Re: [PATCH] - Fix MMC -- was H4 boot with latest git kernel

[Tony Lindgren <tony@atomide.com>]

* Woodruff, Richard <r-woodruff2@ti.com> [070209 13:48]:
> Hi,
> 
> So took a quick look with the emulator and see its hanging in MMC.  I'm
> not an MMC expert but I don't see how you can send an init-stream
> command with no clocks running and if you did it looks like it should be
> 80clocks over 1ms.
> 
> The note in the upper layer in mmc.c says you power it first, then send
> clocks out.  mmc.c calls MMC_POWER_UP twice.  The first time with
> ios->clock = 0 and a second time with iso->clock=f_min.  To me that just
> says set the power bit in the first pass and set the initstream command
> in the second pass.
> 
> The below patch seems to work fine and would appear to be a long
> standing bug.
> 
> Signed-off-by: Richard Woodruff <r-woodruff2.com>
> 
> diff --git a/drivers/mmc/omap.c b/drivers/mmc/omap.c
> index 796172a..55075cc 100644
> --- a/drivers/mmc/omap.c
> +++ b/drivers/mmc/omap.c
> @@ -990,7 +990,7 @@ static void mmc_omap_set_ios(struct mmc_
>  	 * Writing to the CON register twice seems to do the trick. */
>  	for (i = 0; i < 2; i++)
>  		OMAP_MMC_WRITE(host, CON, dsor);
> -	if (ios->power_mode == MMC_POWER_UP) {
> +	if ((ios->power_mode == MMC_POWER_UP) && ios->clock) {
>  		/* Send clock cycles, poll completion */
>  		OMAP_MMC_WRITE(host, IE, 0);
>  		OMAP_MMC_WRITE(host, STAT, 0xffff);
> 

Thanks. Looks like we're still doing the MMC powerup wrong for omap
though. I made a patch for that a while back but it got forgotten
for some reason:

http://lkml.org/lkml/2006/5/4/44

I'll refresh that patch so we can make sure it works on all platforms.

Regards,

Tony