path: root/drivers
diff options
authorTomasz Nowicki <tn@semihalf.com>2016-05-30 17:14:18 +0200
committerGraeme Gregory <graeme.gregory@linaro.org>2016-06-07 14:09:23 +0100
commitece9f05d9cf55494c7bf5d233ed986767d8f37ce (patch)
tree6813e628e323bc642b03583a7c9a28cfcb6b2aa0 /drivers
parentc14326bc2da4d600935969fc2ced6df6ec47f13f (diff)
pci, acpi: add acpi hook to assign domain number.
PCI core code provides a config option (CONFIG_PCI_DOMAINS_GENERIC) that allows assigning the PCI bus domain number generically by relying on device tree bindings, and falling back to a simple counter when the respective DT properties (ie "linux,pci-domain") are not specified in the host bridge device tree node. In a similar way, when a system is booted through ACPI, architectures that are selecting CONFIG_PCI_DOMAINS_GENERIC (ie ARM64) require kernel hooks to retrieve the domain number so that the PCI bus domain number set-up can be handled seamlessly with DT and ACPI in generic core code when CONFIG_PCI_DOMAINS_GENERIC is selected. Since currently it is not possible to retrieve a pointer to the PCI host bridge ACPI device backing the host bridge from core PCI code (which would allow retrieving the domain number in an arch agnostic way through the ACPI _SEG method), an arch specific ACPI hook has to be declared and implemented by all arches that rely on CONFIG_PCI_DOMAINS_GENERIC to retrieve the domain number and set it up in core PCI code. For the aforementioned reasons, this patch introduces a dummy acpi_pci_bus_domain_nr() hook in preparation for per-arch implementation of the same to retrieve the domain number on a per-arch basis when the system boots through ACPI. For the sake of code clarity the current code implementing generic domain number assignment (ie pci_bus_assign_domain_nr(), selected by CONFIG_PCI_DOMAINS_GENERIC) is reshuffled so that the code implementing the DT domain assignment function is stubbed out into a corresponding helper, so that DT and ACPI functions are clearly separated in preparation for arches acpi_pci_bus_domain_nr() implementations. Signed-off-by: Tomasz Nowicki <tn@semihalf.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Diffstat (limited to 'drivers')
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index eb431b5c3685..2b52178a11c9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -7,6 +7,7 @@
* Copyright 1997 -- 2000 Martin Mares <mj@ucw.cz>
+#include <linux/acpi.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/init.h>
@@ -4941,7 +4942,7 @@ int pci_get_new_domain_nr(void)
-void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
+static int of_pci_bus_domain_nr(struct device *parent)
static int use_dt_domains = -1;
int domain = -1;
@@ -4985,7 +4986,13 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
domain = -1;
- bus->domain_nr = domain;
+ return domain;
+void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
+ bus->domain_nr = acpi_disabled ? of_pci_bus_domain_nr(parent) :
+ acpi_pci_bus_domain_nr(bus);