AM62A7-Q1: How to enable DMA for MCSPI0

Tool/software:

Hi,

I am trying to use two devices on mcspi0 with the following device tree overlay:

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2024 Benchmark Electronics B.V.
 * Author: Bas Vermeulen <bas.vermeulen@bench.com>
 */

/dts-v1/;
/plugin/;

#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/interrupt-controller/irq.h>
#include "k3-pinctrl.h"

&main_pmx0 {
        main_spi0_pins_default: main-spi0-pins-default {
                pinctrl-single,pins = <
                        AM62AX_IOPAD(0x1b4, PIN_OUTPUT, 0)      /* (D16) SPI0_CS0 */
                        AM62AX_IOPAD(0x1b8, PIN_OUTPUT, 0)      /* (C16) SPI0_CS1 */
                        AM62AX_IOPAD(0x1bc, PIN_INPUT, 0)       /* (A17) SPI0_CLK */
                        AM62AX_IOPAD(0x1c0, PIN_INPUT, 0)       /* (B15) SPI0_D0 MISO */
                        AM62AX_IOPAD(0x1c4, PIN_OUTPUT, 0)      /* (E15) SPI0_D1 MOSI */
                >;
        };
};

&mcu_pmx0 {
        bmi088_accel_pins_default: bmi088-accel-pins-default {
                pinctrl-single,pins = <
                        AM62AX_MCU_IOPAD(0x030, PIN_INPUT, 7)   /* (C8) MCU_GPIO0_11 INT1 */
                >;
        };
        bmi088_gyro_pins_default: bmi088-gyro-pins-default {
                pinctrl-single,pins = <
                        AM62AX_MCU_IOPAD(0x02c, PIN_INPUT, 7)   /* (C10) MCU_GPIO0_12 INT2 */
                >;
        };
};

&main_spi0 {
        status = "okay";

        pinctrl-names = "default";
        pinctrl-0 = <&main_spi0_pins_default>, <&bmi088_accel_pins_default>, <&bmi088_gyro_pins_default>;

        bmi088-accel@0 {
                compatible = "bosch,bmi088-accel";
                reg = <0>;
                spi-max-frequency = <10000000>;
                interrupt-parent = <&mcu_gpio0>;
                interrupts = <11 IRQ_TYPE_EDGE_RISING>;
                interrupt-names = "INT1";
        };

        bmi088-gyro@1 {
                compatible = "bosch,bmi088_gyro";
                reg = <1>;
                interrupt-parent = <&mcu_gpio0>;
                interrupts = <12 IRQ_TYPE_EDGE_RISING>;
                interrupt-names = "INT2";
        };
};

When I load the device tree overlay, the overlay is active, but the mcspi device (20100000.spi) gets deferred. The only path where this could happen is when the probe function in omap4-mcspi.c can't find the DMAs.

I don't need DMA, but it won't hurt if it's enabled and used.

My questions:

1. How do I enable the mcspi0 in linux without DMA?
2. If I can't, what DMA channels should I be using for mcspi0 with two chip-selects? I'd like to know how to determine the values to put in the device tree so I can do it myself next time.

Regards,

Bas Vermeulen