mmc: Fix missing 1 ms delay after mmc power up

mmc/sd specification requires a 1 ms delay (stable supply voltage)
after vdd was enabled and before issuing first command.

For most sdcard/soc combinations, the missing delay seems to be not a
problem because the processing time between enabling vdd and the first
command is often hundreds of microseconds or more. However, in our
specific case, some sdcards were not detected by u-boot:
* soc: NXP i.MX 93
* sdcards: SanDisk Ultra, 64GB micro SDXC 1,
           MediaRange, 8GB, SDHC
* measured time between vdd and first command: approx. 784us
* symptom: both sdcards did not respond at all to first commands,
           u-boot mmc subsystem ran into timeout and stops to
           initialize the cards

Signed-off-by: Christoph Stoidner <[email protected]>
Cc: Peng Fan <[email protected]>
Cc: Jaehoon Chung <[email protected]>
Signed-off-by: Peng Fan <[email protected]>

0 files changed, 0 insertions, 0 deletions