"Card stuck in programming state! __mmc_switch" problem on i.MX6 + eMMC

["David Müller (ELSOFT AG)" <d.mueller@elsoft.ch>]

Hello

I have a custom i.MX6Q based board with a Hynix eMMC chip attached to
USDHC3. OS is a vanilla Linux 3.16 with some patches.

Loading the iMX SDHC driver results in the following error:

modprobe sdhci-esdhc-imx
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper
mmc0: no vqmmc regulator found
mmc0: SDHCI controller on 2198000.usdhc [2198000.usdhc] using ADMA
mmc0: BKOPS_EN bit is not set
mmc0: Card stuck in programming state! __mmc_switch
mmc0: error -110 whilst initialising MMC card
mmc0: BKOPS_EN bit is not set
mmc0: Card stuck in programming state! __mmc_switch
mmc0: error -110 whilst initialising MMC card
mmc0: BKOPS_EN bit is not set
mmc0: Card stuck in programming state! __mmc_switch
mmc0: error -110 whilst initialising MMC card
mmc0: BKOPS_EN bit is not set
mmc0: Card stuck in programming state! __mmc_switch
mmc0: error -110 whilst initialising MMC card


Pin muxing looks ok nevertheless I played around with it to see if it
makes a difference. I also tried the "Add delay between CMD6 and CMD13
for Sandisk eMMC cards" workaround previously mentioned on this list.

As the whole thing is working under U-Boot as shown below, I tend to
rule out soldering problems and non-functional hardware.

=> ver
U-Boot 2014.07-00045-g0955ecc-dirty (Aug 26 2014 - 12:47:21)
=> mmc dev 1
switch to partitions #0, OK
mmc1(part 0) is current device
=> mmc info
Device: FSL_SDHC
Manufacturer ID: 90
OEM: 14a
Name: H8G2d
Tran Speed: 52000000
Rd Block Len: 512
MMC version 4.41
High Capacity: Yes
Capacity: 7.2 GiB
Bus Width: 8-bit


Any idea what is going wrong?
Has anybody a Hynix eMMC working under Linux?