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From 5a4087004d1adbbb223925f3306db0e5824a2bdc Mon Sep 17 00:00:00 2001
From: Stefano Stabellini <sstabellini@kernel.org>
Date: Tue, 9 Feb 2021 11:53:34 -0800
Subject: [PATCH] xen: workaround missing device_type property in pci/pcie
nodes
PCI buses differ from default buses in a few important ways, so it is
important to detect them properly. Normally, PCI buses are expected to
have the following property:
device_type = "pci"
In reality, it is not always the case. To handle PCI bus nodes that
don't have the device_type property, also consider the node name: if the
node name is "pcie" or "pci" then consider the bus as a PCI bus.
This commit is based on the Linux kernel commit
d1ac0002dd29 "of: address: Work around missing device_type property in
pcie nodes".
This fixes Xen boot on RPi4. Some RPi4 kernels have the following node
on their device trees:
&pcie0 {
pci@1,0 {
#address-cells = <3>;
#size-cells = <2>;
ranges;
reg = <0 0 0 0 0>;
usb@1,0 {
reg = <0x10000 0 0 0 0>;
resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
};
};
};
The pci@1,0 node is a PCI bus. If we parse the node and its children as
a default bus, the reg property under usb@1,0 would have to be
interpreted as an address range mappable by the CPU, which is not the
case and would break.
Link: https://lore.kernel.org/xen-devel/YBmQQ3Tzu++AadKx@mattapan.m5p.com/
[fix style on commit]
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Tested-by: Elliott Mitchell <ehem+xen@m5p.com>
Tested-by: Jukka Kaartinen <jukka.kaartinen@unikie.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
---
xen/common/device_tree.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 18825e333e..03d25a81ce 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -563,14 +563,28 @@ static unsigned int dt_bus_default_get_flags(const __be32 *addr)
* PCI bus specific translator
*/
+static bool dt_node_is_pci(const struct dt_device_node *np)
+{
+ bool is_pci = !strcmp(np->name, "pcie") || !strcmp(np->name, "pci");
+
+ if ( is_pci )
+ printk(XENLOG_WARNING "%s: Missing device_type\n", np->full_name);
+
+ return is_pci;
+}
+
static bool_t dt_bus_pci_match(const struct dt_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" or "pci", accept the device as PCI (with a warning).
*/
return !strcmp(np->type, "pci") || !strcmp(np->type, "pciex") ||
- !strcmp(np->type, "vci") || !strcmp(np->type, "ht");
+ !strcmp(np->type, "vci") || !strcmp(np->type, "ht") ||
+ dt_node_is_pci(np);
}
static void dt_bus_pci_count_cells(const struct dt_device_node *np,
--
2.25.1
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