[U-Boot] [RFC PATCH 07/29] drivers: pci-uclass: add support for Enhanced Allocation in Bridges

[Simon Glass]

Hi Suneel,

On Tue, 29 Oct 2019 at 14:08, Suneel Garapati <suneelglinux at gmail.com> wrote:
>
> From: Suneel Garapati <sgarapati at marvell.com>
>
> If Enhanced Allocation capability is present in bridges, use it
> to read the fixed sub-ordinate bus number.
>
> Signed-off-by: Suneel Garapati <sgarapati at marvell.com>
> ---
>  drivers/pci/pci-uclass.c | 25 +++++++++++++++++++------
>  1 file changed, 19 insertions(+), 6 deletions(-)
>

Reviewed-by: Simon Glass <sjg at chromium.org>

> diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
> index f17e83565c..51f7135723 100644
> --- a/drivers/pci/pci-uclass.c
> +++ b/drivers/pci/pci-uclass.c
> @@ -599,10 +599,20 @@ int dm_pci_hose_probe_bus(struct udevice *bus)
>  {
>         int sub_bus;
>         int ret;
> +       int ea_pos;
> +       u8 reg;
>
>         debug("%s\n", __func__);
>
> -       sub_bus = pci_get_bus_max() + 1;
> +       ea_pos = dm_pci_find_capability(bus, PCI_CAP_ID_EA);
> +
> +       if (ea_pos) {
> +               dm_pci_read_config8(bus, ea_pos + sizeof(u32) + sizeof(u8),
> +                                   &reg);
> +               sub_bus = reg;
> +       } else {
> +               sub_bus = pci_get_bus_max() + 1;
> +       }
>         debug("%s: bus = %d/%s\n", __func__, sub_bus, bus->name);
>         dm_pciauto_prescan_setup_bridge(bus, sub_bus);
>
> @@ -612,12 +622,15 @@ int dm_pci_hose_probe_bus(struct udevice *bus)
>                       ret);
>                 return ret;
>         }
> -       if (sub_bus != bus->seq) {
> -               printf("%s: Internal error, bus '%s' got seq %d, expected %d\n",
> -                      __func__, bus->name, bus->seq, sub_bus);
> -               return -EPIPE;
> +
> +       if (!ea_pos) {
> +               if (sub_bus != bus->seq) {
> +                       printf("%s: Internal error, bus '%s' got seq %d, expected %d\n",
> +                              __func__, bus->name, bus->seq, sub_bus);

Can we change to debug() - for code size?

> +                       return -EPIPE;
> +               }
> +               sub_bus = pci_get_bus_max();
>         }
> -       sub_bus = pci_get_bus_max();
>         dm_pciauto_postscan_setup_bridge(bus, sub_bus);
>
>         return sub_bus;
> --
> 2.23.0
>

Regards,
Simon