scsi_5380.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static	char	*sccsid = "@(#)scsi_5380.c	4.4  (ULTRIX)        1/3/91";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1984,86,87,88,89 by		*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any	other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived	from  software	received  from	the	*
 *   University    of	California,   Berkeley,   and	from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is	subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or	reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *
 * scsi_5380.c	17-Aug-88
 *
 * VAX SCSI device driver (NCR 5380 routines)
 *
 * Modification history:
 *
 *   11/21/90	Robin Miller
 *	o  Added support for 10-byte Read/Write CDB's.
 *	o  Removed '#ifdef FORMAT' conditionalization, since this special
 *	   interface is always desired.
 *	o  Use function sz_cdb_length() to obtain the Command
 *	   Descriptor Block (CDB) length.
 *
 *   08/30/90	Robin Miller
 *	Added check in probe routine to recognize RX26 device type
 *	and setup accordingly for floppy device.
 *
 *   05-Jul-90	Bill Dallas
 *	Added support for the TZK10 and the new device option table
 *
 *   01-Mar-90  Janet Schank / Fred Canter
 *      Added retries on busy in the probe routine.
 *
 *   02-Dec-89	Fred Canter
 *	Calculate the number of PTEs needed to double map the user's
 *	buffer in a machine independant way (no more magic numbers).
 *
 *   13-Nov-89  Janet Schank
 *      scsi_data.c has moved from data/vax/scsi_data.c to data/scsi_data.c
 *
 *   08-Oct-89	Fred Canter
 *	Remove error log #ifdef OLDWAY.
 *
 *   07-Oct-89	Fred Canter
 *	Save removable media bit from inquiry data in sz_softc.
 *
 *   01-Oct-89	Fred Canter
 *	Added error log debug code (#ifdef ELDEBUG). This allows the
 *	driver to produce most error types for uerf debuging.
 *
 *   23-Jul-89	Fred Canter
 *	RX33 support.
 *
 *   14-Jul-89	Fred Canter
 *	Merged Dynamic BBR and error log changes.
 *
 *   24-Jun-89	Fred Canter
 *	Convert printf/mprintf error messages to scsi_logerr() calls.
 *
 *   23-Jun-89	Fred Canter
 *	Save status byte for current command for error log.
 *
 *   22-Jun-89	John A. Gallant
 *	Added the driver completion routine pieces.
 *
 *   18-Jun-89	Fred Canter
 *	Convert to scsi_devtab.
 *
 *   10-Jun-89	Fred Canter
 *	Added #ifdef SZ_BT_DEBUG around disconnect BSY timing debug code.
 *
 *   03-Jun-89	Fred Canter
 *	Move soft copy of scs_selena register to sz_softc.
 *
 *   02-Jun-89	Fred Canter
 *	Fixed a latent bug in the probe routine which cuased a panic
 *	during booting if the second SCSI controller was not present.
 *
 *   29-May-89	Fred Canter
 *	Changed disconnect timeout (timer2) from 4 seconds to 10 seconds
 *	for hard disks and 30 seconds for floppy disks.
 *
 *   24-May-89	Fred Canter
 *	Changes to match the new, more general rzdisk utility.
 *	Changed the mode select data structures so an address and
 *	length are passed with the ioctl. This allows pages to be
 *	added to rzdisk without requiring a kernel rebuild.
 *
 *   24-Apr-89	Fred Canter
 *	Added support for the RX23s SCSI floppy.
 *
 *   23-Apr-89	Fred Canter
 *	If already in the interrupt routine, then don't take another
 *	interrupt when a target disconnects, unless its slow dropping BSY.
 *
 *   06-Apr-89	Fred Canter
 *	Added TZxx (EXABYTE) support:
 *		Add TZxx code to szprobe().
 *		Don't send VU bits with mode select (modsel.pll = 12).
 *		Handle target returning busy status (EXABYTE does this).
 *
 *	Check for hung bus after SSUNIT in szprobe. Reset bus if hung.
 *	Done so inquiry for next device will not fail.
 *
 *	Only timeout disconnect on disk read, write, and read capacity
 *	commands. Disk start unit takes much longer than 4 seconds.
 *
 *	Added the capability to do extended mode select for TZxx tapes.
 *
 *   11-Feb-89	Fred Canter
 *	Fixed yet another bug with 64KB transfers. Use blkcpy instead
 *	of bcopy (bcopy max byte count is 64KB -1 ) for copying
 *	data to and from the users' buffer.
 *
 *   09-Feb-89	Fred Canter
 *	Fixed a bug which cause an inquiry command to hang in data in
 *	phase when executed from rzdisk (DMA data in). The byte count
 *	was never setup. Only worked by luck previously.
 *	Fixed minor typo (SCS_PARCK | SCS_PARCK) in two places.
 *
 *   08-Feb-89	Fred Canter
 *	Changed sc_sel_retry (select timeout retry count) to per target.
 *
 *   07-Feb-89	Fred Canter
 *	Add function header comments for each routine.
 *
 *   06-Feb-89	Fred Canter
 *	Remove rz_max_xfer, cz_max_xfer, and tz_max_xfer.
 *	Cleanup comments and minor code rearranement.
 *
 *   04-Feb-89	Fred Canter
 *	Modified 128KB hardware DMA buffer allocation scheme:
 *	    Allocate in 512 byte chunks instead of 1024 byte chunks.
 *	    Don't use last page (5380 1 byte prefetch on DMA write).
 *	    Allocate fragment to a disk (use all of the buffer).
 *
 *	Fixed a panic caused by transferring odd byte counts, like
 *	8193 to a tape. The 5380 prefetching an extra byte on the
 *	DMA write caused the saved count to be 0 when it should have
 *	been -1 (really one byte left to transfer).
 *
 *   30-Dec-88	Fred Canter
 *	Added szreset() to reset SCSI controllers before calling the
 *	VMB boot drive to write out a crash dump.
 *
 *   21-Dec-88	Fred Canter
 *	Fixed bug in the save data pointer code which reset the sc_savcnt
 *	if the previous phase was not data out. This made the defect
 *	list appear trashed.
 *
 *   18-Dec-88	Fred Canter
 *	Added implied save data pointer to disconnect (only if target
 *	disconnects without sending a save data pointer nmessage first).
 *
 *   17-Dec-88	Fred Canter
 *	Added pseudo commands to resolve the conflict between
 *	SZ_UNLOAD and SZ_SSUNIT both being opcode 0x1b.
 *
 *   16-Dec-88	Fred Canter
 *	Restructure the lost arbitration code to simplify bus reset
 *	detection and improve readability.
 *	Removed sz_ss_oldsel debug code (spin instead of time select).
 *	Close (almost completely) the window for missing detection
 *	of a bus reset in the sz_scsistart() arbitration code.
 *
 *   11-Dec-88	Fred Canter
 *	Modified parity checking and bus reset detection so that we
 *	don't read any of the SCSI controller registers while a DMA
 *	is in progress. Under the old method (using INTPAR) a parity
 *	error on a read would cause a read of the scs_status register
 *	in szintr. Now use PARCK being cleared for bus reset detection.
 *	PARCK is now always on (except during arbitration).
 *
 *	Slight change in select timing to it in line with SCSI spec,
 *	i.e., drop IDs from data bus at same time drop SEL.
 *
 *   04-Dec-88	Fred Canter
 *	Remove hack which limited maximum transfer to 64KB - 512.
 *	64KB transfers used to fail (or so I thought), but work now.
 *	Added debug variable to allow selected target(s) to be ignored.
 *
 *   03-Dec-88	Fred Canter
 *	Don't do the 4 second disconnect timeout on RZSPECIAL commands
 *	(format, reassign, vfy_data, and rdd).
 *
 *   03-Nov-88	Alan Frechette
 *	Added in support for disk maintainence. Added the commands
 *	FORMAT UNIT, REASSIGN BLOCK, READ DEFECT DATA, and VERIFY 
 *	DATA. Modified MODE SELECT and MODE SENSE. Figured out a
 *	better way to determine the length of a SCSI command in
 *	"sz_scsistart()" and "szintr()" during the COMMAND PHASE.
 *	Made the DATA OUT phase in "sz_scsistart()" and "szintr()"
 *	into a switch statement.
 *
 *   16-Oct-88 -- Fred Canter
 *	Massive code and comment cleanup.
 *	Moved #define SZDEBUG to scsireg.h.
 *	Add variable to control width of bus reset.
 *	Add RZxx (non-DEC) disk support.
 *	Fixed a bug in the selection timeout code and
 *	added retires of select failures.
 *	Take a phase mismatch interrupt instead of spinning
 *	waiting for phase changes (critical ones only).
 *	Put #ifdefs arount spin stats code.
 *	Added delay after write to scd_adr register to
 *	work around SCSI/SCSI controller hardware bug.
 *	Modified arbitration and selection code to work around
 *	the latest NCR 5380 chip problem.
 *	Clean up code which waits for BSY to drop after command complete.
 *
 *   28-Sep-88 -- Fred Canter
 *	Clean up comments.
 *	Clean up code and comments for device failed to select timeout.
 *	Remove work around code for hardware loosing interrupts.
 *	Bug fix - waited for 1 second after abort for bus to free up,
 *	changed to 1 MS.
 *	The sz_timer1() is now used as a background timer to catch
 *	bus hangs when the drive is not active.
 *	Dump SCSI registers on CMDCPT BSY held too long error.
 *	Modify order of DMA address and direction register writes
 *	when starting DMA. Also add 3 Usec delay after write to
 *	address register, This works around a bug in SCSI/SCSI chip.
 *	which hangs the SCSI/SCSI controller.
 *	Don't do reselect timeout (timer2) on RRD40. It tries the
 *	reselect for ever.
 *
 *   13-Sep-88 -- Fred Canter
 *	Only check parity on DMA in and read of current data register.
 *	Add spl6() around critical code segment in szintr reselect.
 *	All BSY checks now three times (wire or glitch).
 *	New routine to dump SCSI registers.
 *
 *   21-Aug-88 -- Fred Canter
 *	Improved device failed to select error handling. Spin for a
 *	short time. Use a timeout for the remaining time.
 *	Insure all messages accounted for in unknown/unsupported
 *	message error (MESSI:).
 *	Added sz_reset() and other support for bus reset.
 *
 * 17-Aug-88	Fred Canter
 *	Created this file by moving the SCSI NCR 5380 specific files
 *	from the old combined driver (scsi.c) to scsi_5380.c.
 *
 ***********************************************************************/

/*
 ***********************************************************************
 *
 * NOTES:
 *
 *  1.	SCSI controller registers must not be accessed while a DMA
 *	is in progress. Hardware engineering says the scd_adr & scd_cnt
 *	registers can be accessed safely, but this has not been verified.
 *	They also say all registers can be accessed during a DMA on
 *	the SCSI/SCSI controller. This also has not been verified.
 *
 *  2.	Reading the SCSI bus data bits (scs_curdata) when the signals
 *	are not driven can (and most likely will) cause a psrity error.
 *	In general the signals are not driven when BSY is false. One
 *	exception to this is when a disconnected target reselects the
 *	initator (VS3100 system). BSY is false but the signals are driven.
 *
 *  3.	The ANSI SCSI spec calls for a 250 MS selection timeout. The
 *	timeout is implemented in scsistart and any routines which
 *	call scsistart. If scsistart is called from the probe routine,
 *	we spin for 250 MS in scsistart. Calling scsistart from the
 *	probe routine is always a special case.
 *	On normal calls to scsistart, we spin for 20 MS in scsistart
 *	and if BSY does not set we start a series of timeours (timer3).
 *	We do one 30 MS timeout then four 50 MS timeouts. The messy
 *	part of this is that the routine calling scsistart must
 *	unwind its call and be prepared to be called back when the
 *	timer decides the selection completed or timed out.
 *
 *  4.	The RST (bus reset) bit in the cur_stat register is not latched.
 *	So, the bus reset condition my be gone by the time we get the
 *	interrupt. We always have PARCK set in the mode register.
 *	If PARCK ever gets cleared, we assume a bus reset was the cause.
	PARCK is cleared during arbitration, so the resetting of the
	ARB bit is used to detect a bus reset during arbitration.
 *
 *  5.	This driver contains many code sequences like the following:
 *
 *		if (((szaddr->scs_curstat & SCS_BSY) == 0) &&
 *		    ((szaddr->scs_curstat & SCS_BSY) == 0) &&
 *		    ((szaddr->scs_curstat & SCS_BSY) == 0)) {
 *			do_something_wonderfull.......
 *		}
 *
 *	Checking a bus signal three times takes into account the 400
 *	nanosecond bus settle delay (wired or glitch).
 *
 *  6.	The 5380 detects parity errors on DMA input and CPU reads of
 *	the scs_curdata register. We read this register during programmed
 *	I/O input, reselection, and arbitration. Parity checking (PARCK
 *	bit in mode register) must be disabled during arbitration. This
 *	is because several targets can be driving the bus data lines
 *	during arbitration. This can (in fact does) cause parity errors!
 *
 *
 *  7.	When checking for a hung bus, must realize that any target
 *	on the bus can arbitrate and assert BSY when the target (or
 *	initator) who currently has BSY asserted releases BSY. The
 *	time between one target droping BSY and another target
 *	asserting BSY can be very short (faster than the driver can
 *	detect with a spin loop). If BSY is asserted the bus is
 *	probably hung. However, if SEL and I/O are asserted some
 *	target is doing a reselect (bus not hung).
 *
 ***********************************************************************
 */

#include "../data/scsi_data.c"

/*
 * Define ELDEBUG to create error for uerf debuging.
 * NOTE: must not be defined at submit time (performance hit).
 */
/*#define	ELDEBUG	*/

/*
 * The #define for SZDEBUG is in scsireg.h.
 */
#ifdef SZDEBUG
extern int szdebug;
#define printd if(szdebug)printf
#define printd1 if (szdebug > 1) printf
#define printd2 if (szdebug > 2) printf
#define printd3 if (szdebug > 3) printf
#define printd4 if (szdebug > 4) printf
#define printd5 if (szdebug > 5) printf
#define printd6 if (szdebug > 6) printf
#endif SZDEBUG

/*
 * Controls debug code whichs makes sure each
 * command does a status phase. This bug was fixed
 * but the code hangs around just in case.
 */
/*#define	SZ_DSP_DEBUG*/

/*
 * DEBUG - normally not defined.
 * Number of 10 Usec increments each device
 * held BSY after command complete.
 * CAUTION - must increase array size if NSCSI > 2
 */
/* #define	SZ_BSYCC_STATS	*/

#ifdef	SZ_BSYCC_STATS

int	sz_i_bsycc[16];
int	sz_ss_bsycc[16];

#endif	SZ_BSYCC_STATS

u_char	inicmd_tmp;		/* use to write scs_inicmd reg (can't |= ) */

/*
 * NOTE:
 *	The probe routine is called before cache(s)
 *	are enabled. Microdelay() now deals with this.
 *	Turning cache on broke the ST506 disk driver (sdc.c).
 *	It failed during read if XBNs (DO NOT KNOW WHY).
 */

int	sz_strncmp();
int	sz_strcmp();

extern int rzcomplete();	/* disk driver completion routine */
extern int tzcomplete();	/* tape driver completion routine */
extern int sz_cdb_length();

extern struct nexus nexus[];

extern	int	cpu;

/*
 * Number of seconds to wait for SCSI devices
 * to come ready enough to respond to inquiry
 * after bus reset. Needs to be a variable so
 * users can change it (I am such a nice guy).
 * Factory default is 7 seconds (in scsi_data.c).
 */
extern int sz_wait_for_devices;
extern int sz_max_wait_for_devices;

/*
 * Number of microseconds we wait after each inquiry
 * command. Just to be absolutely sure the bus is free.
 * This is delay may not be necessary, but at one point
 * it appeared the RRD40 held the bus after inquiry.
 */
int	sz_wait_after_inquiry = 1000;

int	sz_scsistart();
int	sz_reset();
int	sz_timer1();


/*
 * Next four variables defined in scsi.c because
 * they are shared between scsi_5380.c and scsi_sii.c.
 */
extern int szp_firstcall;	/* first call to probe routine */