Hi Tero,
On 04/25/2012 02:26 AM, Tero Kristo wrote:
> On Tue, 2012-04-24 at 13:22 -0500, Jon Hunter wrote:
>> Hi Tero,
>>
>> On 04/20/2012 04:33 AM, Tero Kristo wrote:
>>> From: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
>>>
>>> Work around for Errata ID: i632 "LPDDR2 Corruption After OFF Mode
>>> Transition When CS1 Is Used On EMIF" which impacts OMAP443x silicon
>>> The issue occurs when EMIF_SDRAM_CONFIG is restored first before
>>> EMIF_SDRAM_CONFIG_2 is not yet restored, the register configuration
>>> is not set properly, we apply the required workaround allowing
>>> the restore sequence to work properly.
>>>
>>> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
>>> [t-kristo@xxxxxx: moved workaround from omap-sar.c to pm44xx.c]
>>> Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
>>> ---
>>> .../include/mach/ctrl_module_wkup_44xx.h | 2 +
>>> arch/arm/mach-omap2/pm44xx.c | 24 ++++++++++++++++++++
>>> 2 files changed, 26 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-omap2/include/mach/ctrl_module_wkup_44xx.h b/arch/arm/mach-omap2/include/mach/ctrl_module_wkup_44xx.h
>>> index a0af9ba..b763a79 100644
>>> --- a/arch/arm/mach-omap2/include/mach/ctrl_module_wkup_44xx.h
>>> +++ b/arch/arm/mach-omap2/include/mach/ctrl_module_wkup_44xx.h
>>> @@ -28,6 +28,8 @@
>>> #define OMAP4_CTRL_MODULE_WKUP_IP_REVISION 0x0000
>>> #define OMAP4_CTRL_MODULE_WKUP_IP_HWINFO 0x0004
>>> #define OMAP4_CTRL_MODULE_WKUP_IP_SYSCONFIG 0x0010
>>> +#define OMAP4_CTRL_SECURE_EMIF1_SDRAM_CONFIG2_REG 0x0114
>>> +#define OMAP4_CTRL_SECURE_EMIF2_SDRAM_CONFIG2_REG 0x011c
>>> #define OMAP4_CTRL_MODULE_WKUP_CONF_DEBUG_SEL_TST_0 0x0460
>>> #define OMAP4_CTRL_MODULE_WKUP_CONF_DEBUG_SEL_TST_1 0x0464
>>> #define OMAP4_CTRL_MODULE_WKUP_CONF_DEBUG_SEL_TST_2 0x0468
>>> diff --git a/arch/arm/mach-omap2/pm44xx.c b/arch/arm/mach-omap2/pm44xx.c
>>> index 0472921..d4d18d9 100644
>>> --- a/arch/arm/mach-omap2/pm44xx.c
>>> +++ b/arch/arm/mach-omap2/pm44xx.c
>>> @@ -17,6 +17,9 @@
>>> #include <linux/err.h>
>>> #include <linux/slab.h>
>>> #include <asm/system_misc.h>
>>> +#include <linux/io.h>
>>> +
>>> +#include <mach/ctrl_module_wkup_44xx.h>
>>>
>>> #include "common.h"
>>> #include "clockdomain.h"
>>> @@ -215,6 +218,27 @@ static int __init omap4_pm_init(void)
>>>
>>> pr_err("Power Management for TI OMAP4.\n");
>>>
>>> + /*
>>> + * Work around for OMAP443x Errata i632: "LPDDR2 Corruption After OFF
>>> + * Mode Transition When CS1 Is Used On EMIF":
>>> + * Overwrite EMIF1/EMIF2
>>> + * SECURE_EMIF1_SDRAM_CONFIG2_REG
>>> + * SECURE_EMIF2_SDRAM_CONFIG2_REG
>>> + */
>>> + if (cpu_is_omap443x()) {
>>> + void __iomem *secure_ctrl_mod;
>>> +
>>> + secure_ctrl_mod = ioremap(OMAP4_CTRL_MODULE_WKUP, SZ_4K);
>>> + BUG_ON(!secure_ctrl_mod);
>>> +
>>> + __raw_writel(0x10, secure_ctrl_mod +
>>> + OMAP4_CTRL_SECURE_EMIF1_SDRAM_CONFIG2_REG);
>>> + __raw_writel(0x10, secure_ctrl_mod +
>>> + OMAP4_CTRL_SECURE_EMIF2_SDRAM_CONFIG2_REG);
>>
>> According to the erratum description the above registers are used to
>> restore the EMIFx_SDRAM_CONFIG2 registers. So although the value 0x10,
>> maybe the value being used for EMIFx_SDRAM_CONFIG2 registers, shouldn't
>> we read the EMIFx_SDRAM_CONFIG2 registers and store them in the above
>> registers?
>
> This might be a good idea, however, this patch might be tagged as TEMP
> until the EMIF driver is in place, this fix should rather be located
> there. I'll take a look at this if I can change the implementation a
> bit.
By the way, I did dump the EMIF1_SDRAM_CONFIG2 register on a omap4403
and it is configured to 0x10. So I think that reading this register and
saving would be safe.
Cheers
Jon
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