PCI: add a new function to map BAR offsets

Add a function to map a given resource number to a corresponding
register so drivers can get the offset and type of device specific BARs.

Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

3 files changed, 29 insertions, 8 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index deeab19d7d10..7e9c0f3936dd 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2201,6 +2201,28 @@ int pci_select_bars(struct pci_dev *dev, unsigned long flags)
         return bars;
 }
 
+/**
+ * pci_resource_bar - get position of the BAR associated with a resource
+ * @dev: the PCI device
+ * @resno: the resource number
+ * @type: the BAR type to be filled in
+ *
+ * Returns BAR position in config space, or 0 if the BAR is invalid.
+ */
+int pci_resource_bar(struct pci_dev *dev, int resno, enum pci_bar_type *type)
+{
+        if (resno < PCI_ROM_RESOURCE) {
+                *type = pci_bar_unknown;
+                return PCI_BASE_ADDRESS_0 + 4 * resno;
+        } else if (resno == PCI_ROM_RESOURCE) {
+                *type = pci_bar_mem32;
+                return dev->rom_base_reg;
+        }
+
+        dev_err(&dev->dev, "BAR: invalid resource #%d\n", resno);
+        return 0;
+}
+
 static void __devinit pci_no_domains(void)
 {
 #ifdef CONFIG_PCI_DOMAINS
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index d881fde8bb82..c4f4a1e6ea28 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -171,6 +171,8 @@ enum pci_bar_type {
 
 extern int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
                                 struct resource *res, unsigned int reg);
+extern int pci_resource_bar(struct pci_dev *dev, int resno,
+                            enum pci_bar_type *type);
 extern void pci_enable_ari(struct pci_dev *dev);
 /**
  * pci_ari_enabled - query ARI forwarding status
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 3c5203ff53c7..32e8d88a4619 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -31,6 +31,7 @@ void pci_update_resource(struct pci_dev *dev, int resno)
         struct pci_bus_region region;
         u32 new, check, mask;
         int reg;
+        enum pci_bar_type type;
         struct resource *res = dev->resource + resno;
 
         /*
@@ -62,17 +63,13 @@ void pci_update_resource(struct pci_dev *dev, int resno)
         else
                 mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;
 
-        if (resno < 6) {
-                reg = PCI_BASE_ADDRESS_0 + 4 * resno;
-        } else if (resno == PCI_ROM_RESOURCE) {
+        reg = pci_resource_bar(dev, resno, &type);
+        if (!reg)
+                return;
+        if (type != pci_bar_unknown) {
                 if (!(res->flags & IORESOURCE_ROM_ENABLE))
                         return;
                 new |= PCI_ROM_ADDRESS_ENABLE;
-                reg = dev->rom_base_reg;
-        } else {
-                /* Hmm, non-standard resource. */
-        
-                return;         /* kill uninitialised var warning */
         }
 
         pci_write_config_dword(dev, reg, new);