Re: [PATCH v2 3/4] PCI: brcmstb: Wait for Raspberry Pi's firmware when present

[Florian Fainelli]

On 2/20/2020 10:14 AM, Nicolas Saenz Julienne wrote:
> On Wed, 2020-02-19 at 11:21 -0800, Florian Fainelli wrote:
>> On 2/19/20 4:39 AM, Nicolas Saenz Julienne wrote:
>>> xHCI's PCI fixup, run at the end of pcie-brcmstb's probe, depends on
>>> RPi4's VideoCore firmware interface to be up and running. It's possible
>>> for both initializations to race, so make sure it's available prior
>>> starting.
>>>
>>> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
>>
>> Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
>>
>> It does not look like there is something making sure that
>> CONFIG_RASPBERRYPI_FIRMWARE is being selected or depended on, should we
>> have a "default XHCI_PCI" added to drivers/firmware/Kconfig?
> 
> I think having that would enable the firmware interface for all XHCI_PCI users,
> which isn't ideal. The firmware call has stubs for the case the firmware
> interace isn't compiled, so no problem there. Ultimately we want to enable
> CONFIG_RASPBERRYPI_FIRMWARE only when the built image targets the RPi4
> (reglardless of being arm64/arm32). But I don't think that's feasible.

It would enable the driver, which is only functional if the matching
Device Tree node is present, that seems like a reasonable price to pay
for a multiplatform kernel. After all, this is a functional dependency
for the Pi4.
-- 
Florian