Re: [PATCH 1/3] mmc: tegra: prevent HS200 on Tegra 3

Marcel Ziswiler
2018-07-13T15:39:34Z

On Thu, 2018-07-12 at 09:39 +0200, Stefan Agner wrote:
> The stack assumes that SDHC controller which support SD3.0 (SDR104)
> do
> support HS200. This is not the case for Tegra 3, which does support
> SD
> 3.0
> but only supports eMMC spec 4.41.
>
> Use SDHCI_QUIRK2_BROKEN_HS200 to indicate that the controller does
> not
> support HS200.
>
> Note that commit 156e14b126ff ("mmc: sdhci: fix caps2 for HS200")
> added
> the tie between SD3.0 (SDR104) and HS200. I don't think that this is
> necessarly true. It is fully legitimate to support SD3.0 and not
> support
> HS200. The quirk naming suggests something is broken in the
> controller,
> but this is not the case: The controller simply does not support
> HS200.
>
> Fixes: 7ad2ed1dfcbe ("mmc: tegra: enable UHS-I modes")
> Signed-off-by: Stefan Agner <stefan@agner.ch>

The whole series stress-tested overnight on various Apalis T30 as well
as Colibri T30 modules:

Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>

> ---
> drivers/mmc/host/sdhci-tegra.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-
> tegra.c
> index 970d38f68939..137df06b9b6e 100644
> --- a/drivers/mmc/host/sdhci-tegra.c
> +++ b/drivers/mmc/host/sdhci-tegra.c
> @@ -334,7 +334,8 @@ static const struct sdhci_pltfm_data
> sdhci_tegra30_pdata = {
> SDHCI_QUIRK_NO_HISPD_BIT |
> SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
> SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
> - .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
> + .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
> + SDHCI_QUIRK2_BROKEN_HS200,
> .ops = &tegra_sdhci_ops,
> };

Works quite nicely on today's next once [1] is also applied:

root@apalis-t30:~# cat /sys/kernel/debug/mmc1/ios
clock: 52000000 Hz
actual clock: 51000000 Hz
vdd: 21 (3.3 ~ 3.4 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 3 (8 bits)
timing spec: 8 (mmc DDR52)
signal voltage: 1 (1.80 V)
driver type: 0 (driver type B)
root@apalis-t30:~# hdparm -t /dev/mmcblk1

/dev/mmcblk1:
Timing buffered disk reads: 236 MB in 3.01 seconds = 78.42 MB/sec

root@colibri-t30:~# cat /sys/kernel/debug/mmc0/ios
clock: 52000000 Hz
actual clock: 51000000 Hz
vdd: 21 (3.3 ~ 3.4 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 3 (8 bits)
timing spec: 8 (mmc DDR52)
signal voltage: 1 (1.80 V)
driver type: 0 (driver type B)
root@colibri-t30:~# hdparm -t /dev/mmcblk0

/dev/mmcblk0:
Timing buffered disk reads: 168 MB in 3.00 seconds = 55.99 MB/sec

[1] https://lore.kernel.org/lkml/1531487865-17427-1-git-send-email-avie
namo@nvidia.com