MIPS: Avoid destructive invalidation on partial cachelines.

See discussion e9c3a7c20901051031y528d0d31r18d44c5096c59e0@mail.gmail.com.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 21 insertions, 1 deletions

diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 6e99665ae86..c43f4b26a69 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -618,15 +618,35 @@ static void r4k_dma_cache_inv(unsigned long addr, unsigned long size)
         if (cpu_has_inclusive_pcaches) {
                 if (size >= scache_size)
                         r4k_blast_scache();
-                else
+                else {
+                        unsigned long lsize = cpu_scache_line_size();
+                        unsigned long almask = ~(lsize - 1);
+
+                        /*
+                         * There is no clearly documented alignment requirement
+                         * for the cache instruction on MIPS processors and
+                         * some processors, among them the RM5200 and RM7000
+                         * QED processors will throw an address error for cache
+                         * hit ops with insufficient alignment.  Solved by
+                         * aligning the address to cache line size.
+                         */
+                        cache_op(Hit_Writeback_Inv_SD, addr & almask);
+                        cache_op(Hit_Writeback_Inv_SD,
+                                 (addr + size - 1) & almask);
                         blast_inv_scache_range(addr, addr + size);
+                }
                 return;
         }
 
         if (cpu_has_safe_index_cacheops && size >= dcache_size) {
                 r4k_blast_dcache();
         } else {
+                unsigned long lsize = cpu_dcache_line_size();
+                unsigned long almask = ~(lsize - 1);
+
                 R4600_HIT_CACHEOP_WAR_IMPL;
+                cache_op(Hit_Writeback_Inv_D, addr & almask);
+                cache_op(Hit_Writeback_Inv_D, (addr + size - 1)  & almask);
                 blast_inv_dcache_range(addr, addr + size);
         }