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Dominik Brodowski3d068262010-01-16 09:17:10 +01001This file explains the locking and exclusion scheme used in the PCCARD
2and PCMCIA subsystems.
3
4
5A) Overview, Locking Hierarchy:
6===============================
7
8pcmcia_socket_list_rwsem - protects only the list of sockets
9- skt_mutex - serializes card insert / ejection
10 - ops_mutex - serializes socket operation
11
12
13B) Exclusion
14============
15
16The following functions and callbacks to struct pcmcia_socket must
17be called with "skt_mutex" held:
18
19 socket_detect_change()
20 send_event()
21 socket_reset()
22 socket_shutdown()
23 socket_setup()
24 socket_remove()
25 socket_insert()
26 socket_early_resume()
27 socket_late_resume()
28 socket_resume()
29 socket_suspend()
30
31 struct pcmcia_callback *callback
32
33The following functions and callbacks to struct pcmcia_socket must
34be called with "ops_mutex" held:
35
36 socket_reset()
37 socket_setup()
38
Dominik Brodowskicfe5d802010-01-17 19:31:45 +010039 struct pccard_operations *ops
40 struct pccard_resource_ops *resource_ops;
Dominik Brodowski3d068262010-01-16 09:17:10 +010041
42Note that send_event() and struct pcmcia_callback *callback must not be
43called with "ops_mutex" held.
44
45
46C) Protection
47=============
48
491. Global Data:
50---------------
51struct list_head pcmcia_socket_list;
52
53protected by pcmcia_socket_list_rwsem;
54
55
562. Per-Socket Data:
57-------------------
Dominik Brodowskicfe5d802010-01-17 19:31:45 +010058The resource_ops and their data are protected by ops_mutex.
Dominik Brodowski3d068262010-01-16 09:17:10 +010059
60The "main" struct pcmcia_socket is protected as follows (read-only fields
61or single-use fields not mentioned):
62
63- by pcmcia_socket_list_rwsem:
64 struct list_head socket_list;
65
66- by thread_lock:
67 unsigned int thread_events;
68
69- by skt_mutex:
70 u_int suspended_state;
71 void (*tune_bridge);
72 struct pcmcia_callback *callback;
73 int resume_status;
74
75- by ops_mutex:
76 socket_state_t socket;
77 u_int state;
78 u_short lock_count;
79 pccard_mem_map cis_mem;
80 void __iomem *cis_virt;
81 struct { } irq;
82 io_window_t io[];
83 pccard_mem_map win[];
84 struct list_head cis_cache;
85 size_t fake_cis_len;
86 u8 *fake_cis;
87 u_int irq_mask;
88 void (*zoom_video);
89 int (*power_hook);
90 u8 resource...;
91 struct list_head devices_list;
92 u8 device_count;
93 struct pcmcia_state;
Dominik Brodowski94a819f2010-01-17 18:31:34 +010094
95
963. Per PCMCIA-device Data:
97--------------------------
98
99The "main" struct pcmcia_devie is protected as follows (read-only fields
100or single-use fields not mentioned):
101
102
103- by pcmcia_socket->ops_mutex:
104 struct list_head socket_device_list;
105 struct config_t *function_config;
106 u16 _irq:1;
107 u16 _io:1;
108 u16 _win:4;
109 u16 _locked:1;
110 u16 allow_func_id_match:1;
111 u16 suspended:1;
112 u16 _removed:1;
113
114- by the PCMCIA driver:
115 io_req_t io;
116 irq_req_t irq;
117 config_req_t conf;
118 window_handle_t win;