1 /*
2  * Device driver for the SYMBIOS/LSILOGIC 53C8XX and 53C1010 family
3  * of PCI-SCSI IO processors.
4  *
5  * Copyright (C) 1999-2001  Gerard Roudier <groudier@free.fr>
6  *
7  * This driver is derived from the Linux sym53c8xx driver.
8  * Copyright (C) 1998-2000  Gerard Roudier
9  *
10  * The sym53c8xx driver is derived from the ncr53c8xx driver that had been
11  * a port of the FreeBSD ncr driver to Linux-1.2.13.
12  *
13  * The original ncr driver has been written for 386bsd and FreeBSD by
14  *         Wolfgang Stanglmeier        <wolf@cologne.de>
15  *         Stefan Esser                <se@mi.Uni-Koeln.de>
16  * Copyright (C) 1994  Wolfgang Stanglmeier
17  *
18  * Other major contributions:
19  *
20  * NVRAM detection and reading.
21  * Copyright (C) 1997 Richard Waltham <dormouse@farsrobt.demon.co.uk>
22  *
23  *-----------------------------------------------------------------------------
24  *
25  * This program is free software; you can redistribute it and/or modify
26  * it under the terms of the GNU General Public License as published by
27  * the Free Software Foundation; either version 2 of the License, or
28  * (at your option) any later version.
29  *
30  * This program is distributed in the hope that it will be useful,
31  * but WITHOUT ANY WARRANTY; without even the implied warranty of
32  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
33  * GNU General Public License for more details.
34  *
35  * You should have received a copy of the GNU General Public License
36  * along with this program; if not, write to the Free Software
37  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
38  */
39 
40 #include "sym_glue.h"
41 #include "sym_nvram.h"
42 
43 #ifdef	SYM_CONF_DEBUG_NVRAM
44 static u_char Tekram_boot_delay[7] = {3, 5, 10, 20, 30, 60, 120};
45 #endif
46 
47 /*
48  *  Get host setup from NVRAM.
49  */
50 void sym_nvram_setup_host(struct Scsi_Host *shost, struct sym_hcb *np, struct sym_nvram *nvram)
51 {
52 	/*
53 	 *  Get parity checking, host ID, verbose mode
54 	 *  and miscellaneous host flags from NVRAM.
55 	 */
56 	switch (nvram->type) {
57 	case SYM_SYMBIOS_NVRAM:
58 		if (!(nvram->data.Symbios.flags & SYMBIOS_PARITY_ENABLE))
59 			np->rv_scntl0  &= ~0x0a;
60 		np->myaddr = nvram->data.Symbios.host_id & 0x0f;
61 		if (nvram->data.Symbios.flags & SYMBIOS_VERBOSE_MSGS)
62 			np->verbose += 1;
63 		if (nvram->data.Symbios.flags1 & SYMBIOS_SCAN_HI_LO)
64 			shost->reverse_ordering = 1;
65 		if (nvram->data.Symbios.flags2 & SYMBIOS_AVOID_BUS_RESET)
66 			np->usrflags |= SYM_AVOID_BUS_RESET;
67 		break;
68 	case SYM_TEKRAM_NVRAM:
69 		np->myaddr = nvram->data.Tekram.host_id & 0x0f;
70 		break;
71 #ifdef CONFIG_PARISC
72 	case SYM_PARISC_PDC:
73 		if (nvram->data.parisc.host_id != -1)
74 			np->myaddr = nvram->data.parisc.host_id;
75 		if (nvram->data.parisc.factor != -1)
76 			np->minsync = nvram->data.parisc.factor;
77 		if (nvram->data.parisc.width != -1)
78 			np->maxwide = nvram->data.parisc.width;
79 		switch (nvram->data.parisc.mode) {
80 			case 0: np->scsi_mode = SMODE_SE; break;
81 			case 1: np->scsi_mode = SMODE_HVD; break;
82 			case 2: np->scsi_mode = SMODE_LVD; break;
83 			default: break;
84 		}
85 #endif
86 	default:
87 		break;
88 	}
89 }
90 
91 /*
92  *  Get target set-up from Symbios format NVRAM.
93  */
94 static void
95 sym_Symbios_setup_target(struct sym_tcb *tp, int target, Symbios_nvram *nvram)
96 {
97 	Symbios_target *tn = &nvram->target[target];
98 
99 	if (!(tn->flags & SYMBIOS_QUEUE_TAGS_ENABLED))
100 		tp->usrtags = 0;
101 	if (!(tn->flags & SYMBIOS_DISCONNECT_ENABLE))
102 		tp->usrflags &= ~SYM_DISC_ENABLED;
103 	if (!(tn->flags & SYMBIOS_SCAN_AT_BOOT_TIME))
104 		tp->usrflags |= SYM_SCAN_BOOT_DISABLED;
105 	if (!(tn->flags & SYMBIOS_SCAN_LUNS))
106 		tp->usrflags |= SYM_SCAN_LUNS_DISABLED;
107 	tp->usr_period = (tn->sync_period + 3) / 4;
108 	tp->usr_width = (tn->bus_width == 0x8) ? 0 : 1;
109 }
110 
111 static const unsigned char Tekram_sync[16] = {
112 	25, 31, 37, 43, 50, 62, 75, 125, 12, 15, 18, 21, 6, 7, 9, 10
113 };
114 
115 /*
116  *  Get target set-up from Tekram format NVRAM.
117  */
118 static void
119 sym_Tekram_setup_target(struct sym_tcb *tp, int target, Tekram_nvram *nvram)
120 {
121 	struct Tekram_target *tn = &nvram->target[target];
122 
123 	if (tn->flags & TEKRAM_TAGGED_COMMANDS) {
124 		tp->usrtags = 2 << nvram->max_tags_index;
125 	}
126 
127 	if (tn->flags & TEKRAM_DISCONNECT_ENABLE)
128 		tp->usrflags |= SYM_DISC_ENABLED;
129 
130 	if (tn->flags & TEKRAM_SYNC_NEGO)
131 		tp->usr_period = Tekram_sync[tn->sync_index & 0xf];
132 	tp->usr_width = (tn->flags & TEKRAM_WIDE_NEGO) ? 1 : 0;
133 }
134 
135 /*
136  *  Get target setup from NVRAM.
137  */
138 void sym_nvram_setup_target(struct sym_tcb *tp, int target, struct sym_nvram *nvp)
139 {
140 	switch (nvp->type) {
141 	case SYM_SYMBIOS_NVRAM:
142 		sym_Symbios_setup_target(tp, target, &nvp->data.Symbios);
143 		break;
144 	case SYM_TEKRAM_NVRAM:
145 		sym_Tekram_setup_target(tp, target, &nvp->data.Tekram);
146 		break;
147 	default:
148 		break;
149 	}
150 }
151 
152 #ifdef	SYM_CONF_DEBUG_NVRAM
153 /*
154  *  Dump Symbios format NVRAM for debugging purpose.
155  */
156 static void sym_display_Symbios_nvram(struct sym_device *np, Symbios_nvram *nvram)
157 {
158 	int i;
159 
160 	/* display Symbios nvram host data */
161 	printf("%s: HOST ID=%d%s%s%s%s%s%s\n",
162 		sym_name(np), nvram->host_id & 0x0f,
163 		(nvram->flags  & SYMBIOS_SCAM_ENABLE)	? " SCAM"	:"",
164 		(nvram->flags  & SYMBIOS_PARITY_ENABLE)	? " PARITY"	:"",
165 		(nvram->flags  & SYMBIOS_VERBOSE_MSGS)	? " VERBOSE"	:"",
166 		(nvram->flags  & SYMBIOS_CHS_MAPPING)	? " CHS_ALT"	:"",
167 		(nvram->flags2 & SYMBIOS_AVOID_BUS_RESET)?" NO_RESET"	:"",
168 		(nvram->flags1 & SYMBIOS_SCAN_HI_LO)	? " HI_LO"	:"");
169 
170 	/* display Symbios nvram drive data */
171 	for (i = 0 ; i < 15 ; i++) {
172 		struct Symbios_target *tn = &nvram->target[i];
173 		printf("%s-%d:%s%s%s%s WIDTH=%d SYNC=%d TMO=%d\n",
174 		sym_name(np), i,
175 		(tn->flags & SYMBIOS_DISCONNECT_ENABLE)	? " DISC"	: "",
176 		(tn->flags & SYMBIOS_SCAN_AT_BOOT_TIME)	? " SCAN_BOOT"	: "",
177 		(tn->flags & SYMBIOS_SCAN_LUNS)		? " SCAN_LUNS"	: "",
178 		(tn->flags & SYMBIOS_QUEUE_TAGS_ENABLED)? " TCQ"	: "",
179 		tn->bus_width,
180 		tn->sync_period / 4,
181 		tn->timeout);
182 	}
183 }
184 
185 /*
186  *  Dump TEKRAM format NVRAM for debugging purpose.
187  */
188 static void sym_display_Tekram_nvram(struct sym_device *np, Tekram_nvram *nvram)
189 {
190 	int i, tags, boot_delay;
191 	char *rem;
192 
193 	/* display Tekram nvram host data */
194 	tags = 2 << nvram->max_tags_index;
195 	boot_delay = 0;
196 	if (nvram->boot_delay_index < 6)
197 		boot_delay = Tekram_boot_delay[nvram->boot_delay_index];
198 	switch ((nvram->flags & TEKRAM_REMOVABLE_FLAGS) >> 6) {
199 	default:
200 	case 0:	rem = "";			break;
201 	case 1: rem = " REMOVABLE=boot device";	break;
202 	case 2: rem = " REMOVABLE=all";		break;
203 	}
204 
205 	printf("%s: HOST ID=%d%s%s%s%s%s%s%s%s%s BOOT DELAY=%d tags=%d\n",
206 		sym_name(np), nvram->host_id & 0x0f,
207 		(nvram->flags1 & SYMBIOS_SCAM_ENABLE)	? " SCAM"	:"",
208 		(nvram->flags & TEKRAM_MORE_THAN_2_DRIVES) ? " >2DRIVES":"",
209 		(nvram->flags & TEKRAM_DRIVES_SUP_1GB)	? " >1GB"	:"",
210 		(nvram->flags & TEKRAM_RESET_ON_POWER_ON) ? " RESET"	:"",
211 		(nvram->flags & TEKRAM_ACTIVE_NEGATION)	? " ACT_NEG"	:"",
212 		(nvram->flags & TEKRAM_IMMEDIATE_SEEK)	? " IMM_SEEK"	:"",
213 		(nvram->flags & TEKRAM_SCAN_LUNS)	? " SCAN_LUNS"	:"",
214 		(nvram->flags1 & TEKRAM_F2_F6_ENABLED)	? " F2_F6"	:"",
215 		rem, boot_delay, tags);
216 
217 	/* display Tekram nvram drive data */
218 	for (i = 0; i <= 15; i++) {
219 		int sync, j;
220 		struct Tekram_target *tn = &nvram->target[i];
221 		j = tn->sync_index & 0xf;
222 		sync = Tekram_sync[j];
223 		printf("%s-%d:%s%s%s%s%s%s PERIOD=%d\n",
224 		sym_name(np), i,
225 		(tn->flags & TEKRAM_PARITY_CHECK)	? " PARITY"	: "",
226 		(tn->flags & TEKRAM_SYNC_NEGO)		? " SYNC"	: "",
227 		(tn->flags & TEKRAM_DISCONNECT_ENABLE)	? " DISC"	: "",
228 		(tn->flags & TEKRAM_START_CMD)		? " START"	: "",
229 		(tn->flags & TEKRAM_TAGGED_COMMANDS)	? " TCQ"	: "",
230 		(tn->flags & TEKRAM_WIDE_NEGO)		? " WIDE"	: "",
231 		sync);
232 	}
233 }
234 #else
235 static void sym_display_Symbios_nvram(struct sym_device *np, Symbios_nvram *nvram) { (void)np; (void)nvram; }
236 static void sym_display_Tekram_nvram(struct sym_device *np, Tekram_nvram *nvram) { (void)np; (void)nvram; }
237 #endif	/* SYM_CONF_DEBUG_NVRAM */
238 
239 
240 /*
241  *  24C16 EEPROM reading.
242  *
243  *  GPOI0 - data in/data out
244  *  GPIO1 - clock
245  *  Symbios NVRAM wiring now also used by Tekram.
246  */
247 
248 #define SET_BIT 0
249 #define CLR_BIT 1
250 #define SET_CLK 2
251 #define CLR_CLK 3
252 
253 /*
254  *  Set/clear data/clock bit in GPIO0
255  */
256 static void S24C16_set_bit(struct sym_device *np, u_char write_bit, u_char *gpreg,
257 			  int bit_mode)
258 {
259 	udelay(5);
260 	switch (bit_mode) {
261 	case SET_BIT:
262 		*gpreg |= write_bit;
263 		break;
264 	case CLR_BIT:
265 		*gpreg &= 0xfe;
266 		break;
267 	case SET_CLK:
268 		*gpreg |= 0x02;
269 		break;
270 	case CLR_CLK:
271 		*gpreg &= 0xfd;
272 		break;
273 
274 	}
275 	OUTB(np, nc_gpreg, *gpreg);
276 	INB(np, nc_mbox1);
277 	udelay(5);
278 }
279 
280 /*
281  *  Send START condition to NVRAM to wake it up.
282  */
283 static void S24C16_start(struct sym_device *np, u_char *gpreg)
284 {
285 	S24C16_set_bit(np, 1, gpreg, SET_BIT);
286 	S24C16_set_bit(np, 0, gpreg, SET_CLK);
287 	S24C16_set_bit(np, 0, gpreg, CLR_BIT);
288 	S24C16_set_bit(np, 0, gpreg, CLR_CLK);
289 }
290 
291 /*
292  *  Send STOP condition to NVRAM - puts NVRAM to sleep... ZZzzzz!!
293  */
294 static void S24C16_stop(struct sym_device *np, u_char *gpreg)
295 {
296 	S24C16_set_bit(np, 0, gpreg, SET_CLK);
297 	S24C16_set_bit(np, 1, gpreg, SET_BIT);
298 }
299 
300 /*
301  *  Read or write a bit to the NVRAM,
302  *  read if GPIO0 input else write if GPIO0 output
303  */
304 static void S24C16_do_bit(struct sym_device *np, u_char *read_bit, u_char write_bit,
305 			 u_char *gpreg)
306 {
307 	S24C16_set_bit(np, write_bit, gpreg, SET_BIT);
308 	S24C16_set_bit(np, 0, gpreg, SET_CLK);
309 	if (read_bit)
310 		*read_bit = INB(np, nc_gpreg);
311 	S24C16_set_bit(np, 0, gpreg, CLR_CLK);
312 	S24C16_set_bit(np, 0, gpreg, CLR_BIT);
313 }
314 
315 /*
316  *  Output an ACK to the NVRAM after reading,
317  *  change GPIO0 to output and when done back to an input
318  */
319 static void S24C16_write_ack(struct sym_device *np, u_char write_bit, u_char *gpreg,
320 			    u_char *gpcntl)
321 {
322 	OUTB(np, nc_gpcntl, *gpcntl & 0xfe);
323 	S24C16_do_bit(np, NULL, write_bit, gpreg);
324 	OUTB(np, nc_gpcntl, *gpcntl);
325 }
326 
327 /*
328  *  Input an ACK from NVRAM after writing,
329  *  change GPIO0 to input and when done back to an output
330  */
331 static void S24C16_read_ack(struct sym_device *np, u_char *read_bit, u_char *gpreg,
332 			   u_char *gpcntl)
333 {
334 	OUTB(np, nc_gpcntl, *gpcntl | 0x01);
335 	S24C16_do_bit(np, read_bit, 1, gpreg);
336 	OUTB(np, nc_gpcntl, *gpcntl);
337 }
338 
339 /*
340  *  WRITE a byte to the NVRAM and then get an ACK to see it was accepted OK,
341  *  GPIO0 must already be set as an output
342  */
343 static void S24C16_write_byte(struct sym_device *np, u_char *ack_data, u_char write_data,
344 			     u_char *gpreg, u_char *gpcntl)
345 {
346 	int x;
347 
348 	for (x = 0; x < 8; x++)
349 		S24C16_do_bit(np, NULL, (write_data >> (7 - x)) & 0x01, gpreg);
350 
351 	S24C16_read_ack(np, ack_data, gpreg, gpcntl);
352 }
353 
354 /*
355  *  READ a byte from the NVRAM and then send an ACK to say we have got it,
356  *  GPIO0 must already be set as an input
357  */
358 static void S24C16_read_byte(struct sym_device *np, u_char *read_data, u_char ack_data,
359 			    u_char *gpreg, u_char *gpcntl)
360 {
361 	int x;
362 	u_char read_bit;
363 
364 	*read_data = 0;
365 	for (x = 0; x < 8; x++) {
366 		S24C16_do_bit(np, &read_bit, 1, gpreg);
367 		*read_data |= ((read_bit & 0x01) << (7 - x));
368 	}
369 
370 	S24C16_write_ack(np, ack_data, gpreg, gpcntl);
371 }
372 
373 #ifdef SYM_CONF_NVRAM_WRITE_SUPPORT
374 /*
375  *  Write 'len' bytes starting at 'offset'.
376  */
377 static int sym_write_S24C16_nvram(struct sym_device *np, int offset,
378 		u_char *data, int len)
379 {
380 	u_char	gpcntl, gpreg;
381 	u_char	old_gpcntl, old_gpreg;
382 	u_char	ack_data;
383 	int	x;
384 
385 	/* save current state of GPCNTL and GPREG */
386 	old_gpreg	= INB(np, nc_gpreg);
387 	old_gpcntl	= INB(np, nc_gpcntl);
388 	gpcntl		= old_gpcntl & 0x1c;
389 
390 	/* set up GPREG & GPCNTL to set GPIO0 and GPIO1 in to known state */
391 	OUTB(np, nc_gpreg,  old_gpreg);
392 	OUTB(np, nc_gpcntl, gpcntl);
393 
394 	/* this is to set NVRAM into a known state with GPIO0/1 both low */
395 	gpreg = old_gpreg;
396 	S24C16_set_bit(np, 0, &gpreg, CLR_CLK);
397 	S24C16_set_bit(np, 0, &gpreg, CLR_BIT);
398 
399 	/* now set NVRAM inactive with GPIO0/1 both high */
400 	S24C16_stop(np, &gpreg);
401 
402 	/* NVRAM has to be written in segments of 16 bytes */
403 	for (x = 0; x < len ; x += 16) {
404 		do {
405 			S24C16_start(np, &gpreg);
406 			S24C16_write_byte(np, &ack_data,
407 					  0xa0 | (((offset+x) >> 7) & 0x0e),
408 					  &gpreg, &gpcntl);
409 		} while (ack_data & 0x01);
410 
411 		S24C16_write_byte(np, &ack_data, (offset+x) & 0xff,
412 				  &gpreg, &gpcntl);
413 
414 		for (y = 0; y < 16; y++)
415 			S24C16_write_byte(np, &ack_data, data[x+y],
416 					  &gpreg, &gpcntl);
417 		S24C16_stop(np, &gpreg);
418 	}
419 
420 	/* return GPIO0/1 to original states after having accessed NVRAM */
421 	OUTB(np, nc_gpcntl, old_gpcntl);
422 	OUTB(np, nc_gpreg,  old_gpreg);
423 
424 	return 0;
425 }
426 #endif /* SYM_CONF_NVRAM_WRITE_SUPPORT */
427 
428 /*
429  *  Read 'len' bytes starting at 'offset'.
430  */
431 static int sym_read_S24C16_nvram(struct sym_device *np, int offset, u_char *data, int len)
432 {
433 	u_char	gpcntl, gpreg;
434 	u_char	old_gpcntl, old_gpreg;
435 	u_char	ack_data;
436 	int	retv = 1;
437 	int	x;
438 
439 	/* save current state of GPCNTL and GPREG */
440 	old_gpreg	= INB(np, nc_gpreg);
441 	old_gpcntl	= INB(np, nc_gpcntl);
442 	gpcntl		= old_gpcntl & 0x1c;
443 
444 	/* set up GPREG & GPCNTL to set GPIO0 and GPIO1 in to known state */
445 	OUTB(np, nc_gpreg,  old_gpreg);
446 	OUTB(np, nc_gpcntl, gpcntl);
447 
448 	/* this is to set NVRAM into a known state with GPIO0/1 both low */
449 	gpreg = old_gpreg;
450 	S24C16_set_bit(np, 0, &gpreg, CLR_CLK);
451 	S24C16_set_bit(np, 0, &gpreg, CLR_BIT);
452 
453 	/* now set NVRAM inactive with GPIO0/1 both high */
454 	S24C16_stop(np, &gpreg);
455 
456 	/* activate NVRAM */
457 	S24C16_start(np, &gpreg);
458 
459 	/* write device code and random address MSB */
460 	S24C16_write_byte(np, &ack_data,
461 		0xa0 | ((offset >> 7) & 0x0e), &gpreg, &gpcntl);
462 	if (ack_data & 0x01)
463 		goto out;
464 
465 	/* write random address LSB */
466 	S24C16_write_byte(np, &ack_data,
467 		offset & 0xff, &gpreg, &gpcntl);
468 	if (ack_data & 0x01)
469 		goto out;
470 
471 	/* regenerate START state to set up for reading */
472 	S24C16_start(np, &gpreg);
473 
474 	/* rewrite device code and address MSB with read bit set (lsb = 0x01) */
475 	S24C16_write_byte(np, &ack_data,
476 		0xa1 | ((offset >> 7) & 0x0e), &gpreg, &gpcntl);
477 	if (ack_data & 0x01)
478 		goto out;
479 
480 	/* now set up GPIO0 for inputting data */
481 	gpcntl |= 0x01;
482 	OUTB(np, nc_gpcntl, gpcntl);
483 
484 	/* input all requested data - only part of total NVRAM */
485 	for (x = 0; x < len; x++)
486 		S24C16_read_byte(np, &data[x], (x == (len-1)), &gpreg, &gpcntl);
487 
488 	/* finally put NVRAM back in inactive mode */
489 	gpcntl &= 0xfe;
490 	OUTB(np, nc_gpcntl, gpcntl);
491 	S24C16_stop(np, &gpreg);
492 	retv = 0;
493 out:
494 	/* return GPIO0/1 to original states after having accessed NVRAM */
495 	OUTB(np, nc_gpcntl, old_gpcntl);
496 	OUTB(np, nc_gpreg,  old_gpreg);
497 
498 	return retv;
499 }
500 
501 #undef SET_BIT
502 #undef CLR_BIT
503 #undef SET_CLK
504 #undef CLR_CLK
505 
506 /*
507  *  Try reading Symbios NVRAM.
508  *  Return 0 if OK.
509  */
510 static int sym_read_Symbios_nvram(struct sym_device *np, Symbios_nvram *nvram)
511 {
512 	static u_char Symbios_trailer[6] = {0xfe, 0xfe, 0, 0, 0, 0};
513 	u_char *data = (u_char *) nvram;
514 	int len  = sizeof(*nvram);
515 	u_short	csum;
516 	int x;
517 
518 	/* probe the 24c16 and read the SYMBIOS 24c16 area */
519 	if (sym_read_S24C16_nvram (np, SYMBIOS_NVRAM_ADDRESS, data, len))
520 		return 1;
521 
522 	/* check valid NVRAM signature, verify byte count and checksum */
523 	if (nvram->type != 0 ||
524 	    memcmp(nvram->trailer, Symbios_trailer, 6) ||
525 	    nvram->byte_count != len - 12)
526 		return 1;
527 
528 	/* verify checksum */
529 	for (x = 6, csum = 0; x < len - 6; x++)
530 		csum += data[x];
531 	if (csum != nvram->checksum)
532 		return 1;
533 
534 	return 0;
535 }
536 
537 /*
538  *  93C46 EEPROM reading.
539  *
540  *  GPOI0 - data in
541  *  GPIO1 - data out
542  *  GPIO2 - clock
543  *  GPIO4 - chip select
544  *
545  *  Used by Tekram.
546  */
547 
548 /*
549  *  Pulse clock bit in GPIO0
550  */
551 static void T93C46_Clk(struct sym_device *np, u_char *gpreg)
552 {
553 	OUTB(np, nc_gpreg, *gpreg | 0x04);
554 	INB(np, nc_mbox1);
555 	udelay(2);
556 	OUTB(np, nc_gpreg, *gpreg);
557 }
558 
559 /*
560  *  Read bit from NVRAM
561  */
562 static void T93C46_Read_Bit(struct sym_device *np, u_char *read_bit, u_char *gpreg)
563 {
564 	udelay(2);
565 	T93C46_Clk(np, gpreg);
566 	*read_bit = INB(np, nc_gpreg);
567 }
568 
569 /*
570  *  Write bit to GPIO0
571  */
572 static void T93C46_Write_Bit(struct sym_device *np, u_char write_bit, u_char *gpreg)
573 {
574 	if (write_bit & 0x01)
575 		*gpreg |= 0x02;
576 	else
577 		*gpreg &= 0xfd;
578 
579 	*gpreg |= 0x10;
580 
581 	OUTB(np, nc_gpreg, *gpreg);
582 	INB(np, nc_mbox1);
583 	udelay(2);
584 
585 	T93C46_Clk(np, gpreg);
586 }
587 
588 /*
589  *  Send STOP condition to NVRAM - puts NVRAM to sleep... ZZZzzz!!
590  */
591 static void T93C46_Stop(struct sym_device *np, u_char *gpreg)
592 {
593 	*gpreg &= 0xef;
594 	OUTB(np, nc_gpreg, *gpreg);
595 	INB(np, nc_mbox1);
596 	udelay(2);
597 
598 	T93C46_Clk(np, gpreg);
599 }
600 
601 /*
602  *  Send read command and address to NVRAM
603  */
604 static void T93C46_Send_Command(struct sym_device *np, u_short write_data,
605 				u_char *read_bit, u_char *gpreg)
606 {
607 	int x;
608 
609 	/* send 9 bits, start bit (1), command (2), address (6)  */
610 	for (x = 0; x < 9; x++)
611 		T93C46_Write_Bit(np, (u_char) (write_data >> (8 - x)), gpreg);
612 
613 	*read_bit = INB(np, nc_gpreg);
614 }
615 
616 /*
617  *  READ 2 bytes from the NVRAM
618  */
619 static void T93C46_Read_Word(struct sym_device *np,
620 		unsigned short *nvram_data, unsigned char *gpreg)
621 {
622 	int x;
623 	u_char read_bit;
624 
625 	*nvram_data = 0;
626 	for (x = 0; x < 16; x++) {
627 		T93C46_Read_Bit(np, &read_bit, gpreg);
628 
629 		if (read_bit & 0x01)
630 			*nvram_data |=  (0x01 << (15 - x));
631 		else
632 			*nvram_data &= ~(0x01 << (15 - x));
633 	}
634 }
635 
636 /*
637  *  Read Tekram NvRAM data.
638  */
639 static int T93C46_Read_Data(struct sym_device *np, unsigned short *data,
640 		int len, unsigned char *gpreg)
641 {
642 	int x;
643 
644 	for (x = 0; x < len; x++)  {
645 		unsigned char read_bit;
646 		/* output read command and address */
647 		T93C46_Send_Command(np, 0x180 | x, &read_bit, gpreg);
648 		if (read_bit & 0x01)
649 			return 1; /* Bad */
650 		T93C46_Read_Word(np, &data[x], gpreg);
651 		T93C46_Stop(np, gpreg);
652 	}
653 
654 	return 0;
655 }
656 
657 /*
658  *  Try reading 93C46 Tekram NVRAM.
659  */
660 static int sym_read_T93C46_nvram(struct sym_device *np, Tekram_nvram *nvram)
661 {
662 	u_char gpcntl, gpreg;
663 	u_char old_gpcntl, old_gpreg;
664 	int retv = 1;
665 
666 	/* save current state of GPCNTL and GPREG */
667 	old_gpreg	= INB(np, nc_gpreg);
668 	old_gpcntl	= INB(np, nc_gpcntl);
669 
670 	/* set up GPREG & GPCNTL to set GPIO0/1/2/4 in to known state, 0 in,
671 	   1/2/4 out */
672 	gpreg = old_gpreg & 0xe9;
673 	OUTB(np, nc_gpreg, gpreg);
674 	gpcntl = (old_gpcntl & 0xe9) | 0x09;
675 	OUTB(np, nc_gpcntl, gpcntl);
676 
677 	/* input all of NVRAM, 64 words */
678 	retv = T93C46_Read_Data(np, (u_short *) nvram,
679 				sizeof(*nvram) / sizeof(short), &gpreg);
680 
681 	/* return GPIO0/1/2/4 to original states after having accessed NVRAM */
682 	OUTB(np, nc_gpcntl, old_gpcntl);
683 	OUTB(np, nc_gpreg,  old_gpreg);
684 
685 	return retv;
686 }
687 
688 /*
689  *  Try reading Tekram NVRAM.
690  *  Return 0 if OK.
691  */
692 static int sym_read_Tekram_nvram (struct sym_device *np, Tekram_nvram *nvram)
693 {
694 	u_char *data = (u_char *) nvram;
695 	int len = sizeof(*nvram);
696 	u_short	csum;
697 	int x;
698 
699 	switch (np->pdev->device) {
700 	case PCI_DEVICE_ID_NCR_53C885:
701 	case PCI_DEVICE_ID_NCR_53C895:
702 	case PCI_DEVICE_ID_NCR_53C896:
703 		x = sym_read_S24C16_nvram(np, TEKRAM_24C16_NVRAM_ADDRESS,
704 					  data, len);
705 		break;
706 	case PCI_DEVICE_ID_NCR_53C875:
707 		x = sym_read_S24C16_nvram(np, TEKRAM_24C16_NVRAM_ADDRESS,
708 					  data, len);
709 		if (!x)
710 			break;
711 	default:
712 		x = sym_read_T93C46_nvram(np, nvram);
713 		break;
714 	}
715 	if (x)
716 		return 1;
717 
718 	/* verify checksum */
719 	for (x = 0, csum = 0; x < len - 1; x += 2)
720 		csum += data[x] + (data[x+1] << 8);
721 	if (csum != 0x1234)
722 		return 1;
723 
724 	return 0;
725 }
726 
727 #ifdef CONFIG_PARISC
728 /*
729  * Host firmware (PDC) keeps a table for altering SCSI capabilities.
730  * Many newer machines export one channel of 53c896 chip as SE, 50-pin HD.
731  * Also used for Multi-initiator SCSI clusters to set the SCSI Initiator ID.
732  */
733 static int sym_read_parisc_pdc(struct sym_device *np, struct pdc_initiator *pdc)
734 {
735 	struct hardware_path hwpath;
736 	get_pci_node_path(np->pdev, &hwpath);
737 	if (!pdc_get_initiator(&hwpath, pdc))
738 		return 0;
739 
740 	return SYM_PARISC_PDC;
741 }
742 #else
743 static inline int sym_read_parisc_pdc(struct sym_device *np,
744 					struct pdc_initiator *x)
745 {
746 	return 0;
747 }
748 #endif
749 
750 /*
751  *  Try reading Symbios or Tekram NVRAM
752  */
753 int sym_read_nvram(struct sym_device *np, struct sym_nvram *nvp)
754 {
755 	if (!sym_read_Symbios_nvram(np, &nvp->data.Symbios)) {
756 		nvp->type = SYM_SYMBIOS_NVRAM;
757 		sym_display_Symbios_nvram(np, &nvp->data.Symbios);
758 	} else if (!sym_read_Tekram_nvram(np, &nvp->data.Tekram)) {
759 		nvp->type = SYM_TEKRAM_NVRAM;
760 		sym_display_Tekram_nvram(np, &nvp->data.Tekram);
761 	} else {
762 		nvp->type = sym_read_parisc_pdc(np, &nvp->data.parisc);
763 	}
764 	return nvp->type;
765 }
766 
767 char *sym_nvram_type(struct sym_nvram *nvp)
768 {
769 	switch (nvp->type) {
770 	case SYM_SYMBIOS_NVRAM:
771 		return "Symbios NVRAM";
772 	case SYM_TEKRAM_NVRAM:
773 		return "Tekram NVRAM";
774 	case SYM_PARISC_PDC:
775 		return "PA-RISC Firmware";
776 	default:
777 		return "No NVRAM";
778 	}
779 }
780