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author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2009-05-23 15:57:31 -0400 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-05-23 15:57:31 -0400 |
commit | a2ab67fae1ab9226679495a8d260f4e6555efc5f (patch) | |
tree | f7de683c9c8ff0869a7e11f1d40802145d05f5b4 /Documentation/isdn/INTERFACE.CAPI | |
parent | 6d0485a99366d4e0e7e725f14995c74cb7ca4499 (diff) | |
parent | 135cad366b4e7d6a79f6369f6cb5b721985aa62f (diff) |
Merge branch 'for-rmk-devel' of git://git.pengutronix.de/git/imx/linux-2.6 into devel
Conflicts:
arch/arm/Kconfig
arch/arm/Makefile
Diffstat (limited to 'Documentation/isdn/INTERFACE.CAPI')
-rw-r--r-- | Documentation/isdn/INTERFACE.CAPI | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/Documentation/isdn/INTERFACE.CAPI b/Documentation/isdn/INTERFACE.CAPI new file mode 100644 index 000000000000..786d619b36e5 --- /dev/null +++ b/Documentation/isdn/INTERFACE.CAPI | |||
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1 | Kernel CAPI Interface to Hardware Drivers | ||
2 | ----------------------------------------- | ||
3 | |||
4 | 1. Overview | ||
5 | |||
6 | From the CAPI 2.0 specification: | ||
7 | COMMON-ISDN-API (CAPI) is an application programming interface standard used | ||
8 | to access ISDN equipment connected to basic rate interfaces (BRI) and primary | ||
9 | rate interfaces (PRI). | ||
10 | |||
11 | Kernel CAPI operates as a dispatching layer between CAPI applications and CAPI | ||
12 | hardware drivers. Hardware drivers register ISDN devices (controllers, in CAPI | ||
13 | lingo) with Kernel CAPI to indicate their readiness to provide their service | ||
14 | to CAPI applications. CAPI applications also register with Kernel CAPI, | ||
15 | requesting association with a CAPI device. Kernel CAPI then dispatches the | ||
16 | application registration to an available device, forwarding it to the | ||
17 | corresponding hardware driver. Kernel CAPI then forwards CAPI messages in both | ||
18 | directions between the application and the hardware driver. | ||
19 | |||
20 | Format and semantics of CAPI messages are specified in the CAPI 2.0 standard. | ||
21 | This standard is freely available from http://www.capi.org. | ||
22 | |||
23 | |||
24 | 2. Driver and Device Registration | ||
25 | |||
26 | CAPI drivers optionally register themselves with Kernel CAPI by calling the | ||
27 | Kernel CAPI function register_capi_driver() with a pointer to a struct | ||
28 | capi_driver. This structure must be filled with the name and revision of the | ||
29 | driver, and optionally a pointer to a callback function, add_card(). The | ||
30 | registration can be revoked by calling the function unregister_capi_driver() | ||
31 | with a pointer to the same struct capi_driver. | ||
32 | |||
33 | CAPI drivers must register each of the ISDN devices they control with Kernel | ||
34 | CAPI by calling the Kernel CAPI function attach_capi_ctr() with a pointer to a | ||
35 | struct capi_ctr before they can be used. This structure must be filled with | ||
36 | the names of the driver and controller, and a number of callback function | ||
37 | pointers which are subsequently used by Kernel CAPI for communicating with the | ||
38 | driver. The registration can be revoked by calling the function | ||
39 | detach_capi_ctr() with a pointer to the same struct capi_ctr. | ||
40 | |||
41 | Before the device can be actually used, the driver must fill in the device | ||
42 | information fields 'manu', 'version', 'profile' and 'serial' in the capi_ctr | ||
43 | structure of the device, and signal its readiness by calling capi_ctr_ready(). | ||
44 | From then on, Kernel CAPI may call the registered callback functions for the | ||
45 | device. | ||
46 | |||
47 | If the device becomes unusable for any reason (shutdown, disconnect ...), the | ||
48 | driver has to call capi_ctr_reseted(). This will prevent further calls to the | ||
49 | callback functions by Kernel CAPI. | ||
50 | |||
51 | |||
52 | 3. Application Registration and Communication | ||
53 | |||
54 | Kernel CAPI forwards registration requests from applications (calls to CAPI | ||
55 | operation CAPI_REGISTER) to an appropriate hardware driver by calling its | ||
56 | register_appl() callback function. A unique Application ID (ApplID, u16) is | ||
57 | allocated by Kernel CAPI and passed to register_appl() along with the | ||
58 | parameter structure provided by the application. This is analogous to the | ||
59 | open() operation on regular files or character devices. | ||
60 | |||
61 | After a successful return from register_appl(), CAPI messages from the | ||
62 | application may be passed to the driver for the device via calls to the | ||
63 | send_message() callback function. The CAPI message to send is stored in the | ||
64 | data portion of an skb. Conversely, the driver may call Kernel CAPI's | ||
65 | capi_ctr_handle_message() function to pass a received CAPI message to Kernel | ||
66 | CAPI for forwarding to an application, specifying its ApplID. | ||
67 | |||
68 | Deregistration requests (CAPI operation CAPI_RELEASE) from applications are | ||
69 | forwarded as calls to the release_appl() callback function, passing the same | ||
70 | ApplID as with register_appl(). After return from release_appl(), no CAPI | ||
71 | messages for that application may be passed to or from the device anymore. | ||
72 | |||
73 | |||
74 | 4. Data Structures | ||
75 | |||
76 | 4.1 struct capi_driver | ||
77 | |||
78 | This structure describes a Kernel CAPI driver itself. It is used in the | ||
79 | register_capi_driver() and unregister_capi_driver() functions, and contains | ||
80 | the following non-private fields, all to be set by the driver before calling | ||
81 | register_capi_driver(): | ||
82 | |||
83 | char name[32] | ||
84 | the name of the driver, as a zero-terminated ASCII string | ||
85 | char revision[32] | ||
86 | the revision number of the driver, as a zero-terminated ASCII string | ||
87 | int (*add_card)(struct capi_driver *driver, capicardparams *data) | ||
88 | a callback function pointer (may be NULL) | ||
89 | |||
90 | |||
91 | 4.2 struct capi_ctr | ||
92 | |||
93 | This structure describes an ISDN device (controller) handled by a Kernel CAPI | ||
94 | driver. After registration via the attach_capi_ctr() function it is passed to | ||
95 | all controller specific lower layer interface and callback functions to | ||
96 | identify the controller to operate on. | ||
97 | |||
98 | It contains the following non-private fields: | ||
99 | |||
100 | - to be set by the driver before calling attach_capi_ctr(): | ||
101 | |||
102 | struct module *owner | ||
103 | pointer to the driver module owning the device | ||
104 | |||
105 | void *driverdata | ||
106 | an opaque pointer to driver specific data, not touched by Kernel CAPI | ||
107 | |||
108 | char name[32] | ||
109 | the name of the controller, as a zero-terminated ASCII string | ||
110 | |||
111 | char *driver_name | ||
112 | the name of the driver, as a zero-terminated ASCII string | ||
113 | |||
114 | int (*load_firmware)(struct capi_ctr *ctrlr, capiloaddata *ldata) | ||
115 | (optional) pointer to a callback function for sending firmware and | ||
116 | configuration data to the device | ||
117 | |||
118 | void (*reset_ctr)(struct capi_ctr *ctrlr) | ||
119 | pointer to a callback function for performing a reset on the device, | ||
120 | releasing all registered applications | ||
121 | |||
122 | void (*register_appl)(struct capi_ctr *ctrlr, u16 applid, | ||
123 | capi_register_params *rparam) | ||
124 | void (*release_appl)(struct capi_ctr *ctrlr, u16 applid) | ||
125 | pointers to callback functions for registration and deregistration of | ||
126 | applications with the device | ||
127 | |||
128 | u16 (*send_message)(struct capi_ctr *ctrlr, struct sk_buff *skb) | ||
129 | pointer to a callback function for sending a CAPI message to the | ||
130 | device | ||
131 | |||
132 | char *(*procinfo)(struct capi_ctr *ctrlr) | ||
133 | pointer to a callback function returning the entry for the device in | ||
134 | the CAPI controller info table, /proc/capi/controller | ||
135 | |||
136 | read_proc_t *ctr_read_proc | ||
137 | pointer to the read_proc callback function for the device's proc file | ||
138 | system entry, /proc/capi/controllers/<n>; will be called with a | ||
139 | pointer to the device's capi_ctr structure as the last (data) argument | ||
140 | |||
141 | - to be filled in before calling capi_ctr_ready(): | ||
142 | |||
143 | u8 manu[CAPI_MANUFACTURER_LEN] | ||
144 | value to return for CAPI_GET_MANUFACTURER | ||
145 | |||
146 | capi_version version | ||
147 | value to return for CAPI_GET_VERSION | ||
148 | |||
149 | capi_profile profile | ||
150 | value to return for CAPI_GET_PROFILE | ||
151 | |||
152 | u8 serial[CAPI_SERIAL_LEN] | ||
153 | value to return for CAPI_GET_SERIAL | ||
154 | |||
155 | |||
156 | 5. Lower Layer Interface Functions | ||
157 | |||
158 | (declared in <linux/isdn/capilli.h>) | ||
159 | |||
160 | void register_capi_driver(struct capi_driver *drvr) | ||
161 | void unregister_capi_driver(struct capi_driver *drvr) | ||
162 | register/unregister a driver with Kernel CAPI | ||
163 | |||
164 | int attach_capi_ctr(struct capi_ctr *ctrlr) | ||
165 | int detach_capi_ctr(struct capi_ctr *ctrlr) | ||
166 | register/unregister a device (controller) with Kernel CAPI | ||
167 | |||
168 | void capi_ctr_ready(struct capi_ctr *ctrlr) | ||
169 | void capi_ctr_reseted(struct capi_ctr *ctrlr) | ||
170 | signal controller ready/not ready | ||
171 | |||
172 | void capi_ctr_suspend_output(struct capi_ctr *ctrlr) | ||
173 | void capi_ctr_resume_output(struct capi_ctr *ctrlr) | ||
174 | signal suspend/resume | ||
175 | |||
176 | void capi_ctr_handle_message(struct capi_ctr * ctrlr, u16 applid, | ||
177 | struct sk_buff *skb) | ||
178 | pass a received CAPI message to Kernel CAPI | ||
179 | for forwarding to the specified application | ||
180 | |||
181 | |||
182 | 6. Helper Functions and Macros | ||
183 | |||
184 | Library functions (from <linux/isdn/capilli.h>): | ||
185 | |||
186 | void capilib_new_ncci(struct list_head *head, u16 applid, | ||
187 | u32 ncci, u32 winsize) | ||
188 | void capilib_free_ncci(struct list_head *head, u16 applid, u32 ncci) | ||
189 | void capilib_release_appl(struct list_head *head, u16 applid) | ||
190 | void capilib_release(struct list_head *head) | ||
191 | void capilib_data_b3_conf(struct list_head *head, u16 applid, | ||
192 | u32 ncci, u16 msgid) | ||
193 | u16 capilib_data_b3_req(struct list_head *head, u16 applid, | ||
194 | u32 ncci, u16 msgid) | ||
195 | |||
196 | |||
197 | Macros to extract/set element values from/in a CAPI message header | ||
198 | (from <linux/isdn/capiutil.h>): | ||
199 | |||
200 | Get Macro Set Macro Element (Type) | ||
201 | |||
202 | CAPIMSG_LEN(m) CAPIMSG_SETLEN(m, len) Total Length (u16) | ||
203 | CAPIMSG_APPID(m) CAPIMSG_SETAPPID(m, applid) ApplID (u16) | ||
204 | CAPIMSG_COMMAND(m) CAPIMSG_SETCOMMAND(m,cmd) Command (u8) | ||
205 | CAPIMSG_SUBCOMMAND(m) CAPIMSG_SETSUBCOMMAND(m, cmd) Subcommand (u8) | ||
206 | CAPIMSG_CMD(m) - Command*256 | ||
207 | + Subcommand (u16) | ||
208 | CAPIMSG_MSGID(m) CAPIMSG_SETMSGID(m, msgid) Message Number (u16) | ||
209 | |||
210 | CAPIMSG_CONTROL(m) CAPIMSG_SETCONTROL(m, contr) Controller/PLCI/NCCI | ||
211 | (u32) | ||
212 | CAPIMSG_DATALEN(m) CAPIMSG_SETDATALEN(m, len) Data Length (u16) | ||
213 | |||