AM4379: DMA support for MMC

Ivan Debelec2

Prodigy 20 points

Part Number: AM4379

Hello,

I'm not so experienced with Linux and AM4379 processor but I would like to add support for DMA on MMC...

I did some research and we are using kernel 4.14.71 with omap_hsmmc driver, and eMMC and SD card access works fine...

Device tree configuration is following:

/******************************************************************************
 *							MMC
 *****************************************************************************/

	mmc1_pins_default: mmc1_pins_default {
		pinctrl-single,pins = <
			0x100 ( PIN_INPUT_PULLUP | MUX_MODE0 ) /* (D1) mmc0_clk.mmc0_clk */
			0x104 ( PIN_INPUT_PULLUP | MUX_MODE0 ) /* (D2) mmc0_cmd.mmc0_cmd */
			0x0f0 ( PIN_INPUT_PULLUP | MUX_MODE0 ) /* (B1) mmc0_dat3.mmc0_dat3 */
			0x0f4 ( PIN_INPUT_PULLUP | MUX_MODE0 ) /* (B2) mmc0_dat2.mmc0_dat2 */
			0x0f8 ( PIN_INPUT_PULLUP | MUX_MODE0 ) /* (C2) mmc0_dat1.mmc0_dat1 */
			0x0fc ( PIN_INPUT_PULLUP | MUX_MODE0 ) /* (C1) mmc0_dat0.mmc0_dat0 */
		>;
	};

	mmc1_pins_sleep: pinmux_mmc1_pins_sleep {
		pinctrl-single,pins = <
			0x100 (PIN_INPUT_PULLDOWN | MUX_MODE7)
			0x104 (PIN_INPUT | PULL_DISABLE | MUX_MODE7)
			0x0f0 (PIN_INPUT | PULL_DISABLE | MUX_MODE7)
			0x0f4 (PIN_INPUT | PULL_DISABLE | MUX_MODE7)
			0x0f8 (PIN_INPUT | PULL_DISABLE | MUX_MODE7)
			0x0fc (PIN_INPUT | PULL_DISABLE | MUX_MODE7)
		>;
	};

	mmc2_pins_default: mmc2_pins_default {
		pinctrl-single,pins = <
			0x80 ( PIN_INPUT_PULLUP | MUX_MODE2 ) /* (B9) gpmc_csn1.mmc1_clk */
			0x84 ( PIN_INPUT_PULLUP | MUX_MODE2 ) /* (F10) gpmc_csn2.mmc1_cmd */
			0x20 ( PIN_INPUT_PULLUP | MUX_MODE2 ) /* (B10) gpmc_ad8.mmc1_dat0 */
			0x24 ( PIN_INPUT_PULLUP | MUX_MODE2 ) /* (A10) gpmc_ad9.mmc1_dat1 */
			0x28 ( PIN_INPUT_PULLUP | MUX_MODE2 ) /* (F11) gpmc_ad10.mmc1_dat2 */
			0x2c ( PIN_INPUT_PULLUP | MUX_MODE2 ) /* (D11) gpmc_ad11.mmc1_dat3 */
		>;
	};

	mmc2_pins_sleep: mmc2_pins_sleep {
		pinctrl-single,pins = <
			0x20 (PIN_INPUT_PULLDOWN | MUX_MODE7) /* (B10) gpmc_ad8.mmc1_dat0 */
			0x24 (PIN_INPUT_PULLDOWN | MUX_MODE7) /* (A10) gpmc_ad9.mmc1_dat1 */
			0x28 (PIN_INPUT_PULLDOWN | MUX_MODE7) /* (F11) gpmc_ad10.mmc1_dat2 */
			0x2c (PIN_INPUT_PULLDOWN | MUX_MODE7) /* (D11) gpmc_ad11.mmc1_dat3 */
			0x80 (PIN_INPUT_PULLDOWN | MUX_MODE7) /* (B9) gpmc_csn1.mmc1_clk */
			0x84 (PIN_INPUT_PULLDOWN | MUX_MODE7) /* (F10) gpmc_csn2.mmc1_cmd */
		>;
	};

&mmc1 {
	status = "okay";
	vmmc-supply = <&evm_v3_3d>;
	bus-width = <4>;
	pinctrl-names = "default", "sleep";
	pinctrl-0 = <&mmc1_pins_default>;
	pinctrl-1 = <&mmc1_pins_sleep>;
	cd-gpios = <&gpio0 6 GPIO_ACTIVE_HIGH>;
};

/* eMMC sits on mmc2 */
&mmc2 {
	status = "okay"; /* Disable GPMC/NAND when enabling mmc2 */
	vmmc-supply = <&evm_v3_3d>;
	bus-width = <4>;
	pinctrl-names = "default", "sleep";
	pinctrl-0 = <&mmc2_pins_default>;
	pinctrl-1 = <&mmc2_pins_sleep>;
	ti,non-removable;
};

EDMA configuration

&edma {
ti,edma-xbar-event-map = /bits/ 16 <1 22
2 23>;
};

What would be required to add DMA support for eMMC and SD card?

Is it sufficient to add this two lines in e.g. mmc2 to add support on eMMC or is there something additionally needed?

dmas = <&edma 22
&edma 23>;
dma-names = "tx", "rx";

Thanks

Ivan

over 6 years ago

0 Krunal Bhargav34 over 6 years ago

TI__Mastermind 45015 points

Hello Ivan,

Based on the document "linux-4.14.79.../Documentation/devicetree/bindings/mmc/ti-omaap-hsmmc.txt", it seems like your entry is correct.

[generic DMA request binding]

        mmc1: mmc@0x4809c000 {
                compatible = "ti,omap4-hsmmc";
                reg = <0x4809c000 0x400>;
                ti,hwmods = "mmc1";
                ti,dual-volt;
                bus-width = <4>;
                vmmc-supply = <&vmmc>; /* phandle to regulator node */
                ti,non-removable;
                dmas = <&edma 24
                        &edma 25>;
                dma-names = "tx", "rx";
        };

Regards,
Krunal

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AM4379: DMA support for MMC