Stop setting SDRC_POWER.PWDENA on boot. There is a nasty erratum
(34xx erratum 1.150) that can cause memory corruption if PWDENA is
enabled.
Based originally on a patch from Samu P. Onkalo <samu.p.onk...@nokia.com>.
Tested on BeagleBoard rev C2.
Signed-off-by: Paul Walmsley <p...@pwsan.com>
Cc: Samu P. Onkalo <samu.p.onk...@nokia.com>
---
arch/arm/mach-omap2/sdrc.c | 5 ++++-
arch/arm/mach-omap2/sram34xx.S | 2 --
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mach-omap2/sdrc.c b/arch/arm/mach-omap2/sdrc.c
index 2e9e38d..9e3bd4f 100644
--- a/arch/arm/mach-omap2/sdrc.c
+++ b/arch/arm/mach-omap2/sdrc.c
@@ -125,8 +125,11 @@ void __init omap2_sdrc_init(struct omap_sdrc_params
*sdrc_cs0,
sdrc_init_params_cs1 = sdrc_cs1;
/* XXX Enable SRFRONIDLEREQ here also? */
+ /*
+ * PWDENA should not be set due to 34xx erratum 1.150 - PWDENA
+ * can cause random memory corruption
+ */
l = (1 << SDRC_POWER_EXTCLKDIS_SHIFT) |
- (1 << SDRC_POWER_PWDENA_SHIFT) |
(1 << SDRC_POWER_PAGEPOLICY_SHIFT);
sdrc_write_reg(l, SDRC_POWER);
}
diff --git a/arch/arm/mach-omap2/sram34xx.S b/arch/arm/mach-omap2/sram34xx.S
index 3aef744..9c2d046 100644
--- a/arch/arm/mach-omap2/sram34xx.S
+++ b/arch/arm/mach-omap2/sram34xx.S
@@ -58,7 +58,6 @@
/* SDRC_POWER bit settings */
#define SRFRONIDLEREQ_MASK 0x40
-#define PWDENA_MASK 0x4
/* CM_IDLEST1_CORE bit settings */
#define ST_SDRC_MASK 0x2
@@ -160,7 +159,6 @@ sdram_in_selfrefresh:
ldr r12, [r11] @ read the contents of SDRC_POWER
mov r9, r12 @ keep a copy of SDRC_POWER bits
orr r12, r12, #SRFRONIDLEREQ_MASK @ enable self refresh on idle
- bic r12, r12, #PWDENA_MASK @ clear PWDENA
str r12, [r11] @ write back to SDRC_POWER register
ldr r12, [r11] @ posted-write barrier for SDRC
idle_sdrc:
--
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