Re: IOMMU vs Ryzen embedded EMMC controller

[Shah, Nehal-bakulchandra]

Hi Kurf

On 9/27/2019 3:17 PM, Kurt Garloff wrote:
> Hi JÃrg,
> 
> On 25/09/2019 17:42, Joerg Roedel wrote:
>> On Wed, Sep 25, 2019 at 05:27:32PM +0200, Jiri
>> Kosina wrote:
>>> On Sat, 21 Sep 2019, Kurt Garloff wrote:
>>>> [12916.740274] mmc0: sdhci:
>>>> ============================================
>>>> [12916.740337] mmc0: error -5 whilst
>>>> initialising MMC card
>>> Do you have BAR memory allocation failures in
>>> dmesg with IOMMU on?
> 
> No. The device is *not* treated as PCI device and
> I still think that this is the source of the evil.
> 
>>> Actually, sharing both working and non-working
>>> dmesg, as well as
>>> /proc/iomem contents, would be helpful.
>> Yes, can you please grab dmesg from a boot with
>> iommu enabled and add
>> 'amd_iommu_dump' to the kernel command line?
>> That should give some hints
>> on what is going on.
> 
> For now I attach a dmesg and iomem from the boot
> with IOMMU enabled.
> Nothing much interesting without IOMMU, sdhci-acpi
> there just works -- let me know if you still want
> me to send the kernel msg.
> 
> Thanks for looking into this!
> 

I have added Suravee from AMD in the mail loop. He
works on IOMMU part. As per my understanding, it
needs a patch in IOMMU driver for adding support
of EMMC. Note that on Ryzen platform we have EMMC
5.0 as ACPI device.

Thanks

Nehal Shah