From: Stephen Warren <swarren@nvidia.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] Revert "mmc: retry the cmd8 to meet 74 clocks requirement in the spec"
Date: Sat, 19 Nov 2011 12:36:00 -0700 [thread overview]
Message-ID: <4EC80520.3030307@nvidia.com> (raw)
In-Reply-To: <1321349739-15212-1-git-send-email-macpaul@andestech.com>
On 01/-10/-28163 12:59 PM, Macpaul Lin wrote:
> This reverts commit 02f3029f1810b99869254d0cf0a71946a008a728.
>
> This patch add 3 times retry to CMD8 because the Marvell mmc controller
> doesn't obey the power ramp up process in the SD specification 6.4.1.
> (Please refer to figure 6.1 and 6.2 in the specification.)
>
> The CMD0 should be send after power ramp up has been finished.
> However, the Marvell mmc contorller must do power ramp up after the
> first CMD0 command has been send.
>
> This patch also affect existing platforms like Nokia N900 and other
> platforms.
>
> Signed-off-by: Macpaul Lin <macpaul@andestech.com>
> Acked-by: Lei Wen <leiwen@marvell.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
As background, I'm working on patches to support the Toshiba AC100 /
Dynabook AZ in mainline U-Boot. The internal MMC didn't work at all
until this revert was applied. The SD slot worked perfectly though. I
guess this is related to the MMC itself not supporting this
(SD-specific?) command, and the patch caused MMC mode never to be attempted.
next prev parent reply other threads:[~2011-11-19 19:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-11 23:17 [U-Boot] Nokia N900 - eMMC not working after commit 02f3029f1810b99869254d0cf0a71946a008a728 Pali Rohár
2011-11-12 6:13 ` Lei Wen
2011-11-12 15:40 ` Macpaul Lin
2011-11-14 6:14 ` Macpaul Lin
2011-11-14 6:19 ` Lei Wen
2011-11-14 6:36 ` Macpaul Lin
2011-11-14 9:06 ` Lei Wen
2011-11-15 3:34 ` Macpaul Lin
2011-11-15 9:01 ` Lei Wen
2011-11-15 9:14 ` Macpaul Lin
2011-11-15 9:35 ` [U-Boot] [PATCH] Revert "mmc: retry the cmd8 to meet 74 clocks requirement in the spec" Macpaul Lin
2011-11-15 9:41 ` Lei Wen
2011-11-19 19:36 ` Stephen Warren [this message]
2011-11-19 19:45 ` [U-Boot] " Pali Rohár
2011-11-25 23:44 ` [U-Boot] [PATCH] " Andy Fleming
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