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source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Device/Serial/SerialCommand.asm @ 214

Last change on this file since 214 was 214, checked in by gregli@…, 12 years ago
Rework of the serial write loop and read/write timeout code, resulting in significant throughput gains (increase from 8K bytes to 36K bytes, over a 460K baud link connected to a 4.77MHz 8088)
File size: 20.5 KB

Line
1	; Project name : XTIDE Universal BIOS
2	; Description : Serial Device Command functions.
3
4	; Section containing code
5	SECTION .text
6
7	;--------------- UART Equates -----------------------------
8	;
9	; Serial Programming References:
10	; http://en.wikibooks.org/wiki/Serial_Programming
11	;
12
13	SerialCommand_UART_base EQU 0
14	SerialCommand_UART_transmitByte EQU 0
15	SerialCommand_UART_receiveByte EQU 0
16	SerialCommand_UART_divisorLow EQU 0
17	; Values for UART_divisorLow:
18	; 60h = 1200, 30h = 2400, 18h = 4800, 0ch = 9600, 6 = 19200, 3 = 38400, 2 = 57600, 1 = 115200
19
20	SerialCommand_UART_divisorLow_startingBaud EQU 030h
21	; We support 4 baud rates, starting here going higher and skipping every other baud rate
22	; Starting with 30h, that means 30h (1200 baud), 0ch (9600 baud), 3 (38400 baud), and 1 (115200 baud)
23	; Note: hardware baud multipliers (2x, 4x) will impact the final baud rate and are not known at this level
24
25	SerialCommand_UART_interruptEnable EQU 1
26	SerialCommand_UART_divisorHigh EQU 1
27	; UART_divisorHigh is zero for all speeds including and above 1200 baud
28
29	SerialCommand_UART_interruptIdent EQU 2
30	SerialCommand_UART_FIFOControl EQU 2
31
32	SerialCommand_UART_lineControl EQU 3
33
34	SerialCommand_UART_modemControl EQU 4
35
36	SerialCommand_UART_lineStatus EQU 5
37
38	SerialCommand_UART_modemStatus EQU 6
39
40	SerialCommand_UART_scratch EQU 7
41
42	SerialCommand_Protocol_Write EQU 3
43	SerialCommand_Protocol_Read EQU 2
44	SerialCommand_Protocol_Inquire EQU 0
45	SerialCommand_Protocol_Header EQU 0a0h
46
47	;--------------------------------------------------------------------
48	; SerialCommand_OutputWithParameters
49	; Parameters:
50	; BH: Non-zero if 48-bit addressing used
51	; (ignored at present as 48-bit addressing is not supported)
52	; BL: IDE Status Register bit to poll after command
53	; (ignored at present, since there is no IDE status register to poll)
54	; ES:SI: Ptr to buffer (for data transfer commands)
55	; DS:DI: Ptr to DPT (in RAMVARS segment)
56	; SS:BP: Ptr to IDEREGS_AND_INTPACK
57	; Returns:
58	; AH: INT 13h Error Code
59	; CF: Cleared if success, Set if error
60	; Corrupts registers:
61	; AL, BX, CX, DX, (ES:SI for data transfer commands)
62	;--------------------------------------------------------------------
63	ALIGN JUMP_ALIGN
64	SerialCommand_OutputWithParameters:
65
66	mov ah,(SerialCommand_Protocol_Header \| SerialCommand_Protocol_Read)
67
68	mov al,[bp+IDEPACK.bCommand]
69
70	cmp al,20h ; Read Sectors IDE command
71	jz .readOrWrite
72	inc ah ; now SerialCommand_Protocol_Write
73	cmp al,30h ; Write Sectors IDE command
74	jz .readOrWrite
75
76	; all other commands return success
77	; including function 0ech which should return drive information, this is handled with the identify functions
78	xor ah,ah ; also clears carry
79	ret
80
81	.readOrWrite:
82	mov [bp+IDEPACK.bFeatures],ah ; store protocol command
83
84	mov dl, byte [di+DPT.bSerialPortAndBaud]
85
86	; fall-through
87
88	;--------------------------------------------------------------------
89	; SerialCommand_OutputWithParameters_DeviceInDL
90	; Parameters:
91	; AH: Protocol Command
92	; DL: Packed I/O port and baud rate
93	; ES:SI: Ptr to buffer (for data transfer commands)
94	; SS:BP: Ptr to IDEREGS_AND_INTPACK
95	; Returns:
96	; AH: INT 13h Error Code
97	; CF: Cleared if success, Set if error
98	; Corrupts registers:
99	; AL, BX, CX, DX, (ES:SI for data transfer commands)
100	;--------------------------------------------------------------------
101	SerialCommand_OutputWithParameters_DeviceInDL:
102
103	push si
104	push di
105	push bp
106	push es
107
108	;
109	; Unpack I/O port and baud from DPT
110	; Port to DX more or less for the remainder of the routine
111	; Baud in CH until UART initialization is complete
112	;
113	mov dh, ((DEVICE_SERIAL_PACKEDPORTANDBAUD_STARTINGPORT & 0f00h) >> (8+1))
114	shl dx, 1 ; port offset already x4, needs one more shift to be x8
115	mov cl, dl
116
117	and cl, (DEVICE_SERIAL_PACKEDPORTANDBAUD_BAUDMASK << 1)
118	mov ch, SerialCommand_UART_divisorLow_startingBaud
119	shr ch, cl
120	adc ch, 0
121
122	and dl, ((DEVICE_SERIAL_PACKEDPORTANDBAUD_PORTMASK << 1) & 0ffh)
123	add dx, byte (DEVICE_SERIAL_PACKEDPORTANDBAUD_STARTINGPORT & 0ffh)
124
125	mov al,[bp+IDEPACK.bSectorCount]
126
127	;
128	; Command byte and sector count live at the top of the stack, pop/push are used to access
129	;
130	push ax
131
132	; cld ; Shouldn't be needed. DF has already been cleared (line 24, Int13h.asm)
133
134	;----------------------------------------------------------------------
135	;
136	; Initialize UART
137	;
138	; We do this each time since DOS (at boot) or another program may have
139	; decided to reprogram the UART
140	;
141	mov bl,dl ; setup BL with proper values for read/write loops (BH comes later)
142
143	mov al,83h
144	add dl,SerialCommand_UART_lineControl
145	out dx,al
146
147	mov al,ch
148	mov dl,bl ; divisor low
149	out dx,al
150
151	xor ax,ax
152	inc dx ; divisor high
153	push dx
154	out dx,al
155
156	mov al,047h
157	inc dx ; fifo
158	out dx,al
159
160	mov al,03h
161	inc dx ; linecontrol
162	out dx,al
163
164	mov al,0bh
165	inc dx ; modemcontrol
166	out dx,al
167
168	inc dx ; linestatus (no output now, just setting up BH for later use)
169	mov bh,dl
170
171	pop dx ; base, interrupts disabled
172	xor ax,ax
173	out dx,al
174
175	;----------------------------------------------------------------------
176	;
177	; Send Command
178	;
179	; Sends first six bytes of IDEREGS_AND_INTPACK as the command
180	;
181	push es ; save off real buffer location
182	push si
183
184	mov si,bp ; point to IDEREGS for command dispatch;
185	push ss
186	pop es
187
188	mov di,0ffffh ; initialize checksum for write
189	mov bp,di
190
191	mov cx,4 ; writing 3 words (plus 1)
192
193	cli ; interrupts off...
194
195	call SerialCommand_WriteProtocol.entry
196
197	pop di ; restore real buffer location (note change from SI to DI)
198	; Buffer is primarily referenced through ES:DI throughout, since
199	; we need to store (read sector) faster than we read (write sector)
200	pop es
201
202	.nextSectorNormalize:
203
204	call Registers_NormalizeESDI
205
206	pop ax ; load command byte (done before call to .nextSector on subsequent iterations)
207	push ax
208
209	;
210	; Top of the read/write loop, one iteration per sector
211	;
212	.nextSector:
213	mov si,0ffffh ; initialize checksum for read or write
214	mov bp,si
215
216	mov cx,0101h ; writing 256 words (plus 1)
217
218	shr ah,1 ; command byte, are we doing a write?
219	jnc .readEntry
220
221	xchg si,di
222	call SerialCommand_WriteProtocol.entry
223	xchg si,di
224
225	inc cx ; CX = 1 now (0 out of WriteProtocol)
226	jmp .readEntry
227
228	;----------------------------------------------------------------------
229	;
230	; Timeout
231	;
232	; To save code space, we use the contents of DL to decide which byte in the word to return for reading.
233	;
234	.readTimeout:
235	push ax ; not only does this push preserve AX (which we need), but it also
236	; means the stack has the same number of bytes on it as when we are
237	; sending a packet, important for error cleanup and exit
238	mov ah,1
239	call SerialCommand_WaitAndPoll_Read
240	pop ax
241	test dl,1
242	jz .readByte1Ready
243	jmp .readByte2Ready
244
245	;----------------------------------------------------------------------------
246	;
247	; Read Block (without interrupts, used when there is a FIFO, high speed)
248	;
249	; NOTE: This loop is very time sensitive. Literally, another instruction
250	; cannot be inserted into this loop without us falling behind at high
251	; speed (460.8K baud) on a 4.77Mhz 8088, making it hard to receive
252	; a full 512 byte block.
253	;
254	.readLoop:
255	stosw ; store word in caller's data buffer
256
257	add bp, ax ; update Fletcher's checksum
258	adc bp, 0
259	add si, bp
260	adc si, 0
261
262	.readEntry:
263	mov dl,bh
264	in al,dx
265	shr al,1 ; data ready (byte 1)?
266	mov dl,bl ; get ready to read data
267	jnc .readTimeout ; nope not ready, update timeouts
268
269	;
270	; Entry point after initial timeout. We enter here so that the checksum word
271	; is not stored (and is left in AX after the loop is complete).
272	;
273	.readByte1Ready:
274	in al, dx ; read data byte 1
275
276	mov ah, al ; store byte in ah for now
277
278	;
279	; note the placement of this reset of dl to bh, and that it is
280	; before the return, which is assymetric with where this is done
281	; above for byte 1. The value of dl is used by the timeout routine
282	; to know which byte to return to (.read_byte1_ready or
283	; .read_byte2_ready)
284	;
285	mov dl,bh
286
287	in al,dx
288	shr al,1 ; data ready (byte 2)?
289	jnc .readTimeout
290	.readByte2Ready:
291	mov dl,bl
292	in al, dx ; read data byte 2
293
294	xchg al, ah ; ah was holding byte 1, reverse byte order
295
296	loop .readLoop
297
298	sti ; interrupts back on ASAP, between packets
299
300	;
301	; Compare checksums
302	;
303	xchg ax,bp
304	xor ah,al
305	mov cx,si
306	xor cl,ch
307	mov al,cl
308	cmp ax,bp
309	jnz SerialCommand_OutputWithParameters_Error
310
311	;----------------------------------------------------------------------
312	;
313	; Clear read buffer
314	;
315	; In case there are extra characters or an error in the FIFO, clear it out.
316	; In theory the initialization of the UART registers above should have
317	; taken care of this, but I have seen cases where this is not true.
318	;
319	.clearBuffer:
320	mov dl,bh
321	in al,dx
322	mov dl,bl
323	test al,08fh
324	jz .clearBufferComplete
325	shr al,1
326	in al,dx
327	jc .clearBuffer ; note CF from shr above
328	jmp SerialCommand_OutputWithParameters_Error
329
330	.clearBufferComplete:
331
332	pop ax ; sector count and command byte
333	dec al ; decrememnt sector count
334	push ax ; save
335	jz SerialCommand_OutputWithParameters_ReturnCodeInALCF ; CF clear from .clearBuffer test above
336
337	cli ; interrupts back off for ACK byte to host
338	; (host could start sending data immediately)
339	out dx,al ; ACK with next sector number
340
341	;
342	; Normalize buffer pointer for next go round, if needed
343	;
344	test di,di
345	jns short .nextSector
346	jmp short .nextSectorNormalize
347
348	;---------------------------------------------------------------------------
349	;
350	; Cleanup, error reporting, and exit
351	;
352
353	;
354	; Used in situations where a call is underway, such as with SerialCommand_WaitAndPoll
355	;
356	ALIGN JUMP_ALIGN
357	SerialCommand_OutputWithParameters_ErrorAndPop4Words:
358	add sp,8
359
360	ALIGN JUMP_ALIGN
361	SerialCommand_OutputWithParameters_Error:
362	stc
363	mov al,1
364
365	ALIGN JUMP_ALIGN
366	SerialCommand_OutputWithParameters_ReturnCodeInALCF:
367	sti
368	mov ah,al
369
370	pop bp ; recover ax (command and count) from stack, throw away
371
372	pop es
373	pop bp
374	pop di
375	pop si
376
377	ret
378
379	;--------------------------------------------------------------------
380	; SerialCommand_WriteProtocol
381	;
382	; NOTE: As with its read counterpart, this loop is very time sensitive.
383	; Although it will still function, adding additional instructions will
384	; impact the write througput, especially on slower machines.
385	;
386	; Parameters:
387	; ES:SI: Ptr to buffer
388	; CX: Words to write, plus 1
389	; BP/DI: Initialized for Checksum (-1 in each)
390	; DH: I/O Port high byte
391	; BX: LineStatus Register address (BH) and Receive/Transmit Register address (BL)
392	; Returns:
393	; BP/DI: Checksum for written bytes, compared against ACK from server in .readLoop
394	; CX: Zero
395	; DL: Receive/Transmit Register address
396	; Corrupts registers:
397	; AX
398	;--------------------------------------------------------------------
399	ALIGN JUMP_ALIGN
400	SerialCommand_WriteProtocol:
401	.writeLoop:
402	es lodsw ; fetch next word
403
404	out dx,al ; output first byte
405
406	add bp,ax ; update checksum
407	adc bp,0
408	add di,bp
409	adc di,0
410
411	mov dl,bh ; transmit buffer empty?
412	in al,dx
413	test al,20h
414	jz .writeTimeout2 ; nope, use our polling routine
415
416	.writeByte2Ready:
417	mov dl,bl
418	mov al,ah ; output second byte
419	out dx,al
420
421	.entry:
422	mov dl,bh ; transmit buffer empty?
423	in al,dx
424	test al,20h
425	mov dl,bl
426	jz .writeTimeout1 ; nope, use our polling routine
427
428	.writeByte1Ready:
429	loop .writeLoop
430
431	mov ax,di ; fold Fletcher's checksum and output
432	xor al,ah
433	out dx,al ; byte 1
434
435	call SerialCommand_WaitAndPoll_Write
436
437	mov ax,bp
438	xor al,ah
439	out dx,al ; byte 2
440
441	ret
442
443	.writeTimeout2:
444	mov dl,ah ; need to preserve AH, but don't need DL (will be reset upon return)
445	call SerialCommand_WaitAndPoll_Write
446	mov ah,dl
447	jmp .writeByte2Ready
448
449	.writeTimeout1:
450	mov ax,.writeByte1Ready
451	push ax ; return address for ret at end of SC_writeTimeout2
452	;;; fall-through
453
454	;--------------------------------------------------------------------
455	; SerialCommand_WaitAndPoll
456	;
457	; Parameters:
458	; AH: UART_LineStatus bit to test (20h for write, or 1h for read)
459	; One entry point fills in AH with 20h for write
460	; DX: Port address (OK if already incremented to UART_lineStatus)
461	; BX:
462	; Stack: 2 words on the stack below the command/count word
463	; Returns:
464	; Returns when desired UART_LineStatus bit is cleared
465	; Jumps directly to error exit if timeout elapses (and cleans up stack)
466	; Corrupts registers:
467	; AX
468	;--------------------------------------------------------------------
469
470	SerialCommand_WaitAndPoll_SoftDelayTicks EQU 20
471
472	ALIGN JUMP_ALIGN
473	SerialCommand_WaitAndPoll_Write:
474	mov ah,20h
475	;;; fall-through
476
477	ALIGN JUMP_ALIGN
478	SerialCommand_WaitAndPoll_Read:
479	push cx
480	push dx
481
482	;
483	; We first poll in a tight loop, interrupts off, for the next character to come in/be sent
484	;
485	xor cx,cx
486	.readTimeoutLoop:
487	mov dl,bh
488	in al,dx
489	test al,ah
490	jnz .readTimeoutComplete
491	loop .readTimeoutLoop
492
493	;
494	; If that loop completes, then we assume there is a long delay involved, turn interrupts back on
495	; and wait for a given number of timer ticks to pass.
496	;
497	sti
498	mov cl,SerialCommand_WaitAndPoll_SoftDelayTicks
499	call Timer_InitializeTimeoutWithTicksInCL
500	.WaitAndPoll:
501	call Timer_SetCFifTimeout
502	jc SerialCommand_OutputWithParameters_ErrorAndPop4Words
503	in al,dx
504	test al,ah
505	jz .WaitAndPoll
506	cli
507
508	.readTimeoutComplete:
509	pop dx
510	pop cx
511	ret
512
513	;--------------------------------------------------------------------
514	; SerialCommand_IdentifyDeviceToBufferInESSIwithDriveSelectByteInBH
515	; Parameters:
516	; BH: Drive Select byte for Drive and Head Select Register
517	; DS: Segment to RAMVARS
518	; ES:SI: Ptr to buffer to receive 512-byte IDE Information
519	; CS:BP: Ptr to IDEVARS
520	; Returns:
521	; AH: INT 13h Error Code
522	; NOTE: Not set (or checked) during drive detection
523	; CF: Cleared if success, Set if error
524	; Corrupts registers:
525	; AL, BL, CX, DX, SI, DI, ES
526	;--------------------------------------------------------------------
527	ALIGN JUMP_ALIGN
528	SerialCommand_IdentifyDeviceToBufferInESSIwithDriveSelectByteInBH:
529	;
530	; To improve boot time, we do our best to avoid looking for slave serial drives when we already know the results
531	; from the looking for a master. This is particuarly true when doing a COM port scan, as we will end up running
532	; through all the COM ports and baud rates a second time.
533	;
534	; But drive detection isn't the only case - we also need to get the right drive when called on int13h/25h.
535	;
536	; The decision tree:
537	;
538	; Master:
539	; bSerialPackedPortAndBaud Non-Zero: -> Continue with bSerialPackedAndBaud (1)
540	; bSerialPackedPortAndBaud Zero:
541	; bLastSerial Zero: -> Scan (2)
542	; bLastSerial Non-Zero: -> Continue with bLastSerial (3)
543	;
544	; Slave:
545	; bSerialPackedPortAndBaud Non-Zero:
546	; bLastSerial Zero: -> Error - Not Found (4)
547	; bLastSerial Non-Zero: -> Continue with bSerialPackedAndBaud (5)
548	; bSerialPackedPortAndBaud Zero:
549	; bLastSerial Zero: -> Error - Not Found (4)
550	; bLastSerial Non-Zero: -> Continue with bLastSerial (6)
551	;
552	; (1) This was a port/baud that was explicilty set with the configurator. In the drive detection case, as this
553	; is the Master, we are checking out a new controller, and so don't care about the value of bLastSerial.
554	; And as with the int13h/25h case, we just go off and get the needed information using the user's setting.
555	; (2) We are using the special .ideVarsSerialAuto strucutre. During drive detection, we would only be here
556	; if bLastSerial is zero (since we only scan if no explicit drives are set), so we go off to scan.
557	; (3) We are using the special .ideVarsSerialAuto strucutre. We won't get here during drive detection, but
558	; we might get here on an int13h/25h call. If we have scanned COM drives, they are the ONLY serial drives
559	; in use, and so bLastSerial will reflect the port/baud setting for the scanned COM drives.
560	; (4) No master has been found yet, therefore no slave should be found. Avoiding the slave reduces boot time,
561	; especially in the full COM port scan case. Note that this is different from the hardware IDE, where we
562	; will scan for a slave even if a master is not present. Note that if ANY master had been previously found,
563	; we will do the slave scan, which isn't harmful, it just wates time. But the most common case (by a wide
564	; margin) will be just one serial controller.
565	; (5) A COM port scan for a master had been previously completed, and a drive was found. In a multiple serial
566	; controller scenario being called with int13h/25h, we need to use the value in bSerialPackedPortAndBaud
567	; to make sure we get the proper drive.
568	; (6) A COM port scan for a master had been previously completed, and a drive was found. We would only get here
569	; if no serial drive was explicitly set by the user in the configurator or that drive had not been found.
570	; Instead of performing the full COM port scan for the slave, use the port/baud value stored during the
571	; master scan.
572	;
573	mov dl,[cs:bp+IDEVARS.bSerialPackedPortAndBaud]
574	mov al, byte [RAMVARS.xlateVars+XLATEVARS.bLastSerial]
575
576	test bh, FLG_DRVNHEAD_DRV
577	jz .master
578
579	test al,al ; Take care of the case that is different between master and slave.
580	jz .error ; Because we do this here, the jz after the "or" below will not be taken
581
582	; fall-through
583	.master:
584	test dl,dl
585	jnz .identifyDeviceInDL
586
587	or dl,al ; Move bLast into position in dl, as well as test for zero
588	jz .scanSerial
589
590	; fall-through
591	.identifyDeviceInDL:
592
593	push bp ; setup fake IDEREGS_AND_INTPACK
594
595	push dx
596
597	mov cl,1 ; 1 sector to move
598	push cx
599
600	mov bl,0a0h ; protocol command to ah and onto stack with bh
601	mov ah,bl
602
603	push bx
604
605	mov bp,sp
606	call SerialCommand_OutputWithParameters_DeviceInDL
607
608	pop bx
609
610	pop cx
611	pop dx
612
613	pop bp
614	;
615	; place packed port/baud in RAMVARS, read by FinalizeDPT and DetectDrives
616	;
617	; Note that this will be set during an int13h/25h call as well. Which is OK since it is only used (at the
618	; top of this routine) for drives found during a COM scan, and we only COM scan if there were no other
619	; COM drives found. So we will only reaffirm the port/baud for the one COM port/baud that has a drive.
620	;
621	jc .notFound ; only store bLastSerial if success
622	mov byte [RAMVARS.xlateVars+XLATEVARS.bLastSerial], dl
623
624	.notFound:
625	ret
626
627	;----------------------------------------------------------------------
628	;
629	; SerialCommand_AutoSerial
630	;
631	; When the SerialAuto IDEVARS entry is used, scans the COM ports on the machine for a possible serial connection.
632	;
633
634	.scanPortAddresses: db DEVICE_SERIAL_COM7 >> 2
635	db DEVICE_SERIAL_COM6 >> 2
636	db DEVICE_SERIAL_COM5 >> 2
637	db DEVICE_SERIAL_COM4 >> 2
638	db DEVICE_SERIAL_COM3 >> 2
639	db DEVICE_SERIAL_COM2 >> 2
640	db DEVICE_SERIAL_COM1 >> 2
641	db 0
642
643	ALIGN JUMP_ALIGN
644	.scanSerial:
645	mov di,.scanPortAddresses-1
646
647	.nextPort:
648	inc di ; load next port address
649	mov dl,[cs:di]
650
651	mov dh,0 ; shift from one byte to two
652	eSHL_IM dx, 2
653	jz .error
654
655	;
656	; Test for COM port presence, write to and read from registers
657	;
658	push dx
659	add dl,SerialCommand_UART_lineControl
660	mov al, 09ah
661	out dx, al
662	in al, dx
663	pop dx
664	cmp al, 09ah
665	jnz .nextPort
666
667	mov al, 0ch
668	out dx, al
669	in al, dx
670	cmp al, 0ch
671	jnz .nextPort
672
673	;
674	; Pack into dl, baud rate starts at 0
675	;
676	add dx,-(DEVICE_SERIAL_PACKEDPORTANDBAUD_STARTINGPORT)
677	shr dx,1 ; dh is zero at this point, and will be sent to the server,
678	; so we know this is an auto detect
679
680	jmp .testFirstBaud
681
682	;
683	; Walk through 4 possible baud rates
684	;
685	.nextBaud:
686	inc dx
687	test dl,3
688	jz .nextPort
689
690	.testFirstBaud:
691	call .identifyDeviceInDL
692	jc .nextBaud
693
694	ret
695
696	.error:
697	stc
698	; mov ah,1 ; setting the error code is unnecessary as this path can only be taken during
699	; drive detection, and drive detection works off CF and does not check AH
700	ret
701
702

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