i.MX Processors中的主题 Re: iMX6UL - run u-boot from eMMC

iMX6UL - run u-boot from eMMC

nickbedbury — Tue, 10 Jul 2018 19:58:16 GMT

I am trying to bring up a custom iMX6UL board booting from eMMC, and encountering some issues.

I believe eMMC is hooked up properly. Via JTAG, I can load u-boot.bin (built from uboot-fslc-2017.11, the repo Yocto references) to 0x87800000. Then u-boot runs and gives me a console, from which eMMC works successfully ("mmc info", etc).

For production, we are using u-boot and SPL built from this code base:

configs: icore-rqs: Enable falcon mode · Freescale/u-boot-fslc@ca0c3f3 · GitHub

I have loaded the compiled SPL to address 1kB and u-boot.img to address 69kB, as per the iMX6UL EVK. I used the command "dd if=SPL of=/dev/mmcblk1 bs=1k seek=1" to program the SPL for example. When I boot however, I don't see any console. I assume the SPL would print some message if it ran properly?

Based on scoping the eMMC signals, it looks like the iMX6UL ROM bootloader reads 4kB from the eMMC as described in the reference manual section 8.5.3. I verified the bytes at 1kB offset into the 4kB block read are the SPL file.

Other than scoping the eMMC signals, is there another way to verify the SPL works properly? Can I load it via JTAG to SRAM (perhaps address 0x908000?) and mimic a power-up boot?

Re: iMX6UL - run u-boot from eMMC

nickbedbury — Tue, 10 Jul 2018 20:01:28 GMT

As an addendum: I did not use the MMC's boot partitions (/dev/mmcblk1boot0 or /dev/mmcblk1boot1) because I didn't have any way to set "boot_config" as per this post: https://community.nxp.com/thread/429311

I am convinced the SPL and u-boot need to be in /dev/mmcblk1 (the user area) because it's where the ROM bootloader is reading from.

Re: iMX6UL - run u-boot from eMMC

igorpadykov — Tue, 10 Jul 2018 23:15:23 GMT

Hi Nick

one can look at gateworks tutorial

ventana/bootloader/falcon-mode – Gateworks

Also one can test with nxp uboot (guidelines can be found on below link),

however it does not use spl.

i.MX Software|NXP

Best regards
igor
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Re: iMX6UL - run u-boot from eMMC

nickbedbury — Wed, 11 Jul 2018 12:40:19 GMT

Thanks Igor. The nxp uboot you referenced works for me (I booted from eMMC). I guess it was a problem with the uboot variants I had tried to use.