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MIPS: Loongson-3: Set cache flush handlers to cache_noop

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Loongson-3 maintains cache coherency by hardware, this means:
 1) It's icache is coherent with dcache.
 2) It's dcaches don't alias (maybe depend on PAGE_SIZE).
 3) It maintains cache coherency across cores (and for DMA).

So we can skip most cache flush operations by setting relevant handlers
to `cache_noop' in `r4k_cache_init'.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J . Hill <sjhill@realitydiluted.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12752/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Huacai Chen 2016-03-03 09:45:10 +08:00 committed by Ralf Baechle
parent b2edcfc814
commit 37fbe8faa9
1 changed files with 14 additions and 0 deletions
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14
arch/mips/mm/c-r4k.c
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@ -1796,6 +1796,20 @@ void r4k_cache_init(void)
/* Optimization: an L2 flush implicitly flushes the L1 */
current_cpu_data.options |= MIPS_CPU_INCLUSIVE_CACHES;
break;
case CPU_LOONGSON3:
/* Loongson-3 maintains cache coherency by hardware */
__flush_cache_all = cache_noop;
__flush_cache_vmap = cache_noop;
__flush_cache_vunmap = cache_noop;
__flush_kernel_vmap_range = (void *)cache_noop;
flush_cache_mm = (void *)cache_noop;
flush_cache_page = (void *)cache_noop;
flush_cache_range = (void *)cache_noop;
flush_cache_sigtramp = (void *)cache_noop;
flush_icache_all = (void *)cache_noop;
flush_data_cache_page = (void *)cache_noop;
local_flush_data_cache_page = (void *)cache_noop;
break;
}
}