IMX7ULP Single Boot Operation

[ibocakir06]

Hi,

I have designed a custom board with IMX7ULP SoC. The board has the peripherals below:

• 512MiB LPDDR3 16 bit.
• eMMC 4GB is connected to uSHDC0 PORTD.
• Murata WiFi module is connected to uSHDC1 PORTE.
• MC34PF1550A4EP PMIC is connected to I2C3.

My boot mode is fixed to the single boot mode via resistors.

As you can see, I do not have a QSPI flash on my board. This figure is taken from Reference Manual Pg:1466.

I have compiled my u-boot and downloaded it via the uuu tool in serial download mode. It works fine. I can reach eMMC with "mmc info" command. The next step I have to move on is booting the linux.

This is the .auto file I use in uuu.

uuu_version 1.2.39

SDP: boot -f /home/myname/projects/IMX7ULP/u-boot-fslc/u-boot-dtb.imx -nojump
sdpu: delay 100
# SDP: write -f /home/myname/projects/IMX7ULP/linux-fslc/arch/arm/boot/uImage -addr 0x60800000
SDP: write -f /home/myname/projects/IMX7ULP/linux-fscl3/linux-fslc-5.15.x-fslc/arch/arm/boot/uImage -addr 0x60800000
# SDP: write -f /home/myname/projects/IMX7ULP/LF_v5.10.72-2.2.0_images_IMX7ULPEVK/uImage -addr 0x60800000
sdpu: delay 100
SDP: write -f /home/myname/projects/IMX7ULP/DTB/imx.dtb -addr 0x63000000
# SDP: write -f /home/myname/projects/IMX7ULP/LF_v5.10.72-2.2.0_images_IMX7ULPEVK/imx7ulp-evkb-lpuart.dtb -addr 0x63000000
sdpu: delay 100
SDP: write -f /home/myname/projects/IMX7ULP/LF_v5.10.72-2.2.0_images_IMX7ULPEVK/fsl-image-mfgtool-initramfs-imx_mfgtools.cpio.gz.u-boot -addr 0x63800000
# SDP: write -f /home/myname/projects/IMX7ULP/buildroot/output/images/rootfs.ext2.gz.uboot -addr 0x63800000
sdpu: delay 100
SDP: write -f /home/myname/projects/IMX7ULP/LF_v5.10.72-2.2.0_images_IMX7ULPEVK/imx7ulp_m4_demo.img -addr 0x62000000
sdpu: delay 100
SDP: jump -f /home/myname/projects/IMX7ULP/u-boot-fslc/u-boot-dtb.imx
# sdpu: delay 3000
FB: done

1. I download the Kernel uImage to the address 0x60800000
2. I download the ramfs to the address 0x63800000
3. I download the device tree binary file to the address 0x63000000.

Then I run the bootm command to boot from memory. However, the u-boot is stuck at "Starting Kernel".

Question 1: I do nothing about M4 core. Do I have to initialize the M4 core in single boot mode?

If the answer of the question 1 is YES:

Question 2: How can I program M4? I did not expand the SWD pins of M4 out of the board. I can not reach BGA balls. Can I program M4 via u-boot? If yes, do I have to use bootaux command with the patch you mentioned below:

IMX7ULP Bootaux Patch to U-boot 

I have done this patch to the u-boot and followed the instructions. But the result is below. Resetting ...

Can you give some detailed explanation about bootaux operation in u-boot?

Question 3: What can be the problem if it is not related to M4? 

I think u-boot can not load the kernel to RAM. I have used older or newer versions of u-boot from fslc, the result is same.

1. Is it about RAM size? or
2. Is it about PMIC? or
3. Is it about resetting the A7 core from M4? 
4. Or what can it be?

I am forwarding your response.

Thanks.

[ibocakir06]

Thanks for the reply.

As I mentioned before, I do not have QSPI flash placed on my board. 

1. Do I have to program M4 to boot Linux on A7?
2. If yes, how can I do it via u-boot without QSPI Flash?

Thanks.

[ibocakir06]

Any reply will be helpful. 

[Rita_Wang]

For the M4 in the i.MX7ULP you can see the document.