Re: [PATCH v3 0/4] DT schema changes for HiKey970 PCIe hardware to work
From: Mauro Carvalho Chehab
Date: Thu Aug 05 2021 - 03:58:56 EST
Em Thu, 5 Aug 2021 09:46:12 +0200
Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> escreveu:
> Em Wed, 4 Aug 2021 10:28:53 -0600
> Rob Herring <robh@xxxxxxxxxx> escreveu:
>
> > On Wed, Aug 04, 2021 at 08:50:45AM +0200, Mauro Carvalho Chehab wrote:
> > > Em Tue, 3 Aug 2021 16:11:42 -0600
> > > Rob Herring <robh+dt@xxxxxxxxxx> escreveu:
> > >
> > > > On Mon, Aug 2, 2021 at 10:39 PM Mauro Carvalho Chehab
> > > > <mchehab+huawei@xxxxxxxxxx> wrote:
> > > > >
> > > > > Hi Rob,
> > > > >
> > > > > That's the third version of the DT bindings for Kirin 970 PCIE and its
> > > > > corresponding PHY.
> > > > >
> > > > > It is identical to v2, except by:
> > > > > - pcie@7,0 { // Lane 7: Ethernet
> > > > > + pcie@7,0 { // Lane 6: Ethernet
> > > >
> > > > Can you check whether you have DT node links in sysfs for the PCI
> > > > devices? If you don't, then something is wrong still in the topology
> > > > or the PCI core is failing to set the DT node pointer in struct
> > > > device. Though you don't rely on that currently, we want the topology
> > > > to match. It's possible this never worked on arm/arm64 as mainly
> > > > powerpc relied on this.
> > > >
> > > > I'd like some way to validate the DT matches the PCI topology. We
> > > > could have a tool that generates the DT structure based on the PCI
> > > > topology.
> > >
> > > The of_node node link is on those places:
> > >
> > > $ find /sys/devices/platform/soc/f4000000.pcie/ -name of_node
> > > /sys/devices/platform/soc/f4000000.pcie/of_node
> > > /sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/of_node
> > > /sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/pci_bus/0000:01/of_node
> > > /sys/devices/platform/soc/f4000000.pcie/pci0000:00/pci_bus/0000:00/of_node
> >
> > Looks like we're missing some...
> >
> > It's not immediately obvious to me what's wrong here. Only the root
> > bus is getting it's DT node set. The relevant code is pci_scan_device(),
> > pci_set_of_node() and pci_set_bus_of_node(). Give me a few days to try
> > to reproduce and debug it.
>
> I added a printk on both pci_set_*of_node() functions:
>
> [ 4.872991] (null): pci_set_bus_of_node: of_node: /soc/pcie@f4000000
> [ 4.913806] (null): pci_set_of_node: of_node: /soc/pcie@f4000000
> [ 4.978102] pci_bus 0000:01: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
> [ 4.990622] (null): pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
> [ 5.052383] pci_bus 0000:02: pci_set_bus_of_node: of_node: (null)
> [ 5.059263] (null): pci_set_of_node: of_node: (null)
> [ 5.085552] (null): pci_set_of_node: of_node: (null)
> [ 5.112073] (null): pci_set_of_node: of_node: (null)
> [ 5.138320] (null): pci_set_of_node: of_node: (null)
> [ 5.164673] (null): pci_set_of_node: of_node: (null)
> [ 5.233759] pci_bus 0000:03: pci_set_bus_of_node: of_node: (null)
> [ 5.240539] (null): pci_set_of_node: of_node: (null)
> [ 5.310545] pci_bus 0000:04: pci_set_bus_of_node: of_node: (null)
> [ 5.324719] pci_bus 0000:05: pci_set_bus_of_node: of_node: (null)
> [ 5.338914] pci_bus 0000:06: pci_set_bus_of_node: of_node: (null)
> [ 5.345516] (null): pci_set_of_node: of_node: (null)
> [ 5.415795] pci_bus 0000:07: pci_set_bus_of_node: of_node: (null)
The enclosed patch makes the above a clearer:
[ 4.800975] (null): pci_set_bus_of_node: of_node: /soc/pcie@f4000000
[ 4.855983] pci 0000:00:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000
[ 4.879169] pci_bus 0000:01: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
[ 4.900602] pci 0000:01:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
[ 4.953086] pci_bus 0000:02: pci_set_bus_of_node: of_node: (null)
[ 4.968821] pci 0000:02:01.0: pci_set_of_node: of_node: (null)
[ 5.003538] pci 0000:02:04.0: pci_set_of_node: of_node: (null)
[ 5.041348] pci 0000:02:05.0: pci_set_of_node: of_node: (null)
[ 5.092770] pci 0000:02:07.0: pci_set_of_node: of_node: (null)
[ 5.118298] pci 0000:02:09.0: pci_set_of_node: of_node: (null)
[ 5.178215] pci_bus 0000:03: pci_set_bus_of_node: of_node: (null)
[ 5.198433] pci 0000:03:00.0: pci_set_of_node: of_node: (null)
[ 5.233330] pci_bus 0000:04: pci_set_bus_of_node: of_node: (null)
[ 5.247071] pci_bus 0000:05: pci_set_bus_of_node: of_node: (null)
[ 5.260898] pci_bus 0000:06: pci_set_bus_of_node: of_node: (null)
[ 5.293764] pci 0000:06:00.0: pci_set_of_node: of_node: (null)
[ 5.332808] pci_bus 0000:07: pci_set_bus_of_node: of_node: (null)
>
> It sounds that the parent is missing when pci_set_bus_of_node() is
> called on some places. I'll try to identify why.
>
> Thanks,
> Mauro
Thanks,
Mauro
[PATCH] pci: setup PCI before setting the OF node
With this change, it is easier to add a debug printk at
pci_set_of_node() in order to address possible issues.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 79177ac37880..c5dfc1afb1d3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2374,15 +2374,14 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
dev->vendor = l & 0xffff;
dev->device = (l >> 16) & 0xffff;
- pci_set_of_node(dev);
-
if (pci_setup_device(dev)) {
- pci_release_of_node(dev);
pci_bus_put(dev->bus);
kfree(dev);
return NULL;
}
+ pci_set_of_node(dev);
+
return dev;
}