[PATCH] pci: layerscape: Fix spurious writes and panic

[Heiko Thiery]

Hi Michael, Hi Vladimir,

Am Di., 4. Aug. 2020 um 00:24 Uhr schrieb Vladimir Oltean <olteanv at gmail.com>:
>
> Hi Michael,
>
> On Tue, Aug 04, 2020 at 12:16:33AM +0200, Michael Walle wrote:
> > The fdt_fixup_pcie_ls() scans all PCI devices and assumes that all PCI
> > root devices are layerscape PCIe controllers. Unfortunately, this is not
> > true for the LS1028A. There is one additional static PCI root complex
> > (this contains the networking devices) which has nothing to do with the
> > layerscape PCIe controllers. On recent U-Boot versions this results in
> > the following panic:
> >
> > "Synchronous Abort" handler, esr 0x96000044
> > elr: 000000009602fa04 lr : 000000009602f9f4 (reloc)
> > elr: 00000000fbd73a04 lr : 00000000fbd739f4
> > x0 : 0080000002000101 x1 : 0000000000000000
> > x2 : 00000000fbde9000 x3 : 0000000000000001
> > x4 : 0000000000000000 x5 : 0000000000000030
> > x6 : 00000000fbdbd460 x7 : 00000000fbb3d3a0
> > x8 : 0000000000000002 x9 : 000000000000000c
> > x10: 00000000ffffffe8 x11: 0000000000000006
> > x12: 000000000001869f x13: 0000000000000a2c
> > x14: 00000000fbb3d2cc x15: 00000000ffffffff
> > x16: 0000000000010000 x17: 0000000000000000
> > x18: 00000000fbb3fda0 x19: 0000000000000800
> > x20: 0000000000000000 x21: 00000001f0000000
> > x22: 0000000000000800 x23: 0000000000000009
> > x24: 00000000fbdc3c1b x25: 00000000fbdc28e5
> > x26: 00000000fbdcc008 x27: 00000000fbdc16e2
> > x28: 000000000f000000 x29: 00000000fbb3d3a0
> >
> > Code: 394072a1 f94006a0 34000041 5ac00a94 (b8336814)
> > Resetting CPU ...
> >
> > This bug already existed in former versions, but the spurious write was
> > never trapped, because the destination address was a valid address (by
> > pure luck).
> >
> > Make sure the PCI root is actually one of the expected PCIe layerscape
> > controllers by matching its compatible string.
> >
> > Signed-off-by: Michael Walle <michael at walle.cc>
> > ---
>
> This is equivalent to:
> https://github.com/openil/u-boot/commit/6b5f833381a06503bb5fef3ef933cb62d3175e44
>
> Sorry for not upstreaming it (and a bunch of other patches), I simply
> gave up because the maintainer response time in U-Boot is so slow.
>
> Reviewed-by: Vladimir Oltean <vladimir.oltean at nxp.com>

Tested-by: Heiko Thiery <heiko.thiery at gmail.com>

>
> >  drivers/pci/pcie_layerscape_fixup.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/pci/pcie_layerscape_fixup.c b/drivers/pci/pcie_layerscape_fixup.c
> > index 94de4edaf4..76706487e2 100644
> > --- a/drivers/pci/pcie_layerscape_fixup.c
> > +++ b/drivers/pci/pcie_layerscape_fixup.c
> > @@ -187,6 +187,12 @@ static void fdt_fixup_pcie_ls(void *blob)
> >            pci_find_next_device(&dev)) {
> >               for (bus = dev; device_is_on_pci_bus(bus);)
> >                       bus = bus->parent;
> > +
> > +             /* Only do the fixups for layerscape PCIe controllers */
> > +             if (!device_is_compatible(bus, "fsl,ls-pcie") &&
> > +                 !device_is_compatible(bus, CONFIG_FSL_PCIE_COMPAT))
> > +                     continue;
> > +
> >               pcie_rc = dev_get_priv(bus);
> >
> >               streamid = pcie_next_streamid(pcie_rc->stream_id_cur,
> > --
> > 2.20.1
> >
>
> Thanks,
> -Vladimir

-- 
Heiko