate_sdtr |= (1 << target);
    restore_flags(flags);
    return 0;
}
#endif

/*
 * Function : request_disconnect (int host, int on_or_off)
 * 
 * Purpose : KGDB support function, tells us to allow or disallow 
 *	disconnections.
 *
 * Inputs : host - number of SCSI host; on_or_off - non-zero to allow,
 *	zero to disallow.
 *
 * Returns : 0 on success, *	-1 on failure.
 */

static int 
request_disconnect (int host, int on_or_off) {
    struct Scsi_Host *h;
    struct NCR53c7x0_hostdata *hostdata;
    if (!(h = find_host (host)))
	return -1;
    hostdata = (struct NCR53c7x0_hostdata *) h->hostdata[0];
    if (on_or_off) 
	hostdata->options |= OPTION_DISCONNECT;
    else
	hostdata->options &= ~OPTION_DISCONNECT;
    return 0;
}
#endif

/*
 * Function : static void NCR53c7x0_driver_init (struct Scsi_Host *host)
 *
 * Purpose : Initialize internal structures, as required on startup, or 
 *	after a SCSI bus reset.
 * 
 * Inputs : host - pointer to this host adapter's structure
 */

static void 
NCR53c7x0_driver_init (struct Scsi_Host *host) {
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
	host->hostdata[0];
    int i, j;
    u32 *ncrcurrent;

    for (i = 0; i < 16; ++i) {
	hostdata->request_sense[i] = 0;
    	for (j = 0; j < 8; ++j) 
	    hostdata->busy[i][j] = 0;
	set_synchronous (host, i, /* sxfer */ 0, hostdata->saved_scntl3, 0);
    }
    hostdata->issue_queue = NULL;
    hostdata->running_list = hostdata->finished_queue = 
	hostdata->ncrcurrent = NULL;
    for (i = 0, ncrcurrent = (u32 *) hostdata->schedule; 
	i < host->can_queue; ++i, ncrcurrent += 2) {