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

#ifndef NDEBUG
#define NDEBUG (NDEBUG_RESTART_SELECT | NDEBUG_ABORT)
#endif
/* 
 * NCR 5380 generic driver routines.  These should make it *trivial*
 * 	to implement 5380 SCSI drivers under Linux with a non-trantor
 *	architecture.
 *
 *	Note that these routines also work with NR53c400 family chips.
 *
 * Copyright 1993, Drew Eckhardt
 *	Visionary Computing 
 *	(Unix and Linux consulting and custom programming)
 * 	[e-mail]
 *	[phone]
 *
 * DISTRIBUTION RELEASE 6. 
 *
 * For more information, please consult 
 *
 * NCR 5380 Family
 * SCSI Protocol Controller
 * Databook
 *
 * NCR Microelectronics
 * 1635 Aeroplaza Drive
 * Colorado Springs, CO 80916
 * 1+ [phone]
 * 1+ [phone]
 */

/*
 * $Log: NCR5380.c,v $
 * Revision 1.1  1999/04/26 05:53:59  tb
 * 1998-11-30  OKUJI Yoshinori  <[e-mail]>
 *
 * 	Clean up linux emulation code to make it architecture-independent
 * 	as much as possible.
 *
 * 	* linux: Renamed from linuxdev.
 * 	* Makefile.in (objfiles): Add linux.o instead of linuxdev.o.
 * 	(MAKE): New variable. Used for the linux.o target.
 * 	* configure.in: Add AC_CHECK_TOOL(MAKE, make).
 * 	* i386/i386/spl.h: Include <i386/ipl.h>, for compatibility with
 * 	OSF Mach 3.0. Suggested by Elgin Lee <[e-mail]>.
 * 	* linux/src: Renamed from linux/linux.
 * 	* linux/dev: Renamed from linux/mach.
 * 	* linux/Drivers.in (AC_INIT): Use dev/include/linux/autoconf.h,
 * 	instead of mach/include/linux/autoconf.h.
 * 	* Makefile.in (all): Target ../linux.o instead of ../linuxdev.o.
 * 	* linux/dev/drivers/block/genhd.c: Include <machine/spl.h> instead
 * 	of <i386/ipl.h>.
 * 	* linux/dev/drivers/net/auto_irq.c: Remove unneeded header files,
 * 	<i386/ipl.h> and <i386/pic.h>.
 * 	* linux/dev/init/main.c: Many i386-dependent codes moved to ...
 * 	* linux/dev/arch/i386/irq.c: ... here.
 * 	* linux/dev/arch/i386/setup.c: New file.
 * 	* linux/dev/arch/i386/linux_emul.h: Likewise.
 * 	* linux/dev/arch/i386/glue/timer.c: Merged into sched.c.
 * 	* linux/dev/arch/i386/glue/sched.c: Include <machine/spl.h> instead
 * 	of <i386/ipl.h>, and moved to ...
 * 	* linux/dev/kernel/sched.c: ... here.
 * 	* linux/dev/arch/i386/glue/block.c: Include <machine/spl.h> and
 * 	<linux_emul.h>, instead of i386-dependent header files, and
 * 	moved to ...
 * 	* linux/dev/glue/blocl.c: ... here.
 * 	* linux/dev/arch/i386/glue/net.c: Include <machine/spl.h> and
 * 	<linux_emul.h>, instead of i386-dependent header files, and
 * 	moved to ...
 * 	* linux/dev/glue/net.c: ... here.
 * 	* linux/dev/arch/i386/glue/misc.c: Remove `x86' and moved to ...
 * 	* linux/dev/glue/misc.c: ... here.
 * 	* linux/dev/arch/i386/glue/kmem.c: Moved to ...
 * 	* linux/dev/glue/kmem.c: ... here.
 *
 * Revision 1.7  1996/3/2	Ray Van Tassle ([e-mail])
 * added proc_info
 * added support needed for DTC 3180/3280
 * fixed a couple of bugs
 *

 * Revision 1.5  1994/01/19  09:14:57  drew
 * Fixed udelay() hack that was being used on DATAOUT phases
 * instead of a proper wait for the final handshake.
 *
 * Revision 1.4  1994/01/19  06:44:25  drew
 * *** empty log message ***
 *
 * Revision 1.3  1994/01/19  05:24:40  drew
 * Added support for TCR LAST_BYTE_SENT bit.
 *
 * Revision 1.2  1994/01/15  06:14:11  drew
 * REAL DMA support, bug fixes.
 *
 * Revision 1.1  1994/01/15  06:00:54  drew
 * Initial revision
 *
 */

/*
 * Further development / testing that should be done : 
 * 1.  Cleanup the NCR5380_transfer_dma function and DMA operation complete
 *     code so that everything does the same thing that's done at the 
 *     end of a pseudo-DMA read operation.
 *
 * 2.  Fix REAL_DMA (interrupt driven, polled works fine) -
 *     basically, transfer size needs to be reduced by one 
 *     and the last byte read as is done with PSEUDO_DMA.
 * 
 * 3.  Test USLEEP code 
 *
 * 4.  Test SCSI-II tagged queueing (I have no devices which support 
 *	tagged queueing)
 *
 * 5.  Test linked command handling code after Eric is ready with 
 *      the high level code.
 */

#if (NDEBUG & NDEBUG_LISTS)
#define LIST(x,y) {printk("LINE:%d   Adding %p to %p\n", __LINE__, (void*)(x), (void*)(y)); if ((x)==(y)) udelay(5); }
#define REMOVE(w,x,y,z) {printk("LINE:%d   Removing: %p->%p  %p->%p \n", __LINE__, (void*)(w), (void*)(x), (void*)(y), (void*)(z)); if ((x)==(y)) udelay(5); }
#else
#define LIST(x,y)
#define REMOVE(w,x,y,z)
#endif

#ifndef notyet
#undef LINKED
#undef USLEEP
#undef REAL_DMA
#endif

#ifdef REAL_DMA_POLL
#undef READ_OVERRUNS
#define READ_OVERRUNS
#endif

/*
 * Design
 * Issues :
 *
 * The other Linux SCSI drivers were written when Linux was Intel PC-only,
 * and specifically for each board rather than each chip.  This makes their
 * adaptation to platforms like the Mac (Some of which use NCR5380's)
 * more difficult than it has to be.
 *
 * Also, many of the SCSI drivers were written before the command queuing
 * routines were implemented, meaning their implementations of queued 
 * commands were hacked on rather than designed in from the start.
 *
 * When I designed the Linux SCSI drivers I figured that 
 * while having two different SCSI boards in a system might be useful
 * for debugging things, two of the same type wouldn't be used.
 * Well, I was wrong and a number of users have mailed me about running
 * multiple high-performance SCSI boards in a server.
 *
 * Finally, when I get questions from users, I have no idea what 
 * revision of my driver they are running.
 *
 * This driver attempts to address these problems :
 * This is a generic 5380 driver.  To use it on a different platform, 
 * one simply writes appropriate system specific macros (ie, data
 * transfer - some PC's will use the I/O bus, 68K's must use 
 * memory mapped) and drops this file in their 'C' wrapper.
 *
 * As far as command queueing, two queues are maintained for 
 * each 5380 in the system - commands that haven't been issued yet,
 * and commands that are currently executing.  This means that an 
 * unlimited number of commands may be queued, letting 
 * more commands propagate from the higher driver levels giving higher 
 * throughput.  Note that both I_T_L and I_T_L_Q nexuses are supported, 
 * allowing multiple commands to propagate all the way to a SCSI-II device 
 * while a command is already executing.
 *
 * To solve the multiple-boards-in-the-same-system problem, 
 * there is a separate instance structure for each instance
 * of a 5380 in the system.  So, multiple NCR5380 drivers will
 * be able to coexist with appropriate changes to the high level
 * SCSI code.  
 *
 * A NCR5380_PUBLIC_REVISION macro is provided, with the release
 * number (updated for each public release) printed by the 
 * NCR5380_print_options command, which should be called from the 
 * wrapper detect function, so that I know what release of the driver
 * users are using.
 *
 * Issues specific to the NCR5380 : 
 *
 * When used in a PIO or pseudo-dma mode, the NCR5380 is a braindead 
 * piece of hardware that requires you to sit in a loop polling for 
 * the REQ signal as long as you are connected.  Some devices are 
 * brain dead (ie, many TEXEL CD ROM drives) and won't disconnect 
 * while doing long seek operations.
 * 
 * The workaround for this is to keep track of devices that have
 * disconnected.  If the device hasn't disconnected, for commands that
 * should disconnect, we do something like 
 *
 * while (!REQ is asserted) { sleep for N usecs; poll for M usecs }
 * 
 * Some tweaking of N and M needs to be done.  An algorithm based 
 * on "time to data" would give the best results as long as short time
 * to datas (ie, on the same track) were considered, however these 
 * broken devices are the exception rather than the rule and I'd rather
 * spend my time optimizing for the normal case.
 *
 * Architecture :
 *
 * At the heart of the design is a coroutine, NCR5380_main,
 * which is started when not running by the interrupt handler,
 * timer, and queue command function.  It attempts to establish
 * I_T_L or I_T_L_Q nexuses by removing the commands from the 
 * issue queue and calling NCR5380_select() if a nexus 
 * is not established. 
 *
 * Once a nexus is established, the NCR5380_information_transfer()
 * phase goes through the various phases as instructed by the target.
 * if the target goes into MSG IN and sends a DISCONNECT message,
 * the command structure is placed into the per instance disconnected
 * queue, and NCR5380_main tries to find more work.  If USLEEP
 * was defined, and the target is idle for too long, the system
 * will try to sleep.
 *
 * If a command has disconnected, eventually an interrupt will trigger,
 * calling NCR5380_intr()  which will in turn call NCR5380_reselect
 * to reestablish a nexus.  This will run main if necessary.
 *
 * On command termination, the done function will be called as 
 * appropriate.
 *
 * SCSI pointers are maintained in the SCp field of SCSI command 
 * structures, being initialized after the command is connected
 * in NCR5380_select, and set as appropriate in NCR5380_information_transfer.
 * Note that in violation of the standard, an implicit SAVE POINTERS operation
 * is done, since some BROKEN disks fail to issue an explicit SAVE POINTERS.
 */

/*
 * Using this file :
 * This file a skeleton Linux SCSI driver for the NCR 5380 series
 * of chips.  To use it, you write a architecture specific functions 
 * and macros and include this file in your driver.
 *
 * These macros control options : 
 * AUTOPROBE_IRQ - if defined, the NCR5380_probe_irq() function will be 
 *	defined.
 * 
 * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
 *	for commands that return with a CHECK CONDITION status. 
 *
 * DIFFERENTIAL - if defined, NCR53c81 chips will use external differential
 * 	transceivers. 
 *
 * DONT_USE_INTR - if defined, never use interrupts, even if we probe or
 *	override-configure an IRQ.
 *
 * LIMIT_TRANSFERSIZE - if defined, limit the pseudo-dma transfers to 512
 *	bytes at a time.  Since interrupts are disabled by default during
 *	these transfers, we might need this to give reasonable interrupt
 *	service time if the transfer size gets too large.
 *
 * LINKED - if defined, linked commands are supported.
 *
 * PSEUDO_DMA - if defined, PSEUDO DMA is used during the data transfer phases.
 *
 * REAL_DMA - if defined, REAL DMA is used during the data transfer phases.
 *
 * REAL_DMA_POLL - if defined, REAL DMA is used but the driver doesn't
 * 	rely on phase mismatch and EOP interrupts to determine end 
 *	of phase.
 *
 * SCSI2 - if defined, SCSI-2 tagged queuing is used where possible
 *
 * UNSAFE - leave interrupts enabled during pseudo-DMA transfers.  You
 *	    only really want to use this if you're having a problem with
 *	    dropped characters during high speed communications, and even
 *	    then, you're going to be better off twiddling with transfersize
 *	    in the high level code.
 *
 * USLEEP - if defined, on devices that aren't disconnecting from the 
 *	bus, we will go to sleep so that the CPU can get real work done 
 *	when we run a command that won't complete immediately.
 *
 * Note that if USLEEP is defined, NCR5380_TIMER *must* also be
 * defined.
 *
 * Defaults for these will be provided if USLEEP is defined, although
 * the user may want to adjust these to allocate CPU resources to 
 * the SCSI driver or "real" code.
 * 
 * USLEEP_SLEEP - amount of time, in jiffies, to sleep
 *
 * USLEEP_POLL - amount of time, in jiffies, to poll
 *
 * These macros MUST be defined :
 * NCR5380_local_declare() - declare any local variables needed for your
 * 	transfer routines.
 *
 * NCR5380_setup(instance) - initialize any local variables needed from a given
 *	instance of the host adapter for NCR5380_{read,write,pread,pwrite}
 * 
 * NCR5380_read(register)  - read from the specified register
 *
 * NCR5380_write(register, value) - write to the specific register 
 *
 * NCR5380_implementation_fields  - additional fields needed for this 
 *	specific implementation of the NCR5380
 *
 * Either real DMA *or* pseudo DMA may be implemented
 * REAL functions : 
 * NCR5380_REAL_DMA should be defined if real DMA is to be used.
 * Note that the DMA setup functions should return the number of bytes 
 *	that they were able to program the controller for.
 *
 * Also note that generic i386/PC versions of these macros are 
 *	available as NCR5380_i386_dma_write_setup,
 *	NCR5380_i386_dma_read_setup, and NCR5380_i386_dma_residual.
 *
 * NCR5380_dma_write_setup(instance, src, count) - initialize
 * NCR5380_dma_read_setup(instance, dst, count) - initialize
 * NCR5380_dma_residual(instance); - residual count
 *
 * PSEUDO functions :
 * NCR5380_pwrite(instance, src, count)
 * NCR5380_pread(instance, dst, count);
 *
 * If nothing specific to this implementation needs doing (ie, with external
 * hardware), you must also define 
 *  
 * NCR5380_queue_command
 * NCR5380_reset
 * NCR5380_abort
 * NCR5380_proc_info
 *
 * to be the global entry points into the specific driver, ie 
 * #define NCR5380_queue_command t128_queue_command.
 *
 * If this is not done, the routines will be defined as static functions
 * with the NCR5380* names and the user must provide a globally
 * accessible wrapper function.
 *
 * The generic driver is initialized by calling NCR5380_init(instance),
 * after setting the appropriate host specific fields and ID.  If the 
 * driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance,
 * possible) function may be used.  Before the specific driver initialization
 * code finishes, NCR5380_print_options should be called.
 */

static int do_abort (struct Scsi_Host *host);
static void do_reset (struct Scsi_Host *host);
static struct Scsi_Host *first_instance = NULL;
static Scsi_Host_Template *the_template = NULL;

/*
 * Function : void initialize_SCp(Scsi_Cmnd *cmd)
 *
 * Purpose : initialize the saved data pointers for cmd to point to the 
 *	start of the buffer.
 *
 * Inputs : cmd - Scsi_Cmnd structure to have pointers reset.
 */

static __inline__ void initialize_SCp(Scsi_Cmnd *cmd) {
    /* 
     * Initialize the Scsi Pointer field so that all of the commands in the 
     * various queues are valid.
     */

    if (cmd->use_sg) {
	cmd->SCp.buffer = (struct scatterlist *) cmd->buffer;
	cmd->SCp.buffers_residual = cmd->use_sg - 1;
	cmd->SCp.ptr = (char *) cmd->SCp.buffer->address;
	cmd->SCp.this_residual = cmd->SCp.buffer->length;
    } else {
	cmd->SCp.buffer = NULL;
	cmd->SCp.buffers_residual = 0;
	cmd->SCp.ptr = (char *) cmd->request_buffer;
	cmd->SCp.this_residual = cmd->request_bufflen;
    }
}

#include <linux/delay.h>

#ifdef NDEBUG
static struct {
    unsigned char mask;
    const char * name;} 
signals[] = {{ SR_DBP, "PARITY"}, { SR_RST, "RST" }, { SR_BSY, "BSY" }, 
    { SR_REQ, "REQ" }, { SR_MSG, "MSG" }, { SR_CD,  "CD" }, { SR_IO, "IO" }, 
    { SR_SEL, "SEL" }, {0, NULL}}, 
basrs[] = {{BASR_ATN, "ATN"}, {BASR_ACK, "ACK"}, {0, NULL}},
icrs[] = {{ICR_ASSERT_RST, "ASSERT RST"},{ICR_ASSERT_ACK, "ASSERT ACK"},
    {ICR_ASSERT_BSY, "ASSERT BSY"}, {ICR_ASSERT_SEL, "ASSERT SEL"}, 
    {ICR_ASSERT_ATN, "ASSERT ATN"}, {ICR_ASSERT_DATA, "ASSERT DATA"}, 
    {0, NULL}},
mrs[] = {{MR_BLOCK_DMA_MODE, "MODE BLOCK DMA"}, {MR_TARGET, "MODE TARGET"}, 
    {MR_ENABLE_PAR_CHECK, "MODE PARITY CHECK"}, {MR_ENABLE_PAR_INTR, 
    "MODE PARITY INTR"}, {MR_MONITOR_BSY, "MODE MONITOR BSY"},
    {MR_DMA_MODE, "MODE DMA"}, {MR_ARBITRATE, "MODE ARBITRATION"}, 
    {0, NULL}};

/*
 * Function : void NCR5380_print(struct Scsi_Host *instance)
 *
 * Purpose : print the SCSI bus signals for debugging purposes
 *
 * Input : instance - which NCR5380
 */

static void NCR5380_print(struct Scsi_Host *instance) {
    NCR5380_local_declare();
    unsigned char status, data, basr, mr, icr, i;
    NCR5380_setup(instance);
    cli();
    data = NCR5380_read(CURRENT_SCSI_DATA_REG);
    status = NCR5380_read(STATUS_REG);
    mr = NCR5380_read(MODE_REG);
    icr = NCR5380_read(INITIATOR_COMMAND_REG);
    basr = NCR5380_read(BUS_AND_STATUS_REG);
    sti();
    printk("STATUS_REG: %02x ", status);