mmc error while reset and reboot

[yashavanthashet]

Hi,

We are using i.MX8M custom board with Linux4.9.51_ga release.

We are facing mmc error after giving 'reset' command in uboot or  'reboot' command in kernel.

Please see the print below.

--------------------------------------------------------------------------------------

iWave-G27 >
iWave-G27 > reset
resetting ...

U-Boot SPL 2017.03-imx_v2017.03_4.9.51_imx8m_ga+g2537522 (Nov 09 2018 - 11:00:20)
PMIC:  PFUZE100 ID=0x10
check ddr4_pmu_train_imem code
check ddr4_pmu_train_imem code pass
check ddr4_pmu_train_dmem code
check ddr4_pmu_train_dmem code pass
Training FAILED
Training FAILED
check ddr4_pmu_train_imem code
check ddr4_pmu_train_imem code pass
check ddr4_pmu_train_dmem code
check ddr4_pmu_train_dmem code pass
Training FAILED
Normal Boot
Trying to boot from MMC1
mmc_load_image_raw_sector: mmc block read error
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

---------------------------------------------------------------------------------------------

Anyone faced this issue?

Thanks in advance,

Regards,

Yashavantha

[igorpadykov]

Hi Yashavantha

one can check if custom board shortly remove power from board in reboot as it is done on i.MX8M EVK with

nWDOG (pad GPIO1_IO02), U704 UM805RE  p.10 SPF-29615 MX8M EVK schematic,
PMIC_ON_REQ and produced in the same manner as Reset Button SYS_nRST SW1702 switch.

Schematics (1)
Design Files for the i.MX 8M Evaluation Kit (EVK)(REV 0)
https://www.nxp.com/support/developer-resources/run-time-software/i.mx-developer-resources/evaluatio...

Best regards
igor
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[yashavanthashet]

Hi Igor,

Thank you for your reply.

This looks hardware watchdog power recycle implementation. Why it is necessary?
Can SW reboot/reset alone won't work in i.MX8M?

Regards,
Yashavantha

[igorpadykov]

Hi Yashavantha

power recycle implementation avoids having to determine if a component critical

to rebooting the processor is in the necessary state to support a reboot.

Components that fit this category include (but may not be limited to):

    eMMC memory card (if the hardware RST_B pin is not connected.
    SD Card/socket (if the reset pin is not used to remove power to the SD Card)
    QSPI
    NOR
    LPDDR2/3 memory

So you should analyze and determine what causes failure.

Best regards
igor

[yashavanthashet · Accepted solution]

hi,

Since watchdog was not properly implemented in both hardware and software, the above issue had occurred.

Issue solved after proper watchdog implementation.