[edk2-devel] [edk2-platforms][PATCH v3 5/5] Platform/RPi3/PlatformSmbiosDxe: Derive RAM size from board revision
Philippe Mathieu-Daudé
philmd at redhat.com
Mon Oct 14 12:08:10 UTC 2019
On 10/14/19 2:03 PM, Pete Batard wrote:
> On 2019.10.14 12:53, Philippe Mathieu-Daudé wrote:
>> On 10/14/19 1:44 PM, Pete Batard wrote:
>>> Hi Philippe,
>>>
>>> On 2019.10.14 11:01, Philippe Mathieu-Daudé wrote:
>>>> Hi Pete,
>>>>
>>>> On 10/11/19 1:07 PM, Pete Batard wrote:
>>>>> The board revision is the proper channel to use to detect the
>>>>> amount of
>>>>> RAM available as bits [20-22] report the effective RAM size for the
>>>>> board
>>>>> starting with 256 MB (000b) and doubling in size for each value.
>>>>>
>>>>> Signed-off-by: Pete Batard <pete at akeo.ie>
>>>>> Reviewed-by: Leif Lindholm <leif.lindholm at linaro.org>
>>>>> ---
>>>>> Platform/RaspberryPi/RPi3/Drivers/PlatformSmbiosDxe/PlatformSmbiosDxe.c
>>>>> | 18 ++++++++++++------
>>>>> 1 file changed, 12 insertions(+), 6 deletions(-)
>>>>>
>>>>> diff --git
>>>>> a/Platform/RaspberryPi/RPi3/Drivers/PlatformSmbiosDxe/PlatformSmbiosDxe.c
>>>>> b/Platform/RaspberryPi/RPi3/Drivers/PlatformSmbiosDxe/PlatformSmbiosDxe.c
>>>>>
>>>>> index b5dcff897a59..5abc82b8d363 100644
>>>>> ---
>>>>> a/Platform/RaspberryPi/RPi3/Drivers/PlatformSmbiosDxe/PlatformSmbiosDxe.c
>>>>>
>>>>> +++
>>>>> b/Platform/RaspberryPi/RPi3/Drivers/PlatformSmbiosDxe/PlatformSmbiosDxe.c
>>>>>
>>>>> @@ -866,16 +866,22 @@ MemArrMapInfoUpdateSmbiosType19 (
>>>>> )
>>>>> {
>>>>> EFI_STATUS Status;
>>>>> - UINT32 Base;
>>>>> - UINT32 Size;
>>>>> + UINT32 BoardRevision = 0;
>>>>> - Status = mFwProtocol->GetArmMem (&Base, &Size);
>>>>> + // Note: Type 19 addresses are expressed in KB, not bytes
>
> Comment to add:
>
> // The memory layout used in all known Pi SoC's starts at 0
Thanks, Leif do you mind amending this comment?
Reviewed-by: Philippe Mathieu-Daude <philmd at redhat.com>
>>>>> + mMemArrMapInfoType19.StartingAddress = 0;
>>>>
>>>> Now you assume the ARM base RAM address is always 0, why?
>>>
>>> Because, in the case that is of interest to us here (Broadcom SoCs
>>> used for the various Raspberry Pi platforms), this is what the
>>> documentation says.
>>>
>>> If you look at something like
>>> https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
>>> (which, as per the Pi Foundation, also applies to the later models)
>>> and especially the memory layout graphic that you see early in the
>>> document, you can find that the ARM base RAM address is indeed set to
>>> 0 always.
>>>
>>> At this stage, we have no reason to think that we are going to
>>> contend with a model where the RAM base address isn't 0.
>>
>> OK. I have no idea what are Broadcom plans, I read somewhere they were
>> going to use tricks to allow more than 4GB of RAM on the Raspberry Pi
>> 4, so I was wondering, since they provide a firmware API call to get
>> the RAM base address.
>
> Well the thing is, this patch comes straight from work that is being
> carried out to add support for the Pi 4 to edk2-platforms. So we pretty
> much already validated that 0 is what needs to be used for the Pi 4 as
> well...
OK, good news :)
>> Maybe you can add a comment that we expect all following boards to use
>> RAM base at 0 (simply replying to this email, and eventually Leif
>> would amend it previous to push).
>
> Sure. Comment added above.
Thanks!
> Regards,
>
> /Pete
>
>>
>> Otherwise your patch looks OK.
>>
>> Regards,
>>
>> Phil.
>>
>>>>> + // The minimum RAM size used on any Raspberry Pi model is 256 MB
>>>>> + mMemArrMapInfoType19.EndingAddress = 256 * 1024;
>>>>> + Status = mFwProtocol->GetModelRevision (&BoardRevision);
>>>>> if (Status != EFI_SUCCESS) {
>>>>> - DEBUG ((DEBUG_ERROR, "Couldn't get the ARM memory size: %r\n",
>>>>> Status));
>>>>> + DEBUG ((DEBUG_WARNING, "Couldn't get the board memory size -
>>>>> defaulting to 256 MB: %r\n", Status));
>>>>> } else {
>>>>> - mMemArrMapInfoType19.StartingAddress = Base / 1024;
>>>>> - mMemArrMapInfoType19.EndingAddress = (Base + Size - 1) / 1024;
>>>>> + //
>>>>> www.raspberrypi.org/documentation/hardware/raspberrypi/revision-codes/README.md
>>>>>
>>>>> + // Bits [20-22] indicate the amount of memory starting with
>>>>> 256MB (000b)
>>>>> + // and doubling in size for each value (001b = 512 MB, 010b =
>>>>> 1GB, etc.)
>>>>> + mMemArrMapInfoType19.EndingAddress <<= (BoardRevision >> 20) &
>>>>> 0x07;
>>>>> }
>>>>> + mMemArrMapInfoType19.EndingAddress -= 1;
>>>>> LogSmbiosData ((EFI_SMBIOS_TABLE_HEADER*)&mMemArrMapInfoType19,
>>>>> mMemArrMapInfoType19Strings, NULL);
>>>>> }
>>>>>
>>>>
>>>
>>>
>>>
>>>
>>
>
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