1 /* 2 * drivers/pci/setup-irq.c 3 * 4 * Extruded from code written by 5 * Dave Rusling (david.rusling@reo.mts.dec.com) 6 * David Mosberger (davidm@cs.arizona.edu) 7 * David Miller (davem@redhat.com) 8 * 9 * Support routines for initializing a PCI subsystem. 10 */ 11 12 13 #include <linux/kernel.h> 14 #include <linux/pci.h> 15 #include <linux/errno.h> 16 #include <linux/ioport.h> 17 #include <linux/cache.h> 18 #include "pci.h" 19 20 void __weak pcibios_update_irq(struct pci_dev *dev, int irq) 21 { 22 dev_dbg(&dev->dev, "assigning IRQ %02d\n", irq); 23 pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq); 24 } 25 26 void pci_assign_irq(struct pci_dev *dev) 27 { 28 u8 pin; 29 u8 slot = -1; 30 int irq = 0; 31 struct pci_host_bridge *hbrg = pci_find_host_bridge(dev->bus); 32 33 if (!(hbrg->map_irq)) { 34 dev_dbg(&dev->dev, "runtime IRQ mapping not provided by arch\n"); 35 return; 36 } 37 38 /* If this device is not on the primary bus, we need to figure out 39 which interrupt pin it will come in on. We know which slot it 40 will come in on 'cos that slot is where the bridge is. Each 41 time the interrupt line passes through a PCI-PCI bridge we must 42 apply the swizzle function. */ 43 44 pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin); 45 /* Cope with illegal. */ 46 if (pin > 4) 47 pin = 1; 48 49 if (pin) { 50 /* Follow the chain of bridges, swizzling as we go. */ 51 if (hbrg->swizzle_irq) 52 slot = (*(hbrg->swizzle_irq))(dev, &pin); 53 54 /* 55 * If a swizzling function is not used map_irq must 56 * ignore slot 57 */ 58 irq = (*(hbrg->map_irq))(dev, slot, pin); 59 if (irq == -1) 60 irq = 0; 61 } 62 dev->irq = irq; 63 64 dev_dbg(&dev->dev, "assign IRQ: got %d\n", dev->irq); 65 66 /* Always tell the device, so the driver knows what is 67 the real IRQ to use; the device does not use it. */ 68 pcibios_update_irq(dev, irq); 69 } 70 71 void pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *), 72 int (*map_irq)(const struct pci_dev *, u8, u8)) 73 { 74 /* 75 * Implement pci_fixup_irqs() through pci_assign_irq(). 76 * This code should be remove eventually, it is a wrapper 77 * around pci_assign_irq() interface to keep current 78 * pci_fixup_irqs() behaviour unchanged on architecture 79 * code still relying on its interface. 80 */ 81 struct pci_dev *dev = NULL; 82 struct pci_host_bridge *hbrg = NULL; 83 84 for_each_pci_dev(dev) { 85 hbrg = pci_find_host_bridge(dev->bus); 86 hbrg->swizzle_irq = swizzle; 87 hbrg->map_irq = map_irq; 88 pci_assign_irq(dev); 89 hbrg->swizzle_irq = NULL; 90 hbrg->map_irq = NULL; 91 } 92 } 93 EXPORT_SYMBOL_GPL(pci_fixup_irqs); 94