Re: ARM: ixp4xx regression (bisected) since v3.5-rc1

[Brad Parker]

On Sat, Feb 23, 2013 at 4:49 AM, Russell King - ARM Linux
<linux@xxxxxxxxxxxxxxxx> wrote:
> On Sat, Feb 23, 2013 at 01:30:57AM -0500, Brad Parker wrote:
>> I then reversed this commit on 3.7.9 and the board booted
>> successfully. I'm not sure if this affects other boards of the same
>> arch or not, I only have access to a Pronghorn which also requires a
>> patch for the board files as they are not part of mainline.
>
> So it's an externally maintained board which breaks because of changes
> made in mainline?  Likely, it's not been updated for the mainline changes
> correctly.  *Sigh* unmerged external platform support sucks.
>
> What the commit you refer to above does is change the core code to do
> this:
>
> +                       if (hw->scan)
> +                               sys->bus = hw->scan(nr, sys);
> +                       else
> +                               sys->bus = pci_scan_root_bus(NULL, sys->busnr,
> +                                               hw->ops, sys, &sys->resources);
>
> then changes each of the IXP4xx board files:
>
> +       .ops            = &ixp4xx_ops,
> -       .scan           = ixp4xx_scan_bus,
>
> and removes this:
>
> -struct pci_bus * __devinit ixp4xx_scan_bus(int nr, struct pci_sys_data *sys)
> -{
> -       return pci_scan_root_bus(NULL, sys->busnr, &ixp4xx_ops, sys,
> -                                &sys->resources);
> -}
>
> What you will notice is that when .scan = NULL, and .ops = &ixp4xx_ops,
> the code is exactly identical.
>
> So, I doubt this is a regression with the mainline kernel, but is brought
> about by the non-visibility of your platforms code to mainline... I think
> your platform code needs updating appropriately.

You're right. I just forgot to add .ops, now it works without
reverting your commit. I think the patch could be merged in if someone
were willing to clean it up, I just don't really have the time. ADI
originally wrote the patch themselves for 2.6.26 and they claim that
it was included in 2.6.27 upstream, if that's true I assume it has
been removed at some point in the past. OpenWRT also maintains a
similar patch to get the board running on 3.3. I think the only thing
necessary to get it to 3.7/3.8 is remove .swizzle/.scan and add .ops.
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