Re: [PATCH pci] PCI: don't skip probing entire device if first fn OF node has status = "disabled"

Vladimir Oltean
2023-06-02T10:16:35Z

Hi Jianmin,

On Fri, Jun 02, 2023 at 03:36:18PM +0800, Jianmin Lv wrote:
> On 2023/6/2 下午3:21, Liu Peibao wrote:
> > Hi all,
> >
> > It seems that modification for current PCI enumeration framework is
> > needed to solve the problem. If the effect of this modification is not
> > easy to evaluate, for the requirement of Loongson, it should be OK that
> > do the things in Loongson PCI controller driver like discussed
> > before[1].
> >
> > Br,
> > Peibao
> >
> > [1] https://lore.kernel.org/all/20221114074346.23008-1-liupeibao@loongson.cn/
> >
>
> Agree. For current pci core code, all functions of the device will be
> skipped if function 0 is not found, even without the patch 6fffbc7ae137
> (e.g. the func 0 is disabled in bios by setting pci header to 0xffffffff).
> So it seems that there are two ways for the issue:
>
> 1. Adjust the pci scan core code to allow separate function to be
> enumerated, which will affect widely the pci core code.
> 2. Only Adjust loongson pci controller driver as Peibao said, and any
> function of the device should use platform device in DT if function 0 is
> disabled, which is acceptable for loongson.
>
> Thanks,
> Jianmin

How about 3. handle of_device_is_available() in the probe function of
the "loongson, pci-gmac" driver? Would that not work?