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 <tilman@imap.cc> Signed-off-by: Karsten Keil <keil@b1-systems.de> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -8,6 +8,8 @@ INTERFACE
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- description of isdn4linux Link Level and Hardware Level interfaces.
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INTERFACE.fax
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- description of the fax subinterface of isdn4linux.
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INTERFACE.CAPI
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- description of kernel CAPI Link Level to Hardware Level interface.
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README
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- general info on what you need and what to do for Linux ISDN.
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README.FAQ
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207
Documentation/isdn/INTERFACE.CAPI
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207
Documentation/isdn/INTERFACE.CAPI
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@ -0,0 +1,207 @@
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Kernel CAPI Interface to Hardware Drivers
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-----------------------------------------
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1. Overview
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Kernel CAPI operates as a dispatching layer between CAPI applications and CAPI
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hardware drivers. Hardware drivers register ISDN devices (controllers, in CAPI
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lingo) with Kernel CAPI to indicate their readiness to provide their service
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to CAPI applications. CAPI applications also register with Kernel CAPI,
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requesting association with a CAPI device. Kernel CAPI then dispatches the
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application registration to an available device, forwarding it to the
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corresponding hardware driver. Kernel CAPI then forwards CAPI messages in both
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directions between the application and the hardware driver.
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2. Driver and Device Registration
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CAPI drivers optionally register themselves with Kernel CAPI by calling the
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Kernel CAPI function register_capi_driver() with a pointer to a struct
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capi_driver. This structure must be filled with the name and revision of the
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driver, and optionally a pointer to a callback function, add_card(). The
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registration can be revoked by calling the function unregister_capi_driver()
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with a pointer to the same struct capi_driver.
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CAPI drivers must register each of the ISDN devices they control with Kernel
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CAPI by calling the Kernel CAPI function attach_capi_ctr() with a pointer to a
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struct capi_ctr before they can be used. This structure must be filled with
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the names of the driver and controller, and a number of callback function
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pointers which are subsequently used by Kernel CAPI for communicating with the
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driver. The registration can be revoked by calling the function
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detach_capi_ctr() with a pointer to the same struct capi_ctr.
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Before the device can be actually used, the driver must fill in the device
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information fields 'manu', 'version', 'profile' and 'serial' in the capi_ctr
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structure of the device, and signal its readiness by calling capi_ctr_ready().
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From then on, Kernel CAPI may call the registered callback functions for the
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device.
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If the device becomes unusable for any reason (shutdown, disconnect ...), the
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driver has to call capi_ctr_reseted(). This will prevent further calls to the
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callback functions by Kernel CAPI.
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3. Application Registration and Communication
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Kernel CAPI forwards registration requests from applications (calls to CAPI
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operation CAPI_REGISTER) to an appropriate hardware driver by calling its
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register_appl() callback function. A unique Application ID (ApplID, u16) is
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allocated by Kernel CAPI and passed to register_appl() along with the
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parameter structure provided by the application. This is analogous to the
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open() operation on regular files or character devices.
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After a successful return from register_appl(), CAPI messages from the
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application may be passed to the driver for the device via calls to the
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send_message() callback function. The CAPI message to send is stored in the
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data portion of a skb. Conversely, the driver may call Kernel CAPI's
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capi_ctr_handle_message() function to pass a received CAPI message to Kernel
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CAPI for forwarding to an application, specifying its ApplID.
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Format and semantics of CAPI messages are specified in the CAPI 2.0 standard.
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Deregistration requests (CAPI operation CAPI_RELEASE) from applications are
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forwarded as calls to the release_appl() callback function, passing the same
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ApplID as with register_appl(). After return from release_appl(), no CAPI
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messages for that application may be passed to or from the device anymore.
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4. Data Structures
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4.1 struct capi_driver
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This structure describes a Kernel CAPI driver itself. It is used in the
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register_capi_driver() and unregister_capi_driver() functions, and contains
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the following non-private fields, all to be set by the driver before calling
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register_capi_driver():
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char name[32]
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the name of the driver, as a zero terminated ASCII string
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char revision[32]
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the revision number of the driver, as a zero terminated ASCII string
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int (*add_card)(struct capi_driver *driver, capicardparams *data)
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a callback function pointer (may be NULL)
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4.2 struct capi_ctr
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This structure describes an ISDN device (controller) handled by a Kernel CAPI
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driver. After registration via the attach_capi_ctr() function it is passed to
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all controller specific lower layer interface and callback functions to
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identify the controller to operate on.
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It contains the following non-private fields:
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- to be set by the driver before calling attach_capi_ctr():
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struct module *owner
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pointer to the driver module owning the device
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void *driverdata
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an opaque pointer to driver specific data, not touched by Kernel CAPI
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char name[32]
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the name of the controller, as a zero terminated ASCII string
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char *driver_name
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the name of the driver, as a zero terminated ASCII string
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int (*load_firmware)(struct capi_ctr *ctrlr, capiloaddata *ldata)
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(optional) pointer to a callback function for sending firmware and
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configuration data to the device
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void (*reset_ctr)(struct capi_ctr *ctrlr)
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pointer to a callback function for performing a reset on the device,
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releasing all registered applications
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void (*register_appl)(struct capi_ctr *ctrlr, u16 applid,
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capi_register_params *rparam)
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void (*release_appl)(struct capi_ctr *ctrlr, u16 applid)
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pointers to callback functions for registration and deregistration of
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applications with the device
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u16 (*send_message)(struct capi_ctr *ctrlr, struct sk_buff *skb)
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pointer to a callback function for sending a CAPI message to the
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device
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char *(*procinfo)(struct capi_ctr *ctrlr)
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pointer to a callback function returning the entry for the device in
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the CAPI controller info table, /proc/capi/controller
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read_proc_t *ctr_read_proc
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pointer to the read_proc callback function for the device's proc file
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system entry, /proc/capi/controllers/<n>; will be called with a
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pointer to the device's capi_ctr structure as the last (data) argument
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- to be filled in before calling capi_ctr_ready():
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u8 manu[CAPI_MANUFACTURER_LEN]
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value to return for CAPI_GET_MANUFACTURER
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capi_version version
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value to return for CAPI_GET_VERSION
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capi_profile profile
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value to return for CAPI_GET_PROFILE
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u8 serial[CAPI_SERIAL_LEN]
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value to return for CAPI_GET_SERIAL
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5. Lower Layer Interface Functions
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(declared in <linux/isdn/capilli.h>)
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void register_capi_driver(struct capi_driver *drvr)
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void unregister_capi_driver(struct capi_driver *drvr)
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register/unregister a driver with Kernel CAPI
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int attach_capi_ctr(struct capi_ctr *ctrlr)
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int detach_capi_ctr(struct capi_ctr *ctrlr)
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register/unregister a device (controller) with Kernel CAPI
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void capi_ctr_ready(struct capi_ctr *ctrlr)
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void capi_ctr_reseted(struct capi_ctr *ctrlr)
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signal controller ready/not ready
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void capi_ctr_suspend_output(struct capi_ctr *ctrlr)
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void capi_ctr_resume_output(struct capi_ctr *ctrlr)
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signal suspend/resume
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void capi_ctr_handle_message(struct capi_ctr * ctrlr, u16 applid,
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struct sk_buff *skb)
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pass a received CAPI message to Kernel CAPI
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for forwarding to the specified application
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6. Helper Functions and Macros
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Library functions (from <linux/isdn/capilli.h>):
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void capilib_new_ncci(struct list_head *head, u16 applid,
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u32 ncci, u32 winsize)
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void capilib_free_ncci(struct list_head *head, u16 applid, u32 ncci)
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void capilib_release_appl(struct list_head *head, u16 applid)
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void capilib_release(struct list_head *head)
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void capilib_data_b3_conf(struct list_head *head, u16 applid,
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u32 ncci, u16 msgid)
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u16 capilib_data_b3_req(struct list_head *head, u16 applid,
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u32 ncci, u16 msgid)
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Macros to extract/set element values from/in a CAPI message header
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(from <linux/isdn/capiutil.h>):
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Get Macro Set Macro Element (Type)
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CAPIMSG_LEN(m) CAPIMSG_SETLEN(m, len) Total Length (u16)
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CAPIMSG_APPID(m) CAPIMSG_SETAPPID(m, applid) ApplID (u16)
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CAPIMSG_COMMAND(m) CAPIMSG_SETCOMMAND(m,cmd) Command (u8)
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CAPIMSG_SUBCOMMAND(m) CAPIMSG_SETSUBCOMMAND(m, cmd) Subcommand (u8)
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CAPIMSG_CMD(m) - Command*256
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+ Subcommand (u16)
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CAPIMSG_MSGID(m) CAPIMSG_SETMSGID(m, msgid) Message Number (u16)
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CAPIMSG_CONTROL(m) CAPIMSG_SETCONTROL(m, contr) Controller/PLCI/NCCI
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(u32)
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CAPIMSG_DATALEN(m) CAPIMSG_SETDATALEN(m, len) Data Length (u16)
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@ -270,6 +270,15 @@ static void recv_handler(struct work_struct *work)
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mutex_unlock(&ap->recv_mtx);
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}
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/**
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* capi_ctr_handle_message() - handle incoming CAPI message
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* @card: controller descriptor structure.
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* @appl: application ID.
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* @skb: message.
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*
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* Called by hardware driver to pass a CAPI message to the application.
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*/
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void capi_ctr_handle_message(struct capi_ctr * card, u16 appl, struct sk_buff *skb)
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{
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struct capi20_appl *ap;
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@ -348,6 +357,13 @@ void capi_ctr_handle_message(struct capi_ctr * card, u16 appl, struct sk_buff *s
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EXPORT_SYMBOL(capi_ctr_handle_message);
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/**
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* capi_ctr_ready() - signal CAPI controller ready
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* @card: controller descriptor structure.
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*
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* Called by hardware driver to signal that the controller is up and running.
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*/
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void capi_ctr_ready(struct capi_ctr * card)
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{
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card->cardstate = CARD_RUNNING;
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@ -360,6 +376,14 @@ void capi_ctr_ready(struct capi_ctr * card)
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EXPORT_SYMBOL(capi_ctr_ready);
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/**
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* capi_ctr_reseted() - signal CAPI controller reset
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* @card: controller descriptor structure.
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*
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* Called by hardware driver to signal that the controller is down and
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* unavailable for use.
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*/
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void capi_ctr_reseted(struct capi_ctr * card)
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{
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u16 appl;
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@ -391,6 +415,13 @@ void capi_ctr_reseted(struct capi_ctr * card)
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EXPORT_SYMBOL(capi_ctr_reseted);
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/**
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* capi_ctr_suspend_output() - suspend controller
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* @card: controller descriptor structure.
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*
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* Called by hardware driver to stop data flow.
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*/
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void capi_ctr_suspend_output(struct capi_ctr *card)
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{
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if (!card->blocked) {
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@ -401,6 +432,13 @@ void capi_ctr_suspend_output(struct capi_ctr *card)
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EXPORT_SYMBOL(capi_ctr_suspend_output);
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/**
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* capi_ctr_resume_output() - resume controller
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* @card: controller descriptor structure.
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*
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* Called by hardware driver to resume data flow.
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*/
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void capi_ctr_resume_output(struct capi_ctr *card)
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{
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if (card->blocked) {
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@ -413,6 +451,14 @@ EXPORT_SYMBOL(capi_ctr_resume_output);
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/* ------------------------------------------------------------- */
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/**
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* attach_capi_ctr() - register CAPI controller
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* @card: controller descriptor structure.
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*
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* Called by hardware driver to register a controller with the CAPI subsystem.
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* Return value: 0 on success, error code < 0 on error
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*/
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int
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attach_capi_ctr(struct capi_ctr *card)
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{
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@ -459,6 +505,15 @@ attach_capi_ctr(struct capi_ctr *card)
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EXPORT_SYMBOL(attach_capi_ctr);
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/**
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* detach_capi_ctr() - unregister CAPI controller
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* @card: controller descriptor structure.
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*
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* Called by hardware driver to remove the registration of a controller
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* with the CAPI subsystem.
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* Return value: 0 on success, error code < 0 on error
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*/
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int detach_capi_ctr(struct capi_ctr *card)
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{
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if (card->cardstate != CARD_DETECTED)
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@ -479,6 +534,13 @@ int detach_capi_ctr(struct capi_ctr *card)
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EXPORT_SYMBOL(detach_capi_ctr);
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/**
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* register_capi_driver() - register CAPI driver
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* @driver: driver descriptor structure.
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*
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* Called by hardware driver to register itself with the CAPI subsystem.
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*/
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void register_capi_driver(struct capi_driver *driver)
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{
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unsigned long flags;
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@ -490,6 +552,13 @@ void register_capi_driver(struct capi_driver *driver)
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EXPORT_SYMBOL(register_capi_driver);
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/**
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* unregister_capi_driver() - unregister CAPI driver
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* @driver: driver descriptor structure.
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*
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* Called by hardware driver to unregister itself from the CAPI subsystem.
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*/
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void unregister_capi_driver(struct capi_driver *driver)
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{
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unsigned long flags;
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@ -505,6 +574,13 @@ EXPORT_SYMBOL(unregister_capi_driver);
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/* -------- CAPI2.0 Interface ---------------------------------- */
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/* ------------------------------------------------------------- */
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/**
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* capi20_isinstalled() - CAPI 2.0 operation CAPI_INSTALLED
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*
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* Return value: CAPI result code (CAPI_NOERROR if at least one ISDN controller
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* is ready for use, CAPI_REGNOTINSTALLED otherwise)
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*/
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u16 capi20_isinstalled(void)
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{
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int i;
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@ -517,6 +593,18 @@ u16 capi20_isinstalled(void)
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EXPORT_SYMBOL(capi20_isinstalled);
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/**
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* capi20_register() - CAPI 2.0 operation CAPI_REGISTER
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* @ap: CAPI application descriptor structure.
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*
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* Register an application's presence with CAPI.
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* A unique application ID is assigned and stored in @ap->applid.
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* After this function returns successfully, the message receive
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* callback function @ap->recv_message() may be called at any time
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* until capi20_release() has been called for the same @ap.
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* Return value: CAPI result code
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*/
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u16 capi20_register(struct capi20_appl *ap)
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{
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int i;
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@ -571,6 +659,16 @@ u16 capi20_register(struct capi20_appl *ap)
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EXPORT_SYMBOL(capi20_register);
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/**
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* capi20_release() - CAPI 2.0 operation CAPI_RELEASE
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* @ap: CAPI application descriptor structure.
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*
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* Terminate an application's registration with CAPI.
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* After this function returns successfully, the message receive
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* callback function @ap->recv_message() will no longer be called.
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* Return value: CAPI result code
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*/
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u16 capi20_release(struct capi20_appl *ap)
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{
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int i;
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@ -603,6 +701,15 @@ u16 capi20_release(struct capi20_appl *ap)
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EXPORT_SYMBOL(capi20_release);
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/**
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* capi20_put_message() - CAPI 2.0 operation CAPI_PUT_MESSAGE
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* @ap: CAPI application descriptor structure.
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* @skb: CAPI message.
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*
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* Transfer a single message to CAPI.
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* Return value: CAPI result code
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*/
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u16 capi20_put_message(struct capi20_appl *ap, struct sk_buff *skb)
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{
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struct capi_ctr *card;
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@ -668,6 +775,16 @@ u16 capi20_put_message(struct capi20_appl *ap, struct sk_buff *skb)
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EXPORT_SYMBOL(capi20_put_message);
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/**
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* capi20_get_manufacturer() - CAPI 2.0 operation CAPI_GET_MANUFACTURER
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* @contr: controller number.
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* @buf: result buffer (64 bytes).
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*
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* Retrieve information about the manufacturer of the specified ISDN controller
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* or (for @contr == 0) the driver itself.
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* Return value: CAPI result code
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*/
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u16 capi20_get_manufacturer(u32 contr, u8 *buf)
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{
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struct capi_ctr *card;
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@ -685,6 +802,16 @@ u16 capi20_get_manufacturer(u32 contr, u8 *buf)
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EXPORT_SYMBOL(capi20_get_manufacturer);
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/**
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* capi20_get_version() - CAPI 2.0 operation CAPI_GET_VERSION
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* @contr: controller number.
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* @verp: result structure.
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*
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* Retrieve version information for the specified ISDN controller
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* or (for @contr == 0) the driver itself.
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* Return value: CAPI result code
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*/
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u16 capi20_get_version(u32 contr, struct capi_version *verp)
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{
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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))
|
||||
{
|
||||
|
Loading…
Reference in New Issue
Block a user