[U-Boot] [PATCH v2 8/8] MIPS: clear TagLo select 2 during cache init

[Paul Burton]

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 at imgtec.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck at 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 */
-- 
2.2.2