[U-Boot] [PATCH] ARC: invalidate i$ and d$ at startup code

[Eugeniy Paltsev]

This is useful to make sure no stale data exists in caches after bootloaders.
The worst thing could be some lines of cache were locked in a bootloader
for example during DDR recalibration and never unlocked. This may lead
to really unpredictable issues later down the line.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev at synopsys.com>
---
 arch/arc/lib/start.S | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arc/lib/start.S b/arch/arc/lib/start.S
index 95d64f9..0d72fe7 100644
--- a/arch/arc/lib/start.S
+++ b/arch/arc/lib/start.S
@@ -44,6 +44,14 @@ ENTRY(_start)
 #endif
 	sr	r5, [ARC_AUX_IC_CTRL]
 
+	mov	r5, 1
+	sr	r5, [ARC_AUX_IC_IVIC]
+	; As per ARC HS databook (see chapter 5.3.3.2)
+	; it is required to add 3 NOPs after each write to IC_IVIC.
+	nop
+	nop
+	nop
+
 1:
 	; Disable/enable D-cache according to configuration
 	lr	r5, [ARC_BCR_DC_BUILD]
@@ -57,6 +65,10 @@ ENTRY(_start)
 #endif
 	sr	r5, [ARC_AUX_DC_CTRL]
 
+	mov	r5, 1
+	sr	r5, [ARC_AUX_DC_IVDC]
+
+
 1:
 #ifdef CONFIG_ISA_ARCV2
 	; Disable System-Level Cache (SLC)
-- 
2.9.3