Re: [PATCH] mmc: tegra: Disable UHS-I modes for tegra30

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On 05/10/2016 11:16 AM, Jon Hunter wrote:

On 10/05/16 17:34, Stephen Warren wrote:
On 05/10/2016 10:13 AM, Jon Hunter wrote:

[snip]

Stephen, for your u-boot testing, do you are set the bit in the vendor
misc register to enable version 3.0 support for sdhci on tegra30? This
is what the above quirk is doing (and has done so for a very long time).

I don't see anything in the U-Boot driver that is equivalent to the
kernel's NVQUIRK_ENABLE_SDHCI_SPEC_300. I assume that means the
controller advertises an early spec version when in U-Boot, which simply
means U-Boot doesn't know to take advantage of any faster transfer modes
enabled by later specification versions, but I'm not entirely sure what
effect the following kernel code has on the HW:

     /* Erratum: Enable SDHCI spec v3.00 support */
     if (soc_data->nvquirks & NVQUIRK_ENABLE_SDHCI_SPEC_300)
         misc_ctrl |= SDHCI_MISC_CTRL_ENABLE_SDHCI_SPEC_300;

Do you see it touch the SDHCI_TEGRA_VENDOR_MISC_CTRL register?

Not at all. For reference, the register is defined in arch/arm/include/asm/arch-tegra/tegra_mmc.h as venmiscctl, and that symbol isn't referenced anywhere.
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