[U-Boot] [PATCH 5/6] dm: pci: Support bridge device configuration correctly

[Simon Glass]

On 18 July 2015 at 10:20, Bin Meng <bmeng.cn at gmail.com> wrote:
> Commit aec241d "dm: pci: Use the correct hose when configuring devices"
> was an attempt to fix pci bridge device configuration, but unfortunately
> that does not work 100%. In pciauto_config_devices(), the fix tried to
> call pciauto_config_device() with a ctlr_hose which is supposed to be
> the root controller hose, however when walking through a pci topology
> with 2 or more pci bridges this logic simply fails.
>
> The call chain is: pciauto_config_devices()->pciauto_config_device()
> ->dm_pci_hose_probe_bus(). Here the call to dm_pci_hose_probe_bus()
> does not make any sense as the given hose is not the bridge device's
> hose, instead it is either the root controller's hose (case#1: if it
> is the 2nd pci bridge), or the bridge's parent bridge's hose (case#2:
> if it is the 3rd pci bridge). In both cases the logic is wrong.
>
> For example, for failing case#1 if the bridge device to config has the
> same devfn as one of the devices under the root controller, the call
> to pci_bus_find_devfn() will return the udevice of that pci device
> under the root controller as the bus, but this is wrong as the udevice
> is not a bus which does not contain all the necessary bits associated
> with the udevice which causes further failures.
>
> To correctly support pci bridge device configuration, we should still
> call pciauto_config_device() with the pci bridge's hose directly.
> In order to access valid pci region information, we need to refer to
> the root controller simply by a call to pci_bus_to_hose(0) and get the
> region information there in the pciauto_prescan_setup_bridge(),
> pciauto_postscan_setup_bridge() and pciauto_config_device().
>
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> ---
>
>  drivers/pci/pci-uclass.c |  6 +----
>  drivers/pci/pci_auto.c   | 66 +++++++++++++++++++++++++++++++++++++++---------
>  drivers/pci/pci_common.c |  7 ++++-
>  3 files changed, 61 insertions(+), 18 deletions(-)

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