On Tue, Jul 23, 2019 at 12:27:11PM +0300, Jonathan Chocron wrote:
> This basically aligns the usage of PCI_PROBE_ONLY and
> PCI_REASSIGN_ALL_BUS in dw_pcie_host_init() with the logic in
> pci_host_common_probe().
> 
> Now it will be possible to control via the devicetree whether to just
> probe the PCI bus (in cases where FW already configured it) or to fully
> configure it.
> 
> Signed-off-by: Jonathan Chocron <jon...@amazon.com>
> ---
>  .../pci/controller/dwc/pcie-designware-host.c | 23 +++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c 
> b/drivers/pci/controller/dwc/pcie-designware-host.c
> index d2ca748e4c85..0a294d8aa21a 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -342,6 +342,8 @@ int dw_pcie_host_init(struct pcie_port *pp)
>       if (!bridge)
>               return -ENOMEM;
>  
> +     of_pci_check_probe_only();
> +
>       ret = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff,
>                                       &bridge->windows, &pp->io_base);
>       if (ret)
> @@ -474,6 +476,10 @@ int dw_pcie_host_init(struct pcie_port *pp)
>  
>       pp->root_bus_nr = pp->busn->start;
>  
> +     /* Do not reassign bus nums if probe only */
> +     if (!pci_has_flag(PCI_PROBE_ONLY))
> +             pci_add_flags(PCI_REASSIGN_ALL_BUS);

This changes the default for bus reassignment on all DWC host (that are
!PCI_PROBE_ONLY), we should drop this line, it can trigger regressions.

If we still want to merge it as a separate change we must test it on all
DWC host bridges to make sure it does not trigger any issues with
current set-ups, that's not going to be easy though.

Lorenzo

> +
>       bridge->dev.parent = dev;
>       bridge->sysdata = pp;
>       bridge->busnr = pp->root_bus_nr;
> @@ -490,11 +496,20 @@ int dw_pcie_host_init(struct pcie_port *pp)
>       if (pp->ops->scan_bus)
>               pp->ops->scan_bus(pp);
>  
> -     pci_bus_size_bridges(pp->root_bus);
> -     pci_bus_assign_resources(pp->root_bus);
> +     /*
> +      * We insert PCI resources into the iomem_resource and
> +      * ioport_resource trees in either pci_bus_claim_resources()
> +      * or pci_bus_assign_resources().
> +      */
> +     if (pci_has_flag(PCI_PROBE_ONLY)) {
> +             pci_bus_claim_resources(pp->root_bus);
> +     } else {
> +             pci_bus_size_bridges(pp->root_bus);
> +             pci_bus_assign_resources(pp->root_bus);
>  
> -     list_for_each_entry(child, &pp->root_bus->children, node)
> -             pcie_bus_configure_settings(child);
> +             list_for_each_entry(child, &pp->root_bus->children, node)
> +                     pcie_bus_configure_settings(child);
> +     }
>  
>       pci_bus_add_devices(pp->root_bus);
>       return 0;
> -- 
> 2.17.1
> 

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