Linux那些事儿之我是EHCI(3) pci match 和 probe

pci_bus_type 定义如下，
struct bus_type pci_bus_type = ...{
.name = "pci",
.match = pci_bus_match,
.uevent = pci_uevent,
.probe = pci_device_probe,
.remove = pci_device_remove,
.suspend = pci_device_suspend,
.suspend_late = pci_device_suspend_late,
.resume_early = pci_device_resume_early,
.resume = pci_device_resume,
.shutdown = pci_device_shutdown,
.dev_attrs = pci_dev_attrs,
};
static int pci_bus_match(struct device *dev, struct device_driver *drv)
...{
struct pci_dev *pci_dev = to_pci_dev(dev);
struct pci_driver *pci_drv = to_pci_driver(drv);
const struct pci_device_id *found_id;

found_id = pci_match_device(pci_drv, pci_dev);
if (found_id)
return 1;

return 0;
}

总的来说，判断一个设备和驱动是否匹配，是看设备的描述符是否和驱动所支持的一样。pci_match_device()分别在 driver->dynid，driver->id_table这两个列表(由一系列的pci_device_id构成)里面查找。找到则返回这个设备的pci_device_id。(不妨比较一下pci_bus_type->match 和 usb_bus_type->match)
struct pci_device_id ...{
__u32 vendor, device; /**//* Vendor and device ID or PCI_ANY_ID*/
__u32 subvendor, subdevice; /**//* Subsystem ID's or PCI_ANY_ID */
__u32 class, class_mask; /**//* (class,subclass,prog-if) triplet */
kernel_ulong_t driver_data; /**//* Data private to the driver */
};

注意，pci_device_id->driver_data指向了每个pci设备驱动所特有的数据结构，比如ehci来说：.driver_data = (unsigned long) &ehci_pci_hc_driver。

另外就是，
static int pci_device_probe(struct device * dev)
...{
int error = 0;
struct pci_driver *drv;
struct pci_dev *pci_dev;

drv = to_pci_driver(dev->driver);
pci_dev = to_pci_dev(dev);
pci_dev_get(pci_dev);
error = __pci_device_probe(drv, pci_dev);
if (error)
pci_dev_put(pci_dev);

return error;
}

pci_device_probe() ---> __pci_device_probe() ---> pci_call_probe() ---> ( pci_driver->probe() )

而ehci_pci_driver->probe = usb_hcd_pci_probe()。像pci_device_probe的外包函数，就是一种面向对象的设计。不管怎样，经历了千辛万苦，咱终于绕到usb了。