Current MIPS cores from Imagination Technologies use TagLo select 2 for the data cache. The architecture requires that it is safe for software to write to this register even if it isn't present, so take the trivial option of clearing both selects 0 & 2.
Signed-off-by: Paul Burton paul.burton@imgtec.com Cc: Daniel Schwierzeck daniel.schwierzeck@gmail.com --- Changes in v2: - None (rebase atop change to patch 1). --- arch/mips/lib/cache_init.S | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/mips/lib/cache_init.S b/arch/mips/lib/cache_init.S index 04a36b2..137d728 100644 --- a/arch/mips/lib/cache_init.S +++ b/arch/mips/lib/cache_init.S @@ -139,6 +139,14 @@ LEAF(mips_cache_reset) #endif /* CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD */
/* + * The TagLo registers used depend upon the CPU implementation, but the + * architecture requires that it is safe for software to write to both + * TagLo selects 0 & 2 covering supported cases. + */ + mtc0 zero, CP0_TAGLO + mtc0 zero, CP0_TAGLO, 2 + + /* * The caches are probably in an indeterminate state, so we force good * parity into them by doing an invalidate for each line. If * CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD is set then we'll proceed to @@ -151,7 +159,6 @@ LEAF(mips_cache_reset) * Initialize the I-cache first, */ blez t2, 1f - mtc0 zero, CP0_TAGLO PTR_LI t0, INDEX_BASE PTR_ADDU t1, t0, t2 /* clear tag to invalidate */ @@ -169,7 +176,6 @@ LEAF(mips_cache_reset) * then initialize D-cache. */ 1: blez t3, 3f - mtc0 zero, CP0_TAGLO PTR_LI t0, INDEX_BASE PTR_ADDU t1, t0, t3 /* clear all tags */