xref: /linux/arch/mips/kernel/cpu-probe.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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/config.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/ptrace.h>
18 #include <linux/stddef.h>
19 
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 	unsigned long cfg = read_c0_conf();
43 	write_c0_conf(cfg | TX39_CONF_HALT);
44 }
45 
46 static void r4k_wait(void)
47 {
48 	__asm__(".set\tmips3\n\t"
49 		"wait\n\t"
50 		".set\tmips0");
51 }
52 
53 /* The Au1xxx wait is available only if using 32khz counter or
54  * external timer source, but specifically not CP0 Counter. */
55 int allow_au1k_wait;
56 
57 static void au1k_wait(void)
58 {
59 	/* using the wait instruction makes CP0 counter unusable */
60 	__asm__(".set mips3\n\t"
61 		"cache 0x14, 0(%0)\n\t"
62 		"cache 0x14, 32(%0)\n\t"
63 		"sync\n\t"
64 		"nop\n\t"
65 		"wait\n\t"
66 		"nop\n\t"
67 		"nop\n\t"
68 		"nop\n\t"
69 		"nop\n\t"
70 		".set mips0\n\t"
71 		: : "r" (au1k_wait));
72 }
73 
74 static int __initdata nowait = 0;
75 
76 int __init wait_disable(char *s)
77 {
78 	nowait = 1;
79 
80 	return 1;
81 }
82 
83 __setup("nowait", wait_disable);
84 
85 static inline void check_wait(void)
86 {
87 	struct cpuinfo_mips *c = &current_cpu_data;
88 
89 	printk("Checking for 'wait' instruction... ");
90 	if (nowait) {
91 		printk (" disabled.\n");
92 		return;
93 	}
94 
95 	switch (c->cputype) {
96 	case CPU_R3081:
97 	case CPU_R3081E:
98 		cpu_wait = r3081_wait;
99 		printk(" available.\n");
100 		break;
101 	case CPU_TX3927:
102 		cpu_wait = r39xx_wait;
103 		printk(" available.\n");
104 		break;
105 	case CPU_R4200:
106 /*	case CPU_R4300: */
107 	case CPU_R4600:
108 	case CPU_R4640:
109 	case CPU_R4650:
110 	case CPU_R4700:
111 	case CPU_R5000:
112 	case CPU_NEVADA:
113 	case CPU_RM7000:
114 	case CPU_RM9000:
115 	case CPU_TX49XX:
116 	case CPU_4KC:
117 	case CPU_4KEC:
118 	case CPU_4KSC:
119 	case CPU_5KC:
120 /*	case CPU_20KC:*/
121 	case CPU_24K:
122 	case CPU_25KF:
123 	case CPU_34K:
124 	case CPU_74K:
125  	case CPU_PR4450:
126 		cpu_wait = r4k_wait;
127 		printk(" available.\n");
128 		break;
129 	case CPU_AU1000:
130 	case CPU_AU1100:
131 	case CPU_AU1500:
132 	case CPU_AU1550:
133 	case CPU_AU1200:
134 		if (allow_au1k_wait) {
135 			cpu_wait = au1k_wait;
136 			printk(" available.\n");
137 		} else
138 			printk(" unavailable.\n");
139 		break;
140 	default:
141 		printk(" unavailable.\n");
142 		break;
143 	}
144 }
145 
146 void __init check_bugs32(void)
147 {
148 	check_wait();
149 }
150 
151 /*
152  * Probe whether cpu has config register by trying to play with
153  * alternate cache bit and see whether it matters.
154  * It's used by cpu_probe to distinguish between R3000A and R3081.
155  */
156 static inline int cpu_has_confreg(void)
157 {
158 #ifdef CONFIG_CPU_R3000
159 	extern unsigned long r3k_cache_size(unsigned long);
160 	unsigned long size1, size2;
161 	unsigned long cfg = read_c0_conf();
162 
163 	size1 = r3k_cache_size(ST0_ISC);
164 	write_c0_conf(cfg ^ R30XX_CONF_AC);
165 	size2 = r3k_cache_size(ST0_ISC);
166 	write_c0_conf(cfg);
167 	return size1 != size2;
168 #else
169 	return 0;
170 #endif
171 }
172 
173 /*
174  * Get the FPU Implementation/Revision.
175  */
176 static inline unsigned long cpu_get_fpu_id(void)
177 {
178 	unsigned long tmp, fpu_id;
179 
180 	tmp = read_c0_status();
181 	__enable_fpu();
182 	fpu_id = read_32bit_cp1_register(CP1_REVISION);
183 	write_c0_status(tmp);
184 	return fpu_id;
185 }
186 
187 /*
188  * Check the CPU has an FPU the official way.
189  */
190 static inline int __cpu_has_fpu(void)
191 {
192 	return ((cpu_get_fpu_id() & 0xff00) != FPIR_IMP_NONE);
193 }
194 
195 #define R4K_OPTS (MIPS_CPU_TLB | MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE \
196 		| MIPS_CPU_COUNTER)
197 
198 static inline void cpu_probe_legacy(struct cpuinfo_mips *c)
199 {
200 	switch (c->processor_id & 0xff00) {
201 	case PRID_IMP_R2000:
202 		c->cputype = CPU_R2000;
203 		c->isa_level = MIPS_CPU_ISA_I;
204 		c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
205 		             MIPS_CPU_NOFPUEX;
206 		if (__cpu_has_fpu())
207 			c->options |= MIPS_CPU_FPU;
208 		c->tlbsize = 64;
209 		break;
210 	case PRID_IMP_R3000:
211 		if ((c->processor_id & 0xff) == PRID_REV_R3000A)
212 			if (cpu_has_confreg())
213 				c->cputype = CPU_R3081E;
214 			else
215 				c->cputype = CPU_R3000A;
216 		else
217 			c->cputype = CPU_R3000;
218 		c->isa_level = MIPS_CPU_ISA_I;
219 		c->options = MIPS_CPU_TLB | MIPS_CPU_3K_CACHE |
220 		             MIPS_CPU_NOFPUEX;
221 		if (__cpu_has_fpu())
222 			c->options |= MIPS_CPU_FPU;
223 		c->tlbsize = 64;
224 		break;
225 	case PRID_IMP_R4000:
226 		if (read_c0_config() & CONF_SC) {
227 			if ((c->processor_id & 0xff) >= PRID_REV_R4400)
228 				c->cputype = CPU_R4400PC;
229 			else
230 				c->cputype = CPU_R4000PC;
231 		} else {
232 			if ((c->processor_id & 0xff) >= PRID_REV_R4400)
233 				c->cputype = CPU_R4400SC;
234 			else
235 				c->cputype = CPU_R4000SC;
236 		}
237 
238 		c->isa_level = MIPS_CPU_ISA_III;
239 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
240 		             MIPS_CPU_WATCH | MIPS_CPU_VCE |
241 		             MIPS_CPU_LLSC;
242 		c->tlbsize = 48;
243 		break;
244 	case PRID_IMP_VR41XX:
245 		switch (c->processor_id & 0xf0) {
246 		case PRID_REV_VR4111:
247 			c->cputype = CPU_VR4111;
248 			break;
249 		case PRID_REV_VR4121:
250 			c->cputype = CPU_VR4121;
251 			break;
252 		case PRID_REV_VR4122:
253 			if ((c->processor_id & 0xf) < 0x3)
254 				c->cputype = CPU_VR4122;
255 			else
256 				c->cputype = CPU_VR4181A;
257 			break;
258 		case PRID_REV_VR4130:
259 			if ((c->processor_id & 0xf) < 0x4)
260 				c->cputype = CPU_VR4131;
261 			else
262 				c->cputype = CPU_VR4133;
263 			break;
264 		default:
265 			printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
266 			c->cputype = CPU_VR41XX;
267 			break;
268 		}
269 		c->isa_level = MIPS_CPU_ISA_III;
270 		c->options = R4K_OPTS;
271 		c->tlbsize = 32;
272 		break;
273 	case PRID_IMP_R4300:
274 		c->cputype = CPU_R4300;
275 		c->isa_level = MIPS_CPU_ISA_III;
276 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
277 		             MIPS_CPU_LLSC;
278 		c->tlbsize = 32;
279 		break;
280 	case PRID_IMP_R4600:
281 		c->cputype = CPU_R4600;
282 		c->isa_level = MIPS_CPU_ISA_III;
283 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
284 			     MIPS_CPU_LLSC;
285 		c->tlbsize = 48;
286 		break;
287 	#if 0
288  	case PRID_IMP_R4650:
289 		/*
290 		 * This processor doesn't have an MMU, so it's not
291 		 * "real easy" to run Linux on it. It is left purely
292 		 * for documentation.  Commented out because it shares
293 		 * it's c0_prid id number with the TX3900.
294 		 */
295 		c->cputype = CPU_R4650;
296 	 	c->isa_level = MIPS_CPU_ISA_III;
297 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_LLSC;
298 	        c->tlbsize = 48;
299 		break;
300 	#endif
301 	case PRID_IMP_TX39:
302 		c->isa_level = MIPS_CPU_ISA_I;
303 		c->options = MIPS_CPU_TLB | MIPS_CPU_TX39_CACHE;
304 
305 		if ((c->processor_id & 0xf0) == (PRID_REV_TX3927 & 0xf0)) {
306 			c->cputype = CPU_TX3927;
307 			c->tlbsize = 64;
308 		} else {
309 			switch (c->processor_id & 0xff) {
310 			case PRID_REV_TX3912:
311 				c->cputype = CPU_TX3912;
312 				c->tlbsize = 32;
313 				break;
314 			case PRID_REV_TX3922:
315 				c->cputype = CPU_TX3922;
316 				c->tlbsize = 64;
317 				break;
318 			default:
319 				c->cputype = CPU_UNKNOWN;
320 				break;
321 			}
322 		}
323 		break;
324 	case PRID_IMP_R4700:
325 		c->cputype = CPU_R4700;
326 		c->isa_level = MIPS_CPU_ISA_III;
327 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
328 		             MIPS_CPU_LLSC;
329 		c->tlbsize = 48;
330 		break;
331 	case PRID_IMP_TX49:
332 		c->cputype = CPU_TX49XX;
333 		c->isa_level = MIPS_CPU_ISA_III;
334 		c->options = R4K_OPTS | MIPS_CPU_LLSC;
335 		if (!(c->processor_id & 0x08))
336 			c->options |= MIPS_CPU_FPU | MIPS_CPU_32FPR;
337 		c->tlbsize = 48;
338 		break;
339 	case PRID_IMP_R5000:
340 		c->cputype = CPU_R5000;
341 		c->isa_level = MIPS_CPU_ISA_IV;
342 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
343 		             MIPS_CPU_LLSC;
344 		c->tlbsize = 48;
345 		break;
346 	case PRID_IMP_R5432:
347 		c->cputype = CPU_R5432;
348 		c->isa_level = MIPS_CPU_ISA_IV;
349 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
350 		             MIPS_CPU_WATCH | MIPS_CPU_LLSC;
351 		c->tlbsize = 48;
352 		break;
353 	case PRID_IMP_R5500:
354 		c->cputype = CPU_R5500;
355 		c->isa_level = MIPS_CPU_ISA_IV;
356 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
357 		             MIPS_CPU_WATCH | MIPS_CPU_LLSC;
358 		c->tlbsize = 48;
359 		break;
360 	case PRID_IMP_NEVADA:
361 		c->cputype = CPU_NEVADA;
362 		c->isa_level = MIPS_CPU_ISA_IV;
363 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
364 		             MIPS_CPU_DIVEC | MIPS_CPU_LLSC;
365 		c->tlbsize = 48;
366 		break;
367 	case PRID_IMP_R6000:
368 		c->cputype = CPU_R6000;
369 		c->isa_level = MIPS_CPU_ISA_II;
370 		c->options = MIPS_CPU_TLB | MIPS_CPU_FPU |
371 		             MIPS_CPU_LLSC;
372 		c->tlbsize = 32;
373 		break;
374 	case PRID_IMP_R6000A:
375 		c->cputype = CPU_R6000A;
376 		c->isa_level = MIPS_CPU_ISA_II;
377 		c->options = MIPS_CPU_TLB | MIPS_CPU_FPU |
378 		             MIPS_CPU_LLSC;
379 		c->tlbsize = 32;
380 		break;
381 	case PRID_IMP_RM7000:
382 		c->cputype = CPU_RM7000;
383 		c->isa_level = MIPS_CPU_ISA_IV;
384 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
385 		             MIPS_CPU_LLSC;
386 		/*
387 		 * Undocumented RM7000:  Bit 29 in the info register of
388 		 * the RM7000 v2.0 indicates if the TLB has 48 or 64
389 		 * entries.
390 		 *
391 		 * 29      1 =>    64 entry JTLB
392 		 *         0 =>    48 entry JTLB
393 		 */
394 		c->tlbsize = (read_c0_info() & (1 << 29)) ? 64 : 48;
395 		break;
396 	case PRID_IMP_RM9000:
397 		c->cputype = CPU_RM9000;
398 		c->isa_level = MIPS_CPU_ISA_IV;
399 		c->options = R4K_OPTS | MIPS_CPU_FPU | MIPS_CPU_32FPR |
400 		             MIPS_CPU_LLSC;
401 		/*
402 		 * Bit 29 in the info register of the RM9000
403 		 * indicates if the TLB has 48 or 64 entries.
404 		 *
405 		 * 29      1 =>    64 entry JTLB
406 		 *         0 =>    48 entry JTLB
407 		 */
408 		c->tlbsize = (read_c0_info() & (1 << 29)) ? 64 : 48;
409 		break;
410 	case PRID_IMP_R8000:
411 		c->cputype = CPU_R8000;
412 		c->isa_level = MIPS_CPU_ISA_IV;
413 		c->options = MIPS_CPU_TLB | MIPS_CPU_4KEX |
414 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
415 		             MIPS_CPU_LLSC;
416 		c->tlbsize = 384;      /* has weird TLB: 3-way x 128 */
417 		break;
418 	case PRID_IMP_R10000:
419 		c->cputype = CPU_R10000;
420 		c->isa_level = MIPS_CPU_ISA_IV;
421 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
422 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
423 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
424 		             MIPS_CPU_LLSC;
425 		c->tlbsize = 64;
426 		break;
427 	case PRID_IMP_R12000:
428 		c->cputype = CPU_R12000;
429 		c->isa_level = MIPS_CPU_ISA_IV;
430 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
431 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
432 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
433 		             MIPS_CPU_LLSC;
434 		c->tlbsize = 64;
435 		break;
436 	case PRID_IMP_R14000:
437 		c->cputype = CPU_R14000;
438 		c->isa_level = MIPS_CPU_ISA_IV;
439 		c->options = MIPS_CPU_TLB | MIPS_CPU_4K_CACHE | MIPS_CPU_4KEX |
440 		             MIPS_CPU_FPU | MIPS_CPU_32FPR |
441 			     MIPS_CPU_COUNTER | MIPS_CPU_WATCH |
442 		             MIPS_CPU_LLSC;
443 		c->tlbsize = 64;
444 		break;
445 	}
446 }
447 
448 static char unknown_isa[] __initdata = KERN_ERR \
449 	"Unsupported ISA type, c0.config0: %d.";
450 
451 static inline unsigned int decode_config0(struct cpuinfo_mips *c)
452 {
453 	unsigned int config0;
454 	int isa;
455 
456 	config0 = read_c0_config();
457 
458 	if (((config0 & MIPS_CONF_MT) >> 7) == 1)
459 		c->options |= MIPS_CPU_TLB;
460 	isa = (config0 & MIPS_CONF_AT) >> 13;
461 	switch (isa) {
462 	case 0:
463 		switch ((config0 >> 10) & 7) {
464 		case 0:
465 			c->isa_level = MIPS_CPU_ISA_M32R1;
466 			break;
467 		case 1:
468 			c->isa_level = MIPS_CPU_ISA_M32R2;
469 			break;
470 		default:
471 			goto unknown;
472 		}
473 		break;
474 	case 2:
475 		switch ((config0 >> 10) & 7) {
476 		case 0:
477 			c->isa_level = MIPS_CPU_ISA_M64R1;
478 			break;
479 		case 1:
480 			c->isa_level = MIPS_CPU_ISA_M64R2;
481 			break;
482 		default:
483 			goto unknown;
484 		}
485 		break;
486 	default:
487 		goto unknown;
488 	}
489 
490 	return config0 & MIPS_CONF_M;
491 
492 unknown:
493 	panic(unknown_isa, config0);
494 }
495 
496 static inline unsigned int decode_config1(struct cpuinfo_mips *c)
497 {
498 	unsigned int config1;
499 
500 	config1 = read_c0_config1();
501 
502 	if (config1 & MIPS_CONF1_MD)
503 		c->ases |= MIPS_ASE_MDMX;
504 	if (config1 & MIPS_CONF1_WR)
505 		c->options |= MIPS_CPU_WATCH;
506 	if (config1 & MIPS_CONF1_CA)
507 		c->ases |= MIPS_ASE_MIPS16;
508 	if (config1 & MIPS_CONF1_EP)
509 		c->options |= MIPS_CPU_EJTAG;
510 	if (config1 & MIPS_CONF1_FP) {
511 		c->options |= MIPS_CPU_FPU;
512 		c->options |= MIPS_CPU_32FPR;
513 	}
514 	if (cpu_has_tlb)
515 		c->tlbsize = ((config1 & MIPS_CONF1_TLBS) >> 25) + 1;
516 
517 	return config1 & MIPS_CONF_M;
518 }
519 
520 static inline unsigned int decode_config2(struct cpuinfo_mips *c)
521 {
522 	unsigned int config2;
523 
524 	config2 = read_c0_config2();
525 
526 	if (config2 & MIPS_CONF2_SL)
527 		c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
528 
529 	return config2 & MIPS_CONF_M;
530 }
531 
532 static inline unsigned int decode_config3(struct cpuinfo_mips *c)
533 {
534 	unsigned int config3;
535 
536 	config3 = read_c0_config3();
537 
538 	if (config3 & MIPS_CONF3_SM)
539 		c->ases |= MIPS_ASE_SMARTMIPS;
540 	if (config3 & MIPS_CONF3_DSP)
541 		c->ases |= MIPS_ASE_DSP;
542 	if (config3 & MIPS_CONF3_VINT)
543 		c->options |= MIPS_CPU_VINT;
544 	if (config3 & MIPS_CONF3_VEIC)
545 		c->options |= MIPS_CPU_VEIC;
546 	if (config3 & MIPS_CONF3_MT)
547                 c->ases |= MIPS_ASE_MIPSMT;
548 
549 	return config3 & MIPS_CONF_M;
550 }
551 
552 static inline void decode_configs(struct cpuinfo_mips *c)
553 {
554 	/* MIPS32 or MIPS64 compliant CPU.  */
555 	c->options = MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE | MIPS_CPU_COUNTER |
556 	             MIPS_CPU_DIVEC | MIPS_CPU_LLSC | MIPS_CPU_MCHECK;
557 
558 	c->scache.flags = MIPS_CACHE_NOT_PRESENT;
559 
560 	/* Read Config registers.  */
561 	if (!decode_config0(c))
562 		return;			/* actually worth a panic() */
563 	if (!decode_config1(c))
564 		return;
565 	if (!decode_config2(c))
566 		return;
567 	if (!decode_config3(c))
568 		return;
569 }
570 
571 static inline void cpu_probe_mips(struct cpuinfo_mips *c)
572 {
573 	decode_configs(c);
574 	switch (c->processor_id & 0xff00) {
575 	case PRID_IMP_4KC:
576 		c->cputype = CPU_4KC;
577 		break;
578 	case PRID_IMP_4KEC:
579 		c->cputype = CPU_4KEC;
580 		break;
581 	case PRID_IMP_4KECR2:
582 		c->cputype = CPU_4KEC;
583 		break;
584 	case PRID_IMP_4KSC:
585 	case PRID_IMP_4KSD:
586 		c->cputype = CPU_4KSC;
587 		break;
588 	case PRID_IMP_5KC:
589 		c->cputype = CPU_5KC;
590 		break;
591 	case PRID_IMP_20KC:
592 		c->cputype = CPU_20KC;
593 		break;
594 	case PRID_IMP_24K:
595 	case PRID_IMP_24KE:
596 		c->cputype = CPU_24K;
597 		break;
598 	case PRID_IMP_25KF:
599 		c->cputype = CPU_25KF;
600 		/* Probe for L2 cache */
601 		c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
602 		break;
603 	case PRID_IMP_34K:
604 		c->cputype = CPU_34K;
605 		break;
606 	case PRID_IMP_74K:
607 		c->cputype = CPU_74K;
608 		break;
609 	}
610 }
611 
612 static inline void cpu_probe_alchemy(struct cpuinfo_mips *c)
613 {
614 	decode_configs(c);
615 	switch (c->processor_id & 0xff00) {
616 	case PRID_IMP_AU1_REV1:
617 	case PRID_IMP_AU1_REV2:
618 		switch ((c->processor_id >> 24) & 0xff) {
619 		case 0:
620 			c->cputype = CPU_AU1000;
621 			break;
622 		case 1:
623 			c->cputype = CPU_AU1500;
624 			break;
625 		case 2:
626 			c->cputype = CPU_AU1100;
627 			break;
628 		case 3:
629 			c->cputype = CPU_AU1550;
630 			break;
631 		case 4:
632 			c->cputype = CPU_AU1200;
633 			break;
634 		default:
635 			panic("Unknown Au Core!");
636 			break;
637 		}
638 		break;
639 	}
640 }
641 
642 static inline void cpu_probe_sibyte(struct cpuinfo_mips *c)
643 {
644 	decode_configs(c);
645 
646 	/*
647 	 * For historical reasons the SB1 comes with it's own variant of
648 	 * cache code which eventually will be folded into c-r4k.c.  Until
649 	 * then we pretend it's got it's own cache architecture.
650 	 */
651 	c->options &= ~MIPS_CPU_4K_CACHE;
652 	c->options |= MIPS_CPU_SB1_CACHE;
653 
654 	switch (c->processor_id & 0xff00) {
655 	case PRID_IMP_SB1:
656 		c->cputype = CPU_SB1;
657 		/* FPU in pass1 is known to have issues. */
658 		if ((c->processor_id & 0xff) < 0x02)
659 			c->options &= ~(MIPS_CPU_FPU | MIPS_CPU_32FPR);
660 		break;
661 	case PRID_IMP_SB1A:
662 		c->cputype = CPU_SB1A;
663 		break;
664 	}
665 }
666 
667 static inline void cpu_probe_sandcraft(struct cpuinfo_mips *c)
668 {
669 	decode_configs(c);
670 	switch (c->processor_id & 0xff00) {
671 	case PRID_IMP_SR71000:
672 		c->cputype = CPU_SR71000;
673 		c->scache.ways = 8;
674 		c->tlbsize = 64;
675 		break;
676 	}
677 }
678 
679 static inline void cpu_probe_philips(struct cpuinfo_mips *c)
680 {
681 	decode_configs(c);
682 	switch (c->processor_id & 0xff00) {
683 	case PRID_IMP_PR4450:
684 		c->cputype = CPU_PR4450;
685 		c->isa_level = MIPS_CPU_ISA_M32R1;
686 		break;
687 	default:
688 		panic("Unknown Philips Core!"); /* REVISIT: die? */
689 		break;
690 	}
691 }
692 
693 
694 __init void cpu_probe(void)
695 {
696 	struct cpuinfo_mips *c = &current_cpu_data;
697 
698 	c->processor_id	= PRID_IMP_UNKNOWN;
699 	c->fpu_id	= FPIR_IMP_NONE;
700 	c->cputype	= CPU_UNKNOWN;
701 
702 	c->processor_id = read_c0_prid();
703 	switch (c->processor_id & 0xff0000) {
704 	case PRID_COMP_LEGACY:
705 		cpu_probe_legacy(c);
706 		break;
707 	case PRID_COMP_MIPS:
708 		cpu_probe_mips(c);
709 		break;
710 	case PRID_COMP_ALCHEMY:
711 		cpu_probe_alchemy(c);
712 		break;
713 	case PRID_COMP_SIBYTE:
714 		cpu_probe_sibyte(c);
715 		break;
716 	case PRID_COMP_SANDCRAFT:
717 		cpu_probe_sandcraft(c);
718 		break;
719  	case PRID_COMP_PHILIPS:
720 		cpu_probe_philips(c);
721 		break;
722 	default:
723 		c->cputype = CPU_UNKNOWN;
724 	}
725 	if (c->options & MIPS_CPU_FPU) {
726 		c->fpu_id = cpu_get_fpu_id();
727 
728 		if (c->isa_level == MIPS_CPU_ISA_M32R1 ||
729 		    c->isa_level == MIPS_CPU_ISA_M32R2 ||
730 		    c->isa_level == MIPS_CPU_ISA_M64R1 ||
731 		    c->isa_level == MIPS_CPU_ISA_M64R2) {
732 			if (c->fpu_id & MIPS_FPIR_3D)
733 				c->ases |= MIPS_ASE_MIPS3D;
734 		}
735 	}
736 }
737 
738 __init void cpu_report(void)
739 {
740 	struct cpuinfo_mips *c = &current_cpu_data;
741 
742 	printk("CPU revision is: %08x\n", c->processor_id);
743 	if (c->options & MIPS_CPU_FPU)
744 		printk("FPU revision is: %08x\n", c->fpu_id);
745 }
746