AM625: How to enable DMA for McSPI

Hi Tony,

you should be able to model this for AM62x based on the AM64x DTS entry for main_spi0 that can be found at https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am64-main.dtsi?h=ti-linux-5.10.y#n372:

	main_spi0: spi@20100000 {
		compatible = "ti,am654-mcspi", "ti,omap4-mcspi";
		reg = <0x00 0x20100000 0x00 0x400>;
		interrupts = <GIC_SPI 172 IRQ_TYPE_LEVEL_HIGH>;
		#address-cells = <1>;
		#size-cells = <0>;
		power-domains = <&k3_pds 141 TI_SCI_PD_EXCLUSIVE>;
		clocks = <&k3_clks 141 0>;
		dmas = <&main_pktdma 0xc300 0>, <&main_pktdma 0x4300 0>;
		dma-names = "tx0", "rx0";
	};

So it's about adding the dmas and dma-names properties. Note that for main SPI interfaces other than main_spi0 you'll need to update the PSI-L Source and Destination Thread IDs accordingly. For main_spi0 they happen to be the same for AM62x and AM64x so the above example should apply as-is. For the other main SPI interfaces please refer to the respective table in the TISCI User's Guide at https://software-dl.ti.com/tisci/esd/latest/5_soc_doc/am62x/psil_cfg.html. Look for the pdma_main*_mcspi1_rx and pdma_main*_mcspi0_tx entries and update your DTS node accordingly.

Regards, Andreas