Hi Stefano, > On 9 Feb 2021, at 19:53, Stefano Stabellini <sstabell...@kernel.org> wrote: > > 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++aa...@mattapan.m5p.com/ > Signed-off-by: Stefano Stabellini <stefano.stabell...@xilinx.com> With the type, spaces and tab fixes already found:
Reviewed-by: Bertrand Marquis <bertrand.marq...@arm.com> Thanks the commit message is more clear :-) Cheers Bertrand > --- > Changes in v2: > - improve commit message > > diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c > index 18825e333e..f1a96a3b90 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_t 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, >