Intel I350 mini-PCIe card (igb) on Mirabox (mvebu / Armada 370)

[Matthew Minter]

That is indeed correct. Those two patches correct the behaviour fully
on my board. I am by no means an expert on this, but could problem 2
be fixed using resource_alignment?  I am a little fuzzy about how
calls to it work but I know the sysfs entry can force the alignment/
size of PCI resources so presumably the kernel already has this
capability? My board is unfortunately unable to diagnose any possible
issues regarding possibly overlapping device windows as it physically
only allows 1 PCIe device at once.

Again, many thanks with your help, that has indeed fixed it for me.

On 8 April 2014 15:43, Thomas Petazzoni
<thomas.petazzoni at free-electrons.com> wrote:
> Willy, Neil, Matthew,
>
> On Tue, 8 Apr 2014 14:36:32 +0200, Willy Tarreau wrote:
>
>> On Tue, Apr 08, 2014 at 01:31:48PM +0100, Matthew Minter wrote:
>> > To add to my previous point, I would consider releasing these patches
>> > as soon as possible as it seems that it can easily cause panics on a
>> > range of boards. Failing that perhaps it is at least worth releasing a
>> > hotfix which will cause PCI probing to fail should the window not be a
>> > power of two? Thus it will fail early with a warning instead of
>> > potentially causing a kernel crash.
>>
>> Have you tested the whole patch or just the one enforcing the power of 2 ?
>> It would be interesting to know if the one with SZ_4M is needed for you or
>> not (I guess not).
>>
>> I suspect that just this single-liner will work as well, as it does for me.
>>
>> Thanks,
>> Willy
>>
>>
>> diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
>> index 0e79665..552ab73 100644
>> --- a/drivers/pci/host/pci-mvebu.c
>> +++ b/drivers/pci/host/pci-mvebu.c
>> @@ -363,6 +363,7 @@ static void mvebu_pcie_handle_membase_change(struct mvebu_pcie_port *port)
>>       port->memwin_size  =
>>               (((port->bridge.memlimit & 0xFFF0) << 16) | 0xFFFFF) -
>>               port->memwin_base;
>> +     port->memwin_size = roundup_pow_of_two(port->memwin_size);
>>
>>       mvebu_mbus_add_window_by_id(port->mem_target, port->mem_attr,
>>                                   port->memwin_base, port->memwin_size);
>
> Thanks to all of you for the investigation. So if I summarize your
> findings, we have two patches needed to fix the problems of everybody:
>
>  1) The bug fix for the MSI teardown function in irq-armada-370-xp.c.
>     This one is easy, I'll test it right now, and give my formal
>     Acked-by soon.
>
>  2) The problem of non-power of 2 sized windows. This one is more
>     complicated, as we cannot simply round up the size of the windows
>     inside the pci-mvebu.c driver: the Linux PCI core is not aware of
>     this rounding, and might therefore allocate a BAR for the next
>     device at an address that overlaps the previous window we have
>     enlarged to match the power of two size requirement. This is
>     something that was already discussed with the PCI maintainers, but
>     the discussion needs to be revived I guess.
>
> Am I correct, or are other patches needed, or are remaining problems
> not solved by these two fixes?
>
> Thomas
> --
> Thomas Petazzoni, CTO, Free Electrons
> Embedded Linux, Kernel and Android engineering
> http://free-electrons.com

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