[U-Boot] [PATCH V5 1/2] mmc: add bcm2835 driver

[Andy Fleming]

On Tue, Nov 27, 2012 at 8:30 PM, Stephen Warren <swarren at wwwdotorg.org>wrote:

> This adds a simple driver for the BCM2835's SD controller.
>
> Workarounds are implemented for:
> * Register writes can't be too close to each-other in time, or they will
>   be lost.
> * Register accesses must all be 32-bit, so implement custom accessors.
>
> This code was extracted from:
> git://github.com/gonzoua/u-boot-pi.git master
> which was created by Oleksandr Tymoshenko.
>
> Portions of the code there were obviously based on the Linux kernel at:
> git://github.com/raspberrypi/linux.git rpi-3.6.y
> commit f5b930b "Main bcm2708 linux port" signed-off-by Dom Cobley.
>
> swarren changed the following for upstream:
> * Removed hack udelay()s in bcm2835_sdhci_raw_writel(); setting
>   SDHCI_QUIRK_WAIT_SEND_CMD appears to solve the issues.
> * Remove register logging from read*/write* functions.
> * Sort out confusion with min/max_freq values passed to add_sdhci().
> * Use more descriptive variable names and calculations in IO accessors.
> * Simplified and commented twoticks_delay calculation.
> * checkpatch fixes.
>
> Cc: Andy Fleming <afleming at gmail.com>
> Signed-off-by: Oleksandr Tymoshenko <gonzo at bluezbox.com>
> Signed-off-by: Stephen Warren <swarren at wwwdotorg.org>
>
>
Acked-by: Andy Fleming <afleming at freescale.com>