mmc only working when used in U-Boot

[Stefan Roese <stefan.roese@gmail.com>]

Hi!

I've noticed on a custom OMAP3530 board, that the SDcard (mmc1) is only
detected, when its previously used in U-Boot (e.g. by "mmc rescan"). So
I tested on beagleboard and it behaved identical. 

Here the boot log with U-Boot scanning mmc before Linux booting:

root@generic-armv7a:~# dmesg | grep mmc
[    2.225006] of_get_named_gpiod_flags: can't parse gpios property of node '/ocp/mmc@4809c000[0]'
[    2.234100] of_get_named_gpiod_flags: can't parse gpios property of node '/ocp/mmc@4809c000[0]'
[    2.260040] omap_hsmmc 4809c000.mmc: pins are not configured from the driver
[    2.398071] mmc0: host does not support reading read-only switch. assuming write-enable.
[    2.408416] mmc0: new high speed SD card at address 0007
[    2.419128] mmcblk0: mmc0:0007 SD02G 1.90 GiB 
[    2.426025]  mmcblk0: p1 p2
[   10.241638] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[   10.256011] FAT-fs (mmcblk0p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.

Here the boot log without U-Boot touching mmc before Linux booting:

root@generic-armv7a:~# dmesg | grep mmc
[    2.162689] of_get_named_gpiod_flags: can't parse gpios property of node '/ocp/mmc@4809c000[0]'
[    2.171936] of_get_named_gpiod_flags: can't parse gpios property of node '/ocp/mmc@4809c000[0]'
[    2.197906] omap_hsmmc 4809c000.mmc: pins are not configured from the driver

I also added the pin mux'es for the mmc to the dts and the last message
is gone. But this doesn't help with mmc detection.

BTW: This is on latest mainline Linux.

Somehow U-Boot configured/enables something that is missing in the
Linux driver. Is this a known issue? Any ideas?

Thanks,
Stefan