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OMAP2/3 SDRC: don't set SDRC_POWER.PWDENA on boot

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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>
This commit is contained in:
Paul Walmsley 2009-07-24 19:44:01 -06:00 committed by paul
parent 9fb97412c3
commit 75f251e3d0
2 changed files with 4 additions and 3 deletions
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5
arch/arm/mach-omap2/sdrc.c
View File

@ -125,8 +125,11 @@ void __init omap2_sdrc_init(struct omap_sdrc_params *sdrc_cs0,
sdrc_init_params_cs1 = sdrc_cs1; sdrc_init_params_cs1 = sdrc_cs1;
/* XXX Enable SRFRONIDLEREQ here also? */ /* 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) | l = (1 << SDRC_POWER_EXTCLKDIS_SHIFT) |
(1 << SDRC_POWER_PWDENA_SHIFT) |
(1 << SDRC_POWER_PAGEPOLICY_SHIFT); (1 << SDRC_POWER_PAGEPOLICY_SHIFT);
sdrc_write_reg(l, SDRC_POWER); sdrc_write_reg(l, SDRC_POWER);
} }

2
arch/arm/mach-omap2/sram34xx.S
View File

@ -58,7 +58,6 @@
/* SDRC_POWER bit settings */ /* SDRC_POWER bit settings */
#define SRFRONIDLEREQ_MASK 0x40 #define SRFRONIDLEREQ_MASK 0x40
#define PWDENA_MASK 0x4
/* CM_IDLEST1_CORE bit settings */ /* CM_IDLEST1_CORE bit settings */
#define ST_SDRC_MASK 0x2 #define ST_SDRC_MASK 0x2
@ -160,7 +159,6 @@ sdram_in_selfrefresh:
ldr r12, [r11] @ read the contents of SDRC_POWER ldr r12, [r11] @ read the contents of SDRC_POWER
mov r9, r12 @ keep a copy of SDRC_POWER bits mov r9, r12 @ keep a copy of SDRC_POWER bits
orr r12, r12, #SRFRONIDLEREQ_MASK @ enable self refresh on idle 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 str r12, [r11] @ write back to SDRC_POWER register
ldr r12, [r11] @ posted-write barrier for SDRC ldr r12, [r11] @ posted-write barrier for SDRC
idle_sdrc: idle_sdrc: