From 3da3528448850ccde412d52fb939575641ada80d Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Wed, 18 Sep 2013 19:08:15 +0100 Subject: [PATCH 204/215] MIPS: 74K/1074K: Correct erratum workaround. Make sure 74K revision numbers are not applied to the 1074K. Also catch invalid usage. Signed-off-by: Maciej W. Rozycki Cc: Steven J. Hill Cc: Leonid Yegoshin Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5857/ Signed-off-by: Ralf Baechle (cherry picked from commit 9213ad77070ea75fc3a5e43e3d9e9c4146e4930a) --- arch/mips/mm/c-r4k.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -785,20 +785,30 @@ static inline void rm7k_erratum31(void) static inline void alias_74k_erratum(struct cpuinfo_mips *c) { + unsigned int imp = c->processor_id & 0xff00; + unsigned int rev = c->processor_id & PRID_REV_MASK; + /* * 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); + switch (imp) { + case PRID_IMP_74K: + if (rev <= PRID_REV_ENCODE_332(2, 4, 0)) + c->dcache.flags |= MIPS_CACHE_VTAG; + if (rev == PRID_REV_ENCODE_332(2, 4, 0)) + write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND); + break; + case PRID_IMP_1074K: + if (rev <= PRID_REV_ENCODE_332(1, 1, 0)) { + c->dcache.flags |= MIPS_CACHE_VTAG; + write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND); + } + break; + default: + BUG(); } }