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/init.h> 14 #include <linux/kernel.h> 15 #include <linux/pci.h> 16 #include <linux/errno.h> 17 #include <linux/ioport.h> 18 #include <linux/cache.h> 19 20 21 static void __init 22 pdev_fixup_irq(struct pci_dev *dev, 23 u8 (*swizzle)(struct pci_dev *, u8 *), 24 int (*map_irq)(const struct pci_dev *, u8, u8)) 25 { 26 u8 pin, slot; 27 int irq = 0; 28 29 /* If this device is not on the primary bus, we need to figure out 30 which interrupt pin it will come in on. We know which slot it 31 will come in on 'cos that slot is where the bridge is. Each 32 time the interrupt line passes through a PCI-PCI bridge we must 33 apply the swizzle function. */ 34 35 pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin); 36 /* Cope with illegal. */ 37 if (pin > 4) 38 pin = 1; 39 40 if (pin != 0) { 41 /* Follow the chain of bridges, swizzling as we go. */ 42 slot = (*swizzle)(dev, &pin); 43 44 irq = (*map_irq)(dev, slot, pin); 45 if (irq == -1) 46 irq = 0; 47 } 48 dev->irq = irq; 49 50 dev_dbg(&dev->dev, "fixup irq: got %d\n", dev->irq); 51 52 /* Always tell the device, so the driver knows what is 53 the real IRQ to use; the device does not use it. */ 54 pcibios_update_irq(dev, irq); 55 } 56 57 void __init 58 pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *), 59 int (*map_irq)(const struct pci_dev *, u8, u8)) 60 { 61 struct pci_dev *dev = NULL; 62 for_each_pci_dev(dev) 63 pdev_fixup_irq(dev, swizzle, map_irq); 64 } 65