xref: /openbmc/linux/arch/mips/kernel/cpu-probe.c (revision 64c70b1c)
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 
25 /*
26  * Not all of the MIPS CPUs have the "wait" instruction available. Moreover,
27  * the implementation of the "wait" feature differs between CPU families. This
28  * points to the function that implements CPU specific wait.
29  * The wait instruction stops the pipeline and reduces the power consumption of
30  * the CPU very much.
31  */
32 void (*cpu_wait)(void) = NULL;
33 
34 static void r3081_wait(void)
35 {
36 	unsigned long cfg = read_c0_conf();
37 	write_c0_conf(cfg | R30XX_CONF_HALT);
38 }
39 
40 static void r39xx_wait(void)
41 {
42 	local_irq_disable();
43 	if (!need_resched())
44 		write_c0_conf(read_c0_conf() | TX39_CONF_HALT);
45 	local_irq_enable();
46 }
47 
48 /*
49  * There is a race when WAIT instruction executed with interrupt
50  * enabled.
51  * But it is implementation-dependent wheter the pipelie restarts when
52  * a non-enabled interrupt is requested.
53  */
54 static void r4k_wait(void)
55 {
56 	__asm__("	.set	mips3			\n"
57 		"	wait				\n"
58 		"	.set	mips0			\n");
59 }
60 
61 /*
62  * This variant is preferable as it allows testing need_resched and going to
63  * sleep depending on the outcome atomically.  Unfortunately the "It is
64  * implementation-dependent whether the pipeline restarts when a non-enabled
65  * interrupt is requested" restriction in the MIPS32/MIPS64 architecture makes
66  * using this version a gamble.
67  */
68 static void r4k_wait_irqoff(void)
69 {
70 	local_irq_disable();
71 	if (!need_resched())
72 		__asm__("	.set	mips3		\n"
73 			"	wait			\n"
74 			"	.set	mips0		\n");
75 	local_irq_enable();
76 }
77 
78 /* The Au1xxx wait is available only if using 32khz counter or
79  * external timer source, but specifically not CP0 Counter. */
80 int allow_au1k_wait;
81 
82 static void au1k_wait(void)
83 {
84 	/* using the wait instruction makes CP0 counter unusable */
85 	__asm__("	.set	mips3			\n"
86 		"	cache	0x14, 0(%0)		\n"
87 		"	cache	0x14, 32(%0)		\n"
88 		"	sync				\n"
89 		"	nop				\n"
90 		"	wait				\n"
91 		"	nop				\n"
92 		"	nop				\n"
93 		"	nop				\n"
94 		"	nop				\n"
95 		"	.set	mips0			\n"
96 		: : "r" (au1k_wait));
97 }
98 
99 static int __initdata nowait = 0;
100 
101 static int __init wait_disable(char *s)
102 {
103 	nowait = 1;
104 
105 	return 1;
106 }
107 
108 __setup("nowait", wait_disable);
109 
110 static inline void check_wait(void)
111 {
112 	struct cpuinfo_mips *c = &current_cpu_data;
113 
114 	if (nowait) {
115 		printk("Wait instruction disabled.\n");
116 		return;
117 	}
118 
119 	switch (c->cputype) {
120 	case CPU_R3081:
121 	case CPU_R3081E:
122 		cpu_wait = r3081_wait;
123 		break;
124 	case CPU_TX3927:
125 		cpu_wait = r39xx_wait;
126 		break;
127 	case CPU_R4200:
128 /*	case CPU_R4300: */
129 	case CPU_R4600:
130 	case CPU_R4640:
131 	case CPU_R4650:
132 	case CPU_R4700:
133 	case CPU_R5000:
134 	case CPU_NEVADA:
135 	case CPU_RM7000:
136 	case CPU_4KC:
137 	case CPU_4KEC:
138 	case CPU_4KSC:
139 	case CPU_5KC:
140 	case CPU_25KF:
141 	case CPU_PR4450:
142 		cpu_wait = r4k_wait;
143 		break;
144 
145 	case CPU_24K:
146 	case CPU_34K:
147 		cpu_wait = r4k_wait;
148 		if (read_c0_config7() & MIPS_CONF7_WII)
149 			cpu_wait = r4k_wait_irqoff;
150 		break;
151 
152 	case CPU_74K:
153 		cpu_wait = r4k_wait;
154 		if ((c->processor_id & 0xff) >= PRID_REV_ENCODE_332(2, 1, 0))
155 			cpu_wait = r4k_wait_irqoff;
156 		break;
157 
158 	case CPU_TX49XX:
159 		cpu_wait = r4k_wait_irqoff;
160 		break;
161 	case CPU_AU1000:
162 	case CPU_AU1100:
163 	case CPU_AU1500:
164 	case CPU_AU1550:
165 	case CPU_AU1200:
166 		if (allow_au1k_wait)
167 			cpu_wait = au1k_wait;
168 		break;
169 	case CPU_20KC:
170 		/*
171 		 * WAIT on Rev1.0 has E1, E2, E3 and E16.
172 		 * WAIT on Rev2.0 and Rev3.0 has E16.
173 		 * Rev3.1 WAIT is nop, why bother
174 		 */
175 		if ((c->processor_id & 0xff) <= 0x64)
176 			break;
177 
178 		cpu_wait = r4k_wait;
179 		break;
180 	case CPU_RM9000:
181 		if ((c->processor_id & 0x00ff) >= 0x40)
182 			cpu_wait = r4k_wait;
183 		break;
184 	default:
185 		break;
186 	}
187 }
188 
189 static inline void check_errata(void)
190 {
191 	struct cpuinfo_mips *c = &current_cpu_data;
192 
193 	switch (c->cputype) {
194 	case CPU_34K:
195 		/*
196 		 * Erratum "RPS May Cause Incorrect Instruction Execution"
197 		 * This code only handles VPE0, any SMP/SMTC/RTOS code
198 		 * making use of VPE1 will be responsable for that VPE.
199 		 */
200 		if ((c->processor_id & PRID_REV_MASK) <= PRID_REV_34K_V1_0_2)
201 			write_c0_config7(read_c0_config7() | MIPS_CONF7_RPS);
202 		break;
203 	default:
204 		break;
205 	}
206 }
207 
208 void __init check_bugs32(void)
209 {
210 	check_wait();
211 	check_errata();
212 }
213 
214 /*
215  * Probe whether cpu has config register by trying to play with
216  * alternate cache bit and see whether it matters.
217  * It's used by cpu_probe to distinguish between R3000A and R3081.
218  */
219 static inline int cpu_has_confreg(void)
220 {
221 #ifdef CONFIG_CPU_R3000
222 	extern unsigned long r3k_cache_size(unsigned long);
223 	unsigned long size1, size2;
224 	unsigned long cfg = read_c0_conf();
225 
226 	size1 = r3k_cache_size(ST0_ISC);
227 	write_c0_conf(cfg ^ R30XX_CONF_AC);
228 	size2 = r3k_cache_size(ST0_ISC);
229 	write_c0_conf(cfg);
230 	return size1 != size2;
231 #else
232 	return 0;
233 #endif
234 }
235 
236 /*
237  * Get the FPU Implementation/Revision.
238  */
239 static inline unsigned long cpu_get_fpu_id(void)
240 {
241 	unsigned long tmp, fpu_id;
242 
243 	tmp = read_c0_status();
244 	__enable_fpu();
245 	fpu_id = read_32bit_cp1_register(CP1_REVISION);
246 	write_c0_status(tmp);
247 	return fpu_id;
248 }
249 
250 /*
251  * Check the CPU has an FPU the official way.
252  */
253 static inline int __cpu_has_fpu(void)
254 {
255 	return ((cpu_get_fpu_id() & 0xff00) != FPIR_IMP_NONE);
256 }
257 
258 #define R4K_OPTS (MIPS_CPU_TLB | MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE \
259 		| MIPS_CPU_COUNTER)
260 
261 static inline void cpu_probe_legacy(struct cpuinfo_mips *c)
262 {
263 	switch (c->processor_id & 0xff00) {
264 	case PRID_IMP_R2000:
265 		c->cputype = CPU_R2000;
266 		c->isa_level = MIPS_CPU_ISA_I;
267 		c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
268 		             MIPS_CPU_NOFPUEX;
269 		if (__cpu_has_fpu())
270 			c->options |= MIPS_CPU_FPU;
271 		c->tlbsize = 64;
272 		break;
273 	case PRID_IMP_R3000:
274 		if ((c->processor_id & 0xff) == PRID_REV_R3000A)
275 			if (cpu_has_confreg())
276 				c->cputype = CPU_R3081E;
277 			else
278 				c->cputype = CPU_R3000A;
279 		else
280 			c->cputype = CPU_R3000;
281 		c->isa_level = MIPS_CPU_ISA_I;
282 		c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
283 		             MIPS_CPU_NOFPUEX;
284 		if (__cpu_has_fpu())
285 			c->options |= MIPS_CPU_FPU;
286 		c->tlbsize = 64;
287 		break;
288 	case PRID_IMP_R4000:
289 		if (read_c0_config() & CONF_SC) {
290 			if ((c->processor_id & 0xff) >= PRID_REV_R4400)
291 				c->cputype = CPU_R4400PC;
292 			else
293 				c->cputype = CPU_R4000PC;
294 		} else {
295 			if ((c->processor_id & 0xff) >= PRID_REV_R4400)
296 				c->cputype = CPU_R4400SC;
297 			else
298 				c->cputype = CPU_R4000SC;
299 		}
300 
301 		c->isa_level = MIPS_CPU_ISA_III;
302 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
303 		             MIPS_CPU_WATCH | MIPS_CPU_VCE |
304 		             MIPS_CPU_LLSC;
305 		c->tlbsize = 48;
306 		break;
307 	case PRID_IMP_VR41XX:
308 		switch (c->processor_id & 0xf0) {
309 		case PRID_REV_VR4111:
310 			c->cputype = CPU_VR4111;
311 			break;
312 		case PRID_REV_VR4121:
313 			c->cputype = CPU_VR4121;
314 			break;
315 		case PRID_REV_VR4122:
316 			if ((c->processor_id & 0xf) < 0x3)
317 				c->cputype = CPU_VR4122;
318 			else
319 				c->cputype = CPU_VR4181A;
320 			break;
321 		case PRID_REV_VR4130:
322 			if ((c->processor_id & 0xf) < 0x4)
323 				c->cputype = CPU_VR4131;
324 			else
325 				c->cputype = CPU_VR4133;
326 			break;
327 		default:
328 			printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
329 			c->cputype = CPU_VR41XX;
330 			break;
331 		}
332 		c->isa_level = MIPS_CPU_ISA_III;
333 		c->options = R4K_OPTS;
334 		c->tlbsize = 32;
335 		break;
336 	case PRID_IMP_R4300:
337 		c->cputype = CPU_R4300;
338 		c->isa_level = MIPS_CPU_ISA_III;
339 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
340 		             MIPS_CPU_LLSC;
341 		c->tlbsize = 32;
342 		break;
343 	case PRID_IMP_R4600:
344 		c->cputype = CPU_R4600;
345 		c->isa_level = MIPS_CPU_ISA_III;
346 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
347 			     MIPS_CPU_LLSC;
348 		c->tlbsize = 48;
349 		break;
350 	#if 0
351  	case PRID_IMP_R4650:
352 		/*
353 		 * This processor doesn't have an MMU, so it's not
354 		 * "real easy" to run Linux on it. It is left purely
355 		 * for documentation.  Commented out because it shares
356 		 * it's c0_prid id number with the TX3900.
357 		 */
358 		c->cputype = CPU_R4650;
359 	 	c->isa_level = MIPS_CPU_ISA_III;
360 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_LLSC;
361 	        c->tlbsize = 48;
362 		break;
363 	#endif
364 	case PRID_IMP_TX39:
365 		c->isa_level = MIPS_CPU_ISA_I;
366 		c->options = MIPS_CPU_TLB | MIPS_CPU_TX39_CACHE;
367 
368 		if ((c->processor_id & 0xf0) == (PRID_REV_TX3927 & 0xf0)) {
369 			c->cputype = CPU_TX3927;
370 			c->tlbsize = 64;
371 		} else {
372 			switch (c->processor_id & 0xff) {
373 			case PRID_REV_TX3912:
374 				c->cputype = CPU_TX3912;
375 				c->tlbsize = 32;
376 				break;
377 			case PRID_REV_TX3922:
378 				c->cputype = CPU_TX3922;
379 				c->tlbsize = 64;
380 				break;
381 			default:
382 				c->cputype = CPU_UNKNOWN;
383 				break;
384 			}
385 		}
386 		break;
387 	case PRID_IMP_R4700:
388 		c->cputype = CPU_R4700;
389 		c->isa_level = MIPS_CPU_ISA_III;
390 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
391 		             MIPS_CPU_LLSC;
392 		c->tlbsize = 48;
393 		break;
394 	case PRID_IMP_TX49:
395 		c->cputype = CPU_TX49XX;
396 		c->isa_level = MIPS_CPU_ISA_III;
397 		c->options = R4K_OPTS | MIPS_CPU_LLSC;
398 		if (!(c->processor_id & 0x08))
399 			c->options |= MIPS_CPU_FPU | MIPS_CPU_32FPR;
400 		c->tlbsize = 48;
401 		break;
402 	case PRID_IMP_R5000:
403 		c->cputype = CPU_R5000;
404 		c->isa_level = MIPS_CPU_ISA_IV;
405 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
406 		             MIPS_CPU_LLSC;
407 		c->tlbsize = 48;
408 		break;
409 	case PRID_IMP_R5432:
410 		c->cputype = CPU_R5432;
411 		c->isa_level = MIPS_CPU_ISA_IV;
412 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
413 		             MIPS_CPU_WATCH | MIPS_CPU_LLSC;
414 		c->tlbsize = 48;
415 		break;
416 	case PRID_IMP_R5500:
417 		c->cputype = CPU_R5500;
418 		c->isa_level = MIPS_CPU_ISA_IV;
419 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
420 		             MIPS_CPU_WATCH | MIPS_CPU_LLSC;
421 		c->tlbsize = 48;
422 		break;
423 	case PRID_IMP_NEVADA:
424 		c->cputype = CPU_NEVADA;
425 		c->isa_level = MIPS_CPU_ISA_IV;
426 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
427 		             MIPS_CPU_DIVEC | MIPS_CPU_LLSC;
428 		c->tlbsize = 48;
429 		break;
430 	case PRID_IMP_R6000:
431 		c->cputype = CPU_R6000;
432 		c->isa_level = MIPS_CPU_ISA_II;
433 		c->options = MIPS_CPU_TLB | MIPS_CPU_FPU |
434 		             MIPS_CPU_LLSC;
435 		c->tlbsize = 32;
436 		break;
437 	case PRID_IMP_R6000A:
438 		c->cputype = CPU_R6000A;
439 		c->isa_level = MIPS_CPU_ISA_II;
440 		c->options = MIPS_CPU_TLB | MIPS_CPU_FPU |
441 		             MIPS_CPU_LLSC;
442 		c->tlbsize = 32;
443 		break;
444 	case PRID_IMP_RM7000:
445 		c->cputype = CPU_RM7000;
446 		c->isa_level = MIPS_CPU_ISA_IV;
447 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
448 		             MIPS_CPU_LLSC;
449 		/*
450 		 * Undocumented RM7000:  Bit 29 in the info register of
451 		 * the RM7000 v2.0 indicates if the TLB has 48 or 64
452 		 * entries.
453 		 *
454 		 * 29      1 =>    64 entry JTLB
455 		 *         0 =>    48 entry JTLB
456 		 */
457 		c->tlbsize = (read_c0_info() & (1 << 29)) ? 64 : 48;
458 		break;
459 	case PRID_IMP_RM9000:
460 		c->cputype = CPU_RM9000;
461 		c->isa_level = MIPS_CPU_ISA_IV;
462 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
463 		             MIPS_CPU_LLSC;
464 		/*
465 		 * Bit 29 in the info register of the RM9000
466 		 * indicates if the TLB has 48 or 64 entries.
467 		 *
468 		 * 29      1 =>    64 entry JTLB
469 		 *         0 =>    48 entry JTLB
470 		 */
471 		c->tlbsize = (read_c0_info() & (1 << 29)) ? 64 : 48;
472 		break;
473 	case PRID_IMP_R8000:
474 		c->cputype = CPU_R8000;
475 		c->isa_level = MIPS_CPU_ISA_IV;
476 		c->options = MIPS_CPU_TLB | MIPS_CPU_4KEX |
477 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
478 		             MIPS_CPU_LLSC;
479 		c->tlbsize = 384;      /* has weird TLB: 3-way x 128 */
480 		break;
481 	case PRID_IMP_R10000:
482 		c->cputype = CPU_R10000;
483 		c->isa_level = MIPS_CPU_ISA_IV;
484 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
485 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
486 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
487 		             MIPS_CPU_LLSC;
488 		c->tlbsize = 64;
489 		break;
490 	case PRID_IMP_R12000:
491 		c->cputype = CPU_R12000;
492 		c->isa_level = MIPS_CPU_ISA_IV;
493 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
494 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
495 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
496 		             MIPS_CPU_LLSC;
497 		c->tlbsize = 64;
498 		break;
499 	case PRID_IMP_R14000:
500 		c->cputype = CPU_R14000;
501 		c->isa_level = MIPS_CPU_ISA_IV;
502 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
503 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
504 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
505 		             MIPS_CPU_LLSC;
506 		c->tlbsize = 64;
507 		break;
508 	case PRID_IMP_LOONGSON2:
509 		c->cputype = CPU_LOONGSON2;
510 		c->isa_level = MIPS_CPU_ISA_III;
511 		c->options = R4K_OPTS |
512 			     MIPS_CPU_FPU | MIPS_CPU_LLSC |
513 			     MIPS_CPU_32FPR;
514 		c->tlbsize = 64;
515 		break;
516 	}
517 }
518 
519 static char unknown_isa[] __initdata = KERN_ERR \
520 	"Unsupported ISA type, c0.config0: %d.";
521 
522 static inline unsigned int decode_config0(struct cpuinfo_mips *c)
523 {
524 	unsigned int config0;
525 	int isa;
526 
527 	config0 = read_c0_config();
528 
529 	if (((config0 & MIPS_CONF_MT) >> 7) == 1)
530 		c->options |= MIPS_CPU_TLB;
531 	isa = (config0 & MIPS_CONF_AT) >> 13;
532 	switch (isa) {
533 	case 0:
534 		switch ((config0 & MIPS_CONF_AR) >> 10) {
535 		case 0:
536 			c->isa_level = MIPS_CPU_ISA_M32R1;
537 			break;
538 		case 1:
539 			c->isa_level = MIPS_CPU_ISA_M32R2;
540 			break;
541 		default:
542 			goto unknown;
543 		}
544 		break;
545 	case 2:
546 		switch ((config0 & MIPS_CONF_AR) >> 10) {
547 		case 0:
548 			c->isa_level = MIPS_CPU_ISA_M64R1;
549 			break;
550 		case 1:
551 			c->isa_level = MIPS_CPU_ISA_M64R2;
552 			break;
553 		default:
554 			goto unknown;
555 		}
556 		break;
557 	default:
558 		goto unknown;
559 	}
560 
561 	return config0 & MIPS_CONF_M;
562 
563 unknown:
564 	panic(unknown_isa, config0);
565 }
566 
567 static inline unsigned int decode_config1(struct cpuinfo_mips *c)
568 {
569 	unsigned int config1;
570 
571 	config1 = read_c0_config1();
572 
573 	if (config1 & MIPS_CONF1_MD)
574 		c->ases |= MIPS_ASE_MDMX;
575 	if (config1 & MIPS_CONF1_WR)
576 		c->options |= MIPS_CPU_WATCH;
577 	if (config1 & MIPS_CONF1_CA)
578 		c->ases |= MIPS_ASE_MIPS16;
579 	if (config1 & MIPS_CONF1_EP)
580 		c->options |= MIPS_CPU_EJTAG;
581 	if (config1 & MIPS_CONF1_FP) {
582 		c->options |= MIPS_CPU_FPU;
583 		c->options |= MIPS_CPU_32FPR;
584 	}
585 	if (cpu_has_tlb)
586 		c->tlbsize = ((config1 & MIPS_CONF1_TLBS) >> 25) + 1;
587 
588 	return config1 & MIPS_CONF_M;
589 }
590 
591 static inline unsigned int decode_config2(struct cpuinfo_mips *c)
592 {
593 	unsigned int config2;
594 
595 	config2 = read_c0_config2();
596 
597 	if (config2 & MIPS_CONF2_SL)
598 		c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
599 
600 	return config2 & MIPS_CONF_M;
601 }
602 
603 static inline unsigned int decode_config3(struct cpuinfo_mips *c)
604 {
605 	unsigned int config3;
606 
607 	config3 = read_c0_config3();
608 
609 	if (config3 & MIPS_CONF3_SM)
610 		c->ases |= MIPS_ASE_SMARTMIPS;
611 	if (config3 & MIPS_CONF3_DSP)
612 		c->ases |= MIPS_ASE_DSP;
613 	if (config3 & MIPS_CONF3_VINT)
614 		c->options |= MIPS_CPU_VINT;
615 	if (config3 & MIPS_CONF3_VEIC)
616 		c->options |= MIPS_CPU_VEIC;
617 	if (config3 & MIPS_CONF3_MT)
618 	        c->ases |= MIPS_ASE_MIPSMT;
619 	if (config3 & MIPS_CONF3_ULRI)
620 		c->options |= MIPS_CPU_ULRI;
621 
622 	return config3 & MIPS_CONF_M;
623 }
624 
625 static void __init decode_configs(struct cpuinfo_mips *c)
626 {
627 	/* MIPS32 or MIPS64 compliant CPU.  */
628 	c->options = MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE | MIPS_CPU_COUNTER |
629 	             MIPS_CPU_DIVEC | MIPS_CPU_LLSC | MIPS_CPU_MCHECK;
630 
631 	c->scache.flags = MIPS_CACHE_NOT_PRESENT;
632 
633 	/* Read Config registers.  */
634 	if (!decode_config0(c))
635 		return;			/* actually worth a panic() */
636 	if (!decode_config1(c))
637 		return;
638 	if (!decode_config2(c))
639 		return;
640 	if (!decode_config3(c))
641 		return;
642 }
643 
644 static inline void cpu_probe_mips(struct cpuinfo_mips *c)
645 {
646 	decode_configs(c);
647 	switch (c->processor_id & 0xff00) {
648 	case PRID_IMP_4KC:
649 		c->cputype = CPU_4KC;
650 		break;
651 	case PRID_IMP_4KEC:
652 		c->cputype = CPU_4KEC;
653 		break;
654 	case PRID_IMP_4KECR2:
655 		c->cputype = CPU_4KEC;
656 		break;
657 	case PRID_IMP_4KSC:
658 	case PRID_IMP_4KSD:
659 		c->cputype = CPU_4KSC;
660 		break;
661 	case PRID_IMP_5KC:
662 		c->cputype = CPU_5KC;
663 		break;
664 	case PRID_IMP_20KC:
665 		c->cputype = CPU_20KC;
666 		break;
667 	case PRID_IMP_24K:
668 	case PRID_IMP_24KE:
669 		c->cputype = CPU_24K;
670 		break;
671 	case PRID_IMP_25KF:
672 		c->cputype = CPU_25KF;
673 		break;
674 	case PRID_IMP_34K:
675 		c->cputype = CPU_34K;
676 		break;
677 	case PRID_IMP_74K:
678 		c->cputype = CPU_74K;
679 		break;
680 	}
681 }
682 
683 static inline void cpu_probe_alchemy(struct cpuinfo_mips *c)
684 {
685 	decode_configs(c);
686 	switch (c->processor_id & 0xff00) {
687 	case PRID_IMP_AU1_REV1:
688 	case PRID_IMP_AU1_REV2:
689 		switch ((c->processor_id >> 24) & 0xff) {
690 		case 0:
691 			c->cputype = CPU_AU1000;
692 			break;
693 		case 1:
694 			c->cputype = CPU_AU1500;
695 			break;
696 		case 2:
697 			c->cputype = CPU_AU1100;
698 			break;
699 		case 3:
700 			c->cputype = CPU_AU1550;
701 			break;
702 		case 4:
703 			c->cputype = CPU_AU1200;
704 			break;
705 		default:
706 			panic("Unknown Au Core!");
707 			break;
708 		}
709 		break;
710 	}
711 }
712 
713 static inline void cpu_probe_sibyte(struct cpuinfo_mips *c)
714 {
715 	decode_configs(c);
716 
717 	/*
718 	 * For historical reasons the SB1 comes with it's own variant of
719 	 * cache code which eventually will be folded into c-r4k.c.  Until
720 	 * then we pretend it's got it's own cache architecture.
721 	 */
722 	c->options &= ~MIPS_CPU_4K_CACHE;
723 	c->options |= MIPS_CPU_SB1_CACHE;
724 
725 	switch (c->processor_id & 0xff00) {
726 	case PRID_IMP_SB1:
727 		c->cputype = CPU_SB1;
728 		/* FPU in pass1 is known to have issues. */
729 		if ((c->processor_id & 0xff) < 0x02)
730 			c->options &= ~(MIPS_CPU_FPU | MIPS_CPU_32FPR);
731 		break;
732 	case PRID_IMP_SB1A:
733 		c->cputype = CPU_SB1A;
734 		break;
735 	}
736 }
737 
738 static inline void cpu_probe_sandcraft(struct cpuinfo_mips *c)
739 {
740 	decode_configs(c);
741 	switch (c->processor_id & 0xff00) {
742 	case PRID_IMP_SR71000:
743 		c->cputype = CPU_SR71000;
744 		c->scache.ways = 8;
745 		c->tlbsize = 64;
746 		break;
747 	}
748 }
749 
750 static inline void cpu_probe_philips(struct cpuinfo_mips *c)
751 {
752 	decode_configs(c);
753 	switch (c->processor_id & 0xff00) {
754 	case PRID_IMP_PR4450:
755 		c->cputype = CPU_PR4450;
756 		c->isa_level = MIPS_CPU_ISA_M32R1;
757 		break;
758 	default:
759 		panic("Unknown Philips Core!"); /* REVISIT: die? */
760 		break;
761 	}
762 }
763 
764 
765 __init void cpu_probe(void)
766 {
767 	struct cpuinfo_mips *c = &current_cpu_data;
768 
769 	c->processor_id	= PRID_IMP_UNKNOWN;
770 	c->fpu_id	= FPIR_IMP_NONE;
771 	c->cputype	= CPU_UNKNOWN;
772 
773 	c->processor_id = read_c0_prid();
774 	switch (c->processor_id & 0xff0000) {
775 	case PRID_COMP_LEGACY:
776 		cpu_probe_legacy(c);
777 		break;
778 	case PRID_COMP_MIPS:
779 		cpu_probe_mips(c);
780 		break;
781 	case PRID_COMP_ALCHEMY:
782 		cpu_probe_alchemy(c);
783 		break;
784 	case PRID_COMP_SIBYTE:
785 		cpu_probe_sibyte(c);
786 		break;
787 	case PRID_COMP_SANDCRAFT:
788 		cpu_probe_sandcraft(c);
789 		break;
790  	case PRID_COMP_PHILIPS:
791 		cpu_probe_philips(c);
792 		break;
793 	default:
794 		c->cputype = CPU_UNKNOWN;
795 	}
796 	if (c->options & MIPS_CPU_FPU) {
797 		c->fpu_id = cpu_get_fpu_id();
798 
799 		if (c->isa_level == MIPS_CPU_ISA_M32R1 ||
800 		    c->isa_level == MIPS_CPU_ISA_M32R2 ||
801 		    c->isa_level == MIPS_CPU_ISA_M64R1 ||
802 		    c->isa_level == MIPS_CPU_ISA_M64R2) {
803 			if (c->fpu_id & MIPS_FPIR_3D)
804 				c->ases |= MIPS_ASE_MIPS3D;
805 		}
806 	}
807 }
808 
809 __init void cpu_report(void)
810 {
811 	struct cpuinfo_mips *c = &current_cpu_data;
812 
813 	printk("CPU revision is: %08x\n", c->processor_id);
814 	if (c->options & MIPS_CPU_FPU)
815 		printk("FPU revision is: %08x\n", c->fpu_id);
816 }
817