drivers/storage/bayhub: Add support for eMMC tuning

The Bayhub part has support for hardware tuning, but it only supports it
at 4 bits.

I added a new sdhci_send_tuning_cmd because sdhci_send_command_bounced
requires a data buffer, sets up DMA and waits for a different interrupt
then the tuning command returns. Instead of adding a bunch of
conditionals to sdhci_send_tuning_cmd, I added a new function.

TEST=Verified it compiles on grunt

Change-Id: I19ef97b474d1597a55136aa55d4f3e4f992938b9
Signed-off-by: Raul E Rangel <>
Reviewed-by: Julius Werner <>
7 files changed