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From 3da3528448850ccde412d52fb939575641ada80d Mon Sep 17 00:00:00 2001
From: "Maciej W. Rozycki" <macro@linux-mips.org>
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 <macro@linux-mips.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5857/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(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();
}
}
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