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Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

#undef DEBUG
#undef EVENTS
#undef NO_SELECTION_TIMEOUT
#define BIG_ENDIAN

; 53c710 driver.  Modified from Drew Eckhardts driver
; for 53c810 by Richard Hirst [[e-mail]]
;
; I have left the script for the 53c8xx family in here, as it is likely
; to be useful to see what I changed when bug hunting.

; NCR 53c810 driver, main script
; Sponsored by 
;	iX Multiuser Multitasking Magazine
;	[e-mail]
;
; Copyright 1993, 1994, 1995 Drew Eckhardt
;      Visionary Computing 
;      (Unix and Linux consulting and custom programming)
;      [e-mail]
;      [phone]
;
; TolerANT and SCSI SCRIPTS are registered trademarks of NCR Corporation.
;
; PRE-ALPHA
;
; For more information, please consult 
;
; NCR 53C810
; PCI-SCSI I/O Processor
; Data Manual
;
; NCR 53C710 
; SCSI I/O Processor
; Programmers Guide
;
; NCR Microelectronics
; 1635 Aeroplaza Drive
; Colorado Springs, CO 80916
; 1+ [phone]
;
; Toll free literature number
; [phone]
;
; IMPORTANT : This code is self modifying due to the limitations of 
;	the NCR53c7,8xx series chips.  Persons debugging this code with
;	the remote debugger should take this into account, and NOT set
;	breakpoints in modified instructions.
;
; Design:
; The NCR53c7,8xx family of SCSI chips are busmasters with an onboard 
; microcontroller using a simple instruction set.   
;
; So, to minimize the effects of interrupt latency, and to maximize 
; throughput, this driver offloads the practical maximum amount 
; of processing to the SCSI chip while still maintaining a common
; structure.
;
; Where tradeoffs were needed between efficiency on the older
; chips and the newer NCR53c800 series, the NCR53c800 series 
; was chosen.
;
; While the NCR53c700 and NCR53c700-66 lacked the facilities to fully
; automate SCSI transfers without host processor intervention, this 
; isn't the case with the NCR53c710 and newer chips which allow 
;
; - reads and writes to the internal registers from within the SCSI
; 	scripts, allowing the SCSI SCRIPTS(tm) code to save processor
; 	state so that multiple threads of execution are possible, and also
; 	provide an ALU for loop control, etc.
; 
; - table indirect addressing for some instructions. This allows 
;	pointers to be located relative to the DSA ((Data Structure
;	Address) register.
;
; These features make it possible to implement a mailbox style interface,
; where the same piece of code is run to handle I/O for multiple threads
; at once minimizing our need to relocate code.  Since the NCR53c700/
; NCR53c800 series have a unique combination of features, making a 
; a standard ingoing/outgoing mailbox system, costly, I've modified it.
;
; - Mailboxes are a mixture of code and data.  This lets us greatly
; 	simplify the NCR53c810 code and do things that would otherwise
;	not be possible.
;
; The saved data pointer is now implemented as follows :
;
; 	Control flow has been architected such that if control reaches
;	munge_save_data_pointer, on a restore pointers message or 
;	reconnection, a jump to the address formerly in the TEMP register
;	will allow the SCSI command to resume execution.
;

;
; Note : the DSA structures must be aligned on 32 bit boundaries,
; since the source and destination of MOVE MEMORY instructions 
; must share the same alignment and this is the alignment of the
; NCR registers.
;

; For some systems (MVME166, for example) dmode is always the same, so don't
; waste time writing it

#if 1
#define DMODE_MEMORY_TO_NCR
#define DMODE_MEMORY_TO_MEMORY
#define DMODE_NCR_TO_MEMORY
#else
#define DMODE_MEMORY_TO_NCR    MOVE dmode_memory_to_ncr TO DMODE
#define DMODE_MEMORY_TO_MEMORY MOVE dmode_memory_to_memory TO DMODE
#define DMODE_NCR_TO_MEMORY    MOVE dmode_ncr_to_memory TO DMODE
#endif

ABSOLUTE dsa_temp_lun = 0		; Patch to lun for current dsa
ABSOLUTE dsa_temp_next = 0		; Patch to dsa next for current dsa
ABSOLUTE dsa_temp_addr_next = 0		; Patch to address of dsa next address 
					; 	for current dsa
ABSOLUTE dsa_temp_sync = 0		; Patch to address of per-target
					;	sync routine
ABSOLUTE dsa_sscf_710 = 0		; Patch to address of per-target
					;	sscf value (53c710)
ABSOLUTE dsa_temp_target = 0		; Patch to id for current dsa
ABSOLUTE dsa_temp_addr_saved_pointer = 0; Patch to address of per-command
					; 	saved data pointer
ABSOLUTE dsa_temp_addr_residual = 0	; Patch to address of per-command
					;	current residual code
ABSOLUTE dsa_temp_addr_saved_residual = 0; Patch to address of per-command
					; saved residual code
ABSOLUTE dsa_temp_addr_new_value = 0	; Address of value for JUMP operand
ABSOLUTE dsa_temp_addr_array_value = 0 	; Address to copy to
ABSOLUTE dsa_temp_addr_dsa_value = 0	; Address of this DSA value

;
; Once a device has initiated reselection, we need to compare it 
; against the singly linked list of commands which have disconnected
; and are pending reselection.  These commands are maintained in 
; an unordered singly linked list of DSA structures, through the
; DSA pointers at their 'centers' headed by the reconnect_dsa_head
; pointer.
; 
; To avoid complications in removing commands from the list,
; I minimize the amount of expensive (at eight operations per
; addition @ 500-600ns each) pointer operations which must
; be done in the NCR driver by precomputing them on the 
; host processor during dsa structure generation.
;
; The fixed-up per DSA code knows how to recognize the nexus
; associated with the corresponding SCSI command, and modifies
; the source and destination pointers for the MOVE MEMORY 
; instruction which is executed when reselected_ok is called
; to remove the command from the list.  Similarly, DSA is 
; loaded with the address of the next DSA structure and
; reselected_check_next is called if a failure occurs.
;
; Perhaps more concisely, the net effect of the mess is 
;
; for (dsa = reconnect_dsa_head, dest = &reconnect_dsa_head, 
;     src = NULL; dsa; dest = &dsa->next, dsa = dsa->next) {
; 	src = &dsa->next;
; 	if (target_id == dsa->id && target_lun == dsa->lun) {
; 		*dest = *src;
; 		break;
;         }	
; }
;
; if (!dsa)
;           error (int_err_unexpected_reselect);
; else  
;     longjmp (dsa->jump_resume, 0);
;
; 	

#if (CHIP != 700) && (CHIP != 70066)
; Define DSA structure used for mailboxes
ENTRY dsa_code_template
dsa_code_template:
ENTRY dsa_code_begin
dsa_code_begin:
; RGH: Don't care about TEMP and DSA here
	DMODE_MEMORY_TO_NCR
	MOVE MEMORY 4, dsa_temp_addr_dsa_value, addr_scratch
	DMODE_MEMORY_TO_MEMORY
#if (CHIP == 710)
	MOVE MEMORY 4, addr_scratch, saved_dsa
	; We are about to go and select the device, so must set SSCF bits
	MOVE MEMORY 4, dsa_sscf_710, addr_scratch
#ifdef BIG_ENDIAN
	MOVE SCRATCH3 TO SFBR
#else
	MOVE SCRATCH0 TO SFBR
#endif
	MOVE SFBR TO SBCL
	MOVE MEMORY 4, saved_dsa, addr_dsa
#else
	CALL scratch_to_dsa
#endif
	CALL select
; Handle the phase mismatch which may have resulted from the 
; MOVE FROM dsa_msgout if we returned here.  The CLEAR ATN 
; may or may not be necessary, and we should update script_asm.pl
; to handle multiple pieces.
    CLEAR ATN
    CLEAR ACK

; Replace second operand with address of JUMP instruction dest operand
; in schedule table for this DSA.  Becomes dsa_jump_dest in 53c7,8xx.c.
ENTRY dsa_code_fix_jump
dsa_code_fix_jump:
	MOVE MEMORY 4, NOP_insn, 0
	JUMP select_done

; wrong_dsa loads the DSA register with the value of the dsa_next
; field.
;
wrong_dsa:
#if (CHIP == 710)
;                NOTE DSA is corrupt when we arrive here!
#endif
;		Patch the MOVE MEMORY INSTRUCTION such that 
;		the destination address is the address of the OLD 
;		next pointer.
;
	MOVE MEMORY 4, dsa_temp_addr_next, reselected_ok_patch + 8
	DMODE_MEMORY_TO_NCR
;
; 	Move the _contents_ of the next pointer into the DSA register as 
;	the next I_T_L or I_T_L_Q tupple to check against the established
;	nexus.
;
	MOVE MEMORY 4, dsa_temp_next, addr_scratch
	DMODE_MEMORY_TO_MEMORY
#if (CHIP == 710)
	MOVE MEMORY 4, addr_scratch, saved_dsa
	MOVE MEMORY 4, saved_dsa, addr_dsa
#else
	CALL scratch_to_dsa
#endif
	JUMP reselected_check_next

ABSOLUTE dsa_save_data_pointer = 0
ENTRY dsa_code_save_data_pointer
dsa_code_save_data_pointer:
#if (CHIP == 710)
	; When we get here, TEMP has been saved in jump_temp+4, DSA is corrupt
	; We MUST return with DSA correct
    	MOVE MEMORY 4, jump_temp+4, dsa_temp_addr_saved_pointer
; HARD CODED : 24 bytes needs to agree with 53c7,8xx.h
    	MOVE MEMORY 24, dsa_temp_addr_residual, dsa_temp_addr_saved_residual
        CLEAR ACK
#ifdef DEBUG
        INT int_debug_saved
#endif
	MOVE MEMORY 4, saved_dsa, addr_dsa
	JUMP jump_temp
#else
    	DMODE_NCR_TO_MEMORY
    	MOVE MEMORY 4, addr_temp, dsa_temp_addr_saved_pointer
    	DMODE_MEMORY_TO_MEMORY
; HARD CODED : 24 bytes needs to agree with 53c7,8xx.h
    	MOVE MEMORY 24, dsa_temp_addr_residual, dsa_temp_addr_saved_residual
        CLEAR ACK
#ifdef DEBUG
        INT int_debug_saved
#endif
    	RETURN
#endif
ABSOLUTE dsa_restore_pointers = 0
ENTRY dsa_code_restore_pointers
dsa_code_restore_pointers:
#if (CHIP == 710)
	; TEMP and DSA are corrupt when we get here, but who cares!
    	MOVE MEMORY 4, dsa_temp_addr_saved_pointer, jump_temp + 4
; HARD CODED : 24 bytes needs to agree with 53c7,8xx.h
    	MOVE MEMORY 24, dsa_temp_addr_saved_residual, dsa_temp_addr_residual
        CLEAR ACK
	; Restore DSA, note we don't care about TEMP
	MOVE MEMORY 4, saved_dsa, addr_dsa
#ifdef DEBUG
        INT int_debug_restored
#endif
	JUMP jump_temp
#else
    	DMODE_MEMORY_TO_NCR
    	MOVE MEMORY 4, dsa_temp_addr_saved_pointer, addr_temp
    	DMODE_MEMORY_TO_MEMORY
; HARD CODED : 24 bytes needs to agree with 53c7,8xx.h
    	MOVE MEMORY 24, dsa_temp_addr_saved_residual, dsa_temp_addr_residual
        CLEAR ACK
#ifdef DEBUG
        INT int_debug_restored
#endif
    	RETURN
#endif

ABSOLUTE dsa_check_reselect = 0
; dsa_check_reselect determines whether or not the current target and
; lun match the current DSA
ENTRY dsa_code_check_reselect
dsa_code_check_reselect:
#if (CHIP == 710)
	/* Arrives here with DSA correct */
	/* Assumes we are always ID 7 */
	MOVE LCRC TO SFBR		; LCRC has our ID and his ID bits set
	JUMP REL (wrong_dsa), IF NOT dsa_temp_target, AND MASK 0x80
#else
	MOVE SSID TO SFBR		; SSID contains 3 bit target ID
; FIXME : we need to accommodate bit fielded and binary here for '7xx/'8xx chips
	JUMP REL (wrong_dsa), IF NOT dsa_temp_target, AND MASK 0xf8
#endif
;
; Hack - move to scratch first, since SFBR is not writeable
; 	via the CPU and hence a MOVE MEMORY instruction.
;
	DMODE_MEMORY_TO_NCR
	MOVE MEMORY 1, reselected_identify, addr_scratch
	DMODE_MEMORY_TO_MEMORY
#ifdef BIG_ENDIAN
	; BIG ENDIAN ON MVME16x
	MOVE SCRATCH3 TO SFBR
#else
	MOVE SCRATCH0 TO SFBR
#endif
; FIXME : we need to accommodate bit fielded and binary here for '7xx/'8xx chips
; Are you sure about that?  [e-mail]
	JUMP REL (wrong_dsa), IF NOT dsa_temp_lun, AND MASK 0xf8
;		Patch the MOVE MEMORY INSTRUCTION such that
;		the source address is the address of this dsa's
;		next pointer.
	MOVE MEMORY 4, dsa_temp_addr_next, reselected_ok_patch + 4
	CALL reselected_ok
#if (CHIP == 710)
;	Restore DSA following memory moves in reselected_ok
;	dsa_temp_sync doesn't really care about DSA, but it has an
;	optional debug INT so a valid DSA is a good idea.
	MOVE MEMORY 4, saved_dsa, addr_dsa
#endif
	CALL dsa_temp_sync	
; Release ACK on the IDENTIFY message _after_ we've set the synchronous 
; transfer parameters! 
	CLEAR ACK
; Implicitly restore pointers on reselection, so a RETURN
; will transfer control back to the right spot.
    	CALL REL (dsa_code_restore_pointers)
    	RETURN
ENTRY dsa_zero
dsa_zero:
ENTRY dsa_code_template_end
dsa_code_template_end:

; Perform sanity check for dsa_fields_start == dsa_code_template_end - 
; dsa_zero, puke.

ABSOLUTE dsa_fields_start =  0	; Sanity marker
				; 	pad 48 bytes (fix this RSN)
ABSOLUTE dsa_next = 48		; len 4 Next DSA
 				; del 4 Previous DSA address
ABSOLUTE dsa_cmnd = 56		; len 4 Scsi_Cmnd * for this thread.
ABSOLUTE dsa_select = 60	; len 4 Device ID, Period, Offset for 
			 	;	table indirect select
ABSOLUTE dsa_msgout = 64	; len 8 table indirect move parameter for 
				;       select message
ABSOLUTE dsa_cmdout = 72	; len 8 table indirect move parameter for 
				;	command
ABSOLUTE dsa_dataout = 80	; len 4 code pointer for dataout
ABSOLUTE dsa_datain = 84	; len 4 code pointer for datain
ABSOLUTE dsa_msgin = 88		; len 8 table indirect move for msgin
ABSOLUTE dsa_status = 96 	; len 8 table indirect move for status byte
ABSOLUTE dsa_msgout_other = 104	; len 8 table indirect for normal message out
				; (Synchronous transfer negotiation, etc).
ABSOLUTE dsa_end = 112

ABSOLUTE schedule = 0 		; Array of JUMP dsa_begin or JUMP (next),
				; terminated by a call to JUMP wait_reselect

; Linked lists of DSA structures
ABSOLUTE reconnect_dsa_head = 0	; Link list of DSAs which can reconnect
ABSOLUTE addr_reconnect_dsa_head = 0 ; Address of variable containing
				; address of reconnect_dsa_head

; These select the source and destination of a MOVE MEMORY instruction
ABSOLUTE dmode_memory_to_memory = 0x0
ABSOLUTE dmode_memory_to_ncr = 0x0
ABSOLUTE dmode_ncr_to_memory = 0x0

ABSOLUTE addr_scratch = 0x0
ABSOLUTE addr_temp = 0x0
#if (CHIP == 710)
ABSOLUTE saved_dsa = 0x0
ABSOLUTE emulfly = 0x0
ABSOLUTE addr_dsa = 0x0
#endif
#endif /* CHIP != 700 && CHIP != 70066 */

; Interrupts - 
; MSB indicates type
; 0	handle error condition
; 1 	handle message 
; 2 	handle normal condition