mci: sdhci: atmel: avoid buggy SDHCI_RESET_ALL ...

On the sama5d27, currently only the MCI used for boot is operational.
The other one errors out when failing to reset the card.

Changing the RESET_ALL to RESET_CMD | RESET_DATA fixes this.
This might be due to the SoC's "11.1   Software 'Reset For all'
command may not execute properly" erratum[1]:
> The software 'Reset For All' command may not execute properly, and, as
> a result, some registers of the host controller may not reset properly.
> The setting of the different registers must be checked beforere
> initializing the SD card.

[1]: DS80000827A

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

mci: sdhci: atmel: use dev_printf instead of pr_print in common code ...

On boards like the sama5d27 som1 ek, we have two SD card slots, so error
messages are more useful if they refer to the SDHCI instance. We didn't
do this at first, because the common code is compiled for PBL as well.
With a sprinkle of preprocessor ifdeffery, we can have both.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

mci: sdhci: add Atmel SDHCI (sama5d2, sam9x60) support ...

We already support Ethernet and QSPI on the SAMA5D2, but MMC was so far
missing. Port over the at91bootstrap driver to barebox. Some parts are
based on the U-Boot and Linux implementations.

To support future use in PBL, the driver model and driver implementation
parts are split into separate files with the latter being compilable for PBL
as well.

Registers, which are found in the common Linux sdhci.h have been added
to the barebox sdhci.h. Registers which appear to be Atmel specific have
been added to atmel-sdhci-common.c instead.

The driver still misses some parts, which will follow later:

  - ADMA is unsupported, PIO only for now
  - Only the SD/MMC controller already enabled by the first stage
    bootloader is supported. Further clocking changes appear
    to be necessary to enable another

Both can be retrofitted later on and don't hold us back from booting
from MMC.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>