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-rw-r--r--arch/mips/mm/c-r4k.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index f092c265dc63..4c32ede464b5 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -786,6 +786,25 @@ static inline void rm7k_erratum31(void)
}
}
+static inline void alias_74k_erratum(struct cpuinfo_mips *c)
+{
+ /*
+ * Early versions of the 74K do not update the cache tags on a
+ * vtag miss/ptag hit which can occur in the case of KSEG0/KUSEG
+ * aliases. In this case it is better to treat the cache as always
+ * having aliases.
+ */
+ if ((c->processor_id & 0xff) <= PRID_REV_ENCODE_332(2, 4, 0))
+ c->dcache.flags |= MIPS_CACHE_VTAG;
+ if ((c->processor_id & 0xff) == PRID_REV_ENCODE_332(2, 4, 0))
+ write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND);
+ if (((c->processor_id & 0xff00) == PRID_IMP_1074K) &&
+ ((c->processor_id & 0xff) <= PRID_REV_ENCODE_332(1, 1, 0))) {
+ c->dcache.flags |= MIPS_CACHE_VTAG;
+ write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND);
+ }
+}
+
static char *way_string[] __cpuinitdata = { NULL, "direct mapped", "2-way",
"3-way", "4-way", "5-way", "6-way", "7-way", "8-way"
};
@@ -1056,6 +1075,8 @@ static void __cpuinit probe_pcache(void)
case CPU_34K:
case CPU_74K:
case CPU_1004K:
+ if (c->cputype == CPU_74K)
+ alias_74k_erratum(c);
if ((read_c0_config7() & (1 << 16))) {
/* effectively physically indexed dcache,
thus no virtual aliases. */