imx8mm mmc block read error

[jiangxh]

Hi,

We are using i.MX8mm custom board with Linux imx_4.19.35_1.1.0. Some boards will have the problem of mmc block read error during cold start.

But after 10 minutes of power-on, these boards can load the system normally after power-on again.

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U-Boot SPL 2019.04-4.19.35-1.1.0+g6cc5af5 (Oct 07 2021 - 14:26:43 +0000)
power_bd71837_init
DDRINFO: start DRAM init
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
Trying to boot from MMC2
mmc_load_image_raw_sector: mmc block read error
SPL: failed to boot from all boot devices

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Anyone faced this issue?

Thanks in advance,

Regards,

Jiang Xihui

[trongthinh]

I got the same issues, and the watchdog reset the board every 1 min

U-Boot SPL 2022.04-6.4.0-devel+git.7bd2074193e1 (Sep 08 2023 - 01:58:31 +0000)
DDRINFO: start DRAM init
DDRINFO: DRAM rate 3000MTS
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
WDT: Started watchdog@30280000 with servicing (60s timeout)
Trying to boot from MMC2
mmc_load_image_raw_sector: mmc block read error
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

Does anyone resolved it? Please share the solutions.

[igorpadykov]

Hi Bryan

>But after 10 minutes of power-on, these boards can load the system normally after power-on again.

probably heating may improve SD signal shape ( it may be noisy due to impedance mismatch/signal reflections) and one can try to adjust SD drive strength using sect.8.2.5.203 Pad Control Register
(IOMUXC_SW_PAD_CTL_PAD_SD2_CLK)  i.MX 8M Mini Applications Processor Reference Manual

Best regards
igor

[DanielDuJijun]

Hi Igor.

We had check the sect.8.2.5.203 Pad Control Register
(IOMUXC_SW_PAD_CTL_PAD_SD2_CLK)  《i.MX 8M Mini Applications Processor Reference Manual》 and find the Drive Strength Field as following:

would you please help to review and advise which of the following four parameter configurations has the highest drive capability and which has the lowest drive capability?

Thanks.

Drive Strength Field
Control the IO ports DS1/0 by dse[2:1] (lsb of this field is not used):
00X X1 — Drive strength X1
10X X2 — Drive strength X2
01X X4 — Drive strength X4
11X X6 — Drive strength X6