阿扁"辞职"了，kde4发布了，更让我激动的是，英雄志过两天又有更新了，这部连载长达8年的小说，终于要进入精彩的大结局。卢云的命运究竟如何？观海云远，四个性格理念完全不同的人，谁是好，谁是坏，谁是对，谁是错？何谓正道？
接着上回说，usb_hcd_pci_probe这个函数在"我是UHCI"中也有讨论，不过我想按照我的思路写下去。
46 /**//**
47 * usb_hcd_pci_probe - initialize PCI-based HCDs 48 * @dev: USB Host Controller being probed 49 * @id: pci hotplug id connecting controller to HCD framework 50 * Context: !in_interrupt() 51 * 52 * Allocates basic PCI resources for this USB host controller, and 53 * then invokes the start() method for the HCD associated with it 54 * through the hotplug entry's driver_data. 55 * 56 * Store this function in the HCD's struct pci_driver as probe().
57 */
58 int usb_hcd_pci_probe (struct pci_dev *dev, const struct pci_device_id *id) 59 ...{ 60 struct hc_driver *driver; 61 struct usb_hcd *hcd; 62 int retval; 63 64 if (usb_disabled()) 65 return -ENODEV; 66 67 if (!id || !(driver = (struct hc_driver *) id->driver_data)) 68 return -EINVAL; 69 70 if (pci_enable_device (dev) < 0) 71 return -ENODEV; 72 dev->current_state = PCI_D0; 73 dev->dev.power.power_state = PMSG_ON; 74
75 if (!dev->irq) ...{ 76 dev_err (&dev->dev, 77 "Found HC with no IRQ. Check BIOS/PCI %s setup! ", 78 pci_name(dev)); 79 retval = -ENODEV; 80 goto err1;
81 } 82 83 hcd = usb_create_hcd (driver, &dev->dev, pci_name(dev)); 84 if (!hcd) ...{ 85 retval = -ENOMEM; 86 goto err1; 87 } 88 89 if (driver->flags & HCD_MEMORY) ...{ // EHCI, OHCI 90 hcd->rsrc_start = pci_resource_start (dev, 0); 91 hcd->rsrc_len = pci_resource_len (dev, 0); 92 if (!request_mem_region (hcd->rsrc_start, hcd->rsrc_len, 93 driver->description)) ...{ 94 dev_dbg (&dev->dev, "controller already in use "); 95 retval = -EBUSY; 96 goto err2; 97 } 98 hcd->regs = ioremap_nocache (hcd->rsrc_start, hcd->rsrc_len); 99 if (hcd->regs == NULL) ...{ 100 dev_dbg (&dev->dev, "error mapping memory "); 101 retval = -EFAULT; 102 goto err3; 103 } 104 105 } else ...{ // UHCI 106 int region; 107 108 for (region = 0; region < PCI_ROM_RESOURCE; region++) ...{ 109 if (!(pci_resource_flags (dev, region) & 110 IORESOURCE_IO)) 111 continue; 112 113 hcd->rsrc_start = pci_resource_start (dev, region); 114 hcd->rsrc_len = pci_resource_len (dev, region); 115 if (request_region (hcd->rsrc_start, hcd->rsrc_len, 116 driver->description)) 117 break; 118 } 119 if (region == PCI_ROM_RESOURCE) ...{ 120 dev_dbg (&dev->dev, "no i/o regions available "); 121 retval = -EBUSY; 122 goto err1; 123 } 124 } 125 126 pci_set_master (dev); 127 128 retval = usb_add_hcd (hcd, dev->irq, IRQF_SHARED); 129 if (retval != 0) 130 goto err4; 131 return retval; 132 133 err4: 134 if (driver->flags & HCD_MEMORY) ...{ 135 iounmap (hcd->regs); 136 err3: 137 release_mem_region (hcd->rsrc_start, hcd->rsrc_len); 138 } else 139 release_region (hcd->rsrc_start, hcd->rsrc_len); 140 err2: 141 usb_put_hcd (hcd); 142 err1: 143 pci_disable_device (dev); 144 dev_err (&dev->dev, "init %s fail, %d ", pci_name(dev), retval); 145 return retval; 146 }
64行，usb_disabled()判断内核有没有开启支持usb，要是这都不支持，一切都免谈。
70行，pci_enable_device()这是对ehci三类接口中的pci configuration space进行操作，设置其中某个寄存器的值，使设备处于工作状态。调用pci_read_config_word()和pci_write_config_word来读写pci配置空间的寄存器。pci_enable_device -> pci_enable_device_bars -> do_pci_enable_device ... 原理不难，只要对照spec可以看懂。
72，73是电源管理的内容。75判断设备的中断号是否为空。
83，usb_create_hcd() 创建一个usb_hcd机构体。
1480 /**//** 1481 * usb_create_hcd - create and initialize an HCD structure 1482 * @driver: HC driver that will use this hcd 1483 * @dev: device for this HC, stored in hcd->self.controller 1484 * @bus_name: value to store in hcd->self.bus_name 1485 * Context: !in_interrupt() 1486 * 1487 * Allocate a struct usb_hcd, with extra space at the end for the 1488 * HC driver's private data. Initialize the generic members of the 1489 * hcd structure. 1490 * 1491 * If memory is unavailable, returns NULL. 1492 */ 1493 struct usb_hcd *usb_create_hcd (const struct hc_driver *driver, 1494 struct device *dev, char *bus_name) 1495 ...{ 1496 struct usb_hcd *hcd; 1497 1498 hcd = kzalloc(sizeof(*hcd) + driver->hcd_priv_size, GFP_KERNEL); 1499 if (!hcd) ...{ 1500 dev_dbg (dev, "hcd alloc failed "); 1501 return NULL; 1502 } 1503 dev_set_drvdata(dev, hcd); 1504 kref_init(&hcd->kref); 1505 1506 usb_bus_init(&hcd->self); 1507 hcd->self.controller = dev; 1508 hcd->self.bus_name = bus_name; 1509 hcd->self.uses_dma = (dev->dma_mask != NULL); 1510 1511 init_timer(&hcd->rh_timer); 1512 hcd->rh_timer.function = rh_timer_func; 1513 hcd->rh_timer.data = (unsigned long) hcd; 1514 #ifdef CONFIG_PM 1515 INIT_WORK(&hcd->wakeup_work, hcd_resume_work); 1516 #endif 1517 1518 hcd->driver = driver; 1519 hcd->product_desc = (driver->product_desc) ? driver->product_desc : 1520 "