[U-Boot] [U-Boot, 1/4] mmc: dw_mmc: check fifo status with a timeout in fifo mode

[Philipp Tomsich]

> While trying to enable the dw_mmc on rk3188 I managed to confuse
> and hang the dw_mmc controller into not delivering further data.
> The fifo state never became ready and the driver was iterating in
> the while loop reading 0-byte packets forever.
> 
> So inspired by how other implementations handle this, check the fifo-
> state beforhand and add a timeout to catch any glaring fifo issues
> without hanging uboot altogether.
> 
> Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> Acked-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> ---
>  drivers/mmc/dw_mmc.c | 32 ++++++++++++++++++++++++++++++--
>  include/dwmmc.h      |  2 ++
>  2 files changed, 32 insertions(+), 2 deletions(-)
> 

Applied to u-boot-rockchip, thanks!