MIPS: Loongson-3: Set cache flush handlers to cache_noop
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>
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 77fbaf1..3415d3e 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -1796,6 +1796,20 @@
/* 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;
}
}