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Subject[PATCH v10 06/10] PCI: Introduce generic domain handling for PCI busses.
Date
The handling of PCI domains (or PCI segments in ACPI speak) is
usually a straightforward affair but its implementation is
currently left to the architectural code, with pci_domain_nr(b)
querying the value of the domain associated with bus b.

This patch introduces CONFIG_PCI_DOMAINS_GENERIC as an
option that can be selected if an architecture want a
simple implementation where the value of the domain
associated with a bus is stored in struct pci_bus.

The architectures that select CONFIG_PCI_DOMAINS_GENERIC will
then have to implement pci_bus_assign_domain_nr() as a way
of setting the domain number associated with a root bus.
All child busses except the root bus will inherit the domain_nr
value from their parent.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Catalin Marinas <Catalin.Marinas@arm.com>
[Renamed pci_set_domain_nr() to pci_bus_assign_domain_nr()]
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
---
drivers/pci/probe.c | 11 ++++++++---
include/linux/pci.h | 21 +++++++++++++++++++++
2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5ff72ec..ef891d2 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;
}

@@ -672,7 +676,7 @@ 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;

@@ -1768,13 +1772,14 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,

bridge->dev.parent = parent;

- 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_bus_assign_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/pci.h b/include/linux/pci.h
index 61978a4..a494e5d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -456,6 +456,9 @@ 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];

@@ -1288,6 +1291,24 @@ 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 */

+/*
+ * Generic implementation for PCI domain support. If your
+ * architecture does not need custom management of PCI
+ * domains then this implementation will be used
+ */
+#ifdef CONFIG_PCI_DOMAINS_GENERIC
+static inline int pci_domain_nr(struct pci_bus *bus)
+{
+ return bus->domain_nr;
+}
+void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent);
+#else
+static inline void pci_bus_assign_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);
--
2.0.4


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