[U-Boot] [PATCH 1/3] pci: Add error values definitions from the kernel

[Marek Vasut]

On Friday, January 08, 2016 at 01:31:17 AM, Bin Meng wrote:
> On Fri, Jan 8, 2016 at 8:15 AM, Fabio Estevam <festevam at gmail.com> wrote:
> > On Thu, Jan 7, 2016 at 10:02 PM, Bin Meng <bmeng.cn at gmail.com> wrote:
> >> What new feature would benefit from this? These two PCIe drivers are
> >> non-DM drivers and DM PCI is not utilizing those error codes, instead
> >> DM PCI is using U-Boot standard error codes.
> > 
> > but what prevents DM PCI to use the kernel error codes in the future?
> > 
> > Returning PCIBIOS_DEVICE_NOT_FOUND when the config is invalid is a
> > common pattern in the kernel.
> > 
> > Take a look at these drivers:
> > 
> > drivers/pci/access.c
> > drivers/pci/host/pci-mvebu.c
> > drivers/pci/host/pci-xgene.c
> > drivers/pci/host/pcie-altera.c
> > drivers/pci/host/pcie-designware.c
> > drivers/pci/host/pcie-rcar.c
> > drivers/pci/xen-pcifront.c
> > 
> > I don't see why we can't do the same in U-boot.
> 
> I am sorry but this does not convince me. Kernel is using these codes,
> but I don't see any PCI library codes in kernel that actually parses
> these error codes.
> 
> > Feel free to submit a patch with your proposal and the maintainer can
> > then decide which one is more adequate for U-boot.
> 
> My points are:
> 1). These two drivers are non-DM drivers. We should start converting
> them to DM drivers first instead of adding new stuff which is only
> used by legacy drivers. I have pcie_layerscape on my TODO list.

This point is invalid, I see this patch series is just fixing bugs and
converting drivers to DM is _far_ beyond the scope of this series.

> 2). We should stick to the correct behavior. The PCIe controller is
> buggy that it cannot return 0xFFFFFFFF by hardware, like other
> controllers do. IMHO it's completely a horrible controller, that
> comments in ls_pcie_addr_valid() says: "Controller does not support
> multi-function in RC mode".

Can you elaborate on why do you think it is a horrible controller ?
Most of the controllers I saw used on ARM were this way.

> 3). If we want to align with kernel, I want to see a plan of at least
> adopting these error codes in DM PCI. This is something which is not
> clear for now.

No, this is again far beyond the scope of this series. I want PCI on iMX
and LS to work in the current release, period. So from my side, I want
these patches to go in.

> Simon, what's your opinion on this?
> 
> Regards,
> Bin

Best regards,
Marek Vasut