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>

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 0138550dc80681c4d0dde2b5e6d7977fd048338d..79d9d045a1b8b27d86230412090a75166d79dfd8 100644 (file)
--- 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);
 }