PCI SYSFS

我们在调试时最长在PCI SYSFS目录下进行调试，这个目录是怎么生成的？ 

  1. /sys/bus/pci/devices/0000:26:00.0$ ls 
  2. aer_dev_correctable  broken_parity_status      current_link_speed  dma_mask_bits    iommu_group    max_link_speed  numa_node  reset      revision                 sriov_offset     subsystem         vendor
  3. aer_dev_fatal        class                     current_link_width  driver_override  irq            max_link_width  power      resource   rom                      sriov_stride     subsystem_device
  4. aer_dev_nonfatal     config                    d3cold_allowed      enable           local_cpulist  modalias        remove     resource0  sriov_drivers_autoprobe  sriov_totalvfs   subsystem_vendor
  5. ari_enabled          consistent_dma_mask_bits  device              iommu            local_cpus     msi_bus         rescan     resource2  sriov_numvfs             sriov_vf_device  uevent

/sys/bus/pci目录在 pci_driver_init 生成并注册

相关宏

  1. // linux-5.7.14/include/linux/device/bus.h
  3. #define BUS_ATTR_RW(_name) \
  4.         struct bus_attribute bus_attr_##_name = __ATTR_RW(_name)
  5. #define BUS_ATTR_RO(_name) \
  6.         struct bus_attribute bus_attr_##_name = __ATTR_RO(_name)
  7. #define BUS_ATTR_WO(_name) \                                                                                                                                                                                                                                                  
  8.         struct bus_attribute bus_attr_##_name = __ATTR_WO(_name)
  10. // linux-5.7.14/include/linux/device.h         
  11. #define DEVICE_ATTR(_name, _mode, _show, _store) \
  12.         struct device_attribute dev_attr_##_name = __ATTR(_name, _mode, _show, _store)
  13. #define DEVICE_ATTR_PREALLOC(_name, _mode, _show, _store) \
  14.         struct device_attribute dev_attr_##_name = \
  15.                 __ATTR_PREALLOC(_name, _mode, _show, _store)
  16. #define DEVICE_ATTR_RW(_name) \                                                                                                                                                                                                                                               
  17.         struct device_attribute dev_attr_##_name = __ATTR_RW(_name)
  18. #define DEVICE_ATTR_RO(_name) \
  19.         struct device_attribute dev_attr_##_name = __ATTR_RO(_name)
  20. #define DEVICE_ATTR_WO(_name) \
  21.         struct device_attribute dev_attr_##_name = __ATTR_WO(_name)
  22. #define DEVICE_ULONG_ATTR(_name, _mode, _var) \
  23.         struct dev_ext_attribute dev_attr_##_name = \
  24.                 { __ATTR(_name, _mode, device_show_ulong, device_store_ulong), &(_var) }
  25. #define DEVICE_INT_ATTR(_name, _mode, _var) \
  26.         struct dev_ext_attribute dev_attr_##_name = \
  27.                 { __ATTR(_name, _mode, device_show_int, device_store_int), &(_var) }
  28. #define DEVICE_BOOL_ATTR(_name, _mode, _var) \
  29.         struct dev_ext_attribute dev_attr_##_name = \
  30.                 { __ATTR(_name, _mode, device_show_bool, device_store_bool), &(_var) }
  31. #define DEVICE_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
  32.         struct device_attribute dev_attr_##_name =              \
  33.                 __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
  37. // linux-5.7.14/include/linux/sysfs.h
  38. #define __ATTR(_name, _mode, _show, _store) {                           \
  39.         .attr = {.name = __stringify(_name),                            \
  40.                  .mode = VERIFY_OCTAL_PERMISSIONS(_mode) },             \
  41.         .show   = _show,                                                \
  42.         .store  = _store,                                               \
  43. }
  45. #define __ATTR_PREALLOC(_name, _mode, _show, _store) {                  \
  46.         .attr = {.name = __stringify(_name),                            \
  47.                  .mode = SYSFS_PREALLOC | VERIFY_OCTAL_PERMISSIONS(_mode) },\
  48.         .show   = _show,                                                \
  49.         .store  = _store,                                               \
  50. }
  52. #define __ATTR_RO(_name) {                                              \
  53.         .attr   = { .name = __stringify(_name), .mode = 0444 },         \
  54.         .show   = _name##_show,                                         \
  55. }                                                                                                                                                                                                                                                                             
  57. #define __ATTR_RO_MODE(_name, _mode) {                                  \
  58.         .attr   = { .name = __stringify(_name),                         \
  59.                     .mode = VERIFY_OCTAL_PERMISSIONS(_mode) },          \
  60.         .show   = _name##_show,                                         \
  61. }
  63. #define __ATTR_WO(_name) {                                              \
  64.         .attr   = { .name = __stringify(_name), .mode = 0200 },         \
  65.         .store  = _name##_store,                                        \
  66. }
  68. #define __ATTR_RW(_name) __ATTR(_name, 0644, _name##_show, _name##_store)
  70. #define __ATTR_NULL { .attr = { .name = NULL } }
  1. // linux-5.7.14/drivers/pci/pci-driver.c
  2. struct bus_type pci_bus_type = {
  3.         .name           = "pci",
  4.         ......
  5.         .dev_groups     = pci_dev_groups,
  6.         .bus_groups     = pci_bus_groups,
  7.         .drv_groups     = pci_drv_groups,
  8.         .....
  9. };
  11. pci_driver_init
  12.      bus_register(&pcie_port_bus_type);
  13.          priv->devices_kset = kset_create_and_add("devices", NULL,
  14.                          &priv->subsys.kobj);
  15.         kset_create_and_add("drivers", NULL,
  16.                          &priv->subsys.kobj);
  17.         bus_add_groups(bus, bus->bus_groups);
  18.             sysfs_create_groups(&bus->p->subsys.kobj, groups); //  参考bus操作接口
  20. // linux-5.7.14/drivers/pci/pci-sysfs.c
  21. pci_bus_add_device
  22.     pci_create_sysfs_dev_files(dev);
  23.         sysfs_create_bin_file(&pdev->dev.kobj, &pci_config_attr); // config接口
  25.         sysfs_create_bin_file(&pdev->dev.kobj, attr); // if (rom_size) ;option Rom接口

bus操作接口

rescan 重新扫描所有PCI设备

  1. // linux-5.7.14/drivers/pci/pci-sysfs.c
  2. recan属性：WO,
  3. ssize_t rescan_store(struct bus_type *bus, const char *buf, size_t count);
  5. static BUS_ATTR_WO(rescan); ===>
  6. struct bus_attribute bus_attr_rescan = {
  7.         .attr   = { .rescan = __stringify(rescan), .mode = 0200 },         \
  8.         .store  = rescan_store,    
  9. };
  12. static struct attribute *pci_bus_attrs[] = {
  13.     &bus_attr_rescan.attr,
  14.     NULL,
  15. };
  17. static const struct attribute_group pci_bus_group = {
  18.     .attrs = pci_bus_attrs,
  19. };
  21. const struct attribute_group *pci_bus_groups[] = {
  22.     &pci_bus_group,
  23.     NULL,
  24. };

device接口

提供了一大波device的操作接口，太多，不一一列举。

  1. /* show configuration fields */
  2. #define pci_config_attr(field, format_string)                \
  3. static ssize_t                                \
  4. field##_show(struct device *dev, struct device_attribute *attr, char *buf)                \
  5. {                                    \
  6.     struct pci_dev *pdev;                        \
  7.                                     \
  8.     pdev = to_pci_dev(dev);                        \
  9.     return sprintf(buf, format_string, pdev->field);        \
  10. }                                    \
  11. static DEVICE_ATTR_RO(field)
  13. pci_config_attr(vendor, "0x%04x\n");   // 一大波show接口
  14. pci_config_attr(device, "0x%04x\n");
  15. pci_config_attr(subsystem_vendor, "0x%04x\n");
  16. pci_config_attr(subsystem_device, "0x%04x\n");
  17. pci_config_attr(revision, "0x%02x\n");
  18. pci_config_attr(class, "0x%06x\n");
  19. pci_config_attr(irq, "%u\n");
  23. static DEVICE_ATTR_RW(enable); // enable接口
  24. static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
  25.                 char *buf)
  26. static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
  27.                  const char *buf, size_t count)
  30. static struct attribute *pci_dev_attrs[] = {
  31.     &dev_attr_resource.attr,
  32.     &dev_attr_vendor.attr,
  33.     &dev_attr_device.attr,
  34.     &dev_attr_subsystem_vendor.attr,
  35.     &dev_attr_subsystem_device.attr,
  36.     &dev_attr_revision.attr,
  37.     &dev_attr_class.attr,
  38.     &dev_attr_irq.attr,
  39.     &dev_attr_local_cpus.attr,
  40.     &dev_attr_local_cpulist.attr,
  41.     &dev_attr_modalias.attr,
  42. #ifdef CONFIG_NUMA
  43.     &dev_attr_numa_node.attr,
  44. #endif
  45.     &dev_attr_dma_mask_bits.attr,
  46.     &dev_attr_consistent_dma_mask_bits.attr,
  47.     &dev_attr_enable.attr,
  48.     &dev_attr_broken_parity_status.attr,
  49.     &dev_attr_msi_bus.attr,
  50. #if defined(CONFIG_PM) && defined(CONFIG_ACPI)
  51.     &dev_attr_d3cold_allowed.attr,
  52. #endif
  53. #ifdef CONFIG_OF
  54.     &dev_attr_devspec.attr,
  55. #endif
  56.     &dev_attr_driver_override.attr,
  57.     &dev_attr_ari_enabled.attr,
  58.     NULL,
  59. };
  61. static const struct attribute_group pci_dev_group = {
  62.     .attrs = pci_dev_attrs,
  63. };
  65. const struct attribute_group *pci_dev_groups[] = {
  66.     &pci_dev_group,
  67.     NULL,
  68. };

pci_setup_device（pci设备初始化）

PCI是怎么获取配置空间大小的 ？？？pdev->cfg_size 在什么地方填充？

  1. pci_scan_device
  2.     pci_setup_device
  4. pci_setup_device   
  5.     hdr_type = pci_hdr_type(dev); // 读取头部信息
  7.     set_pcie_port_type
  8.         pos = pci_find_capability(pdev, PCI_CAP_ID_EXP); // PCIE一定有0x10的ID配置
  9.             __pci_bus_find_cap_start
  10.                 // 读取pci配置空间的状态位，判断是否capabilities list位是否使能    
  11.                 pci_bus_read_config_word(bus, devfn, PCI_STATUS, &status);
  12.                 // 如果没使能，那配置空间也就0x00-0x3f
  13.                 // 如果使能，返回PCI_CAPABILITY_LIST 0x34，也就是capability指针位置
  14.             __pci_find_next_cap  // 
  15.                 pci_bus_read_config_byte(bus, devfn, pos, &pos); // 读取指针，寻找next
  16.                 ....// 开始遍历capability，寻找ID符合的。也就是PCI_CAP_ID_EXP
  19.     pci_cfg_space_size  // 获取配置空间大小
  20.         // 桥设备暂时不考虑
  21.         if (pci_is_pcie(dev))  // 根据前边获取到的信息，判断是否是pcie设备
  22.             return pci_cfg_space_size_ext(dev);  // 这里边就是尝试读取下0x100以后的数据，