freebsd源代码中设备驱动接口bus_setup_intr怎么实现的

71v5

下面是建议:

1:
认真看一下<Freebsd操作系统设计与实现>第7章第5节,其中关键一句话--"newbus系统在设计上的关键目标是给编写驱动程序的程序员提供一个
稳定的应用程序二进制接口".

2:
参考<Freebsd系统结构手册>第三章的简单描述.

3:
对于/usr/src/sys/kern/ 目录下的.m结尾的文件,以bus_if.m文件为例,可以执行下面:
awk -f /usr/src/sys/tools/makeobjops.awk ./bus_if.m -h -> 生成bus_if.c
awk -f /usr/src/sys/tools/makeobjops.awk ./bus_if.m -c -> 生成bus_if.h

在bus_if.c里面能找到BUS_SETUP_INTR的定义.
上面awk的处理实在构建kernel阶段自动完成的.

4:
看一下freebsd驱动程序的框架.

typedef struct kobj_class        driver_t;
宏DRIVER_MODULE以及驱动程序中如何使用DRIVER_MODULE.

分析完宏DRIVER_MODULE的实现以及在驱动程序代码中如何使用后,你会发现完全可以导出freebsd的设备树结构的简单模型.


5:
在初始化阶段,会先对DRIVER_MODULE注册到内核的模块进行处理,建立必要的数据结构等.

6:
配置设备阶段,看一下函数configure_first就可以,当这个函数执行完后,设备的树形结构就会建立.
SYSINIT(configure1, SI_SUB_CONFIGURE, SI_ORDER_FIRST, configure_first, NULL);

1. /*
   
2. * Determine i/o configuration for a machine.
   
3. */
   
4. static void
   
5. configure_first(dummy)
   
6.         void *dummy;
   
7. {
   
8. 
   
9.         /* nexus0 is the top of the amd64 device tree */
   
10.         device_add_child(root_bus, "nexus", 0);
    
11. }
    
12. 
    
13. 
    
14. 下面是一个简单的设备树:
    
15. nexus0
    
16.   acpi0
    
17.     pcib0
    
18.       pci0
    
19.        em0 <----intel网卡
    
20. 
    
21. 当探测到intel网卡时,驱动程序就会调用函数bus_setup_intr建立中断等.
    
22. 
    
23. /**
    
24. * @brief Wrapper function for BUS_SETUP_INTR().
    
25. *
    
26. * This function simply calls the BUS_SETUP_INTR() method of the
    
27. * parent of @p dev.
    
28. */
    
29. int
    
30. bus_setup_intr(device_t dev, struct resource *r, int flags,
    
31.     driver_filter_t filter, driver_intr_t handler, void *arg, void **cookiep)
    
32. {
    
33.         int error;
    
34. 
    
35.         if (dev->parent == NULL)
    
36.                 return (EINVAL);
    
37.         error = BUS_SETUP_INTR(dev->parent, dev, r, flags, filter, handler,
    
38.             arg, cookiep);
    
39.         if (error != 0)
    
40.                 return (error);
    
41.         if (handler != NULL && !(flags & INTR_MPSAFE))
    
42.                 device_printf(dev, "[GIANT-LOCKED]\n");
    
43.         return (0);
    
44. }
    
45. 
    
46. BUS_SETUP_INTR基本上都是调用父设备的bus_setup_intr方法,在到达设备nexus0之前,相应设备的bus_setup_intr方法可以简单的认为是调用bus_generic_setup_intr方法.
    
47. 
    
48. /**
    
49. * @brief Helper function for implementing BUS_SETUP_INTR().
    
50. *
    
51. * This simple implementation of BUS_SETUP_INTR() simply calls the
    
52. * BUS_SETUP_INTR() method of the parent of @p dev.
    
53. */
    
54. int
    
55. bus_generic_setup_intr(device_t dev, device_t child, struct resource *irq,
    
56.     int flags, driver_filter_t *filter, driver_intr_t *intr, void *arg,
    
57.     void **cookiep)
    
58. {
    
59.         /* Propagate up the bus hierarchy until someone handles it. */
    
60.         if (dev->parent)
    
61.                 return (BUS_SETUP_INTR(dev->parent, child, irq, flags,
    
62.                     filter, intr, arg, cookiep));
    
63.         return (EINVAL);
    
64. }
    
65. 
    
66. 当到达设备nexus0时,将调用nexus_setup_intr方法:
    
67. 
    
68. 下面的在文件/usr/src/sys/x86/x86/nexus.c中:
    
69. /*
    
70. * This code implements a `root nexus' for Intel Architecture
    
71. * machines.  The function of the root nexus is to serve as an
    
72. * attachment point for both processors and buses, and to manage
    
73. * resources which are common to all of them.  In particular,
    
74. * this code implements the core resource managers for interrupt
    
75. * requests, DMA requests (which rightfully should be a part of the
    
76. * ISA code but it's easier to do it here for now), I/O port addresses,
    
77. * and I/O memory address space.
    
78. */
    
79. 
    
80. static device_method_t nexus_methods[] = {
    
81. ..........................................................
    
82.         DEVMETHOD(bus_print_child,      nexus_print_child),
    
83.         DEVMETHOD(bus_add_child,        nexus_add_child),
    
84.         DEVMETHOD(bus_alloc_resource,   nexus_alloc_resource),
    
85.         DEVMETHOD(bus_adjust_resource,  nexus_adjust_resource),
    
86.         DEVMETHOD(bus_release_resource, nexus_release_resource),
    
87.         DEVMETHOD(bus_activate_resource, nexus_activate_resource),
    
88.         DEVMETHOD(bus_deactivate_resource, nexus_deactivate_resource),
    
89.         DEVMETHOD(bus_setup_intr,       nexus_setup_intr), <-------------
    
90.         DEVMETHOD(bus_teardown_intr,    nexus_teardown_intr),
    
91. ...........................................................
    
92. 
    
93.         { 0, 0 }
    
94. };

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