[PATCH 0/3] Fix handling of multi-level OF nodes

[PATCH 0/3] Fix handling of multi-level OF nodes

[Mauro Carvalho Chehab]

Hi Rob,

This series address the issues related to not add all of_node data at sysfs.

Patch 1 is the real fix.
Patch 2 just changes the order of init, in order to allow printing what's
happening when registering a device;
Patch 3 is just debug.

With patch 1 applied, the sysfs nodes seem to match the PCI configuration:

$ 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/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:07.0/of_node
/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:07.0/pci_bus/0000:06/of_node
/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/pci_bus/0000:02/of_node
/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:05.0/of_node
/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:05.0/pci_bus/0000:05/of_node
/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:01.0/of_node
/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:01.0/pci_bus/0000:03/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

Mauro Carvalho Chehab (3):
  PCI: of: Fix handling of multi-level PCI devices
  PCI: of: Setup PCI before setting the OF node
  PCI: of: Add some debug printks to track problems with of_node setup

 drivers/pci/of.c    | 9 +++++++++
 drivers/pci/probe.c | 5 ++---
 2 files changed, 11 insertions(+), 3 deletions(-)

-- 
2.31.1

[PATCH 1/3] PCI: of: Fix handling of multi-level PCI devices

[Mauro Carvalho Chehab]

When the DT schema is like:

	pcie@f4000000 {
		pcie@0,0 {
			pcie@1,0 {
			};
			pcie@5,0 {
			};
			pcie@7,0 {
			};
		};
	};

The logic under pci_set_bus_of_node() will try to setup some
buses with a NULL node, causing it to register just a small
set of devices:

	$ 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

On such case, it needs to go to the parent node, in order to register
everything:

	$ 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/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:07.0/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:07.0/pci_bus/0000:06/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/pci_bus/0000:02/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:05.0/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:05.0/pci_bus/0000:05/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:01.0/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:01.0/pci_bus/0000:03/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

Adding some debug prints with such change will produce the following
output:

	$ dmesg|grep of_node
	[    4.932405]  (null): pci_set_bus_of_node: of_node: /soc/pcie@f4000000
	[    4.985916] pci 0000:00:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000
	[    5.014190] pci_bus 0000:01: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
	[    5.065680] pci 0000:01:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
	[    5.118754] pci_bus 0000:02: pci_set_bus_of_node: use of_node of the parent
	[    5.135279] pci_bus 0000:02: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
	[    5.158921] pci 0000:02:01.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
	[    5.187393] pci 0000:02:04.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
	[    5.215982] pci 0000:02:05.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
	[    5.244607] pci 0000:02:07.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
	[    5.272825] pci 0000:02:09.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
	[    5.335258] pci_bus 0000:03: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@1,0
	[    5.367538] pci 0000:03:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@1,0
	[    5.415959] pci_bus 0000:04: pci_set_bus_of_node: use of_node of the parent
	[    5.424190] pci_bus 0000:04: pci_set_bus_of_node: of_node: (null)
	[    5.438727] pci_bus 0000:05: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@5,0
	[    5.455691] pci_bus 0000:06: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@7,0
	[    5.491643] pci 0000:06:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@7,0
	[    5.526157] pci_bus 0000:07: pci_set_bus_of_node: use of_node of the parent
	[    5.534361] pci_bus 0000:07: pci_set_bus_of_node: of_node: (null)

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 drivers/pci/of.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index a143b02b2dcd..b6fa3bd46ae6 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -41,6 +41,8 @@ void pci_set_bus_of_node(struct pci_bus *bus)
 		node = pcibios_get_phb_of_node(bus);
 	} else {
 		node = of_node_get(bus->self->dev.of_node);
+		if (!node)
+			node = of_node_get(bus->self->dev.parent->of_node);
 		if (node && of_property_read_bool(node, "external-facing"))
 			bus->self->external_facing = true;
 	}
-- 
2.31.1

Re: [PATCH 1/3] PCI: of: Fix handling of multi-level PCI devices

[Bjorn Helgaas]

On Thu, Aug 05, 2021 at 10:28:58AM +0200, Mauro Carvalho Chehab wrote:

> 	$ dmesg|grep of_node

Adding "|cut -b16-" or so would make this more readable.  Could also
indent by two spaces instead of a tab if that would help.

> 	[    4.932405]  (null): pci_set_bus_of_node: of_node: /soc/pcie@f4000000
> 	[    4.985916] pci 0000:00:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000

[PATCH 2/3] PCI: of: Setup PCI before setting the OF node

[Mauro Carvalho Chehab]

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@kernel.org>
---
 drivers/pci/probe.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

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;
 }
 
-- 
2.31.1

[PATCH 3/3] PCI: of: Add some debug printks to track problems with of_node setup

[Mauro Carvalho Chehab]

In order to be able to identify why some of_nodes are not created,
we need to add some debug prints.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 drivers/pci/of.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index b6fa3bd46ae6..7b8c2b87eb25 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -18,6 +18,9 @@
 #ifdef CONFIG_PCI
 void pci_set_of_node(struct pci_dev *dev)
 {
+	dev_dbg(&dev->dev, "%s: of_node: %pOF\n",
+		__func__, dev->bus->dev.of_node);
+
 	if (!dev->bus->dev.of_node)
 		return;
 	dev->dev.of_node = of_pci_find_child_device(dev->bus->dev.of_node,
@@ -41,12 +44,16 @@ void pci_set_bus_of_node(struct pci_bus *bus)
 		node = pcibios_get_phb_of_node(bus);
 	} else {
 		node = of_node_get(bus->self->dev.of_node);
-		if (!node)
+		if (!node) {
 			node = of_node_get(bus->self->dev.parent->of_node);
+			dev_dbg(&bus->dev, "%s: use of_node of the parent",
+				__func__);
+		}
 		if (node && of_property_read_bool(node, "external-facing"))
 			bus->self->external_facing = true;
 	}
 
+	dev_dbg(&bus->dev, "%s: of_node: %pOF\n", __func__, node);
 	bus->dev.of_node = node;
 
 	if (bus->dev.of_node)
-- 
2.31.1