x86/PCI: use config space encoding for interrupt pins

Keep "pin" encoded as it is in the "Interrupt Pin" value in PCI config
space, i.e., 0=device doesn't use interrupts, 1=INTA, ..., 4=INTD.

This makes the bridge INTx swizzle match other architectures.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: hpa@zytor.com
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 20 insertions, 24 deletions

diff --git a/arch/x86/pci/irq.c b/arch/x86/pci/irq.c
index 399a172f047d..cc9d5e254060 100644
--- a/arch/x86/pci/irq.c
+++ b/arch/x86/pci/irq.c
@@ -887,7 +887,6 @@ static int pcibios_lookup_irq(struct pci_dev *dev, int assign)
                 dev_dbg(&dev->dev, "no interrupt pin\n");
                 return 0;
         }
-        pin = pin - 1;
 
         /* Find IRQ routing entry */
 
@@ -897,17 +896,17 @@ static int pcibios_lookup_irq(struct pci_dev *dev, int assign)
         info = pirq_get_info(dev);
         if (!info) {
                 dev_dbg(&dev->dev, "PCI INT %c not found in routing table\n",
-                        'A' + pin);
+                        'A' + pin - 1);
                 return 0;
         }
-        pirq = info->irq[pin].link;
-        mask = info->irq[pin].bitmap;
+        pirq = info->irq[pin - 1].link;
+        mask = info->irq[pin - 1].bitmap;
         if (!pirq) {
-                dev_dbg(&dev->dev, "PCI INT %c not routed\n", 'A' + pin);
+                dev_dbg(&dev->dev, "PCI INT %c not routed\n", 'A' + pin - 1);
                 return 0;
         }
         dev_dbg(&dev->dev, "PCI INT %c -> PIRQ %02x, mask %04x, excl %04x",
-                'A' + pin, pirq, mask, pirq_table->exclusive_irqs);
+                'A' + pin - 1, pirq, mask, pirq_table->exclusive_irqs);
         mask &= pcibios_irq_mask;
 
         /* Work around broken HP Pavilion Notebooks which assign USB to
@@ -949,7 +948,7 @@ static int pcibios_lookup_irq(struct pci_dev *dev, int assign)
                                 newirq = i;
                 }
         }
-        dev_dbg(&dev->dev, "PCI INT %c -> newirq %d", 'A' + pin, newirq);
+        dev_dbg(&dev->dev, "PCI INT %c -> newirq %d", 'A' + pin - 1, newirq);
 
         /* Check if it is hardcoded */
         if ((pirq & 0xf0) == 0xf0) {
@@ -977,18 +976,18 @@ static int pcibios_lookup_irq(struct pci_dev *dev, int assign)
                         return 0;
                 }
         }
-        dev_info(&dev->dev, "%s PCI INT %c -> IRQ %d\n", msg, 'A' + pin, irq);
+        dev_info(&dev->dev, "%s PCI INT %c -> IRQ %d\n", msg, 'A' + pin - 1, irq);
 
         /* Update IRQ for all devices with the same pirq value */
         while ((dev2 = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev2)) != NULL) {
                 pci_read_config_byte(dev2, PCI_INTERRUPT_PIN, &pin);
                 if (!pin)
                         continue;
-                pin--;
+
                 info = pirq_get_info(dev2);
                 if (!info)
                         continue;
-                if (info->irq[pin].link == pirq) {
+                if (info->irq[pin - 1].link == pirq) {
                         /*
                          * We refuse to override the dev->irq
                          * information. Give a warning!
@@ -1055,9 +1054,8 @@ static void __init pcibios_fixup_irqs(void)
                         /*
                          * interrupt pins are numbered starting from 1
                          */
-                        pin--;
                         irq = IO_APIC_get_PCI_irq_vector(dev->bus->number,
-                                PCI_SLOT(dev->devfn), pin);
+                                PCI_SLOT(dev->devfn), pin - 1);
                         /*
                          * Busses behind bridges are typically not listed in the
                          * MP-table.  In this case we have to look up the IRQ
@@ -1070,22 +1068,22 @@ static void __init pcibios_fixup_irqs(void)
                                 struct pci_dev *bridge = dev->bus->self;
                                 int bus;
 
-                                pin = (pin + PCI_SLOT(dev->devfn)) % 4;
+                                pin = (((pin - 1) + PCI_SLOT(dev->devfn)) % 4) + 1;
                                 bus = bridge->bus->number;
                                 irq = IO_APIC_get_PCI_irq_vector(bus,
-                                                PCI_SLOT(bridge->devfn), pin);
+                                                PCI_SLOT(bridge->devfn), pin - 1);
                                 if (irq >= 0)
                                         dev_warn(&dev->dev,
                                                 "using bridge %s INT %c to "
                                                         "get IRQ %d\n",
                                                  pci_name(bridge),
-                                                 'A' + pin, irq);
+                                                 'A' + pin - 1, irq);
                         }
                         if (irq >= 0) {
                                 dev_info(&dev->dev,
                                         "PCI->APIC IRQ transform: INT %c "
                                                 "-> IRQ %d\n",
-                                        'A' + pin, irq);
+                                        'A' + pin - 1, irq);
                                 dev->irq = irq;
                         }
                 }
@@ -1220,12 +1218,10 @@ static int pirq_enable_irq(struct pci_dev *dev)
         if (pin && !pcibios_lookup_irq(dev, 1) && !dev->irq) {
                 char *msg = "";
 
-                pin--; /* interrupt pins are numbered starting from 1 */
-
                 if (io_apic_assign_pci_irqs) {
                         int irq;
 
-                        irq = IO_APIC_get_PCI_irq_vector(dev->bus->number, PCI_SLOT(dev->devfn), pin);
+                        irq = IO_APIC_get_PCI_irq_vector(dev->bus->number, PCI_SLOT(dev->devfn), pin - 1);
                         /*
                          * Busses behind bridges are typically not listed in the MP-table.
                          * In this case we have to look up the IRQ based on the parent bus,
@@ -1236,20 +1232,20 @@ static int pirq_enable_irq(struct pci_dev *dev)
                         while (irq < 0 && dev->bus->parent) { /* go back to the bridge */
                                 struct pci_dev *bridge = dev->bus->self;
 
-                                pin = (pin + PCI_SLOT(dev->devfn)) % 4;
+                                pin = (((pin - 1) + PCI_SLOT(dev->devfn)) % 4) + 1;
                                 irq = IO_APIC_get_PCI_irq_vector(bridge->bus->number,
-                                                PCI_SLOT(bridge->devfn), pin);
+                                                PCI_SLOT(bridge->devfn), pin - 1);
                                 if (irq >= 0)
                                         dev_warn(&dev->dev, "using bridge %s "
                                                  "INT %c to get IRQ %d\n",
-                                                 pci_name(bridge), 'A' + pin,
+                                                 pci_name(bridge), 'A' + pin - 1,
                                                  irq);
                                 dev = bridge;
                         }
                         dev = temp_dev;
                         if (irq >= 0) {
                                 dev_info(&dev->dev, "PCI->APIC IRQ transform: "
-                                         "INT %c -> IRQ %d\n", 'A' + pin, irq);
+                                         "INT %c -> IRQ %d\n", 'A' + pin - 1, irq);
                                 dev->irq = irq;
                                 return 0;
                         } else
@@ -1268,7 +1264,7 @@ static int pirq_enable_irq(struct pci_dev *dev)
                         return 0;
 
                 dev_warn(&dev->dev, "can't find IRQ for PCI INT %c%s\n",
-                         'A' + pin, msg);
+                         'A' + pin - 1, msg);
         }
         return 0;
 }