Re: [PATCH] arm64: dts: ti: k3-j721s2-main: fix msmc node

[Vignesh Raghavendra]

Hi Udit,

On 13/04/23 10:45, Udit Kumar wrote:
> Hi Nishanth,
> 
> On 13/04/23 01:26, Nishanth Menon wrote:
>> On 23:06-20230412, Udit Kumar wrote:
>>> On J721S2 SOC, l3cache-sram size is configured as zero by
>>> system firmware.
>>> Also top 64K of msmc_ram (0x703F_0000 to 0x703F_FFFF) is used by system
>>> firmware tifs-sram.
>>>
>>> This patch removes l3cache-sram node and update range for tifs-sram.
>>>
>>> Fixes: b8545f9d3a54 ("arm64: dts: ti: Add initial support for J721S2
>>> SoC")
>>>
>>> Signed-off-by: Udit Kumar <u-kumar1@xxxxxx>
>>> ---
>>>   arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi | 7 ++-----
>>>   1 file changed, 2 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
>>> b/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
>>> index 2dd7865f7654..cbc784f915a9 100644
>>> --- a/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
>>> +++ b/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
>>> @@ -17,13 +17,10 @@ atf-sram@0 {
>>>               reg = <0x0 0x20000>;
>>>           };
>>>   -        tifs-sram@1f0000 {
>>> -            reg = <0x1f0000 0x10000>;
>>> +        tifs-sram@3f0000 {
>>> +            reg = <0x3f0000 0x10000>;
>>>           };
>>>   -        l3cache-sram@200000 {
>>> -            reg = <0x200000 0x200000>;
>>> -        };
>>>       };
>>>         gic500: interrupt-controller@1800000 {
>>> -- 
>>> 2.34.1
>>>
>> Are you saying that j721s2 is incapable of l3 cache? say some level 1
>> errata?
> No
>> or is it because, the chip is really capable of l3 cache and we are
>> really setting it to 0?
>>
>> https://git.ti.com/cgit/k3-image-gen/k3-image-gen/tree/soc/j721s2/evm/board-cfg.c#n71
> This is because, l3 cache size is set to zero.
>> unless the chip has an errata, you are supposed to fix it up based on
>> configuration by using the API and this patch is a NAK
>> https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/general/core.html#tisci-query-msmc
> ok

U-Boot already does this. See fdt_fixup_msmc_ram() at board/ti/j721s2/evm.c

tifs-sram fixup probably is still needed and possible bug in the original patch?

-- 
Regards
Vignesh