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authorPaul Walmsley <paul@pwsan.com>2009-07-24 19:44:01 -0600
committerpaul <paul@twilight.(none)>2009-07-24 19:44:01 -0600
commit75f251e3d0803b028f3474fdc75be0994c377ab5 (patch)
treefde30e84a66fad4852d6c18131bc260afecc5b7b /arch/arm
parent9fb97412c3be5d0d1dd0e9d7c5268469e4c942aa (diff)
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OMAP2/3 SDRC: don't set SDRC_POWER.PWDENA on boot
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.onkalo@nokia.com>. Tested on BeagleBoard rev C2. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Samu P. Onkalo <samu.p.onkalo@nokia.com>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/mach-omap2/sdrc.c5
-rw-r--r--arch/arm/mach-omap2/sram34xx.S2
2 files changed, 4 insertions, 3 deletions
diff --git a/arch/arm/mach-omap2/sdrc.c b/arch/arm/mach-omap2/sdrc.c
index 2e9e38db30e9..9e3bd4fa7810 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 3aef7448b2a5..9c2d0465a83c 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: