Subject: [PATCH v2 2/3] ARM: OMAP4+: Move SRAM data to DT

From: [email-masked] (Sekhar Nori)
Date: Mon, 2 Sep 2013 22:33:33 +0530

On 8/29/2013 7:21 PM, Santosh Shilimkar wrote:
> On Thursday 29 August 2013 09:50 AM, Rajendra Nayak wrote:
>> On Thursday 29 August 2013 07:01 PM, Santosh Shilimkar wrote:
>>> On Thursday 29 August 2013 09:26 AM, Sekhar Nori wrote:
>>>> On 8/29/2013 4:53 PM, Rajendra Nayak wrote:
>>>>> diff --git a/arch/arm/boot/dts/omap4.dtsi b/arch/arm/boot/dts/omap4.dtsi
>>>>> index 22d9f2b..1ba6a77 100644
>>>>> --- a/arch/arm/boot/dts/omap4.dtsi
>>>>> +++ b/arch/arm/boot/dts/omap4.dtsi
>>>>> @@ -126,6 +126,11 @@
>>>>>  			pinctrl-single,function-mask = <0x7fff>;
>>>>>  		};
>>>>>  
>>>>> +		ocmcram: ocmcram at 40304000 {
>>>>
>>>> This can now be changed to 0x40300000 now that you have moved to
>>>> gen_pool_alloc()?
>>>>
>>> NO.
>>> It won't work on secure devices since first 16 KB is occupied for
>>> default configuration. Its not worth trouble also to handle
>>> secure/non-secure considering the use of SRAM which is actually just
>>> limited to errata. 40304000 will work for both devices.
>>
>> Right. Sekhar, you might have confused because of the existing buggy code
>> in sram.c and sram.h which did this (and is removed in this series)
>>
>> from sram.c
>> -----------
>>  #define OMAP2_SRAM_PUB_PA	(OMAP2_SRAM_PA + 0xf800)
>>  #define OMAP3_SRAM_PUB_PA       (OMAP3_SRAM_PA + 0x8000)
>> -#ifdef CONFIG_OMAP4_ERRATA_I688
>> -#define OMAP4_SRAM_PUB_PA	OMAP4_SRAM_PA
>> -#else
>> -#define OMAP4_SRAM_PUB_PA	(OMAP4_SRAM_PA + 0x4000)
>> -#endif
>> -#define OMAP5_SRAM_PA		0x40300000
>>  
>> from sram.h
>> -----------
>>  #define OMAP2_SRAM_PA		0x40200000
>>  #define OMAP3_SRAM_PA           0x40200000
>> -#ifdef CONFIG_OMAP4_ERRATA_I688
>> -#define OMAP4_SRAM_PA		0x40304000
>> -#define OMAP4_SRAM_VA		0xfe404000
>> -#else
>> -#define OMAP4_SRAM_PA		0x40300000
>> -#endif
>>
>> I am not sure where the checks for CONFIG_OMAP4_ERRATA_I688
>> came in from, but these are done, like Santosh said, to handle
>> secure and non-secure sram across GP and HS devices and in
>> no way related to handling errata I688.
>>
> The check was to ensure that with errata enabled, we don't care
> about first 16 KB ;-)

Hi Rajendra, thanks for the explanation. Other devices like AM437x which
have HS variants might need such adjustment too. It will be nice to
check that.

Thanks,
Sekhar