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authorStephen Warren <swarren@nvidia.com>2013-02-26 12:28:27 +0000
committerAlbert ARIBAUD <albert.u.boot@aribaud.net>2013-03-13 22:24:11 +0100
commit0678587fb6f517d40c461f1d43fe7a6ff430f168 (patch)
treef740ba06aaa5333ba187b291e687a03054bd936f
parentef123c525370463254a6f8e67563fdb0b0b46412 (diff)
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ARM: implement some Cortex-A9 errata workarounds
Various errata exist in the Cortex-A9 CPU, and may be worked around by setting some bits in a CP15 diagnostic register. Add code to implement the workarounds, enabled by new CONFIG_ options. This code was taken from the Linux kernel, v3.8, arch/arm/mm/proc-v7.S, and modified to remove the logic to conditionally apply the WAR (since we know exactly which CPU we're running on given the U-Boot configuration), and use r0 instead of r10 for consistency with the rest of U-Boot's cpu_init_cp15(). Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Simon Glass <sjg@chromium.org>
-rw-r--r--README10
-rw-r--r--arch/arm/cpu/armv7/start.S19
2 files changed, 29 insertions, 0 deletions
diff --git a/README b/README
index d51ece9..e45ae4a 100644
--- a/README
+++ b/README
@@ -485,6 +485,16 @@ The following options need to be configured:
Thumb2 this flag will result in Thumb2 code generated by
GCC.
+ CONFIG_ARM_ERRATA_742230
+ CONFIG_ARM_ERRATA_743622
+ CONFIG_ARM_ERRATA_751472
+
+ If set, the workarounds for these ARM errata are applied early
+ during U-Boot startup. Note that these options force the
+ workarounds to be applied; no CPU-type/version detection
+ exists, unlike the similar options in the Linux kernel. Do not
+ set these options unless they apply!
+
- Linux Kernel Interface:
CONFIG_CLOCKS_IN_MHZ
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index 6b59529d..30f02d3 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -309,6 +309,25 @@ ENTRY(cpu_init_cp15)
orr r0, r0, #0x00001000 @ set bit 12 (I) I-cache
#endif
mcr p15, 0, r0, c1, c0, 0
+
+#ifdef CONFIG_ARM_ERRATA_742230
+ mrc p15, 0, r0, c15, c0, 1 @ read diagnostic register
+ orr r0, r0, #1 << 4 @ set bit #4
+ mcr p15, 0, r0, c15, c0, 1 @ write diagnostic register
+#endif
+
+#ifdef CONFIG_ARM_ERRATA_743622
+ mrc p15, 0, r0, c15, c0, 1 @ read diagnostic register
+ orr r0, r0, #1 << 6 @ set bit #6
+ mcr p15, 0, r0, c15, c0, 1 @ write diagnostic register
+#endif
+
+#ifdef CONFIG_ARM_ERRATA_751472
+ mrc p15, 0, r0, c15, c0, 1 @ read diagnostic register
+ orr r0, r0, #1 << 11 @ set bit #11
+ mcr p15, 0, r0, c15, c0, 1 @ write diagnostic register
+#endif
+
mov pc, lr @ back to my caller
ENDPROC(cpu_init_cp15)