diff options
| author | Lokesh Vutla <lokeshvutla@ti.com> | 2012-05-29 19:26:43 +0000 |
|---|---|---|
| committer | Albert ARIBAUD <albert.u.boot@aribaud.net> | 2012-07-07 14:07:35 +0200 |
| commit | 38f25b125e446ab4a64a54e9aa2c10023d8eccc3 (patch) | |
| tree | b2f9d6a45735cd89f68b7d72f24532c06da0ae0c /arch/arm/cpu | |
| parent | 784229cc25feee0bb3f2bba6c1318f4d73c293e0 (diff) | |
OMAP4+: Force DDR in self-refresh after warm reset
Errata ID:i727
Description: The refresh rate is programmed in the EMIF_SDRAM_REF_CTRL[15:0]
REG_REFRESH_RATE parameter taking into account frequency of the device.
When a warm reset is applied on the system, the OMAP processor restarts
with another OPP and so frequency is not the same. Due to this frequency
change, the refresh rate will be too low and could result in an unexpected
behavior on the memory side.
Workaround:
The workaround is to force self-refresh when coming back from the warm reset
with the following sequence:
• Set EMIF_PWR_MGMT_CTRL[10:8] REG_LP_MODE to 0x2
• Set EMIF_PWR_MGMT_CTRL[7:4] REG_SR_TIM to 0x0
• Do a dummy read (loads automatically new value of sr_tim)
This will reduce the risk of memory content corruption, but memory content
can't be guaranteed after a warm reset.
This errata is impacted on
OMAP4430: 1.0, 2.0, 2.1, 2.2, 2.3
OMAP4460: 1.0, 1.1
OMAP4470: 1.0
OMAP5430: 1.0
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: R Sricharan <r.sricharan@ti.com>
Signed-off-by: Senthilvadivu Guruswamy <svadivu@ti.com>
Diffstat (limited to 'arch/arm/cpu')
| -rw-r--r-- | arch/arm/cpu/armv7/omap-common/emif-common.c | 21 | ||||
| -rw-r--r-- | arch/arm/cpu/armv7/omap-common/hwinit-common.c | 4 |
2 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/omap-common/emif-common.c b/arch/arm/cpu/armv7/omap-common/emif-common.c index edc63fa9c..64427e61d 100644 --- a/arch/arm/cpu/armv7/omap-common/emif-common.c +++ b/arch/arm/cpu/armv7/omap-common/emif-common.c @@ -32,6 +32,27 @@ #include <asm/omap_common.h> #include <asm/utils.h> +void set_lpmode_selfrefresh(u32 base) +{ + struct emif_reg_struct *emif = (struct emif_reg_struct *)base; + u32 reg; + + reg = readl(&emif->emif_pwr_mgmt_ctrl); + reg &= ~EMIF_REG_LP_MODE_MASK; + reg |= LP_MODE_SELF_REFRESH << EMIF_REG_LP_MODE_SHIFT; + reg &= ~EMIF_REG_SR_TIM_MASK; + writel(reg, &emif->emif_pwr_mgmt_ctrl); + + /* dummy read for the new SR_TIM to be loaded */ + readl(&emif->emif_pwr_mgmt_ctrl); +} + +void force_emif_self_refresh() +{ + set_lpmode_selfrefresh(EMIF1_BASE); + set_lpmode_selfrefresh(EMIF2_BASE); +} + inline u32 emif_num(u32 base) { if (base == EMIF1_BASE) diff --git a/arch/arm/cpu/armv7/omap-common/hwinit-common.c b/arch/arm/cpu/armv7/omap-common/hwinit-common.c index 660032330..459ebb55e 100644 --- a/arch/arm/cpu/armv7/omap-common/hwinit-common.c +++ b/arch/arm/cpu/armv7/omap-common/hwinit-common.c @@ -111,6 +111,10 @@ static void init_boot_params(void) void s_init(void) { init_omap_revision(); +#ifdef CONFIG_SPL_BUILD + if (warm_reset() && (omap_revision() <= OMAP5430_ES1_0)) + force_emif_self_refresh(); +#endif watchdog_init(); set_mux_conf_regs(); #ifdef CONFIG_SPL_BUILD |