Add initial configuration parameters for Rasperry Pi 3's sdhost
controller, and then configure and use those parameters.
This change allows warm reboots of UEFI on Raspberry Pi 3B+ where
existing code often fails with "unknown error". See discussion at:
https://github.com/pftf/RPi3/issues/24
The basic idea is that some initial configuration parameters
(clock rate, bus width) aren't configured into the hardware before
commands start being sent. I suspect that the particular setting
that matters is the "slow card" bit, but the initial clock setting
also seemed wrong to me.
Change-Id: I526def340def143f23f3422f1fc14c12c937ca7f
Signed-off-by: Rob Newberry <robthedude@mac.com>
This commit improves the SDHost driver for RPi3 as following:
* Unblock MMC_CMD(17). Using MMC_CMD(17) is more efficient on
block reading.
* In some low probability that SEND_OP_COND might results CRC7
error. We can consider that the command runs correctly. We don't
need to retry this command so removing the code for retry.
* Using MMC_BUS_WIDTH_1 as MMC default value to improve the stability.
* Increase the clock to 50Mhz in data mode to speed up the io.
* Change the pull resistors configuration to gain more stability.
Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
This commit adds SDHost driver for RaspberryPi3. SDHost driver uses the
GPIO driver to connect the SDCard and SDHost. By using this driver it is
able to read/write raw blocks on SDCard.
Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
