53c78xx.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

 * 	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 should 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.
 * 
 *     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.
 */

/*
 * Use pci_chips_ids to translate in both directions between PCI device ID 
 * and chip numbers.  
 */

static struct {
    unsigned short pci_device_id;
    int chip;
/* 
 * The revision field of the PCI_CLASS_REVISION register is compared 
 * against each of these fields if the field is not -1.  If it
 * is less than min_revision or larger than max_revision, a warning
 * message is printed.
 */
    int max_revision;
    int min_revision;
} pci_chip_ids[] = { 
    {PCI_DEVICE_ID_NCR_53C810, 810, 2, 1}, 
    {PCI_DEVICE_ID_NCR_53C815, 815, 3, 2},
    {PCI_DEVICE_ID_NCR_53C820, 820, -1, -1},
    {PCI_DEVICE_ID_NCR_53C825, 825, -1, -1}
};

#define NPCI_CHIP_IDS (sizeof (pci_chip_ids) / sizeof(pci_chip_ids[0]))

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

/* 
 * Forced detection and autoprobe code for various hardware.  Currently, 
 * entry points for these are not included in init/main.c because if the 
 * PCI BIOS code isn't working right, you're not going to be able to use 
 * the hardware anyways; this way we force users to solve their 
 * problems rather than forcing detection and blaming us when it 
 * does not work.
 */

static struct override {
    int chip;	/* 700, 70066, 710, 720, 810, 820 */
    int board;	/* Any special board level gunk */
    unsigned pci:1;
    union {
	struct {
	    int base;	/* Memory address - indicates memory mapped regs */
	    int io_port;/* I/O port address - indicates I/O mapped regs */
    	    int irq;	/* IRQ line */		
    	    int dma;	/* DMA channel 		- often none */
	} normal;
	struct {
	    int bus;
	    int device;
	    int function;
	} pci;
    } data;
    long long options;
} overrides [4] = {{0,},};
static int commandline_current = 0;
static int no_overrides = 0;

#if 0
#define OVERRIDE_LIMIT (sizeof(overrides) / sizeof(struct override))
#else
#define OVERRIDE_LIMIT commandline_current
#endif

/*
 * 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;
}


/*
 * Function : static internal_setup(int board, int chip, char *str, int *ints)
 *
 * Purpose : LILO command line initialization of the overrides array,
 * 
 * Inputs : board - currently, unsupported.  chip - 700, 70066, 710, 720
 * 	810, 815, 820, 825, although currently only the NCR53c810 is 
 *	supported.
 * 
 */

static void 
internal_setup(int board, int chip, char *str, int *ints) {
    unsigned char pci;		/* Specifies a PCI override, with bus, device,
				   function */

    pci = (str && !strcmp (str, "pci")) ? 1 : 0;
    
/*
 * Override syntaxes are as follows : 
 * ncr53c700,ncr53c700-66,ncr53c710,ncr53c720=mem,io,irq,dma
 * ncr53c810,ncr53c820,ncr53c825=mem,io,irq or pci,bus,device,function
 */

    if (commandline_current < OVERRIDE_LIMIT) {
	overrides[commandline_current].pci = pci ? 1 : 0;
	if (!pci) {
	    overrides[commandline_current].data.normal.base = ints[1];
	    overrides[commandline_current].data.normal.io_port = ints[2];
	    overrides[commandline_current].data.normal.irq = ints[3];
    	    overrides[commandline_current].data.normal.dma = (ints[0] >= 4) ?
    	    	ints[4] : DMA_NONE;
	    /* FIXME: options is now a long long */
    	    overrides[commandline_current].options = (ints[0] >= 5) ?
    	    	ints[5] : 0;
	} else {
	    overrides[commandline_current].data.pci.bus = ints[1];
	    overrides[commandline_current].data.pci.device = ints[2];
	    overrides[commandline_current].data.pci.function = ints[3];
	    /* FIXME: options is now a long long */
    	    overrides[commandline_current].options = (ints[0] >= 4) ?
    	    	ints[4] : 0;
	}
	overrides[commandline_current].board = board;
	overrides[commandline_current].chip = chip;
	++commandline_current;
    	++no_overrides;
    } else {
	printk ("53c7,7x0.c:internal_setup() : too many overrides\n");
    }
}

/*
 * XXX - we might want to implement a single override function
 *       with a chip type field, revamp the command line configuration,
 * 	 etc.
 */

#define setup_wrapper(x) 				\
void ncr53c##x##_setup (char *str, int *ints) {		\
    internal_setup (BOARD_GENERIC, x, str, ints);	\
}

setup_wrapper(700)
setup_wrapper(70066)
setup_wrapper(710)
setup_wrapper(720)
setup_wrapper(810)
setup_wrapper(815)
setup_wrapper(820)
setup_wrapper(825)

/* 
 * 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 */
};

/*
 * 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;
}

/*
 * 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;
    } 
#ifndef LINUX_1_2
    else if (target > h->max_id) {
	printk (KERN_ALERT "target %d exceeds maximum of %d\n", target,
	    h->max_id);
	return -1;
    }
#endif
    hostdata = (struct NCR53c7x0_hostdata *)h->hostdata;

    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;
}

/*
 * 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;
    if (on_or_off) 
	hostdata->options |= OPTION_DISCONNECT;
    else
	hostdata->options &= ~OPTION_DISCONNECT;
    return 0;
}

/*
 * 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