Re: [edk2-devel] [edk2-platforms][PATCH 1/8] Platform/RPi: Add model family detection

["Pete Batard" <pete@akeo.ie>]

Hi Michael,

On 2019.11.14 16:36, Michael Brown wrote:
> On 14/11/2019 16:07, Pete Batard wrote:
>> +typedef
>> +EFI_STATUS
>> +(EFIAPI *GET_MODEL_FAMILY) (
>> +  UINT32 *ModelFamily
>> +  );
>> +
>>   typedef
>>   EFI_STATUS
>>   (EFIAPI *GET_FIRMWARE_REVISION) (
>> @@ -143,6 +150,7 @@ typedef struct {
>>     GET_MODEL             GetModel;
>>     GET_MODEL_REVISION    GetModelRevision;
>>     GET_MODEL_NAME        GetModelName;
>> +  GET_MODEL_FAMILY      GetModelFamily;
>>     GET_FIRMWARE_REVISION GetFirmwareRevision;
>>     GET_MANUFACTURER_NAME GetManufacturerName;
>>     GET_CPU_NAME          GetCpuName;
> 
> Is the RASPBERRY_PI_FIRMWARE_PROTOCOL structure expected to be 
> externally consumed at any point?

I don't really expect so. And even if that becomes the case, I think the 
platform is still new enough at this stage not to expect anyone to run 
afoul of ABI breakage.

> If so, then adding a field in the 
> middle of the structure without changing the associated GUID would break 
> the ABI.

I guess we'll take that into consideration if we modify this structure 
again, so thanks for pointing it out. But for now, I would say that this 
concern is mostly irrelevant.

> It's great to see the Pi 4 heading towards having UEFI support; I'm 
> looking forward to trying it out as soon as it's ready.

Well, if you are that eager to look into it, you can already play with 
the 'pi4_dev1' branches we have for edk2-platforms and edk2-non-osi at 
https://github.com/pftf which is what we are currently working with (and 
what this patch series is based on).

Right now, you should get video and you should also be able to run the 
UEFI Shell, but since we don't have xHCI, there's no USB support, so the 
only means of interacting with the firmware is through serial...

Oh, and you must have the official Device Tree on your SD card when 
booting if you want the serial baudrate to be properly set to the 
expected 115200 bauds. On RPI4, it appears that the new VideoCore does 
read the Device Tree behind the scenes to perform some of its own init...

If you build the firmware, a basic config.txt with the following should 
get you sorted:

arm_64bit=1
enable_uart=1
core_freq=250
enable_gic=1
armstub=RPI_EFI.fd
disable_commandline_tags=1

If you need more info, feel free to contact me off-list.

Regards,

/Pete

> 
> Thanks,
> 
> Michael