PCI: Use cached MSI-X cap while enabling MSI-X

The patch uses the cached MSI-X capability offset in
pci_dev instead of reading it from config space when enabling
MSI-X interrupts.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 16 insertions, 20 deletions

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 0138550dc806..79d9d045a1b8 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -598,14 +598,14 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
         return 0;
 }
 
-static void __iomem *msix_map_region(struct pci_dev *dev, unsigned pos,
-                                                        unsigned nr_entries)
+static void __iomem *msix_map_region(struct pci_dev *dev, unsigned nr_entries)
 {
         resource_size_t phys_addr;
         u32 table_offset;
         u8 bir;
 
-        pci_read_config_dword(dev, msix_table_offset_reg(pos), &table_offset);
+        pci_read_config_dword(dev,
+                msix_table_offset_reg(dev->msix_cap), &table_offset);
         bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
         table_offset &= ~PCI_MSIX_FLAGS_BIRMASK;
         phys_addr = pci_resource_start(dev, bir) + table_offset;
@@ -613,9 +613,8 @@ static void __iomem *msix_map_region(struct pci_dev *dev, unsigned pos,
         return ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
 }
 
-static int msix_setup_entries(struct pci_dev *dev, unsigned pos,
-                                void __iomem *base, struct msix_entry *entries,
-                                int nvec)
+static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
+                              struct msix_entry *entries, int nvec)
 {
         struct msi_desc *entry;
         int i;
@@ -635,7 +634,7 @@ static int msix_setup_entries(struct pci_dev *dev, unsigned pos,
                 entry->msi_attrib.is_64         = 1;
                 entry->msi_attrib.entry_nr      = entries[i].entry;
                 entry->msi_attrib.default_irq   = dev->irq;
-                entry->msi_attrib.pos           = pos;
+                entry->msi_attrib.pos           = dev->msix_cap;
                 entry->mask_base                = base;
 
                 list_add_tail(&entry->list, &dev->msi_list);
@@ -645,7 +644,7 @@ static int msix_setup_entries(struct pci_dev *dev, unsigned pos,
 }
 
 static void msix_program_entries(struct pci_dev *dev,
-                                        struct msix_entry *entries)
+                                 struct msix_entry *entries)
 {
         struct msi_desc *entry;
         int i = 0;
@@ -675,23 +674,22 @@ static void msix_program_entries(struct pci_dev *dev,
 static int msix_capability_init(struct pci_dev *dev,
                                 struct msix_entry *entries, int nvec)
 {
-        int pos, ret;
+        int ret;
         u16 control;
         void __iomem *base;
 
-        pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-        pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
+        pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
 
         /* Ensure MSI-X is disabled while it is set up */
         control &= ~PCI_MSIX_FLAGS_ENABLE;
-        pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
+        pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, control);
 
         /* Request & Map MSI-X table region */
-        base = msix_map_region(dev, pos, multi_msix_capable(control));
+        base = msix_map_region(dev, multi_msix_capable(control));
         if (!base)
                 return -ENOMEM;
 
-        ret = msix_setup_entries(dev, pos, base, entries, nvec);
+        ret = msix_setup_entries(dev, base, entries, nvec);
         if (ret)
                 return ret;
 
@@ -705,7 +703,7 @@ static int msix_capability_init(struct pci_dev *dev,
          * interrupts coming in before they're fully set up.
          */
         control |= PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE;
-        pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
+        pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, control);
 
         msix_program_entries(dev, entries);
 
@@ -720,7 +718,7 @@ static int msix_capability_init(struct pci_dev *dev,
         dev->msix_enabled = 1;
 
         control &= ~PCI_MSIX_FLAGS_MASKALL;
-        pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
+        pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, control);
 
         return 0;
 
@@ -906,14 +904,12 @@ EXPORT_SYMBOL(pci_disable_msi);
  */
 int pci_msix_table_size(struct pci_dev *dev)
 {
-        int pos;
         u16 control;
 
-        pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-        if (!pos)
+        if (!dev->msix_cap)
                 return 0;
 
-        pci_read_config_word(dev, msi_control_reg(pos), &control);
+        pci_read_config_word(dev, msi_control_reg(dev->msix_cap), &control);
         return multi_msix_capable(control);
 }