From 554f200e22a13e19bd407d0037e41be0ec8a0a2e Mon Sep 17 00:00:00 2001 From: Tilman Schmidt Date: Thu, 23 Apr 2009 02:24:21 +0000 Subject: [PATCH] Documentation/isdn/INTERFACE.CAPI isdn: document Kernel CAPI driver interface Create a file Documentation/isdn/INTERFACE.CAPI describing the interface between the kernel CAPI subsystem and ISDN device drivers, analogous to the existing Documentation/isdn/INTERFACE for the old isdn4linux subsystem. Also add kerneldoc comments to the exported functions in drivers/isdn/capi/kcapi.c. Impact: Documentation Signed-off-by: Tilman Schmidt Signed-off-by: Karsten Keil Signed-off-by: David S. Miller --- Documentation/isdn/00-INDEX | 2 + Documentation/isdn/INTERFACE.CAPI | 207 ++++++++++++++++++++++++++++++++++++++ drivers/isdn/capi/kcapi.c | 171 +++++++++++++++++++++++++++++++ 3 files changed, 380 insertions(+) create mode 100644 Documentation/isdn/INTERFACE.CAPI diff --git a/Documentation/isdn/00-INDEX b/Documentation/isdn/00-INDEX index d9660ee..5a2d699 100644 --- a/Documentation/isdn/00-INDEX +++ b/Documentation/isdn/00-INDEX @@ -8,6 +8,8 @@ INTERFACE - description of isdn4linux Link Level and Hardware Level interfaces. INTERFACE.fax - description of the fax subinterface of isdn4linux. +INTERFACE.CAPI + - description of kernel CAPI Link Level to Hardware Level interface. README - general info on what you need and what to do for Linux ISDN. README.FAQ diff --git a/Documentation/isdn/INTERFACE.CAPI b/Documentation/isdn/INTERFACE.CAPI new file mode 100644 index 0000000..8947ffc --- /dev/null +++ b/Documentation/isdn/INTERFACE.CAPI @@ -0,0 +1,207 @@ +Kernel CAPI Interface to Hardware Drivers +----------------------------------------- + +1. Overview + +Kernel CAPI operates as a dispatching layer between CAPI applications and CAPI +hardware drivers. Hardware drivers register ISDN devices (controllers, in CAPI +lingo) with Kernel CAPI to indicate their readiness to provide their service +to CAPI applications. CAPI applications also register with Kernel CAPI, +requesting association with a CAPI device. Kernel CAPI then dispatches the +application registration to an available device, forwarding it to the +corresponding hardware driver. Kernel CAPI then forwards CAPI messages in both +directions between the application and the hardware driver. + + +2. Driver and Device Registration + +CAPI drivers optionally register themselves with Kernel CAPI by calling the +Kernel CAPI function register_capi_driver() with a pointer to a struct +capi_driver. This structure must be filled with the name and revision of the +driver, and optionally a pointer to a callback function, add_card(). The +registration can be revoked by calling the function unregister_capi_driver() +with a pointer to the same struct capi_driver. + +CAPI drivers must register each of the ISDN devices they control with Kernel +CAPI by calling the Kernel CAPI function attach_capi_ctr() with a pointer to a +struct capi_ctr before they can be used. This structure must be filled with +the names of the driver and controller, and a number of callback function +pointers which are subsequently used by Kernel CAPI for communicating with the +driver. The registration can be revoked by calling the function +detach_capi_ctr() with a pointer to the same struct capi_ctr. + +Before the device can be actually used, the driver must fill in the device +information fields 'manu', 'version', 'profile' and 'serial' in the capi_ctr +structure of the device, and signal its readiness by calling capi_ctr_ready(). +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 +callback functions by Kernel CAPI. + + +3. Application Registration and Communication + +Kernel CAPI forwards registration requests from applications (calls to CAPI +operation CAPI_REGISTER) to an appropriate hardware driver by calling its +register_appl() callback function. A unique Application ID (ApplID, u16) is +allocated by Kernel CAPI and passed to register_appl() along with the +parameter structure provided by the application. This is analogous to the +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 a 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. + +Format and semantics of CAPI messages are specified in the CAPI 2.0 standard. + +Deregistration requests (CAPI operation CAPI_RELEASE) from applications are +forwarded as calls to the release_appl() callback function, passing the same +ApplID as with register_appl(). After return from release_appl(), no CAPI +messages for that application may be passed to or from the device anymore. + + +4. Data Structures + +4.1 struct capi_driver + +This structure describes a Kernel CAPI driver itself. It is used in the +register_capi_driver() and unregister_capi_driver() functions, and contains +the following non-private fields, all to be set by the driver before calling +register_capi_driver(): + +char name[32] + the name of the driver, as a zero terminated ASCII string +char revision[32] + the revision number of the driver, as a zero terminated ASCII string +int (*add_card)(struct capi_driver *driver, capicardparams *data) + a callback function pointer (may be NULL) + + +4.2 struct capi_ctr + +This structure describes an ISDN device (controller) handled by a Kernel CAPI +driver. After registration via the attach_capi_ctr() function it is passed to +all controller specific lower layer interface and callback functions to +identify the controller to operate on. + +It contains the following non-private fields: + +- to be set by the driver before calling attach_capi_ctr(): + +struct module *owner + pointer to the driver module owning the device + +void *driverdata + an opaque pointer to driver specific data, not touched by Kernel CAPI + +char name[32] + the name of the controller, as a zero terminated ASCII string + +char *driver_name + the name of the driver, as a zero terminated ASCII string + +int (*load_firmware)(struct capi_ctr *ctrlr, capiloaddata *ldata) + (optional) pointer to a callback function for sending firmware and + configuration data to the device + +void (*reset_ctr)(struct capi_ctr *ctrlr) + pointer to a callback function for performing a reset on the device, + releasing all registered applications + +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 + +u16 (*send_message)(struct capi_ctr *ctrlr, struct sk_buff *skb) + pointer to a callback function for sending a CAPI message to the + device + +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/; will be called with a + pointer to the device's capi_ctr structure as the last (data) argument + +- to be filled in before calling capi_ctr_ready(): + +u8 manu[CAPI_MANUFACTURER_LEN] + value to return for CAPI_GET_MANUFACTURER + +capi_version version + value to return for CAPI_GET_VERSION + +capi_profile profile + value to return for CAPI_GET_PROFILE + +u8 serial[CAPI_SERIAL_LEN] + value to return for CAPI_GET_SERIAL + + +5. Lower Layer Interface Functions + +(declared in ) + +void register_capi_driver(struct capi_driver *drvr) +void unregister_capi_driver(struct capi_driver *drvr) + register/unregister a driver with Kernel CAPI + +int attach_capi_ctr(struct capi_ctr *ctrlr) +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) + signal controller ready/not ready + +void capi_ctr_suspend_output(struct capi_ctr *ctrlr) +void capi_ctr_resume_output(struct capi_ctr *ctrlr) + signal suspend/resume + +void capi_ctr_handle_message(struct capi_ctr * ctrlr, u16 applid, + struct sk_buff *skb) + pass a received CAPI message to Kernel CAPI + for forwarding to the specified application + + +6. Helper Functions and Macros + +Library functions (from ): + +void capilib_new_ncci(struct list_head *head, u16 applid, + u32 ncci, u32 winsize) +void capilib_free_ncci(struct list_head *head, u16 applid, u32 ncci) +void capilib_release_appl(struct list_head *head, u16 applid) +void capilib_release(struct list_head *head) +void capilib_data_b3_conf(struct list_head *head, u16 applid, + u32 ncci, u16 msgid) +u16 capilib_data_b3_req(struct list_head *head, u16 applid, + u32 ncci, u16 msgid) + + +Macros to extract/set element values from/in a CAPI message header +(from ): + +Get Macro Set Macro Element (Type) + +CAPIMSG_LEN(m) CAPIMSG_SETLEN(m, len) Total Length (u16) +CAPIMSG_APPID(m) CAPIMSG_SETAPPID(m, applid) ApplID (u16) +CAPIMSG_COMMAND(m) CAPIMSG_SETCOMMAND(m,cmd) Command (u8) +CAPIMSG_SUBCOMMAND(m) CAPIMSG_SETSUBCOMMAND(m, cmd) Subcommand (u8) +CAPIMSG_CMD(m) - Command*256 + + Subcommand (u16) +CAPIMSG_MSGID(m) CAPIMSG_SETMSGID(m, msgid) Message Number (u16) + +CAPIMSG_CONTROL(m) CAPIMSG_SETCONTROL(m, contr) Controller/PLCI/NCCI + (u32) +CAPIMSG_DATALEN(m) CAPIMSG_SETDATALEN(m, len) Data Length (u16) + diff --git a/drivers/isdn/capi/kcapi.c b/drivers/isdn/capi/kcapi.c index 5360c4f..f331703 100644 --- a/drivers/isdn/capi/kcapi.c +++ b/drivers/isdn/capi/kcapi.c @@ -270,6 +270,15 @@ static void recv_handler(struct work_struct *work) mutex_unlock(&ap->recv_mtx); } +/** + * capi_ctr_handle_message() - handle incoming CAPI message + * @card: controller descriptor structure. + * @appl: application ID. + * @skb: message. + * + * Called by hardware driver to pass a CAPI message to the application. + */ + void capi_ctr_handle_message(struct capi_ctr * card, u16 appl, struct sk_buff *skb) { struct capi20_appl *ap; @@ -348,6 +357,13 @@ error: EXPORT_SYMBOL(capi_ctr_handle_message); +/** + * capi_ctr_ready() - signal CAPI controller ready + * @card: controller descriptor structure. + * + * Called by hardware driver to signal that the controller is up and running. + */ + void capi_ctr_ready(struct capi_ctr * card) { card->cardstate = CARD_RUNNING; @@ -360,6 +376,14 @@ void capi_ctr_ready(struct capi_ctr * card) EXPORT_SYMBOL(capi_ctr_ready); +/** + * capi_ctr_reseted() - signal CAPI controller reset + * @card: controller descriptor structure. + * + * Called by hardware driver to signal that the controller is down and + * unavailable for use. + */ + void capi_ctr_reseted(struct capi_ctr * card) { u16 appl; @@ -391,6 +415,13 @@ void capi_ctr_reseted(struct capi_ctr * card) EXPORT_SYMBOL(capi_ctr_reseted); +/** + * capi_ctr_suspend_output() - suspend controller + * @card: controller descriptor structure. + * + * Called by hardware driver to stop data flow. + */ + void capi_ctr_suspend_output(struct capi_ctr *card) { if (!card->blocked) { @@ -401,6 +432,13 @@ void capi_ctr_suspend_output(struct capi_ctr *card) EXPORT_SYMBOL(capi_ctr_suspend_output); +/** + * capi_ctr_resume_output() - resume controller + * @card: controller descriptor structure. + * + * Called by hardware driver to resume data flow. + */ + void capi_ctr_resume_output(struct capi_ctr *card) { if (card->blocked) { @@ -413,6 +451,14 @@ EXPORT_SYMBOL(capi_ctr_resume_output); /* ------------------------------------------------------------- */ +/** + * attach_capi_ctr() - register CAPI controller + * @card: controller descriptor structure. + * + * Called by hardware driver to register a controller with the CAPI subsystem. + * Return value: 0 on success, error code < 0 on error + */ + int attach_capi_ctr(struct capi_ctr *card) { @@ -459,6 +505,15 @@ attach_capi_ctr(struct capi_ctr *card) EXPORT_SYMBOL(attach_capi_ctr); +/** + * detach_capi_ctr() - unregister CAPI controller + * @card: controller descriptor structure. + * + * Called by hardware driver to remove the registration of a controller + * with the CAPI subsystem. + * Return value: 0 on success, error code < 0 on error + */ + int detach_capi_ctr(struct capi_ctr *card) { if (card->cardstate != CARD_DETECTED) @@ -479,6 +534,13 @@ int detach_capi_ctr(struct capi_ctr *card) EXPORT_SYMBOL(detach_capi_ctr); +/** + * register_capi_driver() - register CAPI driver + * @driver: driver descriptor structure. + * + * Called by hardware driver to register itself with the CAPI subsystem. + */ + void register_capi_driver(struct capi_driver *driver) { unsigned long flags; @@ -490,6 +552,13 @@ void register_capi_driver(struct capi_driver *driver) EXPORT_SYMBOL(register_capi_driver); +/** + * unregister_capi_driver() - unregister CAPI driver + * @driver: driver descriptor structure. + * + * Called by hardware driver to unregister itself from the CAPI subsystem. + */ + void unregister_capi_driver(struct capi_driver *driver) { unsigned long flags; @@ -505,6 +574,13 @@ EXPORT_SYMBOL(unregister_capi_driver); /* -------- CAPI2.0 Interface ---------------------------------- */ /* ------------------------------------------------------------- */ +/** + * capi20_isinstalled() - CAPI 2.0 operation CAPI_INSTALLED + * + * Return value: CAPI result code (CAPI_NOERROR if at least one ISDN controller + * is ready for use, CAPI_REGNOTINSTALLED otherwise) + */ + u16 capi20_isinstalled(void) { int i; @@ -517,6 +593,18 @@ u16 capi20_isinstalled(void) EXPORT_SYMBOL(capi20_isinstalled); +/** + * capi20_register() - CAPI 2.0 operation CAPI_REGISTER + * @ap: CAPI application descriptor structure. + * + * Register an application's presence with CAPI. + * A unique application ID is assigned and stored in @ap->applid. + * After this function returns successfully, the message receive + * callback function @ap->recv_message() may be called at any time + * until capi20_release() has been called for the same @ap. + * Return value: CAPI result code + */ + u16 capi20_register(struct capi20_appl *ap) { int i; @@ -571,6 +659,16 @@ u16 capi20_register(struct capi20_appl *ap) EXPORT_SYMBOL(capi20_register); +/** + * capi20_release() - CAPI 2.0 operation CAPI_RELEASE + * @ap: CAPI application descriptor structure. + * + * Terminate an application's registration with CAPI. + * After this function returns successfully, the message receive + * callback function @ap->recv_message() will no longer be called. + * Return value: CAPI result code + */ + u16 capi20_release(struct capi20_appl *ap) { int i; @@ -603,6 +701,15 @@ u16 capi20_release(struct capi20_appl *ap) EXPORT_SYMBOL(capi20_release); +/** + * capi20_put_message() - CAPI 2.0 operation CAPI_PUT_MESSAGE + * @ap: CAPI application descriptor structure. + * @skb: CAPI message. + * + * Transfer a single message to CAPI. + * Return value: CAPI result code + */ + u16 capi20_put_message(struct capi20_appl *ap, struct sk_buff *skb) { struct capi_ctr *card; @@ -668,6 +775,16 @@ u16 capi20_put_message(struct capi20_appl *ap, struct sk_buff *skb) EXPORT_SYMBOL(capi20_put_message); +/** + * capi20_get_manufacturer() - CAPI 2.0 operation CAPI_GET_MANUFACTURER + * @contr: controller number. + * @buf: result buffer (64 bytes). + * + * Retrieve information about the manufacturer of the specified ISDN controller + * or (for @contr == 0) the driver itself. + * Return value: CAPI result code + */ + u16 capi20_get_manufacturer(u32 contr, u8 *buf) { struct capi_ctr *card; @@ -685,6 +802,16 @@ u16 capi20_get_manufacturer(u32 contr, u8 *buf) EXPORT_SYMBOL(capi20_get_manufacturer); +/** + * capi20_get_version() - CAPI 2.0 operation CAPI_GET_VERSION + * @contr: controller number. + * @verp: result structure. + * + * Retrieve version information for the specified ISDN controller + * or (for @contr == 0) the driver itself. + * Return value: CAPI result code + */ + u16 capi20_get_version(u32 contr, struct capi_version *verp) { struct capi_ctr *card; @@ -703,6 +830,16 @@ u16 capi20_get_version(u32 contr, struct capi_version *verp) EXPORT_SYMBOL(capi20_get_version); +/** + * capi20_get_serial() - CAPI 2.0 operation CAPI_GET_SERIAL_NUMBER + * @contr: controller number. + * @serial: result buffer (8 bytes). + * + * Retrieve the serial number of the specified ISDN controller + * or (for @contr == 0) the driver itself. + * Return value: CAPI result code + */ + u16 capi20_get_serial(u32 contr, u8 *serial) { struct capi_ctr *card; @@ -721,6 +858,16 @@ u16 capi20_get_serial(u32 contr, u8 *serial) EXPORT_SYMBOL(capi20_get_serial); +/** + * capi20_get_profile() - CAPI 2.0 operation CAPI_GET_PROFILE + * @contr: controller number. + * @profp: result structure. + * + * Retrieve capability information for the specified ISDN controller + * or (for @contr == 0) the number of installed controllers. + * Return value: CAPI result code + */ + u16 capi20_get_profile(u32 contr, struct capi_profile *profp) { struct capi_ctr *card; @@ -903,6 +1050,15 @@ static int old_capi_manufacturer(unsigned int cmd, void __user *data) } #endif +/** + * capi20_manufacturer() - CAPI 2.0 operation CAPI_MANUFACTURER + * @cmd: command. + * @data: parameter. + * + * Perform manufacturer specific command. + * Return value: CAPI result code + */ + int capi20_manufacturer(unsigned int cmd, void __user *data) { struct capi_ctr *card; @@ -981,6 +1137,21 @@ int capi20_manufacturer(unsigned int cmd, void __user *data) EXPORT_SYMBOL(capi20_manufacturer); /* temporary hack */ + +/** + * capi20_set_callback() - set CAPI application notification callback function + * @ap: CAPI application descriptor structure. + * @callback: callback function (NULL to remove). + * + * If not NULL, the callback function will be called to notify the + * application of the addition or removal of a controller. + * The first argument (cmd) will tell whether the controller was added + * (KCI_CONTRUP) or removed (KCI_CONTRDOWN). + * The second argument (contr) will be the controller number. + * For cmd==KCI_CONTRUP the third argument (data) will be a pointer to the + * new controller's capability profile structure. + */ + void capi20_set_callback(struct capi20_appl *ap, void (*callback) (unsigned int cmd, __u32 contr, void *data)) { -- 2.7.4