Booting From SD card 2 - Mainline Linux

I am trying to use u-boot distro-boot to boot from what i believe is SD/MMC2 (the 4 bit slot). I have our Wifi card in slot1. If I send “mmc info” in u-boot, only the onboard eMMC card is detected. Do I have to do something like select card detect pin polarity? The card slot works, because I can see the card when we have WEC installed. I just can’t get it to recognize in U-boot.

If you are using Apalis Evaluation board 4 bit slot is MMC dev 2. To get info about inserted card please do at U-Boot prompt:

#mmc dev 2
#mmc info

Apalis T30 # mmc dev 2
MMC: no card present
Apalis T30 #

I am using our own carrier board. I believe our card detect polarity is active high.

Could you post the schematic of your sd card slot connections? Have you done any customization for the device tree? Is the card recognized in Linux?

At least on our Apalis Evaluation Board this works just fine. What exact U-Boot version are you using?

This is with the dual-boot chainload from WEC to u-boot. I just realized there probably needs to be an SD card reset of some sort, much like we did for Wifi SD card. In reality, we will be jumping from E-boot to U-boot and not WEC to U-boot, so maybe it’s not necessary.

In any event, how would I set the card polarity in U-boot source and/or disable card detect? And, is there a software way to issue a reset to the SD card? I believe I have seen the same issue with on board eMMC card sometimes as well. Both pertain to the chainload solution.

Could you answer the questions I asked above? Thanks.

Our SD card has Card detect polarity active high (inverted). I’ll have to patch u-boot device tree with
cd-inverted; for distro-boot to work.

Yeah, you can change the U-Boot device tree files.