AM5728: QSPI flash for U-Boot

Frank Vasquez

Part Number: AM5728

I have a custom AM5728 board that I am trying to boot off of a QSPI flash. I just want U-Boot to reside on QSPI flash. The Linux kernel, DTB and root file system will stay on microSD.

I am using U-Boot v2018.01 and patching mux_data.h with data generated from TI's PinMux Tool. CONFIG_TI_QSPI is enabled in u-boot.cfg. I hoped that would be enough to detect the flash but when I "sf probe" from U-Boot I get nothing except "(err=-19)". The QSPI flash is a Micron MT25QL256ABA.

Is there a particular DTB U-Boot needs to detect the QSPI flash or do I need to modify the DTS and build one? What should that DTS (&qspi node) look like?

Cheers,
Frank

over 7 years ago

0 Marcus Cooksey over 7 years ago

TI__Genius 9510 points

You need to update the pinmux the dtb file found in <u-boot>/arch/arm/dts/

Do you know which dtb file being used in u-boot? You can hardcode the dts in u-boot by setting the environment variable "fdtfile"

0 Frank Vasquez over 7 years ago in reply to Marcus Cooksey

Prodigy 160 points

I will give that a go when I have some time. I was able to get Linux to probe the QSPI flash and format it so at leat the hardware appears to be working. We'll see what happens with U-Boot. Thank you, Marcus.

-Frank

0 Frank Vasquez over 7 years ago in reply to Marcus Cooksey

Prodigy 160 points

Hi Marcus,

U-Boot appears to be using am57xx-beagle-x15.dtb. I patched am57xx-beagle-x15.dts as follows and rebuilt U-Boot.

&dra7_pmx_core {
        qspi1_pins_default: qspi1_pins_default {
                pinctrl-single,pins = <
                        DRA7XX_CORE_IOPAD(0x4a003474, 0x50101)  /* qspi1_rtclk */
                        DRA7XX_CORE_IOPAD(0x4a003488, 0x10101)  /* qspi1_sclk */
                        DRA7XX_CORE_IOPAD(0x4a003480, 0x50101)  /* qspi1_d0 */
                        DRA7XX_CORE_IOPAD(0x4a003484, 0x50101)  /* qspi1_d1 */
                        DRA7XX_CORE_IOPAD(0x4a00347c, 0x50101)  /* qspi1_d2 */
                        DRA7XX_CORE_IOPAD(0x4a003478, 0x50101)  /* qspi1_d3 */
                        DRA7XX_CORE_IOPAD(0x4a0034b8, 0x20101)  /* qspi1_cs0 */
                >;
        };
};

/* MT25QL256 QSPI flash */
&qspi {
        status = "okay";
        spi-max-frequency = <48000000>;

        pinctrl-names = "default";
        pinctrl-0 = <&qspi1_pins_default>;

        flash: flash@0 {
                spi-max-frequency = <48000000>;
                reg = <0>;
                compatible = "n25q256a", "jedec,spi-nor";
        };
};

Now I get a different error when I probe the flash from U-Boot so this seems like progress.

=> sf probe
SF: unrecognized JEDEC id bytes: ff, ff, ff
Failed to initialize SPI flash at 0:0 (error -2)

Any ideas? Perhaps bad mux_data.h values?

Cheers,
Frank

0 RonB over 7 years ago in reply to Frank Vasquez

TI__Mastermind 30986 points

Frank,

Did you get a chance to dig into your pin mux? Are you past this issue?

Appendix: Similar issue was fixed here. Please, also check this thread.

Thanks.

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AM5728: QSPI flash for U-Boot