Boot from fuses for eMMC

[jsmith883]

Hello,

I am trying to boot from fuses on an eMMC, but something is not working right.  The eMMC is is on SD4, 8-bit bus width.  Before blowing the fuses, I was booting from GPIOs on the same eMMC.  The SBMR register was reading 0x5870.  I then set the fuses by the following command:

echo 0x5870 > /sys/fsl_otp/HW_OCOTP_CFG5

echo 0x10 > /sys/fsl_otp/HW_OCOTP_CFG6

Once  I reset the board, the board no longer boots.  When I look at the registers now the SBMR is reading 0x0, and the OCOTP_CFG5 is reading 0x5870.  OCOTP_CFG6 is reading 0x10.  SBMR2 is reading 0x71.

However, if I plug in the OTG USB, the manufacturing tool will boot the board immediately, as if it's configured for serial download.  Any idea why this is not working correctly?

[joshbarnheiser]

jsmith883,

You may be able to do the same as the echo commands using the mmc command in the initramfs.

For your configuration try:

mmc bootpart enable 1 1 /dev/mmcblk1

mmc bootbus set single_hs x1 x8 /dev/mmcblk1

Embedded Linux Boot Scenarios 

Cheers,

Josh

[igorpadykov]

Hi jsmith883 

what processor used in the case, in particular for example for i.MX6DQ behaviour

is described in sect.8.2.3 Boot From Fuses mode (BOOT_MODE[1:0] = 00b)

i.MX6DQ Reference Manual :

If set to Boot From Fuses, the boot flow is controlled by the BT_FUSE_SEL eFUSE
value. If BT_FUSE_SEL = 0, indicating that the boot device (for example, flash, SD/
MMC) was not programmed yet, the boot flow jumps directly to the Serial Downloader.

https://www.nxp.com/docs/en/reference-manual/IMX6DQRM.pdf 

Best regards
igor
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[jsmith883]

@igorpadykov,

I have an i.MX6 DUAL/QUAD processor.  I'm reading BT_FUSE_SEL = 1, so it should be booting from fuses.  It was able to boot from the eMMC using the GPIO pins, so I know that it's already flashed and can boot from this device.  Then when I blew the fuses so that it would boot from fuses, it does not boot.  Is there something else I need to do to the eMMC or some other fuse/register that I need to set?

[jsmith883]

igorpadykov‌,

Any thoughts?  Is there something else I need to do to the eMMC or some other fuse/register that I need to set for it to properly boot?

[igorpadykov]

Hi jsmith883 

could you read back fuses and verify that they are programmed correctly.

Q&A: How to program i.MX6 eFUSE? 

Fuse API - Boundary Devices 

Best regards
igor

[jsmith883]

igorpadykov‌,

The fuses are reading back correctly.  Here is what I read via JTAG: OCOTP_CFG5 is reading 0x5870.  OCOTP_CFG6 is reading 0x10.  Before I always had to set the boot_config and boot_bus_config for the eMMC to boot, but I can't do this with the manufacturing tool.

echo 8 > /sys/bus/mmc/devices/mmc1\:0001/boot_config
echo 2 > /sys/bus/mmc/devices/mmc1\:0001/boot_bus_config

Is there a way to set this with the manufacturing tool?

[igorpadykov]

Hi jsmith883 

I believe it may be supported by mfg tool, please check ucl2.xml file

  <LIST name="eMMC" desc="Choose eMMC as media">

in mfg tool package on link below

i.MX Software|NXP 

Best regards
igor