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
int (*load_firmware)(struct capi_ctr *ctrlr, capiloaddata *ldata)
(optional) pointer to a callback function for sending firmware and
configuration data to the device
+ 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,
- releasing all registered applications
+ (optional) pointer to a callback function for performing a reset on
+ the device, releasing all registered applications
+ 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():
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 accomodate the resulting CAPI message.
+
+
5. Lower Layer Interface Functions
(declared in <linux/isdn/capilli.h>)
(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.