Linux/AM4372: U-Boot on Custom Board - MMC/SD Card detect issues

Tool/software: Linux

Hello everyone,

I am porting U-Boot to a custom board and I want to boot the board via an SD-Card.

Placing custom "MLO" and "u-boot.img" on the "/boot" Partition of an SD-Card (created via the "create-sdcard.sh") and plugging this into the SD-Card connector reveals not a single message.
Compiled with default "am43xx_evm_defconfig" but custom device tree.
(Bootmodelist of AM4372 is UART0, NAND_I2C, NAND, MMC0; picture from AM437x TRM page 192 Table 5-10 )

During ROM Code there is action on the MMC lines(verified by analysing with oscillioscope)!

Therefore i went into CCS and loaded files via the JTAG debugger (while a SD Card is plugged into the SD-Card slot):

To see Debug messages I added "#define DEBUG" in "include/configs/am43xx_evm.h"

The steps I took to execute code are (while SD Card is plugged in):

• Launch targetconf (XDS110 and AM4372)
• Connect to Cortex-A9
• CPU-Reset(SW) Shift+CTRL+R
• Tools -> Load Memory -> "u-boot/spl/u-boot-spl.bin" -> Start adress: 0x402f4000
• Set PC to 0x402f4000 and execute (SPL works see console_log.txt) hold debug session
• CPU_Reset(SW) Shift+CTRL+R
• Tools -> Load Memory -> "u-boot/u-boot.bin" -> Start adress: 0x80800000 ( Tutorial wants to do Run->Load Programm but this does not work for me :/ )
• Set PC to 0x80800000 and execute (Works see console_log.txt)
• in Minicom: execute bdinfo, mmc list, mmc rescan, mmc dev 0,1, mmc part

4101.console_log.txt

In my dts file I enabled the mmc1 node with the following extra (template was the original am437x-gp-evm.dts ):

mmc0_pins: mmc0_pins {
	pinctrl-single,pins = <
		0x100 ( PIN_INPUT | MUX_MODE0 ) /*(D1) mmc0_clk.mmc0_clk*/
		0x104 ( PIN_INPUT | MUX_MODE0 )/* (D2) mmc0_cmd.mmc0_cmd */
		0xfc ( PIN_INPUT | MUX_MODE0 ) /* (C1) mmc0_dat0.mmc0_dat0 */
		0xf8 ( PIN_INPUT | MUX_MODE0 ) /* (C2) mmc0_dat1.mmc0_dat1 */
		0xf4 ( PIN_INPUT | MUX_MODE0 ) /* (B2) mmc0_dat2.mmc0_dat2 */
		0xf0 ( PIN_INPUT | MUX_MODE0 ) /* (B1) mmc0_dat3.mmc0_dat3 */
	>;
	}; /* Note: MMC0 Pin mux should be unnecessary here since it will always be enabled in board/ti/am43xx/mux.c ! */
...
&mmc1 {
	status = "okay";
	vmmc-supply = <&vmmcsd_fixed>;
	bus-width = <4>;
	pinctrl-names = "default";
	pinctrl-0 = <&mmc0_pins>; //unnecessary
        /* template references "spi0_cs1.gpio0_6" is that card detect?? i only need it for hotplugging right? */
	u-boot,dm-spl;
};

Conclusion and Questions

I suspect a driver issue (due to misconfig on my part).
It seems it has choosen the correct OMAP SD/MMC controller(enabled via .config) but the commands send to the SD card timeouts.
During debug session, the U-Boot Code should still probe the MMC, right?
Do you have suggestions or any tipps what might have gone wrong?

Thanks Chris

Additional Information:

Hardware:

AM437x GP EVM Revision 1.5B
Custom Board based on AM437x GP EVM
XDS-110 Debug Probe

Software:

Ubuntu 16.04 LTS
ti-processor-sdk-linux-am437x-evm-05.01.00.11
gcc-linaro-7.2.1-2017.11-x86_64_arm-linux-gnueabihf
Code Composer Studio 8.2.0