xref: /linux/drivers/scsi/sym53c8xx_2/sym_nvram.c (revision 60b2737de1b1ddfdb90f3ba622634eb49d6f3603)
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_hcb *np, int target, Symbios_nvram *nvram)
96 {
97 	struct sym_tcb *tp = &np->target[target];
98 	Symbios_target *tn = &nvram->target[target];
99 
100 	tp->usrtags =
101 		(tn->flags & SYMBIOS_QUEUE_TAGS_ENABLED)? SYM_SETUP_MAX_TAG : 0;
102 
103 	if (!(tn->flags & SYMBIOS_DISCONNECT_ENABLE))
104 		tp->usrflags &= ~SYM_DISC_ENABLED;
105 	if (!(tn->flags & SYMBIOS_SCAN_AT_BOOT_TIME))
106 		tp->usrflags |= SYM_SCAN_BOOT_DISABLED;
107 	if (!(tn->flags & SYMBIOS_SCAN_LUNS))
108 		tp->usrflags |= SYM_SCAN_LUNS_DISABLED;
109 }
110 
111 /*
112  *  Get target set-up from Tekram format NVRAM.
113  */
114 static void
115 sym_Tekram_setup_target(struct sym_hcb *np, int target, Tekram_nvram *nvram)
116 {
117 	struct sym_tcb *tp = &np->target[target];
118 	struct Tekram_target *tn = &nvram->target[target];
119 
120 	if (tn->flags & TEKRAM_TAGGED_COMMANDS) {
121 		tp->usrtags = 2 << nvram->max_tags_index;
122 	}
123 
124 	if (tn->flags & TEKRAM_DISCONNECT_ENABLE)
125 		tp->usrflags |= SYM_DISC_ENABLED;
126 
127 	/* If any device does not support parity, we will not use this option */
128 	if (!(tn->flags & TEKRAM_PARITY_CHECK))
129 		np->rv_scntl0  &= ~0x0a; /* SCSI parity checking disabled */
130 }
131 
132 /*
133  *  Get target setup from NVRAM.
134  */
135 void sym_nvram_setup_target(struct sym_hcb *np, int target, struct sym_nvram *nvp)
136 {
137 	switch (nvp->type) {
138 	case SYM_SYMBIOS_NVRAM:
139 		sym_Symbios_setup_target(np, target, &nvp->data.Symbios);
140 		break;
141 	case SYM_TEKRAM_NVRAM:
142 		sym_Tekram_setup_target(np, target, &nvp->data.Tekram);
143 		break;
144 	default:
145 		break;
146 	}
147 }
148 
149 #ifdef	SYM_CONF_DEBUG_NVRAM
150 /*
151  *  Dump Symbios format NVRAM for debugging purpose.
152  */
153 static void sym_display_Symbios_nvram(struct sym_device *np, Symbios_nvram *nvram)
154 {
155 	int i;
156 
157 	/* display Symbios nvram host data */
158 	printf("%s: HOST ID=%d%s%s%s%s%s%s\n",
159 		sym_name(np), nvram->host_id & 0x0f,
160 		(nvram->flags  & SYMBIOS_SCAM_ENABLE)	? " SCAM"	:"",
161 		(nvram->flags  & SYMBIOS_PARITY_ENABLE)	? " PARITY"	:"",
162 		(nvram->flags  & SYMBIOS_VERBOSE_MSGS)	? " VERBOSE"	:"",
163 		(nvram->flags  & SYMBIOS_CHS_MAPPING)	? " CHS_ALT"	:"",
164 		(nvram->flags2 & SYMBIOS_AVOID_BUS_RESET)?" NO_RESET"	:"",
165 		(nvram->flags1 & SYMBIOS_SCAN_HI_LO)	? " HI_LO"	:"");
166 
167 	/* display Symbios nvram drive data */
168 	for (i = 0 ; i < 15 ; i++) {
169 		struct Symbios_target *tn = &nvram->target[i];
170 		printf("%s-%d:%s%s%s%s WIDTH=%d SYNC=%d TMO=%d\n",
171 		sym_name(np), i,
172 		(tn->flags & SYMBIOS_DISCONNECT_ENABLE)	? " DISC"	: "",
173 		(tn->flags & SYMBIOS_SCAN_AT_BOOT_TIME)	? " SCAN_BOOT"	: "",
174 		(tn->flags & SYMBIOS_SCAN_LUNS)		? " SCAN_LUNS"	: "",
175 		(tn->flags & SYMBIOS_QUEUE_TAGS_ENABLED)? " TCQ"	: "",
176 		tn->bus_width,
177 		tn->sync_period / 4,
178 		tn->timeout);
179 	}
180 }
181 
182 /*
183  *  Dump TEKRAM format NVRAM for debugging purpose.
184  */
185 static void sym_display_Tekram_nvram(struct sym_device *np, Tekram_nvram *nvram)
186 {
187 	int i, tags, boot_delay;
188 	char *rem;
189 
190 	/* display Tekram nvram host data */
191 	tags = 2 << nvram->max_tags_index;
192 	boot_delay = 0;
193 	if (nvram->boot_delay_index < 6)
194 		boot_delay = Tekram_boot_delay[nvram->boot_delay_index];
195 	switch ((nvram->flags & TEKRAM_REMOVABLE_FLAGS) >> 6) {
196 	default:
197 	case 0:	rem = "";			break;
198 	case 1: rem = " REMOVABLE=boot device";	break;
199 	case 2: rem = " REMOVABLE=all";		break;
200 	}
201 
202 	printf("%s: HOST ID=%d%s%s%s%s%s%s%s%s%s BOOT DELAY=%d tags=%d\n",
203 		sym_name(np), nvram->host_id & 0x0f,
204 		(nvram->flags1 & SYMBIOS_SCAM_ENABLE)	? " SCAM"	:"",
205 		(nvram->flags & TEKRAM_MORE_THAN_2_DRIVES) ? " >2DRIVES":"",
206 		(nvram->flags & TEKRAM_DRIVES_SUP_1GB)	? " >1GB"	:"",
207 		(nvram->flags & TEKRAM_RESET_ON_POWER_ON) ? " RESET"	:"",
208 		(nvram->flags & TEKRAM_ACTIVE_NEGATION)	? " ACT_NEG"	:"",
209 		(nvram->flags & TEKRAM_IMMEDIATE_SEEK)	? " IMM_SEEK"	:"",
210 		(nvram->flags & TEKRAM_SCAN_LUNS)	? " SCAN_LUNS"	:"",
211 		(nvram->flags1 & TEKRAM_F2_F6_ENABLED)	? " F2_F6"	:"",
212 		rem, boot_delay, tags);
213 
214 	/* display Tekram nvram drive data */
215 	for (i = 0; i <= 15; i++) {
216 		int sync, j;
217 		struct Tekram_target *tn = &nvram->target[i];
218 		j = tn->sync_index & 0xf;
219 		sync = Tekram_sync[j];
220 		printf("%s-%d:%s%s%s%s%s%s PERIOD=%d\n",
221 		sym_name(np), i,
222 		(tn->flags & TEKRAM_PARITY_CHECK)	? " PARITY"	: "",
223 		(tn->flags & TEKRAM_SYNC_NEGO)		? " SYNC"	: "",
224 		(tn->flags & TEKRAM_DISCONNECT_ENABLE)	? " DISC"	: "",
225 		(tn->flags & TEKRAM_START_CMD)		? " START"	: "",
226 		(tn->flags & TEKRAM_TAGGED_COMMANDS)	? " TCQ"	: "",
227 		(tn->flags & TEKRAM_WIDE_NEGO)		? " WIDE"	: "",
228 		sync);
229 	}
230 }
231 #else
232 static void sym_display_Symbios_nvram(struct sym_device *np, Symbios_nvram *nvram) { (void)np; (void)nvram; }
233 static void sym_display_Tekram_nvram(struct sym_device *np, Tekram_nvram *nvram) { (void)np; (void)nvram; }
234 #endif	/* SYM_CONF_DEBUG_NVRAM */
235 
236 
237 /*
238  *  24C16 EEPROM reading.
239  *
240  *  GPOI0 - data in/data out
241  *  GPIO1 - clock
242  *  Symbios NVRAM wiring now also used by Tekram.
243  */
244 
245 #define SET_BIT 0
246 #define CLR_BIT 1
247 #define SET_CLK 2
248 #define CLR_CLK 3
249 
250 /*
251  *  Set/clear data/clock bit in GPIO0
252  */
253 static void S24C16_set_bit(struct sym_device *np, u_char write_bit, u_char *gpreg,
254 			  int bit_mode)
255 {
256 	udelay(5);
257 	switch (bit_mode) {
258 	case SET_BIT:
259 		*gpreg |= write_bit;
260 		break;
261 	case CLR_BIT:
262 		*gpreg &= 0xfe;
263 		break;
264 	case SET_CLK:
265 		*gpreg |= 0x02;
266 		break;
267 	case CLR_CLK:
268 		*gpreg &= 0xfd;
269 		break;
270 
271 	}
272 	OUTB(np, nc_gpreg, *gpreg);
273 	INB(np, nc_mbox1);
274 	udelay(5);
275 }
276 
277 /*
278  *  Send START condition to NVRAM to wake it up.
279  */
280 static void S24C16_start(struct sym_device *np, u_char *gpreg)
281 {
282 	S24C16_set_bit(np, 1, gpreg, SET_BIT);
283 	S24C16_set_bit(np, 0, gpreg, SET_CLK);
284 	S24C16_set_bit(np, 0, gpreg, CLR_BIT);
285 	S24C16_set_bit(np, 0, gpreg, CLR_CLK);
286 }
287 
288 /*
289  *  Send STOP condition to NVRAM - puts NVRAM to sleep... ZZzzzz!!
290  */
291 static void S24C16_stop(struct sym_device *np, u_char *gpreg)
292 {
293 	S24C16_set_bit(np, 0, gpreg, SET_CLK);
294 	S24C16_set_bit(np, 1, gpreg, SET_BIT);
295 }
296 
297 /*
298  *  Read or write a bit to the NVRAM,
299  *  read if GPIO0 input else write if GPIO0 output
300  */
301 static void S24C16_do_bit(struct sym_device *np, u_char *read_bit, u_char write_bit,
302 			 u_char *gpreg)
303 {
304 	S24C16_set_bit(np, write_bit, gpreg, SET_BIT);
305 	S24C16_set_bit(np, 0, gpreg, SET_CLK);
306 	if (read_bit)
307 		*read_bit = INB(np, nc_gpreg);
308 	S24C16_set_bit(np, 0, gpreg, CLR_CLK);
309 	S24C16_set_bit(np, 0, gpreg, CLR_BIT);
310 }
311 
312 /*
313  *  Output an ACK to the NVRAM after reading,
314  *  change GPIO0 to output and when done back to an input
315  */
316 static void S24C16_write_ack(struct sym_device *np, u_char write_bit, u_char *gpreg,
317 			    u_char *gpcntl)
318 {
319 	OUTB(np, nc_gpcntl, *gpcntl & 0xfe);
320 	S24C16_do_bit(np, NULL, write_bit, gpreg);
321 	OUTB(np, nc_gpcntl, *gpcntl);
322 }
323 
324 /*
325  *  Input an ACK from NVRAM after writing,
326  *  change GPIO0 to input and when done back to an output
327  */
328 static void S24C16_read_ack(struct sym_device *np, u_char *read_bit, u_char *gpreg,
329 			   u_char *gpcntl)
330 {
331 	OUTB(np, nc_gpcntl, *gpcntl | 0x01);
332 	S24C16_do_bit(np, read_bit, 1, gpreg);
333 	OUTB(np, nc_gpcntl, *gpcntl);
334 }
335 
336 /*
337  *  WRITE a byte to the NVRAM and then get an ACK to see it was accepted OK,
338  *  GPIO0 must already be set as an output
339  */
340 static void S24C16_write_byte(struct sym_device *np, u_char *ack_data, u_char write_data,
341 			     u_char *gpreg, u_char *gpcntl)
342 {
343 	int x;
344 
345 	for (x = 0; x < 8; x++)
346 		S24C16_do_bit(np, NULL, (write_data >> (7 - x)) & 0x01, gpreg);
347 
348 	S24C16_read_ack(np, ack_data, gpreg, gpcntl);
349 }
350 
351 /*
352  *  READ a byte from the NVRAM and then send an ACK to say we have got it,
353  *  GPIO0 must already be set as an input
354  */
355 static void S24C16_read_byte(struct sym_device *np, u_char *read_data, u_char ack_data,
356 			    u_char *gpreg, u_char *gpcntl)
357 {
358 	int x;
359 	u_char read_bit;
360 
361 	*read_data = 0;
362 	for (x = 0; x < 8; x++) {
363 		S24C16_do_bit(np, &read_bit, 1, gpreg);
364 		*read_data |= ((read_bit & 0x01) << (7 - x));
365 	}
366 
367 	S24C16_write_ack(np, ack_data, gpreg, gpcntl);
368 }
369 
370 #if SYM_CONF_NVRAM_WRITE_SUPPORT
371 /*
372  *  Write 'len' bytes starting at 'offset'.
373  */
374 static int sym_write_S24C16_nvram(struct sym_device *np, int offset,
375 		u_char *data, int len)
376 {
377 	u_char	gpcntl, gpreg;
378 	u_char	old_gpcntl, old_gpreg;
379 	u_char	ack_data;
380 	int	x;
381 
382 	/* save current state of GPCNTL and GPREG */
383 	old_gpreg	= INB(np, nc_gpreg);
384 	old_gpcntl	= INB(np, nc_gpcntl);
385 	gpcntl		= old_gpcntl & 0x1c;
386 
387 	/* set up GPREG & GPCNTL to set GPIO0 and GPIO1 in to known state */
388 	OUTB(np, nc_gpreg,  old_gpreg);
389 	OUTB(np, nc_gpcntl, gpcntl);
390 
391 	/* this is to set NVRAM into a known state with GPIO0/1 both low */
392 	gpreg = old_gpreg;
393 	S24C16_set_bit(np, 0, &gpreg, CLR_CLK);
394 	S24C16_set_bit(np, 0, &gpreg, CLR_BIT);
395 
396 	/* now set NVRAM inactive with GPIO0/1 both high */
397 	S24C16_stop(np, &gpreg);
398 
399 	/* NVRAM has to be written in segments of 16 bytes */
400 	for (x = 0; x < len ; x += 16) {
401 		do {
402 			S24C16_start(np, &gpreg);
403 			S24C16_write_byte(np, &ack_data,
404 					  0xa0 | (((offset+x) >> 7) & 0x0e),
405 					  &gpreg, &gpcntl);
406 		} while (ack_data & 0x01);
407 
408 		S24C16_write_byte(np, &ack_data, (offset+x) & 0xff,
409 				  &gpreg, &gpcntl);
410 
411 		for (y = 0; y < 16; y++)
412 			S24C16_write_byte(np, &ack_data, data[x+y],
413 					  &gpreg, &gpcntl);
414 		S24C16_stop(np, &gpreg);
415 	}
416 
417 	/* return GPIO0/1 to original states after having accessed NVRAM */
418 	OUTB(np, nc_gpcntl, old_gpcntl);
419 	OUTB(np, nc_gpreg,  old_gpreg);
420 
421 	return 0;
422 }
423 #endif /* SYM_CONF_NVRAM_WRITE_SUPPORT */
424 
425 /*
426  *  Read 'len' bytes starting at 'offset'.
427  */
428 static int sym_read_S24C16_nvram(struct sym_device *np, int offset, u_char *data, int len)
429 {
430 	u_char	gpcntl, gpreg;
431 	u_char	old_gpcntl, old_gpreg;
432 	u_char	ack_data;
433 	int	retv = 1;
434 	int	x;
435 
436 	/* save current state of GPCNTL and GPREG */
437 	old_gpreg	= INB(np, nc_gpreg);
438 	old_gpcntl	= INB(np, nc_gpcntl);
439 	gpcntl		= old_gpcntl & 0x1c;
440 
441 	/* set up GPREG & GPCNTL to set GPIO0 and GPIO1 in to known state */
442 	OUTB(np, nc_gpreg,  old_gpreg);
443 	OUTB(np, nc_gpcntl, gpcntl);
444 
445 	/* this is to set NVRAM into a known state with GPIO0/1 both low */
446 	gpreg = old_gpreg;
447 	S24C16_set_bit(np, 0, &gpreg, CLR_CLK);
448 	S24C16_set_bit(np, 0, &gpreg, CLR_BIT);
449 
450 	/* now set NVRAM inactive with GPIO0/1 both high */
451 	S24C16_stop(np, &gpreg);
452 
453 	/* activate NVRAM */
454 	S24C16_start(np, &gpreg);
455 
456 	/* write device code and random address MSB */
457 	S24C16_write_byte(np, &ack_data,
458 		0xa0 | ((offset >> 7) & 0x0e), &gpreg, &gpcntl);
459 	if (ack_data & 0x01)
460 		goto out;
461 
462 	/* write random address LSB */
463 	S24C16_write_byte(np, &ack_data,
464 		offset & 0xff, &gpreg, &gpcntl);
465 	if (ack_data & 0x01)
466 		goto out;
467 
468 	/* regenerate START state to set up for reading */
469 	S24C16_start(np, &gpreg);
470 
471 	/* rewrite device code and address MSB with read bit set (lsb = 0x01) */
472 	S24C16_write_byte(np, &ack_data,
473 		0xa1 | ((offset >> 7) & 0x0e), &gpreg, &gpcntl);
474 	if (ack_data & 0x01)
475 		goto out;
476 
477 	/* now set up GPIO0 for inputting data */
478 	gpcntl |= 0x01;
479 	OUTB(np, nc_gpcntl, gpcntl);
480 
481 	/* input all requested data - only part of total NVRAM */
482 	for (x = 0; x < len; x++)
483 		S24C16_read_byte(np, &data[x], (x == (len-1)), &gpreg, &gpcntl);
484 
485 	/* finally put NVRAM back in inactive mode */
486 	gpcntl &= 0xfe;
487 	OUTB(np, nc_gpcntl, gpcntl);
488 	S24C16_stop(np, &gpreg);
489 	retv = 0;
490 out:
491 	/* return GPIO0/1 to original states after having accessed NVRAM */
492 	OUTB(np, nc_gpcntl, old_gpcntl);
493 	OUTB(np, nc_gpreg,  old_gpreg);
494 
495 	return retv;
496 }
497 
498 #undef SET_BIT
499 #undef CLR_BIT
500 #undef SET_CLK
501 #undef CLR_CLK
502 
503 /*
504  *  Try reading Symbios NVRAM.
505  *  Return 0 if OK.
506  */
507 static int sym_read_Symbios_nvram(struct sym_device *np, Symbios_nvram *nvram)
508 {
509 	static u_char Symbios_trailer[6] = {0xfe, 0xfe, 0, 0, 0, 0};
510 	u_char *data = (u_char *) nvram;
511 	int len  = sizeof(*nvram);
512 	u_short	csum;
513 	int x;
514 
515 	/* probe the 24c16 and read the SYMBIOS 24c16 area */
516 	if (sym_read_S24C16_nvram (np, SYMBIOS_NVRAM_ADDRESS, data, len))
517 		return 1;
518 
519 	/* check valid NVRAM signature, verify byte count and checksum */
520 	if (nvram->type != 0 ||
521 	    memcmp(nvram->trailer, Symbios_trailer, 6) ||
522 	    nvram->byte_count != len - 12)
523 		return 1;
524 
525 	/* verify checksum */
526 	for (x = 6, csum = 0; x < len - 6; x++)
527 		csum += data[x];
528 	if (csum != nvram->checksum)
529 		return 1;
530 
531 	return 0;
532 }
533 
534 /*
535  *  93C46 EEPROM reading.
536  *
537  *  GPOI0 - data in
538  *  GPIO1 - data out
539  *  GPIO2 - clock
540  *  GPIO4 - chip select
541  *
542  *  Used by Tekram.
543  */
544 
545 /*
546  *  Pulse clock bit in GPIO0
547  */
548 static void T93C46_Clk(struct sym_device *np, u_char *gpreg)
549 {
550 	OUTB(np, nc_gpreg, *gpreg | 0x04);
551 	INB(np, nc_mbox1);
552 	udelay(2);
553 	OUTB(np, nc_gpreg, *gpreg);
554 }
555 
556 /*
557  *  Read bit from NVRAM
558  */
559 static void T93C46_Read_Bit(struct sym_device *np, u_char *read_bit, u_char *gpreg)
560 {
561 	udelay(2);
562 	T93C46_Clk(np, gpreg);
563 	*read_bit = INB(np, nc_gpreg);
564 }
565 
566 /*
567  *  Write bit to GPIO0
568  */
569 static void T93C46_Write_Bit(struct sym_device *np, u_char write_bit, u_char *gpreg)
570 {
571 	if (write_bit & 0x01)
572 		*gpreg |= 0x02;
573 	else
574 		*gpreg &= 0xfd;
575 
576 	*gpreg |= 0x10;
577 
578 	OUTB(np, nc_gpreg, *gpreg);
579 	INB(np, nc_mbox1);
580 	udelay(2);
581 
582 	T93C46_Clk(np, gpreg);
583 }
584 
585 /*
586  *  Send STOP condition to NVRAM - puts NVRAM to sleep... ZZZzzz!!
587  */
588 static void T93C46_Stop(struct sym_device *np, u_char *gpreg)
589 {
590 	*gpreg &= 0xef;
591 	OUTB(np, nc_gpreg, *gpreg);
592 	INB(np, nc_mbox1);
593 	udelay(2);
594 
595 	T93C46_Clk(np, gpreg);
596 }
597 
598 /*
599  *  Send read command and address to NVRAM
600  */
601 static void T93C46_Send_Command(struct sym_device *np, u_short write_data,
602 				u_char *read_bit, u_char *gpreg)
603 {
604 	int x;
605 
606 	/* send 9 bits, start bit (1), command (2), address (6)  */
607 	for (x = 0; x < 9; x++)
608 		T93C46_Write_Bit(np, (u_char) (write_data >> (8 - x)), gpreg);
609 
610 	*read_bit = INB(np, nc_gpreg);
611 }
612 
613 /*
614  *  READ 2 bytes from the NVRAM
615  */
616 static void T93C46_Read_Word(struct sym_device *np,
617 		unsigned short *nvram_data, unsigned char *gpreg)
618 {
619 	int x;
620 	u_char read_bit;
621 
622 	*nvram_data = 0;
623 	for (x = 0; x < 16; x++) {
624 		T93C46_Read_Bit(np, &read_bit, gpreg);
625 
626 		if (read_bit & 0x01)
627 			*nvram_data |=  (0x01 << (15 - x));
628 		else
629 			*nvram_data &= ~(0x01 << (15 - x));
630 	}
631 }
632 
633 /*
634  *  Read Tekram NvRAM data.
635  */
636 static int T93C46_Read_Data(struct sym_device *np, unsigned short *data,
637 		int len, unsigned char *gpreg)
638 {
639 	int x;
640 
641 	for (x = 0; x < len; x++)  {
642 		unsigned char read_bit;
643 		/* output read command and address */
644 		T93C46_Send_Command(np, 0x180 | x, &read_bit, gpreg);
645 		if (read_bit & 0x01)
646 			return 1; /* Bad */
647 		T93C46_Read_Word(np, &data[x], gpreg);
648 		T93C46_Stop(np, gpreg);
649 	}
650 
651 	return 0;
652 }
653 
654 /*
655  *  Try reading 93C46 Tekram NVRAM.
656  */
657 static int sym_read_T93C46_nvram(struct sym_device *np, Tekram_nvram *nvram)
658 {
659 	u_char gpcntl, gpreg;
660 	u_char old_gpcntl, old_gpreg;
661 	int retv = 1;
662 
663 	/* save current state of GPCNTL and GPREG */
664 	old_gpreg	= INB(np, nc_gpreg);
665 	old_gpcntl	= INB(np, nc_gpcntl);
666 
667 	/* set up GPREG & GPCNTL to set GPIO0/1/2/4 in to known state, 0 in,
668 	   1/2/4 out */
669 	gpreg = old_gpreg & 0xe9;
670 	OUTB(np, nc_gpreg, gpreg);
671 	gpcntl = (old_gpcntl & 0xe9) | 0x09;
672 	OUTB(np, nc_gpcntl, gpcntl);
673 
674 	/* input all of NVRAM, 64 words */
675 	retv = T93C46_Read_Data(np, (u_short *) nvram,
676 				sizeof(*nvram) / sizeof(short), &gpreg);
677 
678 	/* return GPIO0/1/2/4 to original states after having accessed NVRAM */
679 	OUTB(np, nc_gpcntl, old_gpcntl);
680 	OUTB(np, nc_gpreg,  old_gpreg);
681 
682 	return retv;
683 }
684 
685 /*
686  *  Try reading Tekram NVRAM.
687  *  Return 0 if OK.
688  */
689 static int sym_read_Tekram_nvram (struct sym_device *np, Tekram_nvram *nvram)
690 {
691 	u_char *data = (u_char *) nvram;
692 	int len = sizeof(*nvram);
693 	u_short	csum;
694 	int x;
695 
696 	switch (np->device_id) {
697 	case PCI_DEVICE_ID_NCR_53C885:
698 	case PCI_DEVICE_ID_NCR_53C895:
699 	case PCI_DEVICE_ID_NCR_53C896:
700 		x = sym_read_S24C16_nvram(np, TEKRAM_24C16_NVRAM_ADDRESS,
701 					  data, len);
702 		break;
703 	case PCI_DEVICE_ID_NCR_53C875:
704 		x = sym_read_S24C16_nvram(np, TEKRAM_24C16_NVRAM_ADDRESS,
705 					  data, len);
706 		if (!x)
707 			break;
708 	default:
709 		x = sym_read_T93C46_nvram(np, nvram);
710 		break;
711 	}
712 	if (x)
713 		return 1;
714 
715 	/* verify checksum */
716 	for (x = 0, csum = 0; x < len - 1; x += 2)
717 		csum += data[x] + (data[x+1] << 8);
718 	if (csum != 0x1234)
719 		return 1;
720 
721 	return 0;
722 }
723 
724 #ifdef CONFIG_PARISC
725 /*
726  * Host firmware (PDC) keeps a table for altering SCSI capabilities.
727  * Many newer machines export one channel of 53c896 chip as SE, 50-pin HD.
728  * Also used for Multi-initiator SCSI clusters to set the SCSI Initiator ID.
729  */
730 static int sym_read_parisc_pdc(struct sym_device *np, struct pdc_initiator *pdc)
731 {
732 	struct hardware_path hwpath;
733 	get_pci_node_path(np->pdev, &hwpath);
734 	if (!pdc_get_initiator(&hwpath, pdc))
735 		return 0;
736 
737 	return SYM_PARISC_PDC;
738 }
739 #else
740 static inline int sym_read_parisc_pdc(struct sym_device *np,
741 					struct pdc_initiator *x)
742 {
743 	return 0;
744 }
745 #endif
746 
747 /*
748  *  Try reading Symbios or Tekram NVRAM
749  */
750 int sym_read_nvram(struct sym_device *np, struct sym_nvram *nvp)
751 {
752 	if (!sym_read_Symbios_nvram(np, &nvp->data.Symbios)) {
753 		nvp->type = SYM_SYMBIOS_NVRAM;
754 		sym_display_Symbios_nvram(np, &nvp->data.Symbios);
755 	} else if (!sym_read_Tekram_nvram(np, &nvp->data.Tekram)) {
756 		nvp->type = SYM_TEKRAM_NVRAM;
757 		sym_display_Tekram_nvram(np, &nvp->data.Tekram);
758 	} else {
759 		nvp->type = sym_read_parisc_pdc(np, &nvp->data.parisc);
760 	}
761 	return nvp->type;
762 }
763 
764 char *sym_nvram_type(struct sym_nvram *nvp)
765 {
766 	switch (nvp->type) {
767 	case SYM_SYMBIOS_NVRAM:
768 		return "Symbios NVRAM";
769 	case SYM_TEKRAM_NVRAM:
770 		return "Tekram NVRAM";
771 	case SYM_PARISC_PDC:
772 		return "PA-RISC Firmware";
773 	default:
774 		return "No NVRAM";
775 	}
776 }
777