Re: [PATCH v3 0/4] RPi: SD/WiFi ACPI updates

["Jeremy Linton" <jeremy.linton@arm.com>]

Hi,

On 2/17/21 12:56 AM, Ard Biesheuvel wrote:
> On Wed, 17 Feb 2021 at 07:18, jlinton <lintonrjeremy@gmail.com> wrote:
>>
>> From: Jeremy Linton <jeremy.linton@arm.com>
>>
>> The existing RPi3 ACPI entries for the Arasan
>> and SDHCI controllers need updating to work
>> with the RPi4. This is done by adding a caps
>> override for the legacy Arasan controller and
>> then adding an entirely new entry for the newer
>> eMMC2 controller.
>>
>> Then we flip the default routing to make the eMMC2
>> the default for the SD card, so that the WiFi can
>> start working on the Arasan.
>>
>> Additional we add a menu item to enable the SDMA/ADMA2
>> modes on the controller.
>>
>> v2->v3: Various small review tweaks, whitespace, wording
>>              spelling, etc.
>>
> 
> What happened to the IORT change? Don't we need that to ensure that
> Linux sizes ZONE_DMA appropriately?

Ha, I gave up! There are more important things to fix, especially when I 
found another case that couldn't just be fixed by the IORT tweaking 
without more kernel patches.

The default in this set is PIO mode, no DMA, same as the Arasan. If I 
get motivated (or someone else does) they can pick up the pieces to 
finish turning the DMA on in linux. It also simplifies that IORT disable 
patch I posted separately since I don't have to worry about enabling it 
for a limit <2G.

The sdhci_caps_mask choice is what flags the device as not supporting 
DMA modes unless the user enables it. Yes this hurts perf, but not 
nearly as badly as disabling UHS mode because we can't lower the card 
voltage with the standard sdhci registers (rather having to depend on a 
nonstandard rpi mailbox call which isn't available without a _DSM() or 
something equally undesirable).

Presumably windows, *bsd, etc could make some use of the _DMA in the 
SSDT as well.


> 
> 
>> v1->v2: Add option for user to enable/disable eMMC DMA
>>          Only enable the emmc2 table on rpi4 &
>>              !Arasan routing
>>          Move emmc2 into its own SSDT and drop
>>              second _DMA entry
>>
>> Jeremy Linton (4):
>>    Platform/RaspberryPi: Add Negative table check
>>    Platform/RaspberryPi/Acpitables: Add eMMC2 device and tweak Arasan
>>    Platform/RaspberryPi: User control of eMMC2 DMA
>>    Platform/RaspberryPi: Invert default Arasan, eMMC2 routing
>>
>>   Platform/RaspberryPi/AcpiTables/AcpiTables.inf     |   1 +
>>   Platform/RaspberryPi/AcpiTables/Emmc.asl           | 129 +++++++++++++++++++++
>>   Platform/RaspberryPi/AcpiTables/Sdhc.asl           |  18 ++-
>>   Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c |  26 +++++
>>   .../RaspberryPi/Drivers/ConfigDxe/ConfigDxe.inf    |   1 +
>>   .../RaspberryPi/Drivers/ConfigDxe/ConfigDxeHii.uni |   4 +
>>   .../RaspberryPi/Drivers/ConfigDxe/ConfigDxeHii.vfr |  17 +++
>>   Platform/RaspberryPi/Include/ConfigVars.h          |   8 ++
>>   Platform/RaspberryPi/RPi3/RPi3.dsc                 |   1 +
>>   Platform/RaspberryPi/RPi4/RPi4.dsc                 |   3 +-
>>   Platform/RaspberryPi/RPi4/Readme.md                |   2 +-
>>   Platform/RaspberryPi/RaspberryPi.dec               |   1 +
>>   12 files changed, 206 insertions(+), 5 deletions(-)
>>   create mode 100644 Platform/RaspberryPi/AcpiTables/Emmc.asl
>>
>> --
>> 2.13.7
>>