[PATCH v2] of: address: Work around missing device_type property in pcie nodes

Marc Zyngier
2020-08-19T09:43:13Z

Recent changes to the DT PCI bus parsing made it mandatory for
device tree nodes describing a PCI controller to have the
'device_type = "pci"' property for the node to be matched.

Although this follows the letter of the specification, it
breaks existing device-trees that have been working fine
for years. Rockchip rk3399-based systems are a prime example
of such collateral damage, and have stopped discovering their
PCI bus.

In order to paper over it, let's add a workaround to the code
matching the device type, and accept as PCI any node that is
named "pcie",

A warning will hopefully nudge the user into updating their
DT to a fixed version if they can, but the incentive is
obviously pretty small.

Fixes: 2f96593ecc37 ("of_address: Add bus type match for pci ranges parser")
Suggested-by: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
drivers/of/address.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 590493e04b01..b37bd9cc2810 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -128,15 +128,29 @@ static unsigned int of_bus_pci_get_flags(const __be32 *addr)
* PCI bus specific translator
*/

+static bool of_node_is_pcie(struct device_node *np)
+{
+ bool is_pcie = of_node_name_eq(np, "pcie");
+
+ if (is_pcie)
+ pr_warn_once("%pOF: Missing device_type\n", np);
+
+ return is_pcie;
+}
+
static int of_bus_pci_match(struct device_node *np)
{
/*
* "pciex" is PCI Express
* "vci" is for the /chaos bridge on 1st-gen PCI powermacs
* "ht" is hypertransport
+ *
+ * If none of the device_type match, and that the node name is
+ * "pcie", accept the device as PCI (with a warning).
*/
return of_node_is_type(np, "pci") || of_node_is_type(np, "pciex") ||
- of_node_is_type(np, "vci") || of_node_is_type(np, "ht");
+ of_node_is_type(np, "vci") || of_node_is_type(np, "ht") ||
+ of_node_is_pcie(np);
}

static void of_bus_pci_count_cells(struct device_node *np,
--
2.27.0