U-Boot SD Card Issues on Custom Arria 10 Board

[M_T]

Background:
1. We have a custom board with an Arria 10 SoC.
2. We built U-Boot for this board following the instructions from the RocketBoards wiki: https://www.rocketboards.org/foswiki/Documentation/BuildingBootloaderCycloneVAndArria10#Arria_10_SoC_45_Boot_from_SD_Card

3. In our setup, the FPGA configuration is loaded from Active Serial flash prior to the boot (FPGA MSEL is hard-set to 3), so "HPS QSYS has FPGA select boot source (SD/MMC 1.8V)" set in the platform design configuration.

Issue Description:
1. When booting U-Boot from the SD Card, the process hangs for a few seconds after the autoboot countdown reaches 0, then restarts.

2. Boot log:

U-Boot SPL 2023.10 (May 13 2024 - 10:08:02 +0000)

U-Boot SPL 2023.10 (May 13 2024 - 10:08:02 +0000)
DDRCAL: Success
WDT: Started watchdog@ffd00300 with servicing every 1000ms (10s timeout)
Trying to boot from MMC1


U-Boot 2023.10-31848-g0b3e82ca6e-dirty (Jul 02 2024 - 17:35:12 +0300)socfpga_arria10

CPU: Altera SoCFPGA Arria 10
BOOT: SD/MMC External Transceiver (1.8V)
Model: Altera SOCFPGA Arria 10
DRAM: 2 GiB
Core: 77 devices, 20 uclasses, devicetree: separate
WDT: Started watchdog@ffd00300 with servicing every 1000ms (10s timeout)
MMC: dwmmc0@ff808000: 0
Loading Environment from MMC... *** Warning - bad CRC, using default environment

In: serial
Out: serial
Err: serial
Model: Altera SOCFPGA Arria 10
Net: Could not get PHY for ethernet@ff800000: addr -1
No ethernet found.

Hit any key to stop autoboot:  0 

  

U-Boot SPL 2023.10 (May 13 2024 - 10:08:02 +0000) 

... (Repeats the same)

3. If autoboot is interrupted:
- Basic commands like mmcinfo, clocks, and mmc list work from the U-Boot prompt.
- Attempts to access SDMMC peripheral registers cause the HPS to hang, triggering a watchdog reset after a few seconds.
- Reading other active peripheral registers (e.g., UART1) works as expected.

4. Additional observations:
- sdmmc reset bit in per0modrst register is 0
- sdmmcclken bit in clk_mgr_perpllgrp->en register is 1

We need assistance in troubleshooting this boot issue, particularly the SDMMC-related problems that seem to be causing the system to hang or reset.

[Jeet14]

Hi,

Can you explain how you are accessing the SDMMC register?

Also, your SDMMC is 4-bit or 8-bit?

Regards

Tiwari

[M_T]

After changing the emac setting in the dts, the boot continues without the problem during the SD card access.

I don't sure what is the connection, but this is OK for now.

[Jeet14]

Hi,

Thanks for your confirmation.

Now, we can close this case.

Regards

Tiwari