Re: [PATCH RFC 4/7] pci: Add new start_link() & stop_link function ops

[Bartosz Golaszewski]

On Wed, Jun 26, 2024 at 2:38 PM Krishna chaitanya chundru
<quic_krichai@xxxxxxxxxxx> wrote:
>
> Certain devices like QPS615 which uses PCI pwrctl framework
> needs to stop link training before configuring the PCIe device.
>
> As controller driver already enables link training, we need to
> stop the link training by using stop_link and enable them back after
> device is configured by using start_link.
>
> The stop_link() & start_link() be used to keep the link in D3cold &
> D0 before turning off the power of the device.
>
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@xxxxxxxxxxx>
> ---
>  include/linux/pci.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index fb004fd4e889..3892ff7fd536 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -803,6 +803,8 @@ struct pci_ops {
>         void __iomem *(*map_bus)(struct pci_bus *bus, unsigned int devfn, int where);
>         int (*read)(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val);
>         int (*write)(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val);
> +       int (*start_link)(struct pci_bus *bus);
> +       int (*stop_link)(struct pci_bus *bus);
>  };
>

IMO stop_link() should return void.

Bart