xref: /openbmc/linux/arch/mips/kernel/cpu-probe.c (revision b04b4f78)
1 /*
2  * Processor capabilities determination functions.
3  *
4  * Copyright (C) xxxx  the Anonymous
5  * Copyright (C) 1994 - 2006 Ralf Baechle
6  * Copyright (C) 2003, 2004  Maciej W. Rozycki
7  * Copyright (C) 2001, 2004  MIPS Inc.
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version
12  * 2 of the License, or (at your option) any later version.
13  */
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/ptrace.h>
17 #include <linux/stddef.h>
18 
19 #include <asm/bugs.h>
20 #include <asm/cpu.h>
21 #include <asm/fpu.h>
22 #include <asm/mipsregs.h>
23 #include <asm/system.h>
24 #include <asm/watch.h>
25 
26 /*
27  * Not all of the MIPS CPUs have the "wait" instruction available. Moreover,
28  * the implementation of the "wait" feature differs between CPU families. This
29  * points to the function that implements CPU specific wait.
30  * The wait instruction stops the pipeline and reduces the power consumption of
31  * the CPU very much.
32  */
33 void (*cpu_wait)(void) = NULL;
34 
35 static void r3081_wait(void)
36 {
37 	unsigned long cfg = read_c0_conf();
38 	write_c0_conf(cfg | R30XX_CONF_HALT);
39 }
40 
41 static void r39xx_wait(void)
42 {
43 	local_irq_disable();
44 	if (!need_resched())
45 		write_c0_conf(read_c0_conf() | TX39_CONF_HALT);
46 	local_irq_enable();
47 }
48 
49 extern void r4k_wait(void);
50 
51 /*
52  * This variant is preferable as it allows testing need_resched and going to
53  * sleep depending on the outcome atomically.  Unfortunately the "It is
54  * implementation-dependent whether the pipeline restarts when a non-enabled
55  * interrupt is requested" restriction in the MIPS32/MIPS64 architecture makes
56  * using this version a gamble.
57  */
58 void r4k_wait_irqoff(void)
59 {
60 	local_irq_disable();
61 	if (!need_resched())
62 		__asm__("	.set	push		\n"
63 			"	.set	mips3		\n"
64 			"	wait			\n"
65 			"	.set	pop		\n");
66 	local_irq_enable();
67 	__asm__(" 	.globl __pastwait	\n"
68 		"__pastwait:			\n");
69 	return;
70 }
71 
72 /*
73  * The RM7000 variant has to handle erratum 38.  The workaround is to not
74  * have any pending stores when the WAIT instruction is executed.
75  */
76 static void rm7k_wait_irqoff(void)
77 {
78 	local_irq_disable();
79 	if (!need_resched())
80 		__asm__(
81 		"	.set	push					\n"
82 		"	.set	mips3					\n"
83 		"	.set	noat					\n"
84 		"	mfc0	$1, $12					\n"
85 		"	sync						\n"
86 		"	mtc0	$1, $12		# stalls until W stage	\n"
87 		"	wait						\n"
88 		"	mtc0	$1, $12		# stalls until W stage	\n"
89 		"	.set	pop					\n");
90 	local_irq_enable();
91 }
92 
93 /* The Au1xxx wait is available only if using 32khz counter or
94  * external timer source, but specifically not CP0 Counter. */
95 int allow_au1k_wait;
96 
97 static void au1k_wait(void)
98 {
99 	if (!allow_au1k_wait)
100 		return;
101 
102 	/* using the wait instruction makes CP0 counter unusable */
103 	__asm__("	.set	mips3			\n"
104 		"	cache	0x14, 0(%0)		\n"
105 		"	cache	0x14, 32(%0)		\n"
106 		"	sync				\n"
107 		"	nop				\n"
108 		"	wait				\n"
109 		"	nop				\n"
110 		"	nop				\n"
111 		"	nop				\n"
112 		"	nop				\n"
113 		"	.set	mips0			\n"
114 		: : "r" (au1k_wait));
115 }
116 
117 static int __initdata nowait = 0;
118 
119 static int __init wait_disable(char *s)
120 {
121 	nowait = 1;
122 
123 	return 1;
124 }
125 
126 __setup("nowait", wait_disable);
127 
128 void __init check_wait(void)
129 {
130 	struct cpuinfo_mips *c = &current_cpu_data;
131 
132 	if (nowait) {
133 		printk("Wait instruction disabled.\n");
134 		return;
135 	}
136 
137 	switch (c->cputype) {
138 	case CPU_R3081:
139 	case CPU_R3081E:
140 		cpu_wait = r3081_wait;
141 		break;
142 	case CPU_TX3927:
143 		cpu_wait = r39xx_wait;
144 		break;
145 	case CPU_R4200:
146 /*	case CPU_R4300: */
147 	case CPU_R4600:
148 	case CPU_R4640:
149 	case CPU_R4650:
150 	case CPU_R4700:
151 	case CPU_R5000:
152 	case CPU_R5500:
153 	case CPU_NEVADA:
154 	case CPU_4KC:
155 	case CPU_4KEC:
156 	case CPU_4KSC:
157 	case CPU_5KC:
158 	case CPU_25KF:
159 	case CPU_PR4450:
160 	case CPU_BCM3302:
161 	case CPU_CAVIUM_OCTEON:
162 		cpu_wait = r4k_wait;
163 		break;
164 
165 	case CPU_RM7000:
166 		cpu_wait = rm7k_wait_irqoff;
167 		break;
168 
169 	case CPU_24K:
170 	case CPU_34K:
171 	case CPU_1004K:
172 		cpu_wait = r4k_wait;
173 		if (read_c0_config7() & MIPS_CONF7_WII)
174 			cpu_wait = r4k_wait_irqoff;
175 		break;
176 
177 	case CPU_74K:
178 		cpu_wait = r4k_wait;
179 		if ((c->processor_id & 0xff) >= PRID_REV_ENCODE_332(2, 1, 0))
180 			cpu_wait = r4k_wait_irqoff;
181 		break;
182 
183 	case CPU_TX49XX:
184 		cpu_wait = r4k_wait_irqoff;
185 		break;
186 	case CPU_ALCHEMY:
187 		cpu_wait = au1k_wait;
188 		break;
189 	case CPU_20KC:
190 		/*
191 		 * WAIT on Rev1.0 has E1, E2, E3 and E16.
192 		 * WAIT on Rev2.0 and Rev3.0 has E16.
193 		 * Rev3.1 WAIT is nop, why bother
194 		 */
195 		if ((c->processor_id & 0xff) <= 0x64)
196 			break;
197 
198 		/*
199 		 * Another rev is incremeting c0_count at a reduced clock
200 		 * rate while in WAIT mode.  So we basically have the choice
201 		 * between using the cp0 timer as clocksource or avoiding
202 		 * the WAIT instruction.  Until more details are known,
203 		 * disable the use of WAIT for 20Kc entirely.
204 		   cpu_wait = r4k_wait;
205 		 */
206 		break;
207 	case CPU_RM9000:
208 		if ((c->processor_id & 0x00ff) >= 0x40)
209 			cpu_wait = r4k_wait;
210 		break;
211 	default:
212 		break;
213 	}
214 }
215 
216 static inline void check_errata(void)
217 {
218 	struct cpuinfo_mips *c = &current_cpu_data;
219 
220 	switch (c->cputype) {
221 	case CPU_34K:
222 		/*
223 		 * Erratum "RPS May Cause Incorrect Instruction Execution"
224 		 * This code only handles VPE0, any SMP/SMTC/RTOS code
225 		 * making use of VPE1 will be responsable for that VPE.
226 		 */
227 		if ((c->processor_id & PRID_REV_MASK) <= PRID_REV_34K_V1_0_2)
228 			write_c0_config7(read_c0_config7() | MIPS_CONF7_RPS);
229 		break;
230 	default:
231 		break;
232 	}
233 }
234 
235 void __init check_bugs32(void)
236 {
237 	check_errata();
238 }
239 
240 /*
241  * Probe whether cpu has config register by trying to play with
242  * alternate cache bit and see whether it matters.
243  * It's used by cpu_probe to distinguish between R3000A and R3081.
244  */
245 static inline int cpu_has_confreg(void)
246 {
247 #ifdef CONFIG_CPU_R3000
248 	extern unsigned long r3k_cache_size(unsigned long);
249 	unsigned long size1, size2;
250 	unsigned long cfg = read_c0_conf();
251 
252 	size1 = r3k_cache_size(ST0_ISC);
253 	write_c0_conf(cfg ^ R30XX_CONF_AC);
254 	size2 = r3k_cache_size(ST0_ISC);
255 	write_c0_conf(cfg);
256 	return size1 != size2;
257 #else
258 	return 0;
259 #endif
260 }
261 
262 /*
263  * Get the FPU Implementation/Revision.
264  */
265 static inline unsigned long cpu_get_fpu_id(void)
266 {
267 	unsigned long tmp, fpu_id;
268 
269 	tmp = read_c0_status();
270 	__enable_fpu();
271 	fpu_id = read_32bit_cp1_register(CP1_REVISION);
272 	write_c0_status(tmp);
273 	return fpu_id;
274 }
275 
276 /*
277  * Check the CPU has an FPU the official way.
278  */
279 static inline int __cpu_has_fpu(void)
280 {
281 	return ((cpu_get_fpu_id() & 0xff00) != FPIR_IMP_NONE);
282 }
283 
284 #define R4K_OPTS (MIPS_CPU_TLB | MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE \
285 		| MIPS_CPU_COUNTER)
286 
287 static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
288 {
289 	switch (c->processor_id & 0xff00) {
290 	case PRID_IMP_R2000:
291 		c->cputype = CPU_R2000;
292 		__cpu_name[cpu] = "R2000";
293 		c->isa_level = MIPS_CPU_ISA_I;
294 		c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
295 		             MIPS_CPU_NOFPUEX;
296 		if (__cpu_has_fpu())
297 			c->options |= MIPS_CPU_FPU;
298 		c->tlbsize = 64;
299 		break;
300 	case PRID_IMP_R3000:
301 		if ((c->processor_id & 0xff) == PRID_REV_R3000A) {
302 			if (cpu_has_confreg()) {
303 				c->cputype = CPU_R3081E;
304 				__cpu_name[cpu] = "R3081";
305 			} else {
306 				c->cputype = CPU_R3000A;
307 				__cpu_name[cpu] = "R3000A";
308 			}
309 			break;
310 		} else {
311 			c->cputype = CPU_R3000;
312 			__cpu_name[cpu] = "R3000";
313 		}
314 		c->isa_level = MIPS_CPU_ISA_I;
315 		c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
316 		             MIPS_CPU_NOFPUEX;
317 		if (__cpu_has_fpu())
318 			c->options |= MIPS_CPU_FPU;
319 		c->tlbsize = 64;
320 		break;
321 	case PRID_IMP_R4000:
322 		if (read_c0_config() & CONF_SC) {
323 			if ((c->processor_id & 0xff) >= PRID_REV_R4400) {
324 				c->cputype = CPU_R4400PC;
325 				__cpu_name[cpu] = "R4400PC";
326 			} else {
327 				c->cputype = CPU_R4000PC;
328 				__cpu_name[cpu] = "R4000PC";
329 			}
330 		} else {
331 			if ((c->processor_id & 0xff) >= PRID_REV_R4400) {
332 				c->cputype = CPU_R4400SC;
333 				__cpu_name[cpu] = "R4400SC";
334 			} else {
335 				c->cputype = CPU_R4000SC;
336 				__cpu_name[cpu] = "R4000SC";
337 			}
338 		}
339 
340 		c->isa_level = MIPS_CPU_ISA_III;
341 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
342 		             MIPS_CPU_WATCH | MIPS_CPU_VCE |
343 		             MIPS_CPU_LLSC;
344 		c->tlbsize = 48;
345 		break;
346 	case PRID_IMP_VR41XX:
347 		switch (c->processor_id & 0xf0) {
348 		case PRID_REV_VR4111:
349 			c->cputype = CPU_VR4111;
350 			__cpu_name[cpu] = "NEC VR4111";
351 			break;
352 		case PRID_REV_VR4121:
353 			c->cputype = CPU_VR4121;
354 			__cpu_name[cpu] = "NEC VR4121";
355 			break;
356 		case PRID_REV_VR4122:
357 			if ((c->processor_id & 0xf) < 0x3) {
358 				c->cputype = CPU_VR4122;
359 				__cpu_name[cpu] = "NEC VR4122";
360 			} else {
361 				c->cputype = CPU_VR4181A;
362 				__cpu_name[cpu] = "NEC VR4181A";
363 			}
364 			break;
365 		case PRID_REV_VR4130:
366 			if ((c->processor_id & 0xf) < 0x4) {
367 				c->cputype = CPU_VR4131;
368 				__cpu_name[cpu] = "NEC VR4131";
369 			} else {
370 				c->cputype = CPU_VR4133;
371 				__cpu_name[cpu] = "NEC VR4133";
372 			}
373 			break;
374 		default:
375 			printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
376 			c->cputype = CPU_VR41XX;
377 			__cpu_name[cpu] = "NEC Vr41xx";
378 			break;
379 		}
380 		c->isa_level = MIPS_CPU_ISA_III;
381 		c->options = R4K_OPTS;
382 		c->tlbsize = 32;
383 		break;
384 	case PRID_IMP_R4300:
385 		c->cputype = CPU_R4300;
386 		__cpu_name[cpu] = "R4300";
387 		c->isa_level = MIPS_CPU_ISA_III;
388 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
389 		             MIPS_CPU_LLSC;
390 		c->tlbsize = 32;
391 		break;
392 	case PRID_IMP_R4600:
393 		c->cputype = CPU_R4600;
394 		__cpu_name[cpu] = "R4600";
395 		c->isa_level = MIPS_CPU_ISA_III;
396 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
397 			     MIPS_CPU_LLSC;
398 		c->tlbsize = 48;
399 		break;
400 	#if 0
401  	case PRID_IMP_R4650:
402 		/*
403 		 * This processor doesn't have an MMU, so it's not
404 		 * "real easy" to run Linux on it. It is left purely
405 		 * for documentation.  Commented out because it shares
406 		 * it's c0_prid id number with the TX3900.
407 		 */
408 		c->cputype = CPU_R4650;
409 		__cpu_name[cpu] = "R4650";
410 	 	c->isa_level = MIPS_CPU_ISA_III;
411 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_LLSC;
412 	        c->tlbsize = 48;
413 		break;
414 	#endif
415 	case PRID_IMP_TX39:
416 		c->isa_level = MIPS_CPU_ISA_I;
417 		c->options = MIPS_CPU_TLB | MIPS_CPU_TX39_CACHE;
418 
419 		if ((c->processor_id & 0xf0) == (PRID_REV_TX3927 & 0xf0)) {
420 			c->cputype = CPU_TX3927;
421 			__cpu_name[cpu] = "TX3927";
422 			c->tlbsize = 64;
423 		} else {
424 			switch (c->processor_id & 0xff) {
425 			case PRID_REV_TX3912:
426 				c->cputype = CPU_TX3912;
427 				__cpu_name[cpu] = "TX3912";
428 				c->tlbsize = 32;
429 				break;
430 			case PRID_REV_TX3922:
431 				c->cputype = CPU_TX3922;
432 				__cpu_name[cpu] = "TX3922";
433 				c->tlbsize = 64;
434 				break;
435 			}
436 		}
437 		break;
438 	case PRID_IMP_R4700:
439 		c->cputype = CPU_R4700;
440 		__cpu_name[cpu] = "R4700";
441 		c->isa_level = MIPS_CPU_ISA_III;
442 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
443 		             MIPS_CPU_LLSC;
444 		c->tlbsize = 48;
445 		break;
446 	case PRID_IMP_TX49:
447 		c->cputype = CPU_TX49XX;
448 		__cpu_name[cpu] = "R49XX";
449 		c->isa_level = MIPS_CPU_ISA_III;
450 		c->options = R4K_OPTS | MIPS_CPU_LLSC;
451 		if (!(c->processor_id & 0x08))
452 			c->options |= MIPS_CPU_FPU | MIPS_CPU_32FPR;
453 		c->tlbsize = 48;
454 		break;
455 	case PRID_IMP_R5000:
456 		c->cputype = CPU_R5000;
457 		__cpu_name[cpu] = "R5000";
458 		c->isa_level = MIPS_CPU_ISA_IV;
459 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
460 		             MIPS_CPU_LLSC;
461 		c->tlbsize = 48;
462 		break;
463 	case PRID_IMP_R5432:
464 		c->cputype = CPU_R5432;
465 		__cpu_name[cpu] = "R5432";
466 		c->isa_level = MIPS_CPU_ISA_IV;
467 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
468 		             MIPS_CPU_WATCH | MIPS_CPU_LLSC;
469 		c->tlbsize = 48;
470 		break;
471 	case PRID_IMP_R5500:
472 		c->cputype = CPU_R5500;
473 		__cpu_name[cpu] = "R5500";
474 		c->isa_level = MIPS_CPU_ISA_IV;
475 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
476 		             MIPS_CPU_WATCH | MIPS_CPU_LLSC;
477 		c->tlbsize = 48;
478 		break;
479 	case PRID_IMP_NEVADA:
480 		c->cputype = CPU_NEVADA;
481 		__cpu_name[cpu] = "Nevada";
482 		c->isa_level = MIPS_CPU_ISA_IV;
483 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
484 		             MIPS_CPU_DIVEC | MIPS_CPU_LLSC;
485 		c->tlbsize = 48;
486 		break;
487 	case PRID_IMP_R6000:
488 		c->cputype = CPU_R6000;
489 		__cpu_name[cpu] = "R6000";
490 		c->isa_level = MIPS_CPU_ISA_II;
491 		c->options = MIPS_CPU_TLB | MIPS_CPU_FPU |
492 		             MIPS_CPU_LLSC;
493 		c->tlbsize = 32;
494 		break;
495 	case PRID_IMP_R6000A:
496 		c->cputype = CPU_R6000A;
497 		__cpu_name[cpu] = "R6000A";
498 		c->isa_level = MIPS_CPU_ISA_II;
499 		c->options = MIPS_CPU_TLB | MIPS_CPU_FPU |
500 		             MIPS_CPU_LLSC;
501 		c->tlbsize = 32;
502 		break;
503 	case PRID_IMP_RM7000:
504 		c->cputype = CPU_RM7000;
505 		__cpu_name[cpu] = "RM7000";
506 		c->isa_level = MIPS_CPU_ISA_IV;
507 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
508 		             MIPS_CPU_LLSC;
509 		/*
510 		 * Undocumented RM7000:  Bit 29 in the info register of
511 		 * the RM7000 v2.0 indicates if the TLB has 48 or 64
512 		 * entries.
513 		 *
514 		 * 29      1 =>    64 entry JTLB
515 		 *         0 =>    48 entry JTLB
516 		 */
517 		c->tlbsize = (read_c0_info() & (1 << 29)) ? 64 : 48;
518 		break;
519 	case PRID_IMP_RM9000:
520 		c->cputype = CPU_RM9000;
521 		__cpu_name[cpu] = "RM9000";
522 		c->isa_level = MIPS_CPU_ISA_IV;
523 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
524 		             MIPS_CPU_LLSC;
525 		/*
526 		 * Bit 29 in the info register of the RM9000
527 		 * indicates if the TLB has 48 or 64 entries.
528 		 *
529 		 * 29      1 =>    64 entry JTLB
530 		 *         0 =>    48 entry JTLB
531 		 */
532 		c->tlbsize = (read_c0_info() & (1 << 29)) ? 64 : 48;
533 		break;
534 	case PRID_IMP_R8000:
535 		c->cputype = CPU_R8000;
536 		__cpu_name[cpu] = "RM8000";
537 		c->isa_level = MIPS_CPU_ISA_IV;
538 		c->options = MIPS_CPU_TLB | MIPS_CPU_4KEX |
539 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
540 		             MIPS_CPU_LLSC;
541 		c->tlbsize = 384;      /* has weird TLB: 3-way x 128 */
542 		break;
543 	case PRID_IMP_R10000:
544 		c->cputype = CPU_R10000;
545 		__cpu_name[cpu] = "R10000";
546 		c->isa_level = MIPS_CPU_ISA_IV;
547 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
548 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
549 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
550 		             MIPS_CPU_LLSC;
551 		c->tlbsize = 64;
552 		break;
553 	case PRID_IMP_R12000:
554 		c->cputype = CPU_R12000;
555 		__cpu_name[cpu] = "R12000";
556 		c->isa_level = MIPS_CPU_ISA_IV;
557 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
558 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
559 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
560 		             MIPS_CPU_LLSC;
561 		c->tlbsize = 64;
562 		break;
563 	case PRID_IMP_R14000:
564 		c->cputype = CPU_R14000;
565 		__cpu_name[cpu] = "R14000";
566 		c->isa_level = MIPS_CPU_ISA_IV;
567 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
568 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
569 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
570 		             MIPS_CPU_LLSC;
571 		c->tlbsize = 64;
572 		break;
573 	case PRID_IMP_LOONGSON2:
574 		c->cputype = CPU_LOONGSON2;
575 		__cpu_name[cpu] = "ICT Loongson-2";
576 		c->isa_level = MIPS_CPU_ISA_III;
577 		c->options = R4K_OPTS |
578 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
579 			     MIPS_CPU_32FPR;
580 		c->tlbsize = 64;
581 		break;
582 	}
583 }
584 
585 static char unknown_isa[] __cpuinitdata = KERN_ERR \
586 	"Unsupported ISA type, c0.config0: %d.";
587 
588 static inline unsigned int decode_config0(struct cpuinfo_mips *c)
589 {
590 	unsigned int config0;
591 	int isa;
592 
593 	config0 = read_c0_config();
594 
595 	if (((config0 & MIPS_CONF_MT) >> 7) == 1)
596 		c->options |= MIPS_CPU_TLB;
597 	isa = (config0 & MIPS_CONF_AT) >> 13;
598 	switch (isa) {
599 	case 0:
600 		switch ((config0 & MIPS_CONF_AR) >> 10) {
601 		case 0:
602 			c->isa_level = MIPS_CPU_ISA_M32R1;
603 			break;
604 		case 1:
605 			c->isa_level = MIPS_CPU_ISA_M32R2;
606 			break;
607 		default:
608 			goto unknown;
609 		}
610 		break;
611 	case 2:
612 		switch ((config0 & MIPS_CONF_AR) >> 10) {
613 		case 0:
614 			c->isa_level = MIPS_CPU_ISA_M64R1;
615 			break;
616 		case 1:
617 			c->isa_level = MIPS_CPU_ISA_M64R2;
618 			break;
619 		default:
620 			goto unknown;
621 		}
622 		break;
623 	default:
624 		goto unknown;
625 	}
626 
627 	return config0 & MIPS_CONF_M;
628 
629 unknown:
630 	panic(unknown_isa, config0);
631 }
632 
633 static inline unsigned int decode_config1(struct cpuinfo_mips *c)
634 {
635 	unsigned int config1;
636 
637 	config1 = read_c0_config1();
638 
639 	if (config1 & MIPS_CONF1_MD)
640 		c->ases |= MIPS_ASE_MDMX;
641 	if (config1 & MIPS_CONF1_WR)
642 		c->options |= MIPS_CPU_WATCH;
643 	if (config1 & MIPS_CONF1_CA)
644 		c->ases |= MIPS_ASE_MIPS16;
645 	if (config1 & MIPS_CONF1_EP)
646 		c->options |= MIPS_CPU_EJTAG;
647 	if (config1 & MIPS_CONF1_FP) {
648 		c->options |= MIPS_CPU_FPU;
649 		c->options |= MIPS_CPU_32FPR;
650 	}
651 	if (cpu_has_tlb)
652 		c->tlbsize = ((config1 & MIPS_CONF1_TLBS) >> 25) + 1;
653 
654 	return config1 & MIPS_CONF_M;
655 }
656 
657 static inline unsigned int decode_config2(struct cpuinfo_mips *c)
658 {
659 	unsigned int config2;
660 
661 	config2 = read_c0_config2();
662 
663 	if (config2 & MIPS_CONF2_SL)
664 		c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
665 
666 	return config2 & MIPS_CONF_M;
667 }
668 
669 static inline unsigned int decode_config3(struct cpuinfo_mips *c)
670 {
671 	unsigned int config3;
672 
673 	config3 = read_c0_config3();
674 
675 	if (config3 & MIPS_CONF3_SM)
676 		c->ases |= MIPS_ASE_SMARTMIPS;
677 	if (config3 & MIPS_CONF3_DSP)
678 		c->ases |= MIPS_ASE_DSP;
679 	if (config3 & MIPS_CONF3_VINT)
680 		c->options |= MIPS_CPU_VINT;
681 	if (config3 & MIPS_CONF3_VEIC)
682 		c->options |= MIPS_CPU_VEIC;
683 	if (config3 & MIPS_CONF3_MT)
684 	        c->ases |= MIPS_ASE_MIPSMT;
685 	if (config3 & MIPS_CONF3_ULRI)
686 		c->options |= MIPS_CPU_ULRI;
687 
688 	return config3 & MIPS_CONF_M;
689 }
690 
691 static void __cpuinit decode_configs(struct cpuinfo_mips *c)
692 {
693 	int ok;
694 
695 	/* MIPS32 or MIPS64 compliant CPU.  */
696 	c->options = MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE | MIPS_CPU_COUNTER |
697 	             MIPS_CPU_DIVEC | MIPS_CPU_LLSC | MIPS_CPU_MCHECK;
698 
699 	c->scache.flags = MIPS_CACHE_NOT_PRESENT;
700 
701 	ok = decode_config0(c);			/* Read Config registers.  */
702 	BUG_ON(!ok);				/* Arch spec violation!  */
703 	if (ok)
704 		ok = decode_config1(c);
705 	if (ok)
706 		ok = decode_config2(c);
707 	if (ok)
708 		ok = decode_config3(c);
709 
710 	mips_probe_watch_registers(c);
711 }
712 
713 #ifdef CONFIG_CPU_MIPSR2
714 extern void spram_config(void);
715 #else
716 static inline void spram_config(void) {}
717 #endif
718 
719 static inline void cpu_probe_mips(struct cpuinfo_mips *c, unsigned int cpu)
720 {
721 	decode_configs(c);
722 	switch (c->processor_id & 0xff00) {
723 	case PRID_IMP_4KC:
724 		c->cputype = CPU_4KC;
725 		__cpu_name[cpu] = "MIPS 4Kc";
726 		break;
727 	case PRID_IMP_4KEC:
728 		c->cputype = CPU_4KEC;
729 		__cpu_name[cpu] = "MIPS 4KEc";
730 		break;
731 	case PRID_IMP_4KECR2:
732 		c->cputype = CPU_4KEC;
733 		__cpu_name[cpu] = "MIPS 4KEc";
734 		break;
735 	case PRID_IMP_4KSC:
736 	case PRID_IMP_4KSD:
737 		c->cputype = CPU_4KSC;
738 		__cpu_name[cpu] = "MIPS 4KSc";
739 		break;
740 	case PRID_IMP_5KC:
741 		c->cputype = CPU_5KC;
742 		__cpu_name[cpu] = "MIPS 5Kc";
743 		break;
744 	case PRID_IMP_20KC:
745 		c->cputype = CPU_20KC;
746 		__cpu_name[cpu] = "MIPS 20Kc";
747 		break;
748 	case PRID_IMP_24K:
749 	case PRID_IMP_24KE:
750 		c->cputype = CPU_24K;
751 		__cpu_name[cpu] = "MIPS 24Kc";
752 		break;
753 	case PRID_IMP_25KF:
754 		c->cputype = CPU_25KF;
755 		__cpu_name[cpu] = "MIPS 25Kc";
756 		break;
757 	case PRID_IMP_34K:
758 		c->cputype = CPU_34K;
759 		__cpu_name[cpu] = "MIPS 34Kc";
760 		break;
761 	case PRID_IMP_74K:
762 		c->cputype = CPU_74K;
763 		__cpu_name[cpu] = "MIPS 74Kc";
764 		break;
765 	case PRID_IMP_1004K:
766 		c->cputype = CPU_1004K;
767 		__cpu_name[cpu] = "MIPS 1004Kc";
768 		break;
769 	}
770 
771 	spram_config();
772 }
773 
774 static inline void cpu_probe_alchemy(struct cpuinfo_mips *c, unsigned int cpu)
775 {
776 	decode_configs(c);
777 	switch (c->processor_id & 0xff00) {
778 	case PRID_IMP_AU1_REV1:
779 	case PRID_IMP_AU1_REV2:
780 		c->cputype = CPU_ALCHEMY;
781 		switch ((c->processor_id >> 24) & 0xff) {
782 		case 0:
783 			__cpu_name[cpu] = "Au1000";
784 			break;
785 		case 1:
786 			__cpu_name[cpu] = "Au1500";
787 			break;
788 		case 2:
789 			__cpu_name[cpu] = "Au1100";
790 			break;
791 		case 3:
792 			__cpu_name[cpu] = "Au1550";
793 			break;
794 		case 4:
795 			__cpu_name[cpu] = "Au1200";
796 			if ((c->processor_id & 0xff) == 2)
797 				__cpu_name[cpu] = "Au1250";
798 			break;
799 		case 5:
800 			__cpu_name[cpu] = "Au1210";
801 			break;
802 		default:
803 			__cpu_name[cpu] = "Au1xxx";
804 			break;
805 		}
806 		break;
807 	}
808 }
809 
810 static inline void cpu_probe_sibyte(struct cpuinfo_mips *c, unsigned int cpu)
811 {
812 	decode_configs(c);
813 
814 	switch (c->processor_id & 0xff00) {
815 	case PRID_IMP_SB1:
816 		c->cputype = CPU_SB1;
817 		__cpu_name[cpu] = "SiByte SB1";
818 		/* FPU in pass1 is known to have issues. */
819 		if ((c->processor_id & 0xff) < 0x02)
820 			c->options &= ~(MIPS_CPU_FPU | MIPS_CPU_32FPR);
821 		break;
822 	case PRID_IMP_SB1A:
823 		c->cputype = CPU_SB1A;
824 		__cpu_name[cpu] = "SiByte SB1A";
825 		break;
826 	}
827 }
828 
829 static inline void cpu_probe_sandcraft(struct cpuinfo_mips *c, unsigned int cpu)
830 {
831 	decode_configs(c);
832 	switch (c->processor_id & 0xff00) {
833 	case PRID_IMP_SR71000:
834 		c->cputype = CPU_SR71000;
835 		__cpu_name[cpu] = "Sandcraft SR71000";
836 		c->scache.ways = 8;
837 		c->tlbsize = 64;
838 		break;
839 	}
840 }
841 
842 static inline void cpu_probe_nxp(struct cpuinfo_mips *c, unsigned int cpu)
843 {
844 	decode_configs(c);
845 	switch (c->processor_id & 0xff00) {
846 	case PRID_IMP_PR4450:
847 		c->cputype = CPU_PR4450;
848 		__cpu_name[cpu] = "Philips PR4450";
849 		c->isa_level = MIPS_CPU_ISA_M32R1;
850 		break;
851 	}
852 }
853 
854 static inline void cpu_probe_broadcom(struct cpuinfo_mips *c, unsigned int cpu)
855 {
856 	decode_configs(c);
857 	switch (c->processor_id & 0xff00) {
858 	case PRID_IMP_BCM3302:
859 		c->cputype = CPU_BCM3302;
860 		__cpu_name[cpu] = "Broadcom BCM3302";
861 		break;
862 	case PRID_IMP_BCM4710:
863 		c->cputype = CPU_BCM4710;
864 		__cpu_name[cpu] = "Broadcom BCM4710";
865 		break;
866 	}
867 }
868 
869 static inline void cpu_probe_cavium(struct cpuinfo_mips *c, unsigned int cpu)
870 {
871 	decode_configs(c);
872 	switch (c->processor_id & 0xff00) {
873 	case PRID_IMP_CAVIUM_CN38XX:
874 	case PRID_IMP_CAVIUM_CN31XX:
875 	case PRID_IMP_CAVIUM_CN30XX:
876 	case PRID_IMP_CAVIUM_CN58XX:
877 	case PRID_IMP_CAVIUM_CN56XX:
878 	case PRID_IMP_CAVIUM_CN50XX:
879 	case PRID_IMP_CAVIUM_CN52XX:
880 		c->cputype = CPU_CAVIUM_OCTEON;
881 		__cpu_name[cpu] = "Cavium Octeon";
882 		break;
883 	default:
884 		printk(KERN_INFO "Unknown Octeon chip!\n");
885 		c->cputype = CPU_UNKNOWN;
886 		break;
887 	}
888 }
889 
890 const char *__cpu_name[NR_CPUS];
891 
892 __cpuinit void cpu_probe(void)
893 {
894 	struct cpuinfo_mips *c = &current_cpu_data;
895 	unsigned int cpu = smp_processor_id();
896 
897 	c->processor_id	= PRID_IMP_UNKNOWN;
898 	c->fpu_id	= FPIR_IMP_NONE;
899 	c->cputype	= CPU_UNKNOWN;
900 
901 	c->processor_id = read_c0_prid();
902 	switch (c->processor_id & 0xff0000) {
903 	case PRID_COMP_LEGACY:
904 		cpu_probe_legacy(c, cpu);
905 		break;
906 	case PRID_COMP_MIPS:
907 		cpu_probe_mips(c, cpu);
908 		break;
909 	case PRID_COMP_ALCHEMY:
910 		cpu_probe_alchemy(c, cpu);
911 		break;
912 	case PRID_COMP_SIBYTE:
913 		cpu_probe_sibyte(c, cpu);
914 		break;
915 	case PRID_COMP_BROADCOM:
916 		cpu_probe_broadcom(c, cpu);
917 		break;
918 	case PRID_COMP_SANDCRAFT:
919 		cpu_probe_sandcraft(c, cpu);
920 		break;
921 	case PRID_COMP_NXP:
922 		cpu_probe_nxp(c, cpu);
923 		break;
924 	case PRID_COMP_CAVIUM:
925 		cpu_probe_cavium(c, cpu);
926 		break;
927 	}
928 
929 	BUG_ON(!__cpu_name[cpu]);
930 	BUG_ON(c->cputype == CPU_UNKNOWN);
931 
932 	/*
933 	 * Platform code can force the cpu type to optimize code
934 	 * generation. In that case be sure the cpu type is correctly
935 	 * manually setup otherwise it could trigger some nasty bugs.
936 	 */
937 	BUG_ON(current_cpu_type() != c->cputype);
938 
939 	if (c->options & MIPS_CPU_FPU) {
940 		c->fpu_id = cpu_get_fpu_id();
941 
942 		if (c->isa_level == MIPS_CPU_ISA_M32R1 ||
943 		    c->isa_level == MIPS_CPU_ISA_M32R2 ||
944 		    c->isa_level == MIPS_CPU_ISA_M64R1 ||
945 		    c->isa_level == MIPS_CPU_ISA_M64R2) {
946 			if (c->fpu_id & MIPS_FPIR_3D)
947 				c->ases |= MIPS_ASE_MIPS3D;
948 		}
949 	}
950 
951 	if (cpu_has_mips_r2)
952 		c->srsets = ((read_c0_srsctl() >> 26) & 0x0f) + 1;
953 	else
954 		c->srsets = 1;
955 }
956 
957 __cpuinit void cpu_report(void)
958 {
959 	struct cpuinfo_mips *c = &current_cpu_data;
960 
961 	printk(KERN_INFO "CPU revision is: %08x (%s)\n",
962 	       c->processor_id, cpu_name_string());
963 	if (c->options & MIPS_CPU_FPU)
964 		printk(KERN_INFO "FPU revision is: %08x\n", c->fpu_id);
965 }
966