[U-Boot] raspberrypi compute module3 emmc not usable

[Belisko Marek]

Hello,

I'm trying to use u-boot on CM3 (which contains eMMC) to boot kernel.
I'm using u-boot 2018.05 and it can start fine like:
U-Boot 2018.05 (Jul 10 2018 - 20:32:05 +0000)

DRAM:  948 MiB
RPI Compute Module 3 (0xa220a0)
MMC:   sdhci at 7e300000: 0
Loading Environment from FAT... unable to select a mode
** No partition table - mmc 0 **
Failed (-5)
In:    serial
Out:   vidconsole
Err:   vidconsole
Net:   No ethernet found.
starting USB...
USB0:   scanning bus 0 for devices... 1 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found
Hit any key to stop autoboot:  0
U-Boot>
U-Boot>
U-Boot>
U-Boot> mmc info
Device: sdhci at 7e300000
Manufacturer ID: 15
OEM: 100
Name: 4FPD3
Bus Speed: 52000000
Mode : MMC legacy
Rd Block Len: 512
MMC version 5.0
High Capacity: Yes
Capacity: 3.6 GiB
Bus Width: 1-bit
Erase Group Size: 512 KiB
HC WP Group Size: 8 MiB
User Capacity: 3.6 GiB WRREL
Boot Capacity: 4 MiB ENH
RPMB Capacity: 512 KiB ENH
U-Boot> mmc part
## Unknown partition table type 0
U-Boot> mmc read $loadaddr 0 2

but reading from eMMC fails with:

MMC read: dev # 0, block # 0, count 2 ... 0 blocks read: ERROR

so it looks like eMMC is not properly working with CM3 in this
version? Any ideas what to check to have it working before I dig to
debugging session ;). Thanks.

BR,

marek

-- 
as simple and primitive as possible
-------------------------------------------------
Marek Belisko - OPEN-NANDRA
Freelance Developer

Ruska Nova Ves 219 | Presov, 08005 Slovak Republic
Tel: +421 915 052 184
skype: marekwhite
twitter: #opennandra
web: http://open-nandra.com