[PATCH] pci: Add support for generic domain_nr in pci_bus

[Catalin Marinas]

This patch adds domain_nr in struct pci_bus if
CONFIG_PCI_DOMAINS_GENERIC is enabled. The default implementation for
pci_domain_nr() simply returns bus->domain_nr. For the root bus, the
core PCI code calls pci_set_domain_nr(bus, parent_device) while the
child buses inherit the domain nr of the parent bus.

This patch also adds an of_pci_set_domain_nr() implementation which
parses the device tree for the "pci-domain" property or sets domain_nr
to the next available value (this function could also be implemented
entirely in arm64).

Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
---
 arch/arm64/Kconfig           |  3 +++
 arch/arm64/include/asm/pci.h | 10 ----------
 arch/arm64/kernel/pci.c      |  5 +++++
 drivers/of/of_pci.c          | 20 +++++++++++++-------
 drivers/pci/probe.c          | 11 ++++++++---
 include/linux/of_pci.h       |  5 +++++
 include/linux/pci.h          | 15 +++++++++++++++
 7 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 48ed631adde2..2c884f7453ba 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -160,6 +160,9 @@ config PCI
 config PCI_DOMAINS
 	def_bool PCI
 
+config PCI_DOMAINS_GENERIC
+	def_bool PCI
+
 config PCI_SYSCALL
 	def_bool PCI
 
diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h
index 3f7856e92d66..4f091a5135b7 100644
--- a/arch/arm64/include/asm/pci.h
+++ b/arch/arm64/include/asm/pci.h
@@ -29,16 +29,6 @@ struct pci_host_bridge *find_pci_host_bridge(struct pci_bus *bus);
 extern int isa_dma_bridge_buggy;
 
 #ifdef CONFIG_PCI
-static inline int pci_domain_nr(struct pci_bus *bus)
-{
-	struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
-
-	if (bridge)
-		return bridge->domain_nr;
-
-	return 0;
-}
-
 static inline int pci_proc_domain(struct pci_bus *bus)
 {
 	return 1;
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index 955d6d1cb011..d5ed1afb0d88 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -36,3 +36,8 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
 {
 	return res->start;
 }
+
+void pci_set_domain_nr(struct pci_bus *bus, struct device *parent)
+{
+	of_pci_set_domain_nr(bus, parent);
+}
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index e81402af5cde..54f06b748bf1 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -175,7 +175,7 @@ static atomic_t domain_nr = ATOMIC_INIT(-1);
 struct pci_host_bridge *
 of_create_pci_host_bridge(struct device *parent, struct pci_ops *ops, void *host_data)
 {
-	int err, domain, busno;
+	int err, busno;
 	struct resource *bus_range;
 	struct pci_bus *root_bus;
 	struct pci_host_bridge *bridge;
@@ -186,10 +186,6 @@ of_create_pci_host_bridge(struct device *parent, struct pci_ops *ops, void *host
 	if (!bus_range)
 		return ERR_PTR(-ENOMEM);
 
-	domain = of_alias_get_id(parent->of_node, "pci-domain");
-	if (domain == -ENODEV)
-		domain = atomic_inc_return(&domain_nr);
-
 	err = of_pci_parse_bus_range(parent->of_node, bus_range);
 	if (err) {
 		dev_info(parent, "No bus range for %s, using default [0-255]\n",
@@ -207,8 +203,7 @@ of_create_pci_host_bridge(struct device *parent, struct pci_ops *ops, void *host
 		goto err_create;
 
 	/* then create the root bus */
-	root_bus = pci_create_root_bus_in_domain(parent, domain, busno,
-						ops, host_data, &res);
+	root_bus = pci_create_root_bus(parent, busno, ops, host_data, &res);
 	if (IS_ERR(root_bus)) {
 		err = PTR_ERR(root_bus);
 		goto err_create;
@@ -225,6 +220,17 @@ err_create:
 }
 EXPORT_SYMBOL_GPL(of_create_pci_host_bridge);
 
+void of_pci_set_domain_nr(struct pci_bus *bus, struct device *parent)
+{
+	int domain;
+
+	domain = of_alias_get_id(parent->of_node, "pci-domain");
+	if (domain == -ENODEV)
+		domain = atomic_inc_return(&domain_nr);
+
+	bus->domain_nr = domain;
+}
+
 #ifdef CONFIG_PCI_MSI
 
 static LIST_HEAD(of_pci_msi_chip_list);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 2c9266237edc..aa30a9e8915d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -485,7 +485,7 @@ void pci_read_bridge_bases(struct pci_bus *child)
 	}
 }
 
-static struct pci_bus *pci_alloc_bus(void)
+static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
 {
 	struct pci_bus *b;
 
@@ -500,6 +500,10 @@ static struct pci_bus *pci_alloc_bus(void)
 	INIT_LIST_HEAD(&b->resources);
 	b->max_bus_speed = PCI_SPEED_UNKNOWN;
 	b->cur_bus_speed = PCI_SPEED_UNKNOWN;
+#ifdef CONFIG_PCI_DOMAINS_GENERIC
+	if (parent)
+		b->domain_nr = parent->domain_nr;
+#endif
 	return b;
 }
 
@@ -670,7 +674,7 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
 	/*
 	 * Allocate a new bus, and inherit stuff from the parent..
 	 */
-	child = pci_alloc_bus();
+	child = pci_alloc_bus(parent);
 	if (!child)
 		return NULL;
 
@@ -1767,13 +1771,14 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 	bridge->dev.parent = parent;
 	bridge->dev.release = pci_release_host_bridge_dev;
 
-	b = pci_alloc_bus();
+	b = pci_alloc_bus(NULL);
 	if (!b)
 		goto err_out;
 
 	b->sysdata = sysdata;
 	b->ops = ops;
 	b->number = b->busn_res.start = bus;
+	pci_set_domain_nr(b, parent);
 	b2 = pci_find_bus(pci_domain_nr(b), bus);
 	if (b2) {
 		/* If we already got to this bus through a different bridge, ignore it */
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index 71e36d091db2..af16ac40c7a2 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -17,6 +17,7 @@ int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
 int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
 struct pci_host_bridge *of_create_pci_host_bridge(struct device *parent,
 					struct pci_ops *ops, void *host_data);
+void of_pci_set_domain_nr(struct pci_bus *bus, struct device *parent);
 
 #else
 static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
@@ -53,6 +54,10 @@ of_create_pci_host_bridge(struct device *parent, struct pci_ops *ops,
 {
 	return NULL;
 }
+
+static inline void of_pci_set_domain_nr(struct pci_bus *bus, struct device *parent)
+{
+}
 #endif
 
 #if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d32b4ed1f411..9113f62c5038 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -457,6 +457,9 @@ struct pci_bus {
 	unsigned char	primary;	/* number of primary bridge */
 	unsigned char	max_bus_speed;	/* enum pci_bus_speed */
 	unsigned char	cur_bus_speed;	/* enum pci_bus_speed */
+#ifdef CONFIG_PCI_DOMAINS_GENERIC
+	int		domain_nr;
+#endif
 
 	char		name[48];
 
@@ -1292,6 +1295,18 @@ static inline int pci_domain_nr(struct pci_bus *bus) { return 0; }
 static inline int pci_proc_domain(struct pci_bus *bus) { return 0; }
 #endif /* CONFIG_PCI_DOMAINS */
 
+#ifdef CONFIG_PCI_DOMAINS_GENERIC
+static inline int pci_domain_nr(struct pci_bus *bus)
+{
+	return bus->domain_nr;
+}
+extern void pci_set_domain_nr(struct pci_bus *bus, struct device *parent);
+#else
+static inline void pci_set_domain_nr(struct pci_bus *bus, struct device *parent)
+{
+}
+#endif
+
 /* some architectures require additional setup to direct VGA traffic */
 typedef int (*arch_set_vga_state_t)(struct pci_dev *pdev, bool decode,
 		      unsigned int command_bits, u32 flags);
--
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