Re: [PATCH v6 06/11] arm64: dts: ti: k3-am62a7-sk: Enable IPC with remote processors

[Judith Mendez <jm@ti.com>]

Hi Devarsh,

On 4/7/25 8:54 AM, Devarsh Thakkar wrote:
> Hi Judith,
> 
> On 05/04/25 05:45, Judith Mendez wrote:
>  > From: Devarsh Thakkar <devarsht@ti.com>
>>
> 
> Thanks for the patch.
> 
>> For each remote proc, reserve memory for IPC and bind the mailbox
>> assignments. Two memory regions are reserved for each remote processor.
>> The first region of 1MB of memory is used for Vring shared buffers
>> and the second region is used as external memory to the remote processor
>> for the resource table and for tracebuffer allocations.
>>
>> Signed-off-by: Devarsh Thakkar <devarsht@ti.com>
>> Signed-off-by: Hari Nagalla <hnagalla@ti.com>
>> Signed-off-by: Judith Mendez <jm@ti.com>
>> ---
>>   arch/arm64/boot/dts/ti/k3-am62a7-sk.dts | 96 +++++++++++++++++++++++--
>>   1 file changed, 90 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts 
>> b/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
>> index 1c9d95696c839..7d817b447c1d0 100644
>> --- a/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
>> +++ b/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
>> @@ -52,6 +52,42 @@ linux,cma {
>>               linux,cma-default;
>>           };
>> +        c7x_0_dma_memory_region: c7x-dma-memory@99800000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x99800000 0x00 0x100000>;
>> +            no-map;
>> +        };
>> +
>> +        c7x_0_memory_region: c7x-memory@99900000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x99900000 0x00 0xf00000>;
>> +            no-map;
>> +        };
>> +
>> +        mcu_r5fss0_core0_dma_memory_region: r5f-dma-memory@9b800000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x9b800000 0x00 0x100000>;
>> +            no-map;
>> +        };
>> +
>> +        mcu_r5fss0_core0_memory_region: r5f-dma-memory@9b900000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x9b900000 0x00 0xf00000>;
>> +            no-map;
>> +        };
>> +
>> +        wkup_r5fss0_core0_dma_memory_region: r5f-dma-memory@9c800000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x9c800000 0x00 0x100000>;
>> +            no-map;
>> +        };
>> +
>> +        wkup_r5fss0_core0_memory_region: r5f-dma-memory@9c900000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x9c900000 0x00 0xf00000>;
>> +            no-map;
>> +        };
>> +
>>           secure_tfa_ddr: tfa@9e780000 {
>>               reg = <0x00 0x9e780000 0x00 0x80000>;
>>               alignment = <0x1000>;
>> @@ -63,12 +99,6 @@ secure_ddr: optee@9e800000 {
>>               alignment = <0x1000>;
>>               no-map;
>>           };
>> -
>> -        wkup_r5fss0_core0_memory_region: r5f-dma-memory@9c900000 {
>> -            compatible = "shared-dma-pool";
>> -            reg = <0x00 0x9c900000 0x00 0x01e00000>;
>> -            no-map;
>> -        };
>>       };
> 
> This is missing the edgeAI specific remote-core carveouts and 
> RTOS-to-RTOS IPC memory regions [1] being used by edgeAI firmwares which 
> come as pre-packaged in the official SDK release for AM62A.
> 
> There is only one official SDK release for AM62A (which is edgeAI based) 
> [2] which packages these edgeAI remoteproc firmwares and in my view it 
> is a fair expectation that remote core careveouts in device-tree should 
> align with firmwares released in SDK.
> 
> This is because most developers (including me) and vendors download this 
> official SDK release and use it with latest upstream kernel and modules 
> (right now we are applying required patches locally) and this patch 
> won't suffice for this, in-fact it won't work since the remoteproc 
> firmwares are already using regions beyond the reserved-regions from 
> this patch.

I understand your point, currently with this patch remoteproc loading
will not work for some cores. However, the goal here is to standardize
as much as possible the memory carveout sizes, push the "demo firmware"
to request resources the correct way from resource table, and move away
from this dependency and limitations that we have with our firmware. We
should soon be able to generate our own firmware using Zephyr,  which
Andrew is pioneering, so with this firmware we should move to the
correct direction upstream. Downstream we are still using the memory
carveout sizes that the firmware folk want so desperately to keep, for
now..

~ Judith

> 
> [1]: 
> https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts?h=ti-linux-6.6.y-cicd#n103
> [2]: https://www.ti.com/tool/PROCESSOR-SDK-AM62A
> 
> Regards
> Devarsh
> 
>>       opp-table {
>> @@ -741,3 +771,57 @@ dpi1_out: endpoint {
>>           };
>>       };
>>   };
>> +
>> +&mailbox0_cluster0 {
>> +    status = "okay";
>> +
>> +    mbox_r5_0: mbox-r5-0 {
>> +        ti,mbox-rx = <0 0 0>;
>> +        ti,mbox-tx = <1 0 0>;
>> +    };
>> +};
>> +
>> +&mailbox0_cluster1 {
>> +    status = "okay";
>> +
>> +    mbox_c7x_0: mbox-c7x-0 {
>> +        ti,mbox-rx = <0 0 0>;
>> +        ti,mbox-tx = <1 0 0>;
>> +    };
>> +};
>> +
>> +&mailbox0_cluster2 {
>> +    status = "okay";
>> +
>> +    mbox_mcu_r5_0: mbox-mcu-r5-0 {
>> +        ti,mbox-rx = <0 0 0>;
>> +        ti,mbox-tx = <1 0 0>;
>> +    };
>> +};
>> +
>> +&wkup_r5fss0 {
>> +    status = "okay";
>> +};
>> +
>> +&wkup_r5fss0_core0 {
>> +    mboxes = <&mailbox0_cluster0>, <&mbox_r5_0>;
>> +    memory-region = <&wkup_r5fss0_core0_dma_memory_region>,
>> +            <&wkup_r5fss0_core0_memory_region>;
>> +};
>> +
>> +&mcu_r5fss0 {
>> +    status = "okay";
>> +};
>> +
>> +&mcu_r5fss0_core0 {
>> +    mboxes = <&mailbox0_cluster2>, <&mbox_mcu_r5_0>;
>> +    memory-region = <&mcu_r5fss0_core0_dma_memory_region>,
>> +            <&mcu_r5fss0_core0_memory_region>;
>> +};
>> +
>> +&c7x_0 {
>> +    mboxes = <&mailbox0_cluster1>, <&mbox_c7x_0>;
>> +    memory-region = <&c7x_0_dma_memory_region>,
>> +            <&c7x_0_memory_region>;
>> +    status = "okay";
>> +};
>