Stop setting SDRC_POWER.PWDENA on boot. Turns out 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 <[email protected]>. Tested on BeagleBoard rev C2. Signed-off-by: Paul Walmsley <[email protected]> Cc: Samu P. Onkalo <[email protected]>. --- 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: -- 1.6.3.3.334.g916e1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
