xref: /openbmc/linux/arch/microblaze/kernel/cpu/cache.c (revision e15a5365)
1 /*
2  * Cache control for MicroBlaze cache memories
3  *
4  * Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
5  * Copyright (C) 2007-2009 PetaLogix
6  * Copyright (C) 2007-2009 John Williams <john.williams@petalogix.com>
7  *
8  * This file is subject to the terms and conditions of the GNU General
9  * Public License. See the file COPYING in the main directory of this
10  * archive for more details.
11  */
12 
13 #include <asm/cacheflush.h>
14 #include <linux/cache.h>
15 #include <asm/cpuinfo.h>
16 #include <asm/pvr.h>
17 
18 static inline void __enable_icache_msr(void)
19 {
20 	__asm__ __volatile__ ("	 msrset	r0, %0;"	\
21 				"nop;"			\
22 			: : "i" (MSR_ICE) : "memory");
23 }
24 
25 static inline void __disable_icache_msr(void)
26 {
27 	__asm__ __volatile__ ("	 msrclr	r0, %0;"	\
28 				"nop;"			\
29 			: : "i" (MSR_ICE) : "memory");
30 }
31 
32 static inline void __enable_dcache_msr(void)
33 {
34 	__asm__ __volatile__ ("	 msrset	r0, %0;"	\
35 				"nop;"			\
36 			: : "i" (MSR_DCE) : "memory");
37 }
38 
39 static inline void __disable_dcache_msr(void)
40 {
41 	__asm__ __volatile__ ("	 msrclr	r0, %0;"	\
42 				"nop; "			\
43 			: : "i" (MSR_DCE) : "memory");
44 }
45 
46 static inline void __enable_icache_nomsr(void)
47 {
48 	__asm__ __volatile__ ("	 mfs	r12, rmsr;"	\
49 				"nop;"			\
50 				"ori	r12, r12, %0;"	\
51 				"mts	rmsr, r12;"	\
52 				"nop;"			\
53 			: : "i" (MSR_ICE) : "memory", "r12");
54 }
55 
56 static inline void __disable_icache_nomsr(void)
57 {
58 	__asm__ __volatile__ ("	 mfs	r12, rmsr;"	\
59 				"nop;"			\
60 				"andi	r12, r12, ~%0;"	\
61 				"mts	rmsr, r12;"	\
62 				"nop;"			\
63 			: : "i" (MSR_ICE) : "memory", "r12");
64 }
65 
66 static inline void __enable_dcache_nomsr(void)
67 {
68 	__asm__ __volatile__ ("	 mfs	r12, rmsr;"	\
69 				"nop;"			\
70 				"ori	r12, r12, %0;"	\
71 				"mts	rmsr, r12;"	\
72 				"nop;"			\
73 			: : "i" (MSR_DCE) : "memory", "r12");
74 }
75 
76 static inline void __disable_dcache_nomsr(void)
77 {
78 	__asm__ __volatile__ ("	 mfs	r12, rmsr;"	\
79 				"nop;"			\
80 				"andi	r12, r12, ~%0;"	\
81 				"mts	rmsr, r12;"	\
82 				"nop;"			\
83 			: : "i" (MSR_DCE) : "memory", "r12");
84 }
85 
86 
87 /* Helper macro for computing the limits of cache range loops
88  *
89  * End address can be unaligned which is OK for C implementation.
90  * ASM implementation align it in ASM macros
91  */
92 #define CACHE_LOOP_LIMITS(start, end, cache_line_length, cache_size)	\
93 do {									\
94 	int align = ~(cache_line_length - 1);				\
95 	if (start <  UINT_MAX - cache_size)				\
96 		end = min(start + cache_size, end);			\
97 	start &= align;							\
98 } while (0)
99 
100 /*
101  * Helper macro to loop over the specified cache_size/line_length and
102  * execute 'op' on that cacheline
103  */
104 #define CACHE_ALL_LOOP(cache_size, line_length, op)			\
105 do {									\
106 	unsigned int len = cache_size - line_length;			\
107 	int step = -line_length;					\
108 	WARN_ON(step >= 0);						\
109 									\
110 	__asm__ __volatile__ (" 1:      " #op " %0, r0;"		\
111 					"bgtid   %0, 1b;"		\
112 					"addk    %0, %0, %1;"		\
113 					: : "r" (len), "r" (step)	\
114 					: "memory");			\
115 } while (0)
116 
117 /* Used for wdc.flush/clear which can use rB for offset which is not possible
118  * to use for simple wdc or wic.
119  *
120  * start address is cache aligned
121  * end address is not aligned, if end is aligned then I have to subtract
122  * cacheline length because I can't flush/invalidate the next cacheline.
123  * If is not, I align it because I will flush/invalidate whole line.
124  */
125 #define CACHE_RANGE_LOOP_2(start, end, line_length, op)			\
126 do {									\
127 	int step = -line_length;					\
128 	int align = ~(line_length - 1);					\
129 	int count;							\
130 	end = ((end & align) == end) ? end - line_length : end & align;	\
131 	count = end - start;						\
132 	WARN_ON(count < 0);						\
133 									\
134 	__asm__ __volatile__ (" 1:	" #op "	%0, %1;"		\
135 					"bgtid	%1, 1b;"		\
136 					"addk	%1, %1, %2;"		\
137 					: : "r" (start), "r" (count),	\
138 					"r" (step) : "memory");		\
139 } while (0)
140 
141 /* It is used only first parameter for OP - for wic, wdc */
142 #define CACHE_RANGE_LOOP_1(start, end, line_length, op)			\
143 do {									\
144 	unsigned int volatile temp = 0;						\
145 	unsigned int align = ~(line_length - 1);					\
146 	end = ((end & align) == end) ? end - line_length : end & align;	\
147 	WARN_ON(end < start);					\
148 									\
149 	__asm__ __volatile__ (" 1:	" #op "	%1, r0;"		\
150 					"cmpu	%0, %1, %2;"		\
151 					"bgtid	%0, 1b;"		\
152 					"addk	%1, %1, %3;"		\
153 				: : "r" (temp), "r" (start), "r" (end),	\
154 					"r" (line_length) : "memory");	\
155 } while (0)
156 
157 #define ASM_LOOP
158 
159 static void __flush_icache_range_msr_irq(unsigned long start, unsigned long end)
160 {
161 	unsigned long flags;
162 #ifndef ASM_LOOP
163 	int i;
164 #endif
165 	pr_debug("%s: start 0x%x, end 0x%x\n", __func__,
166 				(unsigned int)start, (unsigned int) end);
167 
168 	CACHE_LOOP_LIMITS(start, end,
169 			cpuinfo.icache_line_length, cpuinfo.icache_size);
170 
171 	local_irq_save(flags);
172 	__disable_icache_msr();
173 
174 #ifdef ASM_LOOP
175 	CACHE_RANGE_LOOP_1(start, end, cpuinfo.icache_line_length, wic);
176 #else
177 	for (i = start; i < end; i += cpuinfo.icache_line_length)
178 		__asm__ __volatile__ ("wic	%0, r0;"	\
179 				: : "r" (i));
180 #endif
181 	__enable_icache_msr();
182 	local_irq_restore(flags);
183 }
184 
185 static void __flush_icache_range_nomsr_irq(unsigned long start,
186 				unsigned long end)
187 {
188 	unsigned long flags;
189 #ifndef ASM_LOOP
190 	int i;
191 #endif
192 	pr_debug("%s: start 0x%x, end 0x%x\n", __func__,
193 				(unsigned int)start, (unsigned int) end);
194 
195 	CACHE_LOOP_LIMITS(start, end,
196 			cpuinfo.icache_line_length, cpuinfo.icache_size);
197 
198 	local_irq_save(flags);
199 	__disable_icache_nomsr();
200 
201 #ifdef ASM_LOOP
202 	CACHE_RANGE_LOOP_1(start, end, cpuinfo.icache_line_length, wic);
203 #else
204 	for (i = start; i < end; i += cpuinfo.icache_line_length)
205 		__asm__ __volatile__ ("wic	%0, r0;"	\
206 				: : "r" (i));
207 #endif
208 
209 	__enable_icache_nomsr();
210 	local_irq_restore(flags);
211 }
212 
213 static void __flush_icache_range_noirq(unsigned long start,
214 				unsigned long end)
215 {
216 #ifndef ASM_LOOP
217 	int i;
218 #endif
219 	pr_debug("%s: start 0x%x, end 0x%x\n", __func__,
220 				(unsigned int)start, (unsigned int) end);
221 
222 	CACHE_LOOP_LIMITS(start, end,
223 			cpuinfo.icache_line_length, cpuinfo.icache_size);
224 #ifdef ASM_LOOP
225 	CACHE_RANGE_LOOP_1(start, end, cpuinfo.icache_line_length, wic);
226 #else
227 	for (i = start; i < end; i += cpuinfo.icache_line_length)
228 		__asm__ __volatile__ ("wic	%0, r0;"	\
229 				: : "r" (i));
230 #endif
231 }
232 
233 static void __flush_icache_all_msr_irq(void)
234 {
235 	unsigned long flags;
236 #ifndef ASM_LOOP
237 	int i;
238 #endif
239 	pr_debug("%s\n", __func__);
240 
241 	local_irq_save(flags);
242 	__disable_icache_msr();
243 #ifdef ASM_LOOP
244 	CACHE_ALL_LOOP(cpuinfo.icache_size, cpuinfo.icache_line_length, wic);
245 #else
246 	for (i = 0; i < cpuinfo.icache_size;
247 		 i += cpuinfo.icache_line_length)
248 			__asm__ __volatile__ ("wic	%0, r0;" \
249 					: : "r" (i));
250 #endif
251 	__enable_icache_msr();
252 	local_irq_restore(flags);
253 }
254 
255 static void __flush_icache_all_nomsr_irq(void)
256 {
257 	unsigned long flags;
258 #ifndef ASM_LOOP
259 	int i;
260 #endif
261 	pr_debug("%s\n", __func__);
262 
263 	local_irq_save(flags);
264 	__disable_icache_nomsr();
265 #ifdef ASM_LOOP
266 	CACHE_ALL_LOOP(cpuinfo.icache_size, cpuinfo.icache_line_length, wic);
267 #else
268 	for (i = 0; i < cpuinfo.icache_size;
269 		 i += cpuinfo.icache_line_length)
270 			__asm__ __volatile__ ("wic	%0, r0;" \
271 					: : "r" (i));
272 #endif
273 	__enable_icache_nomsr();
274 	local_irq_restore(flags);
275 }
276 
277 static void __flush_icache_all_noirq(void)
278 {
279 #ifndef ASM_LOOP
280 	int i;
281 #endif
282 	pr_debug("%s\n", __func__);
283 #ifdef ASM_LOOP
284 	CACHE_ALL_LOOP(cpuinfo.icache_size, cpuinfo.icache_line_length, wic);
285 #else
286 	for (i = 0; i < cpuinfo.icache_size;
287 		 i += cpuinfo.icache_line_length)
288 			__asm__ __volatile__ ("wic	%0, r0;" \
289 					: : "r" (i));
290 #endif
291 }
292 
293 static void __invalidate_dcache_all_msr_irq(void)
294 {
295 	unsigned long flags;
296 #ifndef ASM_LOOP
297 	int i;
298 #endif
299 	pr_debug("%s\n", __func__);
300 
301 	local_irq_save(flags);
302 	__disable_dcache_msr();
303 #ifdef ASM_LOOP
304 	CACHE_ALL_LOOP(cpuinfo.dcache_size, cpuinfo.dcache_line_length, wdc);
305 #else
306 	for (i = 0; i < cpuinfo.dcache_size;
307 		 i += cpuinfo.dcache_line_length)
308 			__asm__ __volatile__ ("wdc	%0, r0;" \
309 					: : "r" (i));
310 #endif
311 	__enable_dcache_msr();
312 	local_irq_restore(flags);
313 }
314 
315 static void __invalidate_dcache_all_nomsr_irq(void)
316 {
317 	unsigned long flags;
318 #ifndef ASM_LOOP
319 	int i;
320 #endif
321 	pr_debug("%s\n", __func__);
322 
323 	local_irq_save(flags);
324 	__disable_dcache_nomsr();
325 #ifdef ASM_LOOP
326 	CACHE_ALL_LOOP(cpuinfo.dcache_size, cpuinfo.dcache_line_length, wdc);
327 #else
328 	for (i = 0; i < cpuinfo.dcache_size;
329 		 i += cpuinfo.dcache_line_length)
330 			__asm__ __volatile__ ("wdc	%0, r0;" \
331 					: : "r" (i));
332 #endif
333 	__enable_dcache_nomsr();
334 	local_irq_restore(flags);
335 }
336 
337 static void __invalidate_dcache_all_noirq_wt(void)
338 {
339 #ifndef ASM_LOOP
340 	int i;
341 #endif
342 	pr_debug("%s\n", __func__);
343 #ifdef ASM_LOOP
344 	CACHE_ALL_LOOP(cpuinfo.dcache_size, cpuinfo.dcache_line_length, wdc);
345 #else
346 	for (i = 0; i < cpuinfo.dcache_size;
347 		 i += cpuinfo.dcache_line_length)
348 			__asm__ __volatile__ ("wdc	%0, r0;" \
349 					: : "r" (i));
350 #endif
351 }
352 
353 /*
354  * FIXME It is blindly invalidation as is expected
355  * but can't be called on noMMU in microblaze_cache_init below
356  *
357  * MS: noMMU kernel won't boot if simple wdc is used
358  * The reason should be that there are discared data which kernel needs
359  */
360 static void __invalidate_dcache_all_wb(void)
361 {
362 #ifndef ASM_LOOP
363 	int i;
364 #endif
365 	pr_debug("%s\n", __func__);
366 #ifdef ASM_LOOP
367 	CACHE_ALL_LOOP(cpuinfo.dcache_size, cpuinfo.dcache_line_length,
368 					wdc);
369 #else
370 	for (i = 0; i < cpuinfo.dcache_size;
371 		 i += cpuinfo.dcache_line_length)
372 			__asm__ __volatile__ ("wdc	%0, r0;" \
373 					: : "r" (i));
374 #endif
375 }
376 
377 static void __invalidate_dcache_range_wb(unsigned long start,
378 						unsigned long end)
379 {
380 #ifndef ASM_LOOP
381 	int i;
382 #endif
383 	pr_debug("%s: start 0x%x, end 0x%x\n", __func__,
384 				(unsigned int)start, (unsigned int) end);
385 
386 	CACHE_LOOP_LIMITS(start, end,
387 			cpuinfo.dcache_line_length, cpuinfo.dcache_size);
388 #ifdef ASM_LOOP
389 	CACHE_RANGE_LOOP_2(start, end, cpuinfo.dcache_line_length, wdc.clear);
390 #else
391 	for (i = start; i < end; i += cpuinfo.dcache_line_length)
392 		__asm__ __volatile__ ("wdc.clear	%0, r0;"	\
393 				: : "r" (i));
394 #endif
395 }
396 
397 static void __invalidate_dcache_range_nomsr_wt(unsigned long start,
398 							unsigned long end)
399 {
400 #ifndef ASM_LOOP
401 	int i;
402 #endif
403 	pr_debug("%s: start 0x%x, end 0x%x\n", __func__,
404 				(unsigned int)start, (unsigned int) end);
405 	CACHE_LOOP_LIMITS(start, end,
406 			cpuinfo.dcache_line_length, cpuinfo.dcache_size);
407 
408 #ifdef ASM_LOOP
409 	CACHE_RANGE_LOOP_1(start, end, cpuinfo.dcache_line_length, wdc);
410 #else
411 	for (i = start; i < end; i += cpuinfo.dcache_line_length)
412 		__asm__ __volatile__ ("wdc	%0, r0;"	\
413 				: : "r" (i));
414 #endif
415 }
416 
417 static void __invalidate_dcache_range_msr_irq_wt(unsigned long start,
418 							unsigned long end)
419 {
420 	unsigned long flags;
421 #ifndef ASM_LOOP
422 	int i;
423 #endif
424 	pr_debug("%s: start 0x%x, end 0x%x\n", __func__,
425 				(unsigned int)start, (unsigned int) end);
426 	CACHE_LOOP_LIMITS(start, end,
427 			cpuinfo.dcache_line_length, cpuinfo.dcache_size);
428 
429 	local_irq_save(flags);
430 	__disable_dcache_msr();
431 
432 #ifdef ASM_LOOP
433 	CACHE_RANGE_LOOP_1(start, end, cpuinfo.dcache_line_length, wdc);
434 #else
435 	for (i = start; i < end; i += cpuinfo.dcache_line_length)
436 		__asm__ __volatile__ ("wdc	%0, r0;"	\
437 				: : "r" (i));
438 #endif
439 
440 	__enable_dcache_msr();
441 	local_irq_restore(flags);
442 }
443 
444 static void __invalidate_dcache_range_nomsr_irq(unsigned long start,
445 							unsigned long end)
446 {
447 	unsigned long flags;
448 #ifndef ASM_LOOP
449 	int i;
450 #endif
451 	pr_debug("%s: start 0x%x, end 0x%x\n", __func__,
452 				(unsigned int)start, (unsigned int) end);
453 
454 	CACHE_LOOP_LIMITS(start, end,
455 			cpuinfo.dcache_line_length, cpuinfo.dcache_size);
456 
457 	local_irq_save(flags);
458 	__disable_dcache_nomsr();
459 
460 #ifdef ASM_LOOP
461 	CACHE_RANGE_LOOP_1(start, end, cpuinfo.dcache_line_length, wdc);
462 #else
463 	for (i = start; i < end; i += cpuinfo.dcache_line_length)
464 		__asm__ __volatile__ ("wdc	%0, r0;"	\
465 				: : "r" (i));
466 #endif
467 
468 	__enable_dcache_nomsr();
469 	local_irq_restore(flags);
470 }
471 
472 static void __flush_dcache_all_wb(void)
473 {
474 #ifndef ASM_LOOP
475 	int i;
476 #endif
477 	pr_debug("%s\n", __func__);
478 #ifdef ASM_LOOP
479 	CACHE_ALL_LOOP(cpuinfo.dcache_size, cpuinfo.dcache_line_length,
480 				wdc.flush);
481 #else
482 	for (i = 0; i < cpuinfo.dcache_size;
483 		 i += cpuinfo.dcache_line_length)
484 			__asm__ __volatile__ ("wdc.flush	%0, r0;" \
485 					: : "r" (i));
486 #endif
487 }
488 
489 static void __flush_dcache_range_wb(unsigned long start, unsigned long end)
490 {
491 #ifndef ASM_LOOP
492 	int i;
493 #endif
494 	pr_debug("%s: start 0x%x, end 0x%x\n", __func__,
495 				(unsigned int)start, (unsigned int) end);
496 
497 	CACHE_LOOP_LIMITS(start, end,
498 			cpuinfo.dcache_line_length, cpuinfo.dcache_size);
499 #ifdef ASM_LOOP
500 	CACHE_RANGE_LOOP_2(start, end, cpuinfo.dcache_line_length, wdc.flush);
501 #else
502 	for (i = start; i < end; i += cpuinfo.dcache_line_length)
503 		__asm__ __volatile__ ("wdc.flush	%0, r0;"	\
504 				: : "r" (i));
505 #endif
506 }
507 
508 /* struct for wb caches and for wt caches */
509 struct scache *mbc;
510 
511 /* new wb cache model */
512 static const struct scache wb_msr = {
513 	.ie = __enable_icache_msr,
514 	.id = __disable_icache_msr,
515 	.ifl = __flush_icache_all_noirq,
516 	.iflr = __flush_icache_range_noirq,
517 	.iin = __flush_icache_all_noirq,
518 	.iinr = __flush_icache_range_noirq,
519 	.de = __enable_dcache_msr,
520 	.dd = __disable_dcache_msr,
521 	.dfl = __flush_dcache_all_wb,
522 	.dflr = __flush_dcache_range_wb,
523 	.din = __invalidate_dcache_all_wb,
524 	.dinr = __invalidate_dcache_range_wb,
525 };
526 
527 /* There is only difference in ie, id, de, dd functions */
528 static const struct scache wb_nomsr = {
529 	.ie = __enable_icache_nomsr,
530 	.id = __disable_icache_nomsr,
531 	.ifl = __flush_icache_all_noirq,
532 	.iflr = __flush_icache_range_noirq,
533 	.iin = __flush_icache_all_noirq,
534 	.iinr = __flush_icache_range_noirq,
535 	.de = __enable_dcache_nomsr,
536 	.dd = __disable_dcache_nomsr,
537 	.dfl = __flush_dcache_all_wb,
538 	.dflr = __flush_dcache_range_wb,
539 	.din = __invalidate_dcache_all_wb,
540 	.dinr = __invalidate_dcache_range_wb,
541 };
542 
543 /* Old wt cache model with disabling irq and turn off cache */
544 static const struct scache wt_msr = {
545 	.ie = __enable_icache_msr,
546 	.id = __disable_icache_msr,
547 	.ifl = __flush_icache_all_msr_irq,
548 	.iflr = __flush_icache_range_msr_irq,
549 	.iin = __flush_icache_all_msr_irq,
550 	.iinr = __flush_icache_range_msr_irq,
551 	.de = __enable_dcache_msr,
552 	.dd = __disable_dcache_msr,
553 	.dfl = __invalidate_dcache_all_msr_irq,
554 	.dflr = __invalidate_dcache_range_msr_irq_wt,
555 	.din = __invalidate_dcache_all_msr_irq,
556 	.dinr = __invalidate_dcache_range_msr_irq_wt,
557 };
558 
559 static const struct scache wt_nomsr = {
560 	.ie = __enable_icache_nomsr,
561 	.id = __disable_icache_nomsr,
562 	.ifl = __flush_icache_all_nomsr_irq,
563 	.iflr = __flush_icache_range_nomsr_irq,
564 	.iin = __flush_icache_all_nomsr_irq,
565 	.iinr = __flush_icache_range_nomsr_irq,
566 	.de = __enable_dcache_nomsr,
567 	.dd = __disable_dcache_nomsr,
568 	.dfl = __invalidate_dcache_all_nomsr_irq,
569 	.dflr = __invalidate_dcache_range_nomsr_irq,
570 	.din = __invalidate_dcache_all_nomsr_irq,
571 	.dinr = __invalidate_dcache_range_nomsr_irq,
572 };
573 
574 /* New wt cache model for newer Microblaze versions */
575 static const struct scache wt_msr_noirq = {
576 	.ie = __enable_icache_msr,
577 	.id = __disable_icache_msr,
578 	.ifl = __flush_icache_all_noirq,
579 	.iflr = __flush_icache_range_noirq,
580 	.iin = __flush_icache_all_noirq,
581 	.iinr = __flush_icache_range_noirq,
582 	.de = __enable_dcache_msr,
583 	.dd = __disable_dcache_msr,
584 	.dfl = __invalidate_dcache_all_noirq_wt,
585 	.dflr = __invalidate_dcache_range_nomsr_wt,
586 	.din = __invalidate_dcache_all_noirq_wt,
587 	.dinr = __invalidate_dcache_range_nomsr_wt,
588 };
589 
590 static const struct scache wt_nomsr_noirq = {
591 	.ie = __enable_icache_nomsr,
592 	.id = __disable_icache_nomsr,
593 	.ifl = __flush_icache_all_noirq,
594 	.iflr = __flush_icache_range_noirq,
595 	.iin = __flush_icache_all_noirq,
596 	.iinr = __flush_icache_range_noirq,
597 	.de = __enable_dcache_nomsr,
598 	.dd = __disable_dcache_nomsr,
599 	.dfl = __invalidate_dcache_all_noirq_wt,
600 	.dflr = __invalidate_dcache_range_nomsr_wt,
601 	.din = __invalidate_dcache_all_noirq_wt,
602 	.dinr = __invalidate_dcache_range_nomsr_wt,
603 };
604 
605 /* CPU version code for 7.20.c - see arch/microblaze/kernel/cpu/cpuinfo.c */
606 #define CPUVER_7_20_A	0x0c
607 #define CPUVER_7_20_D	0x0f
608 
609 void microblaze_cache_init(void)
610 {
611 	if (cpuinfo.use_instr & PVR2_USE_MSR_INSTR) {
612 		if (cpuinfo.dcache_wb) {
613 			pr_info("wb_msr\n");
614 			mbc = (struct scache *)&wb_msr;
615 			if (cpuinfo.ver_code <= CPUVER_7_20_D) {
616 				/* MS: problem with signal handling - hw bug */
617 				pr_info("WB won't work properly\n");
618 			}
619 		} else {
620 			if (cpuinfo.ver_code >= CPUVER_7_20_A) {
621 				pr_info("wt_msr_noirq\n");
622 				mbc = (struct scache *)&wt_msr_noirq;
623 			} else {
624 				pr_info("wt_msr\n");
625 				mbc = (struct scache *)&wt_msr;
626 			}
627 		}
628 	} else {
629 		if (cpuinfo.dcache_wb) {
630 			pr_info("wb_nomsr\n");
631 			mbc = (struct scache *)&wb_nomsr;
632 			if (cpuinfo.ver_code <= CPUVER_7_20_D) {
633 				/* MS: problem with signal handling - hw bug */
634 				pr_info("WB won't work properly\n");
635 			}
636 		} else {
637 			if (cpuinfo.ver_code >= CPUVER_7_20_A) {
638 				pr_info("wt_nomsr_noirq\n");
639 				mbc = (struct scache *)&wt_nomsr_noirq;
640 			} else {
641 				pr_info("wt_nomsr\n");
642 				mbc = (struct scache *)&wt_nomsr;
643 			}
644 		}
645 	}
646 	/*
647 	 * FIXME Invalidation is done in U-BOOT
648 	 * WT cache: Data is already written to main memory
649 	 * WB cache: Discard data on noMMU which caused that kernel doesn't boot
650 	 */
651 	/* invalidate_dcache(); */
652 	enable_dcache();
653 
654 	invalidate_icache();
655 	enable_icache();
656 }
657