[PATCH v2] board: ti: am62ax: tifs-rm-cfg/rm-cfg: Update DMA resource sharing for CPSW

[Anshul Dalal]

On Thu May 7, 2026 at 6:01 PM IST, Siddharth Vadapalli wrote:
> The CPSW3G instance of CPSW on AM62AX SoC provides Ethernet functionality.
> Currently, Ethernet is supported on Linux which runs on the A53 core on the
> SoC, by allocating all of the DMA resources associated with CPSW to A53_2.
>
> In order to enable use-cases where the Ethernet traffic is sent from or
> consumed by various CPU cores on the SoC simultaneously, while at the
> same time, maintaining backward compatibility with the existing use-case
> of A53 being the sole entity that exchanges traffic with CPSW via DMA,
> update the DMA resource sharing scheme on AM62AX SoC to the following:
>
> ---------------      --------------   -------------  ----------------
>    Resource              WKUP_R5         MCU_R5            A53_2
> ---------------      --------------   -------------  ----------------
> TX Channels [8]  =>    4 (Primary)     4 (Primary)     8 (Secondary)
> TX Rings   [64]  =>   32 (Primary)    32 (Primary)    64 (Secondary)
> RX Channels [1]  =>    1 (Primary)     0               1 (Secondary)
> RX Flows   [16]  =>    6 (Primary)    10 (Primary)    16 (Secondary)
>
> In the absence of primary owners of resources (existing use-case
> where A53 owns all of the CPSW DMA resources), the secondary owner
> can claim all of the resources as its own. For shared use-cases,
> the resources that are not claimed by the primary are communicated
> to the secondary owner allowing it to claim them. This ensures that
> Linux on A53_2 can continue claiming all DMA resources associated
> with CPSW in the absence of primary owners, while at the same time
> providing users the flexibility to share CPSW DMA resources across
> various CPU cores listed above if needed.
>
> While Linux has been mentioned as the Operating System running
> on A53, there is no dependency between the Operating System
> running on A53 and its ability to claim the CPSW DMA resources
> listed above.
>
> Signed-off-by: Siddharth Vadapalli <s-vadapalli at ti.com>

Acked-by: Anshul Dalal <anshuld at ti.com>