[PATCH 08/28] PCI: Introduce pci_host_assign_domain_nr() to assign domain

Yijing Wang
2015-01-16T03:48:04Z

Introduce pci_host_assign_domain_nr() to assign domain
number for pci_host_bridge. Later we will remove
pci_bus_assign_domain_nr().

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
---
drivers/pci/pci.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/pci.h | 4 ++++
2 files changed, 51 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index c419554..8b35e8e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4443,6 +4443,53 @@ int pci_get_new_domain_nr(void)
}

#ifdef CONFIG_PCI_DOMAINS_GENERIC
+void pci_host_assign_domain_nr(struct pci_host_bridge *host)
+{
+ static int use_dt_domains = -1;
+ struct device *parent = host->dev.parent;
+ int domain = of_get_pci_domain_nr(parent->of_node);
+
+ /*
+ * Check DT domain and use_dt_domains values.
+ *
+ * If DT domain property is valid (domain >= 0) and
+ * use_dt_domains != 0, the DT assignment is valid since this means
+ * we have not previously allocated a domain number by using
+ * pci_get_new_domain_nr(); we should also update use_dt_domains to
+ * 1, to indicate that we have just assigned a domain number from
+ * DT.
+ *
+ * If DT domain property value is not valid (ie domain < 0), and we
+ * have not previously assigned a domain number from DT
+ * (use_dt_domains != 1) we should assign a domain number by
+ * using the:
+ *
+ * pci_get_new_domain_nr()
+ *
+ * API and update the use_dt_domains value to keep track of method we
+ * are using to assign domain numbers (use_dt_domains = 0).
+ *
+ * All other combinations imply we have a platform that is trying
+ * to mix domain numbers obtained from DT and pci_get_new_domain_nr(),
+ * which is a recipe for domain mishandling and it is prevented by
+ * invalidating the domain value (domain = -1) and printing a
+ * corresponding error.
+ */
+ if (domain >= 0 && use_dt_domains) {
+ use_dt_domains = 1;
+ } else if (domain < 0 && use_dt_domains != 1) {
+ use_dt_domains = 0;
+ domain = pci_get_new_domain_nr();
+ } else {
+ dev_err(parent, "Node %s has inconsistent \"linux,pci-domain\" property in DT\n",
+ parent->of_node->full_name);
+ domain = -1;
+ }
+
+ host->domain_nr = domain;
+}
+
+
void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
{
static int use_dt_domains = -1;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c771508..1b9c799 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1316,11 +1316,15 @@ 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);
+void pci_host_assign_domain_nr(struct pci_host_bridge *host);
#else
static inline void pci_bus_assign_domain_nr(struct pci_bus *bus,
struct device *parent)
{
}
+static inline void pci_host_assign_domain_nr(struct pci_host_bridge *host)
+{
+}
#endif

/* some architectures require additional setup to direct VGA traffic */
--
1.7.1