xref: /openbmc/linux/arch/mips/kernel/cpu-probe.c (revision e8e0929d)
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/smp.h>
18 #include <linux/stddef.h>
19 
20 #include <asm/bugs.h>
21 #include <asm/cpu.h>
22 #include <asm/fpu.h>
23 #include <asm/mipsregs.h>
24 #include <asm/system.h>
25 #include <asm/watch.h>
26 
27 /*
28  * Not all of the MIPS CPUs have the "wait" instruction available. Moreover,
29  * the implementation of the "wait" feature differs between CPU families. This
30  * points to the function that implements CPU specific wait.
31  * The wait instruction stops the pipeline and reduces the power consumption of
32  * the CPU very much.
33  */
34 void (*cpu_wait)(void);
35 
36 static void r3081_wait(void)
37 {
38 	unsigned long cfg = read_c0_conf();
39 	write_c0_conf(cfg | R30XX_CONF_HALT);
40 }
41 
42 static void r39xx_wait(void)
43 {
44 	local_irq_disable();
45 	if (!need_resched())
46 		write_c0_conf(read_c0_conf() | TX39_CONF_HALT);
47 	local_irq_enable();
48 }
49 
50 extern void r4k_wait(void);
51 
52 /*
53  * This variant is preferable as it allows testing need_resched and going to
54  * sleep depending on the outcome atomically.  Unfortunately the "It is
55  * implementation-dependent whether the pipeline restarts when a non-enabled
56  * interrupt is requested" restriction in the MIPS32/MIPS64 architecture makes
57  * using this version a gamble.
58  */
59 void r4k_wait_irqoff(void)
60 {
61 	local_irq_disable();
62 	if (!need_resched())
63 		__asm__("	.set	push		\n"
64 			"	.set	mips3		\n"
65 			"	wait			\n"
66 			"	.set	pop		\n");
67 	local_irq_enable();
68 	__asm__(" 	.globl __pastwait	\n"
69 		"__pastwait:			\n");
70 	return;
71 }
72 
73 /*
74  * The RM7000 variant has to handle erratum 38.  The workaround is to not
75  * have any pending stores when the WAIT instruction is executed.
76  */
77 static void rm7k_wait_irqoff(void)
78 {
79 	local_irq_disable();
80 	if (!need_resched())
81 		__asm__(
82 		"	.set	push					\n"
83 		"	.set	mips3					\n"
84 		"	.set	noat					\n"
85 		"	mfc0	$1, $12					\n"
86 		"	sync						\n"
87 		"	mtc0	$1, $12		# stalls until W stage	\n"
88 		"	wait						\n"
89 		"	mtc0	$1, $12		# stalls until W stage	\n"
90 		"	.set	pop					\n");
91 	local_irq_enable();
92 }
93 
94 /*
95  * The Au1xxx wait is available only if using 32khz counter or
96  * external timer source, but specifically not CP0 Counter.
97  * alchemy/common/time.c may override cpu_wait!
98  */
99 static void au1k_wait(void)
100 {
101 	__asm__("	.set	mips3			\n"
102 		"	cache	0x14, 0(%0)		\n"
103 		"	cache	0x14, 32(%0)		\n"
104 		"	sync				\n"
105 		"	nop				\n"
106 		"	wait				\n"
107 		"	nop				\n"
108 		"	nop				\n"
109 		"	nop				\n"
110 		"	nop				\n"
111 		"	.set	mips0			\n"
112 		: : "r" (au1k_wait));
113 }
114 
115 static int __initdata nowait;
116 
117 static int __init wait_disable(char *s)
118 {
119 	nowait = 1;
120 
121 	return 1;
122 }
123 
124 __setup("nowait", wait_disable);
125 
126 void __init check_wait(void)
127 {
128 	struct cpuinfo_mips *c = &current_cpu_data;
129 
130 	if (nowait) {
131 		printk("Wait instruction disabled.\n");
132 		return;
133 	}
134 
135 	switch (c->cputype) {
136 	case CPU_R3081:
137 	case CPU_R3081E:
138 		cpu_wait = r3081_wait;
139 		break;
140 	case CPU_TX3927:
141 		cpu_wait = r39xx_wait;
142 		break;
143 	case CPU_R4200:
144 /*	case CPU_R4300: */
145 	case CPU_R4600:
146 	case CPU_R4640:
147 	case CPU_R4650:
148 	case CPU_R4700:
149 	case CPU_R5000:
150 	case CPU_R5500:
151 	case CPU_NEVADA:
152 	case CPU_4KC:
153 	case CPU_4KEC:
154 	case CPU_4KSC:
155 	case CPU_5KC:
156 	case CPU_25KF:
157 	case CPU_PR4450:
158 	case CPU_BCM3302:
159 	case CPU_BCM6338:
160 	case CPU_BCM6348:
161 	case CPU_BCM6358:
162 	case CPU_CAVIUM_OCTEON:
163 		cpu_wait = r4k_wait;
164 		break;
165 
166 	case CPU_RM7000:
167 		cpu_wait = rm7k_wait_irqoff;
168 		break;
169 
170 	case CPU_24K:
171 	case CPU_34K:
172 	case CPU_1004K:
173 		cpu_wait = r4k_wait;
174 		if (read_c0_config7() & MIPS_CONF7_WII)
175 			cpu_wait = r4k_wait_irqoff;
176 		break;
177 
178 	case CPU_74K:
179 		cpu_wait = r4k_wait;
180 		if ((c->processor_id & 0xff) >= PRID_REV_ENCODE_332(2, 1, 0))
181 			cpu_wait = r4k_wait_irqoff;
182 		break;
183 
184 	case CPU_TX49XX:
185 		cpu_wait = r4k_wait_irqoff;
186 		break;
187 	case CPU_ALCHEMY:
188 		cpu_wait = au1k_wait;
189 		break;
190 	case CPU_20KC:
191 		/*
192 		 * WAIT on Rev1.0 has E1, E2, E3 and E16.
193 		 * WAIT on Rev2.0 and Rev3.0 has E16.
194 		 * Rev3.1 WAIT is nop, why bother
195 		 */
196 		if ((c->processor_id & 0xff) <= 0x64)
197 			break;
198 
199 		/*
200 		 * Another rev is incremeting c0_count at a reduced clock
201 		 * rate while in WAIT mode.  So we basically have the choice
202 		 * between using the cp0 timer as clocksource or avoiding
203 		 * the WAIT instruction.  Until more details are known,
204 		 * disable the use of WAIT for 20Kc entirely.
205 		   cpu_wait = r4k_wait;
206 		 */
207 		break;
208 	case CPU_RM9000:
209 		if ((c->processor_id & 0x00ff) >= 0x40)
210 			cpu_wait = r4k_wait;
211 		break;
212 	default:
213 		break;
214 	}
215 }
216 
217 static inline void check_errata(void)
218 {
219 	struct cpuinfo_mips *c = &current_cpu_data;
220 
221 	switch (c->cputype) {
222 	case CPU_34K:
223 		/*
224 		 * Erratum "RPS May Cause Incorrect Instruction Execution"
225 		 * This code only handles VPE0, any SMP/SMTC/RTOS code
226 		 * making use of VPE1 will be responsable for that VPE.
227 		 */
228 		if ((c->processor_id & PRID_REV_MASK) <= PRID_REV_34K_V1_0_2)
229 			write_c0_config7(read_c0_config7() | MIPS_CONF7_RPS);
230 		break;
231 	default:
232 		break;
233 	}
234 }
235 
236 void __init check_bugs32(void)
237 {
238 	check_errata();
239 }
240 
241 /*
242  * Probe whether cpu has config register by trying to play with
243  * alternate cache bit and see whether it matters.
244  * It's used by cpu_probe to distinguish between R3000A and R3081.
245  */
246 static inline int cpu_has_confreg(void)
247 {
248 #ifdef CONFIG_CPU_R3000
249 	extern unsigned long r3k_cache_size(unsigned long);
250 	unsigned long size1, size2;
251 	unsigned long cfg = read_c0_conf();
252 
253 	size1 = r3k_cache_size(ST0_ISC);
254 	write_c0_conf(cfg ^ R30XX_CONF_AC);
255 	size2 = r3k_cache_size(ST0_ISC);
256 	write_c0_conf(cfg);
257 	return size1 != size2;
258 #else
259 	return 0;
260 #endif
261 }
262 
263 /*
264  * Get the FPU Implementation/Revision.
265  */
266 static inline unsigned long cpu_get_fpu_id(void)
267 {
268 	unsigned long tmp, fpu_id;
269 
270 	tmp = read_c0_status();
271 	__enable_fpu();
272 	fpu_id = read_32bit_cp1_register(CP1_REVISION);
273 	write_c0_status(tmp);
274 	return fpu_id;
275 }
276 
277 /*
278  * Check the CPU has an FPU the official way.
279  */
280 static inline int __cpu_has_fpu(void)
281 {
282 	return ((cpu_get_fpu_id() & 0xff00) != FPIR_IMP_NONE);
283 }
284 
285 #define R4K_OPTS (MIPS_CPU_TLB | MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE \
286 		| MIPS_CPU_COUNTER)
287 
288 static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
289 {
290 	switch (c->processor_id & 0xff00) {
291 	case PRID_IMP_R2000:
292 		c->cputype = CPU_R2000;
293 		__cpu_name[cpu] = "R2000";
294 		c->isa_level = MIPS_CPU_ISA_I;
295 		c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
296 		             MIPS_CPU_NOFPUEX;
297 		if (__cpu_has_fpu())
298 			c->options |= MIPS_CPU_FPU;
299 		c->tlbsize = 64;
300 		break;
301 	case PRID_IMP_R3000:
302 		if ((c->processor_id & 0xff) == PRID_REV_R3000A) {
303 			if (cpu_has_confreg()) {
304 				c->cputype = CPU_R3081E;
305 				__cpu_name[cpu] = "R3081";
306 			} else {
307 				c->cputype = CPU_R3000A;
308 				__cpu_name[cpu] = "R3000A";
309 			}
310 			break;
311 		} else {
312 			c->cputype = CPU_R3000;
313 			__cpu_name[cpu] = "R3000";
314 		}
315 		c->isa_level = MIPS_CPU_ISA_I;
316 		c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
317 		             MIPS_CPU_NOFPUEX;
318 		if (__cpu_has_fpu())
319 			c->options |= MIPS_CPU_FPU;
320 		c->tlbsize = 64;
321 		break;
322 	case PRID_IMP_R4000:
323 		if (read_c0_config() & CONF_SC) {
324 			if ((c->processor_id & 0xff) >= PRID_REV_R4400) {
325 				c->cputype = CPU_R4400PC;
326 				__cpu_name[cpu] = "R4400PC";
327 			} else {
328 				c->cputype = CPU_R4000PC;
329 				__cpu_name[cpu] = "R4000PC";
330 			}
331 		} else {
332 			if ((c->processor_id & 0xff) >= PRID_REV_R4400) {
333 				c->cputype = CPU_R4400SC;
334 				__cpu_name[cpu] = "R4400SC";
335 			} else {
336 				c->cputype = CPU_R4000SC;
337 				__cpu_name[cpu] = "R4000SC";
338 			}
339 		}
340 
341 		c->isa_level = MIPS_CPU_ISA_III;
342 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
343 		             MIPS_CPU_WATCH | MIPS_CPU_VCE |
344 		             MIPS_CPU_LLSC;
345 		c->tlbsize = 48;
346 		break;
347 	case PRID_IMP_VR41XX:
348 		switch (c->processor_id & 0xf0) {
349 		case PRID_REV_VR4111:
350 			c->cputype = CPU_VR4111;
351 			__cpu_name[cpu] = "NEC VR4111";
352 			break;
353 		case PRID_REV_VR4121:
354 			c->cputype = CPU_VR4121;
355 			__cpu_name[cpu] = "NEC VR4121";
356 			break;
357 		case PRID_REV_VR4122:
358 			if ((c->processor_id & 0xf) < 0x3) {
359 				c->cputype = CPU_VR4122;
360 				__cpu_name[cpu] = "NEC VR4122";
361 			} else {
362 				c->cputype = CPU_VR4181A;
363 				__cpu_name[cpu] = "NEC VR4181A";
364 			}
365 			break;
366 		case PRID_REV_VR4130:
367 			if ((c->processor_id & 0xf) < 0x4) {
368 				c->cputype = CPU_VR4131;
369 				__cpu_name[cpu] = "NEC VR4131";
370 			} else {
371 				c->cputype = CPU_VR4133;
372 				__cpu_name[cpu] = "NEC VR4133";
373 			}
374 			break;
375 		default:
376 			printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
377 			c->cputype = CPU_VR41XX;
378 			__cpu_name[cpu] = "NEC Vr41xx";
379 			break;
380 		}
381 		c->isa_level = MIPS_CPU_ISA_III;
382 		c->options = R4K_OPTS;
383 		c->tlbsize = 32;
384 		break;
385 	case PRID_IMP_R4300:
386 		c->cputype = CPU_R4300;
387 		__cpu_name[cpu] = "R4300";
388 		c->isa_level = MIPS_CPU_ISA_III;
389 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
390 		             MIPS_CPU_LLSC;
391 		c->tlbsize = 32;
392 		break;
393 	case PRID_IMP_R4600:
394 		c->cputype = CPU_R4600;
395 		__cpu_name[cpu] = "R4600";
396 		c->isa_level = MIPS_CPU_ISA_III;
397 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
398 			     MIPS_CPU_LLSC;
399 		c->tlbsize = 48;
400 		break;
401 	#if 0
402  	case PRID_IMP_R4650:
403 		/*
404 		 * This processor doesn't have an MMU, so it's not
405 		 * "real easy" to run Linux on it. It is left purely
406 		 * for documentation.  Commented out because it shares
407 		 * it's c0_prid id number with the TX3900.
408 		 */
409 		c->cputype = CPU_R4650;
410 		__cpu_name[cpu] = "R4650";
411 	 	c->isa_level = MIPS_CPU_ISA_III;
412 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_LLSC;
413 	        c->tlbsize = 48;
414 		break;
415 	#endif
416 	case PRID_IMP_TX39:
417 		c->isa_level = MIPS_CPU_ISA_I;
418 		c->options = MIPS_CPU_TLB | MIPS_CPU_TX39_CACHE;
419 
420 		if ((c->processor_id & 0xf0) == (PRID_REV_TX3927 & 0xf0)) {
421 			c->cputype = CPU_TX3927;
422 			__cpu_name[cpu] = "TX3927";
423 			c->tlbsize = 64;
424 		} else {
425 			switch (c->processor_id & 0xff) {
426 			case PRID_REV_TX3912:
427 				c->cputype = CPU_TX3912;
428 				__cpu_name[cpu] = "TX3912";
429 				c->tlbsize = 32;
430 				break;
431 			case PRID_REV_TX3922:
432 				c->cputype = CPU_TX3922;
433 				__cpu_name[cpu] = "TX3922";
434 				c->tlbsize = 64;
435 				break;
436 			}
437 		}
438 		break;
439 	case PRID_IMP_R4700:
440 		c->cputype = CPU_R4700;
441 		__cpu_name[cpu] = "R4700";
442 		c->isa_level = MIPS_CPU_ISA_III;
443 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
444 		             MIPS_CPU_LLSC;
445 		c->tlbsize = 48;
446 		break;
447 	case PRID_IMP_TX49:
448 		c->cputype = CPU_TX49XX;
449 		__cpu_name[cpu] = "R49XX";
450 		c->isa_level = MIPS_CPU_ISA_III;
451 		c->options = R4K_OPTS | MIPS_CPU_LLSC;
452 		if (!(c->processor_id & 0x08))
453 			c->options |= MIPS_CPU_FPU | MIPS_CPU_32FPR;
454 		c->tlbsize = 48;
455 		break;
456 	case PRID_IMP_R5000:
457 		c->cputype = CPU_R5000;
458 		__cpu_name[cpu] = "R5000";
459 		c->isa_level = MIPS_CPU_ISA_IV;
460 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
461 		             MIPS_CPU_LLSC;
462 		c->tlbsize = 48;
463 		break;
464 	case PRID_IMP_R5432:
465 		c->cputype = CPU_R5432;
466 		__cpu_name[cpu] = "R5432";
467 		c->isa_level = MIPS_CPU_ISA_IV;
468 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
469 		             MIPS_CPU_WATCH | MIPS_CPU_LLSC;
470 		c->tlbsize = 48;
471 		break;
472 	case PRID_IMP_R5500:
473 		c->cputype = CPU_R5500;
474 		__cpu_name[cpu] = "R5500";
475 		c->isa_level = MIPS_CPU_ISA_IV;
476 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
477 		             MIPS_CPU_WATCH | MIPS_CPU_LLSC;
478 		c->tlbsize = 48;
479 		break;
480 	case PRID_IMP_NEVADA:
481 		c->cputype = CPU_NEVADA;
482 		__cpu_name[cpu] = "Nevada";
483 		c->isa_level = MIPS_CPU_ISA_IV;
484 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
485 		             MIPS_CPU_DIVEC | MIPS_CPU_LLSC;
486 		c->tlbsize = 48;
487 		break;
488 	case PRID_IMP_R6000:
489 		c->cputype = CPU_R6000;
490 		__cpu_name[cpu] = "R6000";
491 		c->isa_level = MIPS_CPU_ISA_II;
492 		c->options = MIPS_CPU_TLB | MIPS_CPU_FPU |
493 		             MIPS_CPU_LLSC;
494 		c->tlbsize = 32;
495 		break;
496 	case PRID_IMP_R6000A:
497 		c->cputype = CPU_R6000A;
498 		__cpu_name[cpu] = "R6000A";
499 		c->isa_level = MIPS_CPU_ISA_II;
500 		c->options = MIPS_CPU_TLB | MIPS_CPU_FPU |
501 		             MIPS_CPU_LLSC;
502 		c->tlbsize = 32;
503 		break;
504 	case PRID_IMP_RM7000:
505 		c->cputype = CPU_RM7000;
506 		__cpu_name[cpu] = "RM7000";
507 		c->isa_level = MIPS_CPU_ISA_IV;
508 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
509 		             MIPS_CPU_LLSC;
510 		/*
511 		 * Undocumented RM7000:  Bit 29 in the info register of
512 		 * the RM7000 v2.0 indicates if the TLB has 48 or 64
513 		 * entries.
514 		 *
515 		 * 29      1 =>    64 entry JTLB
516 		 *         0 =>    48 entry JTLB
517 		 */
518 		c->tlbsize = (read_c0_info() & (1 << 29)) ? 64 : 48;
519 		break;
520 	case PRID_IMP_RM9000:
521 		c->cputype = CPU_RM9000;
522 		__cpu_name[cpu] = "RM9000";
523 		c->isa_level = MIPS_CPU_ISA_IV;
524 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
525 		             MIPS_CPU_LLSC;
526 		/*
527 		 * Bit 29 in the info register of the RM9000
528 		 * indicates if the TLB has 48 or 64 entries.
529 		 *
530 		 * 29      1 =>    64 entry JTLB
531 		 *         0 =>    48 entry JTLB
532 		 */
533 		c->tlbsize = (read_c0_info() & (1 << 29)) ? 64 : 48;
534 		break;
535 	case PRID_IMP_R8000:
536 		c->cputype = CPU_R8000;
537 		__cpu_name[cpu] = "RM8000";
538 		c->isa_level = MIPS_CPU_ISA_IV;
539 		c->options = MIPS_CPU_TLB | MIPS_CPU_4KEX |
540 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
541 		             MIPS_CPU_LLSC;
542 		c->tlbsize = 384;      /* has weird TLB: 3-way x 128 */
543 		break;
544 	case PRID_IMP_R10000:
545 		c->cputype = CPU_R10000;
546 		__cpu_name[cpu] = "R10000";
547 		c->isa_level = MIPS_CPU_ISA_IV;
548 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
549 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
550 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
551 		             MIPS_CPU_LLSC;
552 		c->tlbsize = 64;
553 		break;
554 	case PRID_IMP_R12000:
555 		c->cputype = CPU_R12000;
556 		__cpu_name[cpu] = "R12000";
557 		c->isa_level = MIPS_CPU_ISA_IV;
558 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
559 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
560 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
561 		             MIPS_CPU_LLSC;
562 		c->tlbsize = 64;
563 		break;
564 	case PRID_IMP_R14000:
565 		c->cputype = CPU_R14000;
566 		__cpu_name[cpu] = "R14000";
567 		c->isa_level = MIPS_CPU_ISA_IV;
568 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
569 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
570 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
571 		             MIPS_CPU_LLSC;
572 		c->tlbsize = 64;
573 		break;
574 	case PRID_IMP_LOONGSON2:
575 		c->cputype = CPU_LOONGSON2;
576 		__cpu_name[cpu] = "ICT Loongson-2";
577 		c->isa_level = MIPS_CPU_ISA_III;
578 		c->options = R4K_OPTS |
579 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
580 			     MIPS_CPU_32FPR;
581 		c->tlbsize = 64;
582 		break;
583 	}
584 }
585 
586 static char unknown_isa[] __cpuinitdata = KERN_ERR \
587 	"Unsupported ISA type, c0.config0: %d.";
588 
589 static inline unsigned int decode_config0(struct cpuinfo_mips *c)
590 {
591 	unsigned int config0;
592 	int isa;
593 
594 	config0 = read_c0_config();
595 
596 	if (((config0 & MIPS_CONF_MT) >> 7) == 1)
597 		c->options |= MIPS_CPU_TLB;
598 	isa = (config0 & MIPS_CONF_AT) >> 13;
599 	switch (isa) {
600 	case 0:
601 		switch ((config0 & MIPS_CONF_AR) >> 10) {
602 		case 0:
603 			c->isa_level = MIPS_CPU_ISA_M32R1;
604 			break;
605 		case 1:
606 			c->isa_level = MIPS_CPU_ISA_M32R2;
607 			break;
608 		default:
609 			goto unknown;
610 		}
611 		break;
612 	case 2:
613 		switch ((config0 & MIPS_CONF_AR) >> 10) {
614 		case 0:
615 			c->isa_level = MIPS_CPU_ISA_M64R1;
616 			break;
617 		case 1:
618 			c->isa_level = MIPS_CPU_ISA_M64R2;
619 			break;
620 		default:
621 			goto unknown;
622 		}
623 		break;
624 	default:
625 		goto unknown;
626 	}
627 
628 	return config0 & MIPS_CONF_M;
629 
630 unknown:
631 	panic(unknown_isa, config0);
632 }
633 
634 static inline unsigned int decode_config1(struct cpuinfo_mips *c)
635 {
636 	unsigned int config1;
637 
638 	config1 = read_c0_config1();
639 
640 	if (config1 & MIPS_CONF1_MD)
641 		c->ases |= MIPS_ASE_MDMX;
642 	if (config1 & MIPS_CONF1_WR)
643 		c->options |= MIPS_CPU_WATCH;
644 	if (config1 & MIPS_CONF1_CA)
645 		c->ases |= MIPS_ASE_MIPS16;
646 	if (config1 & MIPS_CONF1_EP)
647 		c->options |= MIPS_CPU_EJTAG;
648 	if (config1 & MIPS_CONF1_FP) {
649 		c->options |= MIPS_CPU_FPU;
650 		c->options |= MIPS_CPU_32FPR;
651 	}
652 	if (cpu_has_tlb)
653 		c->tlbsize = ((config1 & MIPS_CONF1_TLBS) >> 25) + 1;
654 
655 	return config1 & MIPS_CONF_M;
656 }
657 
658 static inline unsigned int decode_config2(struct cpuinfo_mips *c)
659 {
660 	unsigned int config2;
661 
662 	config2 = read_c0_config2();
663 
664 	if (config2 & MIPS_CONF2_SL)
665 		c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
666 
667 	return config2 & MIPS_CONF_M;
668 }
669 
670 static inline unsigned int decode_config3(struct cpuinfo_mips *c)
671 {
672 	unsigned int config3;
673 
674 	config3 = read_c0_config3();
675 
676 	if (config3 & MIPS_CONF3_SM)
677 		c->ases |= MIPS_ASE_SMARTMIPS;
678 	if (config3 & MIPS_CONF3_DSP)
679 		c->ases |= MIPS_ASE_DSP;
680 	if (config3 & MIPS_CONF3_VINT)
681 		c->options |= MIPS_CPU_VINT;
682 	if (config3 & MIPS_CONF3_VEIC)
683 		c->options |= MIPS_CPU_VEIC;
684 	if (config3 & MIPS_CONF3_MT)
685 	        c->ases |= MIPS_ASE_MIPSMT;
686 	if (config3 & MIPS_CONF3_ULRI)
687 		c->options |= MIPS_CPU_ULRI;
688 
689 	return config3 & MIPS_CONF_M;
690 }
691 
692 static void __cpuinit decode_configs(struct cpuinfo_mips *c)
693 {
694 	int ok;
695 
696 	/* MIPS32 or MIPS64 compliant CPU.  */
697 	c->options = MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE | MIPS_CPU_COUNTER |
698 	             MIPS_CPU_DIVEC | MIPS_CPU_LLSC | MIPS_CPU_MCHECK;
699 
700 	c->scache.flags = MIPS_CACHE_NOT_PRESENT;
701 
702 	ok = decode_config0(c);			/* Read Config registers.  */
703 	BUG_ON(!ok);				/* Arch spec violation!  */
704 	if (ok)
705 		ok = decode_config1(c);
706 	if (ok)
707 		ok = decode_config2(c);
708 	if (ok)
709 		ok = decode_config3(c);
710 
711 	mips_probe_watch_registers(c);
712 }
713 
714 #ifdef CONFIG_CPU_MIPSR2
715 extern void spram_config(void);
716 #else
717 static inline void spram_config(void) {}
718 #endif
719 
720 static inline void cpu_probe_mips(struct cpuinfo_mips *c, unsigned int cpu)
721 {
722 	decode_configs(c);
723 	switch (c->processor_id & 0xff00) {
724 	case PRID_IMP_4KC:
725 		c->cputype = CPU_4KC;
726 		__cpu_name[cpu] = "MIPS 4Kc";
727 		break;
728 	case PRID_IMP_4KEC:
729 		c->cputype = CPU_4KEC;
730 		__cpu_name[cpu] = "MIPS 4KEc";
731 		break;
732 	case PRID_IMP_4KECR2:
733 		c->cputype = CPU_4KEC;
734 		__cpu_name[cpu] = "MIPS 4KEc";
735 		break;
736 	case PRID_IMP_4KSC:
737 	case PRID_IMP_4KSD:
738 		c->cputype = CPU_4KSC;
739 		__cpu_name[cpu] = "MIPS 4KSc";
740 		break;
741 	case PRID_IMP_5KC:
742 		c->cputype = CPU_5KC;
743 		__cpu_name[cpu] = "MIPS 5Kc";
744 		break;
745 	case PRID_IMP_20KC:
746 		c->cputype = CPU_20KC;
747 		__cpu_name[cpu] = "MIPS 20Kc";
748 		break;
749 	case PRID_IMP_24K:
750 	case PRID_IMP_24KE:
751 		c->cputype = CPU_24K;
752 		__cpu_name[cpu] = "MIPS 24Kc";
753 		break;
754 	case PRID_IMP_25KF:
755 		c->cputype = CPU_25KF;
756 		__cpu_name[cpu] = "MIPS 25Kc";
757 		break;
758 	case PRID_IMP_34K:
759 		c->cputype = CPU_34K;
760 		__cpu_name[cpu] = "MIPS 34Kc";
761 		break;
762 	case PRID_IMP_74K:
763 		c->cputype = CPU_74K;
764 		__cpu_name[cpu] = "MIPS 74Kc";
765 		break;
766 	case PRID_IMP_1004K:
767 		c->cputype = CPU_1004K;
768 		__cpu_name[cpu] = "MIPS 1004Kc";
769 		break;
770 	}
771 
772 	spram_config();
773 }
774 
775 static inline void cpu_probe_alchemy(struct cpuinfo_mips *c, unsigned int cpu)
776 {
777 	decode_configs(c);
778 	switch (c->processor_id & 0xff00) {
779 	case PRID_IMP_AU1_REV1:
780 	case PRID_IMP_AU1_REV2:
781 		c->cputype = CPU_ALCHEMY;
782 		switch ((c->processor_id >> 24) & 0xff) {
783 		case 0:
784 			__cpu_name[cpu] = "Au1000";
785 			break;
786 		case 1:
787 			__cpu_name[cpu] = "Au1500";
788 			break;
789 		case 2:
790 			__cpu_name[cpu] = "Au1100";
791 			break;
792 		case 3:
793 			__cpu_name[cpu] = "Au1550";
794 			break;
795 		case 4:
796 			__cpu_name[cpu] = "Au1200";
797 			if ((c->processor_id & 0xff) == 2)
798 				__cpu_name[cpu] = "Au1250";
799 			break;
800 		case 5:
801 			__cpu_name[cpu] = "Au1210";
802 			break;
803 		default:
804 			__cpu_name[cpu] = "Au1xxx";
805 			break;
806 		}
807 		break;
808 	}
809 }
810 
811 static inline void cpu_probe_sibyte(struct cpuinfo_mips *c, unsigned int cpu)
812 {
813 	decode_configs(c);
814 
815 	switch (c->processor_id & 0xff00) {
816 	case PRID_IMP_SB1:
817 		c->cputype = CPU_SB1;
818 		__cpu_name[cpu] = "SiByte SB1";
819 		/* FPU in pass1 is known to have issues. */
820 		if ((c->processor_id & 0xff) < 0x02)
821 			c->options &= ~(MIPS_CPU_FPU | MIPS_CPU_32FPR);
822 		break;
823 	case PRID_IMP_SB1A:
824 		c->cputype = CPU_SB1A;
825 		__cpu_name[cpu] = "SiByte SB1A";
826 		break;
827 	}
828 }
829 
830 static inline void cpu_probe_sandcraft(struct cpuinfo_mips *c, unsigned int cpu)
831 {
832 	decode_configs(c);
833 	switch (c->processor_id & 0xff00) {
834 	case PRID_IMP_SR71000:
835 		c->cputype = CPU_SR71000;
836 		__cpu_name[cpu] = "Sandcraft SR71000";
837 		c->scache.ways = 8;
838 		c->tlbsize = 64;
839 		break;
840 	}
841 }
842 
843 static inline void cpu_probe_nxp(struct cpuinfo_mips *c, unsigned int cpu)
844 {
845 	decode_configs(c);
846 	switch (c->processor_id & 0xff00) {
847 	case PRID_IMP_PR4450:
848 		c->cputype = CPU_PR4450;
849 		__cpu_name[cpu] = "Philips PR4450";
850 		c->isa_level = MIPS_CPU_ISA_M32R1;
851 		break;
852 	}
853 }
854 
855 static inline void cpu_probe_broadcom(struct cpuinfo_mips *c, unsigned int cpu)
856 {
857 	decode_configs(c);
858 	switch (c->processor_id & 0xff00) {
859 	case PRID_IMP_BCM3302:
860 	 /* same as PRID_IMP_BCM6338 */
861 		c->cputype = CPU_BCM3302;
862 		__cpu_name[cpu] = "Broadcom BCM3302";
863 		break;
864 	case PRID_IMP_BCM4710:
865 		c->cputype = CPU_BCM4710;
866 		__cpu_name[cpu] = "Broadcom BCM4710";
867 		break;
868 	case PRID_IMP_BCM6345:
869 		c->cputype = CPU_BCM6345;
870 		__cpu_name[cpu] = "Broadcom BCM6345";
871 		break;
872 	case PRID_IMP_BCM6348:
873 		c->cputype = CPU_BCM6348;
874 		__cpu_name[cpu] = "Broadcom BCM6348";
875 		break;
876 	case PRID_IMP_BCM4350:
877 		switch (c->processor_id & 0xf0) {
878 		case PRID_REV_BCM6358:
879 			c->cputype = CPU_BCM6358;
880 			__cpu_name[cpu] = "Broadcom BCM6358";
881 			break;
882 		default:
883 			c->cputype = CPU_UNKNOWN;
884 			break;
885 		}
886 		break;
887 	}
888 }
889 
890 static inline void cpu_probe_cavium(struct cpuinfo_mips *c, unsigned int cpu)
891 {
892 	decode_configs(c);
893 	switch (c->processor_id & 0xff00) {
894 	case PRID_IMP_CAVIUM_CN38XX:
895 	case PRID_IMP_CAVIUM_CN31XX:
896 	case PRID_IMP_CAVIUM_CN30XX:
897 	case PRID_IMP_CAVIUM_CN58XX:
898 	case PRID_IMP_CAVIUM_CN56XX:
899 	case PRID_IMP_CAVIUM_CN50XX:
900 	case PRID_IMP_CAVIUM_CN52XX:
901 		c->cputype = CPU_CAVIUM_OCTEON;
902 		__cpu_name[cpu] = "Cavium Octeon";
903 		break;
904 	default:
905 		printk(KERN_INFO "Unknown Octeon chip!\n");
906 		c->cputype = CPU_UNKNOWN;
907 		break;
908 	}
909 }
910 
911 const char *__cpu_name[NR_CPUS];
912 
913 __cpuinit void cpu_probe(void)
914 {
915 	struct cpuinfo_mips *c = &current_cpu_data;
916 	unsigned int cpu = smp_processor_id();
917 
918 	c->processor_id	= PRID_IMP_UNKNOWN;
919 	c->fpu_id	= FPIR_IMP_NONE;
920 	c->cputype	= CPU_UNKNOWN;
921 
922 	c->processor_id = read_c0_prid();
923 	switch (c->processor_id & 0xff0000) {
924 	case PRID_COMP_LEGACY:
925 		cpu_probe_legacy(c, cpu);
926 		break;
927 	case PRID_COMP_MIPS:
928 		cpu_probe_mips(c, cpu);
929 		break;
930 	case PRID_COMP_ALCHEMY:
931 		cpu_probe_alchemy(c, cpu);
932 		break;
933 	case PRID_COMP_SIBYTE:
934 		cpu_probe_sibyte(c, cpu);
935 		break;
936 	case PRID_COMP_BROADCOM:
937 		cpu_probe_broadcom(c, cpu);
938 		break;
939 	case PRID_COMP_SANDCRAFT:
940 		cpu_probe_sandcraft(c, cpu);
941 		break;
942 	case PRID_COMP_NXP:
943 		cpu_probe_nxp(c, cpu);
944 		break;
945 	case PRID_COMP_CAVIUM:
946 		cpu_probe_cavium(c, cpu);
947 		break;
948 	}
949 
950 	BUG_ON(!__cpu_name[cpu]);
951 	BUG_ON(c->cputype == CPU_UNKNOWN);
952 
953 	/*
954 	 * Platform code can force the cpu type to optimize code
955 	 * generation. In that case be sure the cpu type is correctly
956 	 * manually setup otherwise it could trigger some nasty bugs.
957 	 */
958 	BUG_ON(current_cpu_type() != c->cputype);
959 
960 	if (c->options & MIPS_CPU_FPU) {
961 		c->fpu_id = cpu_get_fpu_id();
962 
963 		if (c->isa_level == MIPS_CPU_ISA_M32R1 ||
964 		    c->isa_level == MIPS_CPU_ISA_M32R2 ||
965 		    c->isa_level == MIPS_CPU_ISA_M64R1 ||
966 		    c->isa_level == MIPS_CPU_ISA_M64R2) {
967 			if (c->fpu_id & MIPS_FPIR_3D)
968 				c->ases |= MIPS_ASE_MIPS3D;
969 		}
970 	}
971 
972 	if (cpu_has_mips_r2)
973 		c->srsets = ((read_c0_srsctl() >> 26) & 0x0f) + 1;
974 	else
975 		c->srsets = 1;
976 }
977 
978 __cpuinit void cpu_report(void)
979 {
980 	struct cpuinfo_mips *c = &current_cpu_data;
981 
982 	printk(KERN_INFO "CPU revision is: %08x (%s)\n",
983 	       c->processor_id, cpu_name_string());
984 	if (c->options & MIPS_CPU_FPU)
985 		printk(KERN_INFO "FPU revision is: %08x\n", c->fpu_id);
986 }
987