Re: [U-Boot] [PATCH V6 04/11] ARM: Introduce erratum workaround for 621766

2015-03-11 Thread Tom Rini
On Mon, Mar 09, 2015 at 05:12:02PM -0500, Nishanth Menon wrote:

 621766: Under a specific set of conditions, executing a sequence of
   NEON or vfp load instructions can cause processor deadlock
 Impacts: Every Cortex-A8 processors with revision lower than r2p1
 Work around: Set L1NEON to 1
 
 Based on ARM errata Document revision 20.0 (13 Nov 2010)
 
 Signed-off-by: Nishanth Menon n...@ti.com

Reviewed-by: Tom Rini tr...@konsulko.com

-- 
Tom


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[U-Boot] [PATCH V6 04/11] ARM: Introduce erratum workaround for 621766

2015-03-09 Thread Nishanth Menon
621766: Under a specific set of conditions, executing a sequence of
NEON or vfp load instructions can cause processor deadlock
Impacts: Every Cortex-A8 processors with revision lower than r2p1
Work around: Set L1NEON to 1

Based on ARM errata Document revision 20.0 (13 Nov 2010)

Signed-off-by: Nishanth Menon n...@ti.com
---
 README |1 +
 arch/arm/cpu/armv7/start.S |   13 +
 2 files changed, 14 insertions(+)

diff --git a/README b/README
index 82f7e10c71d6..e7e90a08145e 100644
--- a/README
+++ b/README
@@ -695,6 +695,7 @@ The following options need to be configured:
specific checks, but expect no product checks.
CONFIG_ARM_ERRATA_430973
CONFIG_ARM_ERRATA_454179
+   CONFIG_ARM_ERRATA_621766
CONFIG_ARM_ERRATA_798870
 
 - Driver Model
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index 41fb24cf321b..5050021e0210 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -215,6 +215,19 @@ skip_errata_454179:
 skip_errata_430973:
 #endif
 
+#ifdef CONFIG_ARM_ERRATA_621766
+   cmp r2, #0x21   @ Only on  r2p1
+   bge skip_errata_621766
+
+   mrc p15, 0, r0, c1, c0, 1   @ Read ACR
+   orr r0, r0, #(0x1  5) @ Set L1NEON bit
+   push{r1-r5} @ Save the cpu info registers
+   bl  v7_arch_cp15_set_acr
+   pop {r1-r5} @ Restore the cpu info - fall through
+
+skip_errata_621766:
+#endif
+
mov pc, r5  @ back to my caller
 ENDPROC(cpu_init_cp15)
 
-- 
1.7.9.5

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