CRISv32: add cache flush operations

These are needed due to a cache bug, and can be used to make sure that the
DMA descriptors are flushed to memory and can be safely handled by DMA.

flush_dma_descr - Flush one DMA descriptor.
flush_dma_list - Flush a complete list of DMA descriptors.
cris_flush_cache - Flush the complete cache.
cris_flush_cache_range - Flush only the specified range

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

authored by

Jesper Nilsson and committed by

Linus Torvalds 18 years ago 57c230a8 d8e5219f

+127

2 changed files

expand all

arch

cris

arch-v32

kernel

cache.c

cacheflush.S

+33

arch/cris/arch-v32/kernel/cache.c

··· 1 + #include <linux/module.h> 2 + #include <asm/io.h> 3 + #include <asm/arch/cache.h> 4 + #include <asm/arch/hwregs/dma.h> 5 + 6 + /* This file is used to workaround a cache bug, Guinness TR 106. */ 7 + 8 + inline void flush_dma_descr(struct dma_descr_data *descr, int flush_buf) 9 + { 10 + /* Flush descriptor to make sure we get correct in_eop and after. */ 11 + asm volatile ("ftagd [%0]" :: "r" (descr)); 12 + /* Flush buffer pointed out by descriptor. */ 13 + if (flush_buf) 14 + cris_flush_cache_range(phys_to_virt((unsigned)descr->buf), 15 + (unsigned)(descr->after - descr->buf)); 16 + } 17 + EXPORT_SYMBOL(flush_dma_descr); 18 + 19 + void flush_dma_list(struct dma_descr_data *descr) 20 + { 21 + while (1) { 22 + flush_dma_descr(descr, 1); 23 + if (descr->eol) 24 + break; 25 + descr = phys_to_virt((unsigned)descr->next); 26 + } 27 + } 28 + EXPORT_SYMBOL(flush_dma_list); 29 + 30 + /* From cacheflush.S */ 31 + EXPORT_SYMBOL(cris_flush_cache); 32 + /* From cacheflush.S */ 33 + EXPORT_SYMBOL(cris_flush_cache_range);

+94

arch/cris/arch-v32/kernel/cacheflush.S

··· 1 + .global cris_flush_cache_range 2 + cris_flush_cache_range: 3 + move.d 1024, $r12 4 + cmp.d $r11, $r12 5 + bhi cris_flush_1KB 6 + nop 7 + add.d $r10, $r11 8 + ftagd [$r10] 9 + cris_flush_last: 10 + addq 32, $r10 11 + cmp.d $r11, $r10 12 + blt cris_flush_last 13 + ftagd [$r10] 14 + ret 15 + nop 16 + cris_flush_1KB: 17 + ftagd [$r10] 18 + addq 32, $r10 19 + ftagd [$r10] 20 + addq 32, $r10 21 + ftagd [$r10] 22 + addq 32, $r10 23 + ftagd [$r10] 24 + addq 32, $r10 25 + ftagd [$r10] 26 + addq 32, $r10 27 + ftagd [$r10] 28 + addq 32, $r10 29 + ftagd [$r10] 30 + addq 32, $r10 31 + ftagd [$r10] 32 + addq 32, $r10 33 + ftagd [$r10] 34 + addq 32, $r10 35 + ftagd [$r10] 36 + addq 32, $r10 37 + ftagd [$r10] 38 + addq 32, $r10 39 + ftagd [$r10] 40 + addq 32, $r10 41 + ftagd [$r10] 42 + addq 32, $r10 43 + ftagd [$r10] 44 + addq 32, $r10 45 + ftagd [$r10] 46 + addq 32, $r10 47 + ftagd [$r10] 48 + addq 32, $r10 49 + ftagd [$r10] 50 + addq 32, $r10 51 + ftagd [$r10] 52 + addq 32, $r10 53 + ftagd [$r10] 54 + addq 32, $r10 55 + ftagd [$r10] 56 + addq 32, $r10 57 + ftagd [$r10] 58 + addq 32, $r10 59 + ftagd [$r10] 60 + addq 32, $r10 61 + ftagd [$r10] 62 + addq 32, $r10 63 + ftagd [$r10] 64 + addq 32, $r10 65 + ftagd [$r10] 66 + addq 32, $r10 67 + ftagd [$r10] 68 + addq 32, $r10 69 + ftagd [$r10] 70 + addq 32, $r10 71 + ftagd [$r10] 72 + addq 32, $r10 73 + ftagd [$r10] 74 + addq 32, $r10 75 + ftagd [$r10] 76 + addq 32, $r10 77 + ftagd [$r10] 78 + addq 32, $r10 79 + ftagd [$r10] 80 + addq 32, $r10 81 + ba cris_flush_cache_range 82 + sub.d $r12, $r11 83 + 84 + .global cris_flush_cache 85 + cris_flush_cache: 86 + moveq 0, $r10 87 + cris_flush_line: 88 + move.d 16*1024, $r11 89 + addq 16, $r10 90 + cmp.d $r10, $r11 91 + blt cris_flush_line 92 + fidxd [$r10] 93 + ret 94 + nop

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