Hi,
I got similar issues that Marek had: http://lists.denx.de/pipermail/u-boot/2015-October/231420.html.
When trying to initialize an eMMC on a SAMA5D4 based board the CPU stuck. However, the fix sent by Marek was not enough for me and after digging in the sources and trying many combinations I found that the culprit was the switch command (CMD 6). A small delay was needed after this command before the next one. The MMC spec seems to confirm that by speaking about waiting 8 clocks after this command.
In the following patch I removed the delay introduced by Marek, and instead I added a 8 clocks wait just after the switch command.
Marek, could you test it on your board and confirm that it is still work for you?
Thanks,
Gregory CLEMENT (1): mmc: atmel: Properly fix clock configuration
drivers/mmc/gen_atmel_mci.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)