"Shilimkar, Santosh" <santosh.shilimkar@xxxxxx> writes:
> On Thu, May 17, 2012 at 5:45 AM, Kevin Hilman <khilman@xxxxxx> wrote:
>> Tero Kristo <t-kristo@xxxxxx> writes:
>>
>>> 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.
>>
>> Please summarize the workaround here as well.
>>
> ok
>>> 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 | 37 ++++++++++++++++++++
>>> 2 files changed, 39 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 215b80e..dfaa254 100644
>>> --- a/arch/arm/mach-omap2/pm44xx.c
>>> +++ b/arch/arm/mach-omap2/pm44xx.c
>>> @@ -17,12 +17,18 @@
>>> #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 <mach/hardware.h>
>>>
>>> #include "common.h"
>>> #include "clockdomain.h"
>>> #include "powerdomain.h"
>>> #include "pm.h"
>>>
>>> +#define EMIF_SDRAM_CONFIG2_OFFSET 0xc
>>> +
>>> struct power_state {
>>> struct powerdomain *pwrdm;
>>> u32 next_state;
>>> @@ -215,6 +221,37 @@ 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()) {
>>
>> This should probably be done later in this function, after PM_ERRATUM
>> flags are setup, and then it should use a PM_ERRATUM flag instead of cpu_is*
>>
> ok
>
>>> + void __iomem *secure_ctrl_mod;
>>> + void __iomem *emif1;
>>> + void __iomem *emif2;
>>> + u32 val;
>>> +
>>> + secure_ctrl_mod = ioremap(OMAP4_CTRL_MODULE_WKUP, SZ_4K);
>>> + emif1 = ioremap(OMAP44XX_EMIF1_BASE, SZ_1M);
>>> + emif2 = ioremap(OMAP44XX_EMIF2_BASE, SZ_1M);
>>> +
>>> + BUG_ON(!secure_ctrl_mod || !emif1 || !emif2);
>>
>> Please avoid BUG_ON() and use proper error recovery. This is not a
>> condition where the entire kernel should panic.
>>
> Agree. WARN_ON() should suffice.
A WARN_ON() is ok (but noisy). Better is a pr_warn() with some proper
error recovery.
Kevin
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
