1#include <linux/kernel.h> 2#include <linux/of_pci.h> 3#include <linux/of_irq.h> 4#include <linux/export.h> 5#include <asm/prom.h> 6 7/** 8 * of_irq_map_pci - Resolve the interrupt for a PCI device 9 * @pdev: the device whose interrupt is to be resolved 10 * @out_irq: structure of_irq filled by this function 11 * 12 * This function resolves the PCI interrupt for a given PCI device. If a 13 * device-node exists for a given pci_dev, it will use normal OF tree 14 * walking. If not, it will implement standard swizzling and walk up the 15 * PCI tree until an device-node is found, at which point it will finish 16 * resolving using the OF tree walking. 17 */ 18int of_irq_map_pci(struct pci_dev *pdev, struct of_irq *out_irq) 19{ 20 struct device_node *dn, *ppnode; 21 struct pci_dev *ppdev; 22 u32 lspec; 23 __be32 lspec_be; 24 __be32 laddr[3]; 25 u8 pin; 26 int rc; 27 28 /* Check if we have a device node, if yes, fallback to standard 29 * device tree parsing 30 */ 31 dn = pci_device_to_OF_node(pdev); 32 if (dn) { 33 rc = of_irq_map_one(dn, 0, out_irq); 34 if (!rc) 35 return rc; 36 } 37 38 /* Ok, we don't, time to have fun. Let's start by building up an 39 * interrupt spec. we assume #interrupt-cells is 1, which is standard 40 * for PCI. If you do different, then don't use that routine. 41 */ 42 rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin); 43 if (rc != 0) 44 return rc; 45 /* No pin, exit */ 46 if (pin == 0) 47 return -ENODEV; 48 49 /* Now we walk up the PCI tree */ 50 lspec = pin; 51 for (;;) { 52 /* Get the pci_dev of our parent */ 53 ppdev = pdev->bus->self; 54 55 /* Ouch, it's a host bridge... */ 56 if (ppdev == NULL) { 57 ppnode = pci_bus_to_OF_node(pdev->bus); 58 59 /* No node for host bridge ? give up */ 60 if (ppnode == NULL) 61 return -EINVAL; 62 } else { 63 /* We found a P2P bridge, check if it has a node */ 64 ppnode = pci_device_to_OF_node(ppdev); 65 } 66 67 /* Ok, we have found a parent with a device-node, hand over to 68 * the OF parsing code. 69 * We build a unit address from the linux device to be used for 70 * resolution. Note that we use the linux bus number which may 71 * not match your firmware bus numbering. 72 * Fortunately, in most cases, interrupt-map-mask doesn't 73 * include the bus number as part of the matching. 74 * You should still be careful about that though if you intend 75 * to rely on this function (you ship a firmware that doesn't 76 * create device nodes for all PCI devices). 77 */ 78 if (ppnode) 79 break; 80 81 /* We can only get here if we hit a P2P bridge with no node, 82 * let's do standard swizzling and try again 83 */ 84 lspec = pci_swizzle_interrupt_pin(pdev, lspec); 85 pdev = ppdev; 86 } 87 88 lspec_be = cpu_to_be32(lspec); 89 laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8)); 90 laddr[1] = laddr[2] = cpu_to_be32(0); 91 return of_irq_map_raw(ppnode, &lspec_be, 1, laddr, out_irq); 92} 93EXPORT_SYMBOL_GPL(of_irq_map_pci); 94