diff options
Diffstat (limited to 'Documentation/isdn/INTERFACE.CAPI')
| -rw-r--r-- | Documentation/isdn/INTERFACE.CAPI | 164 |
1 files changed, 153 insertions, 11 deletions
diff --git a/Documentation/isdn/INTERFACE.CAPI b/Documentation/isdn/INTERFACE.CAPI index 786d619b36e..1688b5a1fd7 100644 --- a/Documentation/isdn/INTERFACE.CAPI +++ b/Documentation/isdn/INTERFACE.CAPI @@ -45,7 +45,7 @@ From then on, Kernel CAPI may call the registered callback functions for the device. If the device becomes unusable for any reason (shutdown, disconnect ...), the -driver has to call capi_ctr_reseted(). This will prevent further calls to the +driver has to call capi_ctr_down(). This will prevent further calls to the callback functions by Kernel CAPI. @@ -60,10 +60,9 @@ open() operation on regular files or character devices. After a successful return from register_appl(), CAPI messages from the application may be passed to the driver for the device via calls to the -send_message() callback function. The CAPI message to send is stored in the -data portion of an skb. Conversely, the driver may call Kernel CAPI's -capi_ctr_handle_message() function to pass a received CAPI message to Kernel -CAPI for forwarding to an application, specifying its ApplID. +send_message() callback function. Conversely, the driver may call Kernel +CAPI's capi_ctr_handle_message() function to pass a received CAPI message to +Kernel CAPI for forwarding to an application, specifying its ApplID. Deregistration requests (CAPI operation CAPI_RELEASE) from applications are forwarded as calls to the release_appl() callback function, passing the same @@ -114,29 +113,54 @@ char *driver_name int (*load_firmware)(struct capi_ctr *ctrlr, capiloaddata *ldata) (optional) pointer to a callback function for sending firmware and configuration data to the device + The function may return before the operation has completed. + Completion must be signalled by a call to capi_ctr_ready(). + Return value: 0 on success, error code on error + Called in process context. void (*reset_ctr)(struct capi_ctr *ctrlr) - pointer to a callback function for performing a reset on the device, + (optional) pointer to a callback function for stopping the device, releasing all registered applications + The function may return before the operation has completed. + Completion must be signalled by a call to capi_ctr_down(). + Called in process context. void (*register_appl)(struct capi_ctr *ctrlr, u16 applid, capi_register_params *rparam) void (*release_appl)(struct capi_ctr *ctrlr, u16 applid) pointers to callback functions for registration and deregistration of applications with the device + Calls to these functions are serialized by Kernel CAPI so that only + one call to any of them is active at any time. u16 (*send_message)(struct capi_ctr *ctrlr, struct sk_buff *skb) pointer to a callback function for sending a CAPI message to the device + Return value: CAPI error code + If the method returns 0 (CAPI_NOERROR) the driver has taken ownership + of the skb and the caller may no longer access it. If it returns a + non-zero (error) value then ownership of the skb returns to the caller + who may reuse or free it. + The return value should only be used to signal problems with respect + to accepting or queueing the message. Errors occurring during the + actual processing of the message should be signaled with an + appropriate reply message. + May be called in process or interrupt context. + Calls to this function are not serialized by Kernel CAPI, ie. it must + be prepared to be re-entered. char *(*procinfo)(struct capi_ctr *ctrlr) pointer to a callback function returning the entry for the device in the CAPI controller info table, /proc/capi/controller -read_proc_t *ctr_read_proc - pointer to the read_proc callback function for the device's proc file - system entry, /proc/capi/controllers/<n>; will be called with a - pointer to the device's capi_ctr structure as the last (data) argument +const struct file_operations *proc_fops + pointers to callback functions for the device's proc file + system entry, /proc/capi/controllers/<n>; pointer to the device's + capi_ctr structure is available from struct proc_dir_entry::data + which is available from struct inode. + +Note: Callback functions except send_message() are never called in interrupt +context. - to be filled in before calling capi_ctr_ready(): @@ -153,6 +177,72 @@ u8 serial[CAPI_SERIAL_LEN] value to return for CAPI_GET_SERIAL +4.3 SKBs + +CAPI messages are passed between Kernel CAPI and the driver via send_message() +and capi_ctr_handle_message(), stored in the data portion of a socket buffer +(skb). Each skb contains a single CAPI message coded according to the CAPI 2.0 +standard. + +For the data transfer messages, DATA_B3_REQ and DATA_B3_IND, the actual +payload data immediately follows the CAPI message itself within the same skb. +The Data and Data64 parameters are not used for processing. The Data64 +parameter may be omitted by setting the length field of the CAPI message to 22 +instead of 30. + + +4.4 The _cmsg Structure + +(declared in <linux/isdn/capiutil.h>) + +The _cmsg structure stores the contents of a CAPI 2.0 message in an easily +accessible form. It contains members for all possible CAPI 2.0 parameters, +including subparameters of the Additional Info and B Protocol structured +parameters, with the following exceptions: + +* second Calling party number (CONNECT_IND) + +* Data64 (DATA_B3_REQ and DATA_B3_IND) + +* Sending complete (subparameter of Additional Info, CONNECT_REQ and INFO_REQ) + +* Global Configuration (subparameter of B Protocol, CONNECT_REQ, CONNECT_RESP + and SELECT_B_PROTOCOL_REQ) + +Only those parameters appearing in the message type currently being processed +are actually used. Unused members should be set to zero. + +Members are named after the CAPI 2.0 standard names of the parameters they +represent. See <linux/isdn/capiutil.h> for the exact spelling. Member data +types are: + +u8 for CAPI parameters of type 'byte' + +u16 for CAPI parameters of type 'word' + +u32 for CAPI parameters of type 'dword' + +_cstruct for CAPI parameters of type 'struct' + The member is a pointer to a buffer containing the parameter in + CAPI encoding (length + content). It may also be NULL, which will + be taken to represent an empty (zero length) parameter. + Subparameters are stored in encoded form within the content part. + +_cmstruct alternative representation for CAPI parameters of type 'struct' + (used only for the 'Additional Info' and 'B Protocol' parameters) + The representation is a single byte containing one of the values: + CAPI_DEFAULT: The parameter is empty/absent. + CAPI_COMPOSE: The parameter is present. + Subparameter values are stored individually in the corresponding + _cmsg structure members. + +Functions capi_cmsg2message() and capi_message2cmsg() are provided to convert +messages between their transport encoding described in the CAPI 2.0 standard +and their _cmsg structure representation. Note that capi_cmsg2message() does +not know or check the size of its destination buffer. The caller must make +sure it is big enough to accommodate the resulting CAPI message. + + 5. Lower Layer Interface Functions (declared in <linux/isdn/capilli.h>) @@ -166,7 +256,7 @@ int detach_capi_ctr(struct capi_ctr *ctrlr) register/unregister a device (controller) with Kernel CAPI void capi_ctr_ready(struct capi_ctr *ctrlr) -void capi_ctr_reseted(struct capi_ctr *ctrlr) +void capi_ctr_down(struct capi_ctr *ctrlr) signal controller ready/not ready void capi_ctr_suspend_output(struct capi_ctr *ctrlr) @@ -211,3 +301,55 @@ CAPIMSG_CONTROL(m) CAPIMSG_SETCONTROL(m, contr) Controller/PLCI/NCCI (u32) CAPIMSG_DATALEN(m) CAPIMSG_SETDATALEN(m, len) Data Length (u16) + +Library functions for working with _cmsg structures +(from <linux/isdn/capiutil.h>): + +unsigned capi_cmsg2message(_cmsg *cmsg, u8 *msg) + Assembles a CAPI 2.0 message from the parameters in *cmsg, storing the + result in *msg. + +unsigned capi_message2cmsg(_cmsg *cmsg, u8 *msg) + Disassembles the CAPI 2.0 message in *msg, storing the parameters in + *cmsg. + +unsigned capi_cmsg_header(_cmsg *cmsg, u16 ApplId, u8 Command, u8 Subcommand, + u16 Messagenumber, u32 Controller) + Fills the header part and address field of the _cmsg structure *cmsg + with the given values, zeroing the remainder of the structure so only + parameters with non-default values need to be changed before sending + the message. + +void capi_cmsg_answer(_cmsg *cmsg) + Sets the low bit of the Subcommand field in *cmsg, thereby converting + _REQ to _CONF and _IND to _RESP. + +char *capi_cmd2str(u8 Command, u8 Subcommand) + Returns the CAPI 2.0 message name corresponding to the given command + and subcommand values, as a static ASCII string. The return value may + be NULL if the command/subcommand is not one of those defined in the + CAPI 2.0 standard. + + +7. Debugging + +The module kernelcapi has a module parameter showcapimsgs controlling some +debugging output produced by the module. It can only be set when the module is +loaded, via a parameter "showcapimsgs=<n>" to the modprobe command, either on +the command line or in the configuration file. + +If the lowest bit of showcapimsgs is set, kernelcapi logs controller and +application up and down events. + +In addition, every registered CAPI controller has an associated traceflag +parameter controlling how CAPI messages sent from and to tha controller are +logged. The traceflag parameter is initialized with the value of the +showcapimsgs parameter when the controller is registered, but can later be +changed via the MANUFACTURER_REQ command KCAPI_CMD_TRACE. + +If the value of traceflag is non-zero, CAPI messages are logged. +DATA_B3 messages are only logged if the value of traceflag is > 2. + +If the lowest bit of traceflag is set, only the command/subcommand and message +length are logged. Otherwise, kernelcapi logs a readable representation of +the entire message. |