53c7xx.scr

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

; can go on to the next data phase block move statement.

ENTRY other_out
other_out:
#if 0
    INT 0x03ffdead
#endif
    INT int_err_unexpected_phase, WHEN CMD
    JUMP msg_in_restart, WHEN MSG_IN 
    INT int_err_unexpected_phase, WHEN MSG_OUT
    INT int_err_unexpected_phase, WHEN DATA_IN
    JUMP command_complete, WHEN STATUS
    JUMP other_out, WHEN NOT DATA_OUT
#if (CHIP == 710)
; TEMP should be OK, as we got here from a call in the user dataout code.
#endif
    RETURN

ENTRY other_in
other_in:
#if 0
    INT 0x03ffdead
#endif
    INT int_err_unexpected_phase, WHEN CMD
    JUMP msg_in_restart, WHEN MSG_IN 
    INT int_err_unexpected_phase, WHEN MSG_OUT
    INT int_err_unexpected_phase, WHEN DATA_OUT
    JUMP command_complete, WHEN STATUS
    JUMP other_in, WHEN NOT DATA_IN
#if (CHIP == 710)
; TEMP should be OK, as we got here from a call in the user datain code.
#endif
    RETURN


ENTRY other_transfer
other_transfer:
    INT int_err_unexpected_phase, WHEN CMD
    CALL msg_in, WHEN MSG_IN
    INT int_err_unexpected_phase, WHEN MSG_OUT
    INT int_err_unexpected_phase, WHEN DATA_OUT
    INT int_err_unexpected_phase, WHEN DATA_IN
    JUMP command_complete, WHEN STATUS
    JUMP other_transfer

;
; msg_in_restart
; msg_in
; munge_msg
;
; PURPOSE : process messages from a target.  msg_in is called when the 
;	caller hasn't read the first byte of the message.  munge_message
;	is called when the caller has read the first byte of the message,
;	and left it in SFBR.  msg_in_restart is called when the caller 
;	hasn't read the first byte of the message, and wishes RETURN
;	to transfer control back to the address of the conditional
;	CALL instruction rather than to the instruction after it.
;
;	Various int_* interrupts are generated when the host system
;	needs to intervene, as is the case with SDTR, WDTR, and
;	INITIATE RECOVERY messages.
;
;	When the host system handles one of these interrupts,
;	it can respond by reentering at reject_message, 
;	which rejects the message and returns control to
;	the caller of msg_in or munge_msg, accept_message
;	which clears ACK and returns control, or reply_message
;	which sends the message pointed to by the DSA 
;	msgout_other table indirect field.
;
;	DISCONNECT messages are handled by moving the command
;	to the reconnect_dsa_queue.
#if (CHIP == 710)
; NOTE: DSA should be valid when we get here - we cannot save both it
;	and TEMP in this routine.
#endif
;
; INPUTS : DSA - SCSI COMMAND, SFBR - first byte of message (munge_msg
;	only)
;
; CALLS : NO.  The TEMP register isn't backed up to allow nested calls.
;
; MODIFIES : SCRATCH, DSA on DISCONNECT
;
; EXITS : On receipt of SAVE DATA POINTER, RESTORE POINTERS,
;	and normal return from message handlers running under
;	Linux, control is returned to the caller.  Receipt
;	of DISCONNECT messages pass control to dsa_schedule.
;
ENTRY msg_in_restart
msg_in_restart:
; XXX - hackish
;
; Since it's easier to debug changes to the statically 
; compiled code, rather than the dynamically generated 
; stuff, such as
;
; 	MOVE x, y, WHEN data_phase
; 	CALL other_z, WHEN NOT data_phase
; 	MOVE x, y, WHEN data_phase
;
; I'd like to have certain routines (notably the message handler)
; restart on the conditional call rather than the next instruction.
;
; So, subtract 8 from the return address

    MOVE TEMP0 + 0xf8 TO TEMP0
    MOVE TEMP1 + 0xff TO TEMP1 WITH CARRY
    MOVE TEMP2 + 0xff TO TEMP2 WITH CARRY
    MOVE TEMP3 + 0xff TO TEMP3 WITH CARRY

ENTRY msg_in
msg_in:
    MOVE 1, msg_buf, WHEN MSG_IN

munge_msg:
    JUMP munge_extended, IF 0x01		; EXTENDED MESSAGE
    JUMP munge_2, IF 0x20, AND MASK 0xdf	; two byte message
;
; XXX - I've seen a handful of broken SCSI devices which fail to issue
; 	a SAVE POINTERS message before disconnecting in the middle of 
; 	a transfer, assuming that the DATA POINTER will be implicitly 
; 	restored.  
;
; Historically, I've often done an implicit save when the DISCONNECT
; message is processed.  We may want to consider having the option of 
; doing that here. 
;
    JUMP munge_save_data_pointer, IF 0x02	; SAVE DATA POINTER
    JUMP munge_restore_pointers, IF 0x03	; RESTORE POINTERS 
    JUMP munge_disconnect, IF 0x04		; DISCONNECT
    INT int_msg_1, IF 0x07			; MESSAGE REJECT
    INT int_msg_1, IF 0x0f			; INITIATE RECOVERY
#ifdef EVENTS 
    INT int_EVENT_SELECT_FAILED 
#endif
    JUMP reject_message

munge_2:
    JUMP reject_message
;
; The SCSI standard allows targets to recover from transient 
; error conditions by backing up the data pointer with a 
; RESTORE POINTERS message.  
;	
; So, we must save and restore the _residual_ code as well as 
; the current instruction pointer.  Because of this messiness,
; it is simpler to put dynamic code in the dsa for this and to
; just do a simple jump down there. 
;

munge_save_data_pointer:
#if (CHIP == 710)
    ; We have something in TEMP here, so first we must save that
    MOVE TEMP0 TO SFBR
    MOVE SFBR TO SCRATCH0
    MOVE TEMP1 TO SFBR
    MOVE SFBR TO SCRATCH1
    MOVE TEMP2 TO SFBR
    MOVE SFBR TO SCRATCH2
    MOVE TEMP3 TO SFBR
    MOVE SFBR TO SCRATCH3
    MOVE MEMORY 4, addr_scratch, jump_temp + 4
    ; Now restore DSA
    MOVE MEMORY 4, saved_dsa, addr_dsa
#endif
    MOVE DSA0 + dsa_save_data_pointer TO SFBR
    MOVE SFBR TO SCRATCH0
    MOVE DSA1 + 0xff TO SFBR WITH CARRY
    MOVE SFBR TO SCRATCH1
    MOVE DSA2 + 0xff TO SFBR WITH CARRY 
    MOVE SFBR TO SCRATCH2
    MOVE DSA3 + 0xff TO SFBR WITH CARRY
    MOVE SFBR TO SCRATCH3

    DMODE_NCR_TO_MEMORY
    MOVE MEMORY 4, addr_scratch, jump_dsa_save + 4
    DMODE_MEMORY_TO_MEMORY
jump_dsa_save:
    JUMP 0

munge_restore_pointers:
#if (CHIP == 710)
    ; The code at dsa_restore_pointers will RETURN, but we don't care
    ; about TEMP here, as it will overwrite it anyway.
#endif
    MOVE DSA0 + dsa_restore_pointers TO SFBR
    MOVE SFBR TO SCRATCH0
    MOVE DSA1 + 0xff TO SFBR WITH CARRY
    MOVE SFBR TO SCRATCH1
    MOVE DSA2 + 0xff TO SFBR WITH CARRY
    MOVE SFBR TO SCRATCH2
    MOVE DSA3 + 0xff TO SFBR WITH CARRY
    MOVE SFBR TO SCRATCH3

    DMODE_NCR_TO_MEMORY
    MOVE MEMORY 4, addr_scratch, jump_dsa_restore + 4
    DMODE_MEMORY_TO_MEMORY
jump_dsa_restore:
    JUMP 0


munge_disconnect:
#ifdef DEBUG
    INT int_debug_disconnect_msg
#endif

/* 
 * Before, we overlapped processing with waiting for disconnect, but
 * debugging was beginning to appear messy.  Temporarily move things
 * to just before the WAIT DISCONNECT.
 */
 
#ifdef ORIGINAL
#if (CHIP == 710)
; Following clears Unexpected Disconnect bit.  What do we do?
#else
    MOVE SCNTL2 & 0x7f TO SCNTL2
#endif
    CLEAR ACK
#endif

#if (CHIP != 700) && (CHIP != 70066)
    JUMP dsa_schedule
#else
    WAIT DISCONNECT
    INT int_norm_disconnected
#endif

munge_extended:
    CLEAR ACK
    INT int_err_unexpected_phase, WHEN NOT MSG_IN
    MOVE 1, msg_buf + 1, WHEN MSG_IN
    JUMP munge_extended_2, IF 0x02
    JUMP munge_extended_3, IF 0x03 
    JUMP reject_message

munge_extended_2:
    CLEAR ACK
    MOVE 1, msg_buf + 2, WHEN MSG_IN
    JUMP reject_message, IF NOT 0x02	; Must be WDTR
    CLEAR ACK
    MOVE 1, msg_buf + 3, WHEN MSG_IN
    INT int_msg_wdtr

munge_extended_3:
    CLEAR ACK
    MOVE 1, msg_buf + 2, WHEN MSG_IN
    JUMP reject_message, IF NOT 0x01	; Must be SDTR
    CLEAR ACK
    MOVE 2, msg_buf + 3, WHEN MSG_IN
    INT int_msg_sdtr

ENTRY reject_message
reject_message:
    SET ATN
    CLEAR ACK
    MOVE 1, NCR53c7xx_msg_reject, WHEN MSG_OUT
    RETURN

ENTRY accept_message
accept_message:
    CLEAR ATN
    CLEAR ACK
    RETURN

ENTRY respond_message
respond_message:
    SET ATN
    CLEAR ACK
    MOVE FROM dsa_msgout_other, WHEN MSG_OUT
    RETURN

;
; command_complete
;
; PURPOSE : handle command termination when STATUS IN is detected by reading
;	a status byte followed by a command termination message. 
;
;	Normal termination results in an INTFLY instruction, and 
;	the host system can pick out which command terminated by 
;	examining the MESSAGE and STATUS buffers of all currently 
;	executing commands;
;
;	Abnormal (CHECK_CONDITION) termination results in an
;	int_err_check_condition interrupt so that a REQUEST SENSE
;	command can be issued out-of-order so that no other command
;	clears the contingent allegiance condition.
;	
;
; INPUTS : DSA - command	
;
; CALLS : OK
;
; EXITS : On successful termination, control is passed to schedule.
;	On abnormal termination, the user will usually modify the 
;	DSA fields and corresponding buffers and return control
;	to select.
;

ENTRY command_complete
command_complete:
    MOVE FROM dsa_status, WHEN STATUS
#if (CHIP != 700) && (CHIP != 70066)
    MOVE SFBR TO SCRATCH0		; Save status
#endif /* (CHIP != 700) && (CHIP != 70066) */
ENTRY command_complete_msgin
command_complete_msgin:
    MOVE FROM dsa_msgin, WHEN MSG_IN
; Indicate that we should be expecting a disconnect
#if (CHIP != 710)
    MOVE SCNTL2 & 0x7f TO SCNTL2
#else
    ; Above code cleared the Unexpected Disconnect bit, what do we do?
#endif
    CLEAR ACK
#if (CHIP != 700) && (CHIP != 70066)
    WAIT DISCONNECT

;
; The SCSI specification states that when a UNIT ATTENTION condition
; is pending, as indicated by a CHECK CONDITION status message,
; the target shall revert to asynchronous transfers.  Since
; synchronous transfers parameters are maintained on a per INITIATOR/TARGET 
; basis, and returning control to our scheduler could work on a command
; running on another lun on that target using the old parameters, we must
; interrupt the host processor to get them changed, or change them ourselves.
;
; Once SCSI-II tagged queueing is implemented, things will be even more
; hairy, since contingent allegiance conditions exist on a per-target/lun
; basis, and issuing a new command with a different tag would clear it.
; In these cases, we must interrupt the host processor to get a request 
; added to the HEAD of the queue with the request sense command, or we
; must automatically issue the request sense command.

#if 0
    MOVE SCRATCH0 TO SFBR			
    JUMP command_failed, IF 0x02
#endif
#if (CHIP == 710)
#if defined(MVME16x_INTFLY)
; For MVME16x (ie CHIP=710) we will force an INTFLY by triggering a software
; interupt (SW7).  We can use SCRATCH, as we are about to jump to
; schedule, which corrupts it anyway.  Will probably remove this later,
; but want to check performance effects first.

#define INTFLY_ADDR     0xfff40070

    MOVE 0 TO SCRATCH0
    MOVE 0x80 TO SCRATCH1
    MOVE 0 TO SCRATCH2
    MOVE 0 TO SCRATCH3
    MOVE MEMORY 4, addr_scratch, INTFLY_ADDR
#else
    INT int_norm_emulateintfly
#endif
#else
    INTFLY
#endif
#endif /* (CHIP != 700) && (CHIP != 70066) */
#if (CHIP == 710)
    ; Time to correct DSA following memory move
    MOVE MEMORY 4, saved_dsa, addr_dsa
#endif
#ifdef EVENTS
    INT int_EVENT_COMPLETE
#endif
#if (CHIP != 700) && (CHIP != 70066)
    JUMP schedule
command_failed:
    INT int_err_check_condition
#else
    INT int_norm_command_complete
#endif

;
; wait_reselect
;
; PURPOSE : This is essentially the idle routine, where control lands
;	when there are no new processes to schedule.  wait_reselect
;	waits for reselection, selection, and new commands.
;
;	When a successful reselection occurs, with the aid 
;	of fixed up code in each DSA, wait_reselect walks the 
;	reconnect_dsa_queue, asking each dsa if the target ID
;	and LUN match its.
;
;	If a match is found, a call is made back to reselected_ok,
;	which through the miracles of self modifying code, extracts
;	the found DSA from the reconnect_dsa_queue and then 
;	returns control to the DSAs thread of execution.
;
; INPUTS : NONE
;
; CALLS : OK
;
; MODIFIES : DSA,
;