[U-Boot,v2,1/4] tegra2: Seaboard's MMC has an 8-bit bus

Modify board_mmc_init to configure SDMMC4 for an 8-bit bus, since that's
what is wired up on the board.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
Note: These patches build on various Tegra2-related patches recently posted
by Simon Glass; see v2 of the 6-entry patchset shown at:
http://patchwork.ozlabs.org/project/uboot/list/?submitter=6170&state=1&q=tegra2

 board/nvidia/common/board.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

Stephen,

> -----Original Message-----
> From: Stephen Warren [mailto:swarren@nvidia.com]
> Sent: Tuesday, October 04, 2011 10:33 AM
> To: U-Boot Mailing List
> Cc: Tom Warren; Simon Glass; Stephen Warren
> Subject: [PATCH v2 1/4] tegra2: Seaboard's MMC has an 8-bit bus
> 
> Modify board_mmc_init to configure SDMMC4 for an 8-bit bus, since that's
> what is wired up on the board.
> 
[Tom Warren] Did you try this and then do a mmcinfo to see what you get back? On my Seaboard T20-A03, initializing with 8-bit arg gets you 1-bit back on mmcinfo; using 4-bit (as I had it) gets you back 4-bit. Although it's wired for all 8 data bits, I'm not sure the eMMC controller or device or I/F handles 8 bits correctly. Need to do some more research here, but we should leave this @ 4-bit for now IMO.

Tom

> Signed-off-by: Stephen Warren <swarren@nvidia.com>
> ---
> Note: These patches build on various Tegra2-related patches recently posted
> by Simon Glass; see v2 of the 6-entry patchset shown at:
> http://patchwork.ozlabs.org/project/uboot/list/?submitter=6170&state=1&q=teg
> ra2
> 
>  board/nvidia/common/board.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/board/nvidia/common/board.c b/board/nvidia/common/board.c
> index d13537d..8033612 100644
> --- a/board/nvidia/common/board.c
> +++ b/board/nvidia/common/board.c
> @@ -163,8 +163,8 @@ int board_mmc_init(bd_t *bd)
>  	gpio_config_mmc();
> 
>  	debug("board_mmc_init: init eMMC\n");
> -	/* init dev 0, eMMC chip, with 4-bit bus */
> -	tegra2_mmc_init(0, 4);
> +	/* init dev 0, eMMC chip, with 8-bit bus */
> +	tegra2_mmc_init(0, 8);
> 
>  	debug("board_mmc_init: init SD slot\n");
>  	/* init dev 1, SD slot, with 4-bit bus */
> --
> 1.7.0.4

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Tom Warren wrote at Tuesday, October 04, 2011 2:52 PM:
> Stephen Warren wrote at Tuesday, October 04, 2011 10:33 AM:
> > Modify board_mmc_init to configure SDMMC4 for an 8-bit bus, since that's
> > what is wired up on the board.
> >
> [Tom Warren] Did you try this and then do a mmcinfo to see what you get back? On my Seaboard T20-A03,
> initializing with 8-bit arg gets you 1-bit back on mmcinfo; using 4-bit (as I had it) gets you back 4-
> bit. Although it's wired for all 8 data bits, I'm not sure the eMMC controller or device or I/F
> handles 8 bits correctly. Need to do some more research here, but we should leave this @ 4-bit for now
> IMO.

Ah yes, I see the same issue. I had only validated that running "mmc part"
and ext2load still operated correctly.

I see the exact same issue on Harmony's J26 port, which I'd also marked
as 8-bit.

I guess the Tegra MMC driver doesn't support 8-bit mode or something.
I'll take a quick look and see if there's anything obvious. If not,
I'll just drop that patch from the series.

Thanks for taking a look.