pcie设备驱动无法工作排查

pci_register_driver() (include/linux/pci.h)
  -->pci_register_driver()  (drivers/pci/pci-driver.c)
    -->driver_register()  (drivers/base/driver.c)
      -->bus_add_driver (drivers/base/driver.c)
        -->driver_attach() (drivers/base/dd.c)
          -->__driver_attach()  (drivers/base/dd.c)
            -->driver_match_device()
                pci_bus_match

driver_match_device()
  -->pci_bus_match  (drivers/pci/pci-driver.c)
    -->pci_match_device() (drivers/pci/pci-driver.c)
      -->pci_match_id() (drivers/pci/pci-driver.c)
        -->pci_match_one_device （drivers/pci/pci.h）     

整个驱动的注册后触发使能的过程如上。这里核心位于bus_for_each_dev

int bus_for_each_dev(struct bus_type *bus, struct device *start,
     void *data, int (*fn)(struct device *, void *))
{
struct klist_iter i;
struct device *dev;
int error = 0;

if (!bus || !bus->p)
return -EINVAL;

klist_iter_init_node(&bus->p->klist_devices, &i,
     (start ? &start->p->knode_bus : NULL));
while (!error && (dev = next_device(&i)))
error = fn(dev, data);
klist_iter_exit(&i);
return error;
}
EXPORT_SYMBOL_GPL(bus_for_each_dev);

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;
const struct pci_device_id *found_id;

if (!pci_dev->match_driver)
return 0;

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

return 0;
}

static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
    struct pci_dev *dev)
{
struct pci_dynid *dynid;
const struct pci_device_id *found_id = NULL;

/* When driver_override is set, only bind to the matching driver */
if (dev->driver_override && strcmp(dev->driver_override, drv->name))
return NULL;

/* Look at the dynamic ids first, before the static ones */
spin_lock(&drv->dynids.lock);
list_for_each_entry(dynid, &drv->dynids.list, node) {
if (pci_match_one_device(&dynid->id, dev)) {
found_id = &dynid->id;
break;
}
}
spin_unlock(&drv->dynids.lock);

if (!found_id)
found_id = pci_match_id(drv->id_table, dev);

/* driver_override will always match, send a dummy id */
if (!found_id && dev->driver_override)
found_id = &pci_device_id_any;

return found_id;
}

为了查看为什么驱动匹配不到设备，我写了如下测试代码。当然必须重构部分数据结构，因为没有导出。

int test_bus_for_each_dev( void )
{
struct klist_iter i;
struct device *dev;
int error = 0;
    struct device *start = NULL;

    struct bus_type *bus = &pci_bus_type;

    printk("pci_bus_type %lx \n", pci_bus_type);

klist_iter_init_node(&bus->p->klist_devices, &i,
     ( NULL));
while (!error && (dev = next_device(&i))){
        struct pci_dev *pci_dev = to_pci_dev(dev);
        printk("pci_dev %x %x match driver %x \n", 
            pci_dev->vendor, pci_dev->device, pci_dev->match_driver);
    }
klist_iter_exit(&i);
return error;
}

最后发现pci_dev->match_driver没有使能。

原文地址：https://blog.csdn.net/bme314/article/details/135620636

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