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

[Simon Glass]

On 19 July 2015 at 19:59, Simon Glass <sjg at chromium.org> wrote:
> 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>

Applied to u-boot-x86, thanks!