diff options
| author |   Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 12:17:53 -0700 |
|---|---|---|
| committer | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 15:44:42 -0700 |
| commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
| tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/DocBook/media/dvb/kdapi.xml | |
| parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) | |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/Documentation/DocBook/media/dvb/kdapi.xml')
| -rw-r--r-- | kernel/Documentation/DocBook/media/dvb/kdapi.xml | 2309 |
1 files changed, 2309 insertions, 0 deletions
diff --git a/kernel/Documentation/DocBook/media/dvb/kdapi.xml b/kernel/Documentation/DocBook/media/dvb/kdapi.xml new file mode 100644 index 000000000..6c11ec52c --- /dev/null +++ b/kernel/Documentation/DocBook/media/dvb/kdapi.xml @@ -0,0 +1,2309 @@ +<title>Kernel Demux API</title> +<para>The kernel demux API defines a driver-internal interface for registering low-level, +hardware specific driver to a hardware independent demux layer. It is only of interest for +DVB device driver writers. The header file for this API is named <emphasis role="tt">demux.h</emphasis> and located in +<emphasis role="tt">drivers/media/dvb-core</emphasis>. +</para> +<para>Maintainer note: This section must be reviewed. It is probably out of date. +</para> + +<section id="kernel_demux_data_types"> +<title>Kernel Demux Data Types</title> + + +<section id="dmx_success_t"> +<title>dmx_success_t</title> + <programlisting> + typedef enum { + DMX_OK = 0, /⋆ Received Ok ⋆/ + DMX_LENGTH_ERROR, /⋆ Incorrect length ⋆/ + DMX_OVERRUN_ERROR, /⋆ Receiver ring buffer overrun ⋆/ + DMX_CRC_ERROR, /⋆ Incorrect CRC ⋆/ + DMX_FRAME_ERROR, /⋆ Frame alignment error ⋆/ + DMX_FIFO_ERROR, /⋆ Receiver FIFO overrun ⋆/ + DMX_MISSED_ERROR /⋆ Receiver missed packet ⋆/ + } dmx_success_t; +</programlisting> + +</section> +<section id="ts_filter_types"> +<title>TS filter types</title> + <programlisting> + /⋆--------------------------------------------------------------------------⋆/ + /⋆ TS packet reception ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + /⋆ TS filter type for set_type() ⋆/ + + #define TS_PACKET 1 /⋆ send TS packets (188 bytes) to callback (default) ⋆/ + #define TS_PAYLOAD_ONLY 2 /⋆ in case TS_PACKET is set, only send the TS + payload (<=184 bytes per packet) to callback ⋆/ + #define TS_DECODER 4 /⋆ send stream to built-in decoder (if present) ⋆/ +</programlisting> + +</section> +<section id="dmx_ts_pes_t"> +<title>dmx_ts_pes_t</title> +<para>The structure +</para> +<programlisting> + typedef enum + { + DMX_TS_PES_AUDIO, /⋆ also send packets to audio decoder (if it exists) ⋆/ + DMX_TS_PES_VIDEO, /⋆ ... ⋆/ + DMX_TS_PES_TELETEXT, + DMX_TS_PES_SUBTITLE, + DMX_TS_PES_PCR, + DMX_TS_PES_OTHER, + } dmx_ts_pes_t; +</programlisting> +<para>describes the PES type for filters which write to a built-in decoder. The correspond (and +should be kept identical) to the types in the demux device. +</para> +<programlisting> + struct dmx_ts_feed_s { + int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/ + struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + int (⋆set) (struct dmx_ts_feed_s⋆ feed, + __u16 pid, + size_t callback_length, + size_t circular_buffer_size, + int descramble, + struct timespec timeout); + int (⋆start_filtering) (struct dmx_ts_feed_s⋆ feed); + int (⋆stop_filtering) (struct dmx_ts_feed_s⋆ feed); + int (⋆set_type) (struct dmx_ts_feed_s⋆ feed, + int type, + dmx_ts_pes_t pes_type); + }; + + typedef struct dmx_ts_feed_s dmx_ts_feed_t; +</programlisting> + <programlisting> + /⋆--------------------------------------------------------------------------⋆/ + /⋆ PES packet reception (not supported yet) ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + typedef struct dmx_pes_filter_s { + struct dmx_pes_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + } dmx_pes_filter_t; +</programlisting> + <programlisting> + typedef struct dmx_pes_feed_s { + int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/ + struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + int (⋆set) (struct dmx_pes_feed_s⋆ feed, + __u16 pid, + size_t circular_buffer_size, + int descramble, + struct timespec timeout); + int (⋆start_filtering) (struct dmx_pes_feed_s⋆ feed); + int (⋆stop_filtering) (struct dmx_pes_feed_s⋆ feed); + int (⋆allocate_filter) (struct dmx_pes_feed_s⋆ feed, + dmx_pes_filter_t⋆⋆ filter); + int (⋆release_filter) (struct dmx_pes_feed_s⋆ feed, + dmx_pes_filter_t⋆ filter); + } dmx_pes_feed_t; +</programlisting> + <programlisting> + typedef struct { + __u8 filter_value [DMX_MAX_FILTER_SIZE]; + __u8 filter_mask [DMX_MAX_FILTER_SIZE]; + struct dmx_section_feed_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + } dmx_section_filter_t; +</programlisting> + <programlisting> + struct dmx_section_feed_s { + int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/ + struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + int (⋆set) (struct dmx_section_feed_s⋆ feed, + __u16 pid, + size_t circular_buffer_size, + int descramble, + int check_crc); + int (⋆allocate_filter) (struct dmx_section_feed_s⋆ feed, + dmx_section_filter_t⋆⋆ filter); + int (⋆release_filter) (struct dmx_section_feed_s⋆ feed, + dmx_section_filter_t⋆ filter); + int (⋆start_filtering) (struct dmx_section_feed_s⋆ feed); + int (⋆stop_filtering) (struct dmx_section_feed_s⋆ feed); + }; + typedef struct dmx_section_feed_s dmx_section_feed_t; + + /⋆--------------------------------------------------------------------------⋆/ + /⋆ Callback functions ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + typedef int (⋆dmx_ts_cb) ( __u8 ⋆ buffer1, + size_t buffer1_length, + __u8 ⋆ buffer2, + size_t buffer2_length, + dmx_ts_feed_t⋆ source, + dmx_success_t success); + + typedef int (⋆dmx_section_cb) ( __u8 ⋆ buffer1, + size_t buffer1_len, + __u8 ⋆ buffer2, + size_t buffer2_len, + dmx_section_filter_t ⋆ source, + dmx_success_t success); + + typedef int (⋆dmx_pes_cb) ( __u8 ⋆ buffer1, + size_t buffer1_len, + __u8 ⋆ buffer2, + size_t buffer2_len, + dmx_pes_filter_t⋆ source, + dmx_success_t success); + + /⋆--------------------------------------------------------------------------⋆/ + /⋆ DVB Front-End ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + typedef enum { + DMX_OTHER_FE = 0, + DMX_SATELLITE_FE, + DMX_CABLE_FE, + DMX_TERRESTRIAL_FE, + DMX_LVDS_FE, + DMX_ASI_FE, /⋆ DVB-ASI interface ⋆/ + DMX_MEMORY_FE + } dmx_frontend_source_t; + + typedef struct { + /⋆ The following char⋆ fields point to NULL terminated strings ⋆/ + char⋆ id; /⋆ Unique front-end identifier ⋆/ + char⋆ vendor; /⋆ Name of the front-end vendor ⋆/ + char⋆ model; /⋆ Name of the front-end model ⋆/ + struct list_head connectivity_list; /⋆ List of front-ends that can + be connected to a particular + demux ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + dmx_frontend_source_t source; + } dmx_frontend_t; + + /⋆--------------------------------------------------------------------------⋆/ + /⋆ MPEG-2 TS Demux ⋆/ + /⋆--------------------------------------------------------------------------⋆/ + + /⋆ + ⋆ Flags OR'ed in the capabilites field of struct dmx_demux_s. + ⋆/ + + #define DMX_TS_FILTERING 1 + #define DMX_PES_FILTERING 2 + #define DMX_SECTION_FILTERING 4 + #define DMX_MEMORY_BASED_FILTERING 8 /⋆ write() available ⋆/ + #define DMX_CRC_CHECKING 16 + #define DMX_TS_DESCRAMBLING 32 + #define DMX_SECTION_PAYLOAD_DESCRAMBLING 64 + #define DMX_MAC_ADDRESS_DESCRAMBLING 128 +</programlisting> + +</section> +<section id="demux_demux_t"> +<title>demux_demux_t</title> + <programlisting> + /⋆ + ⋆ DMX_FE_ENTRY(): Casts elements in the list of registered + ⋆ front-ends from the generic type struct list_head + ⋆ to the type ⋆ dmx_frontend_t + ⋆. + ⋆/ + + #define DMX_FE_ENTRY(list) list_entry(list, dmx_frontend_t, connectivity_list) + + struct dmx_demux_s { + /⋆ The following char⋆ fields point to NULL terminated strings ⋆/ + char⋆ id; /⋆ Unique demux identifier ⋆/ + char⋆ vendor; /⋆ Name of the demux vendor ⋆/ + char⋆ model; /⋆ Name of the demux model ⋆/ + __u32 capabilities; /⋆ Bitfield of capability flags ⋆/ + dmx_frontend_t⋆ frontend; /⋆ Front-end connected to the demux ⋆/ + struct list_head reg_list; /⋆ List of registered demuxes ⋆/ + void⋆ priv; /⋆ Pointer to private data of the API client ⋆/ + int users; /⋆ Number of users ⋆/ + int (⋆open) (struct dmx_demux_s⋆ demux); + int (⋆close) (struct dmx_demux_s⋆ demux); + int (⋆write) (struct dmx_demux_s⋆ demux, const char⋆ buf, size_t count); + int (⋆allocate_ts_feed) (struct dmx_demux_s⋆ demux, + dmx_ts_feed_t⋆⋆ feed, + dmx_ts_cb callback); + int (⋆release_ts_feed) (struct dmx_demux_s⋆ demux, + dmx_ts_feed_t⋆ feed); + int (⋆allocate_pes_feed) (struct dmx_demux_s⋆ demux, + dmx_pes_feed_t⋆⋆ feed, + dmx_pes_cb callback); + int (⋆release_pes_feed) (struct dmx_demux_s⋆ demux, + dmx_pes_feed_t⋆ feed); + int (⋆allocate_section_feed) (struct dmx_demux_s⋆ demux, + dmx_section_feed_t⋆⋆ feed, + dmx_section_cb callback); + int (⋆release_section_feed) (struct dmx_demux_s⋆ demux, + dmx_section_feed_t⋆ feed); + int (⋆descramble_mac_address) (struct dmx_demux_s⋆ demux, + __u8⋆ buffer1, + size_t buffer1_length, + __u8⋆ buffer2, + size_t buffer2_length, + __u16 pid); + int (⋆descramble_section_payload) (struct dmx_demux_s⋆ demux, + __u8⋆ buffer1, + size_t buffer1_length, + __u8⋆ buffer2, size_t buffer2_length, + __u16 pid); + int (⋆add_frontend) (struct dmx_demux_s⋆ demux, + dmx_frontend_t⋆ frontend); + int (⋆remove_frontend) (struct dmx_demux_s⋆ demux, + dmx_frontend_t⋆ frontend); + struct list_head⋆ (⋆get_frontends) (struct dmx_demux_s⋆ demux); + int (⋆connect_frontend) (struct dmx_demux_s⋆ demux, + dmx_frontend_t⋆ frontend); + int (⋆disconnect_frontend) (struct dmx_demux_s⋆ demux); + + + /⋆ added because js cannot keep track of these himself ⋆/ + int (⋆get_pes_pids) (struct dmx_demux_s⋆ demux, __u16 ⋆pids); + }; + typedef struct dmx_demux_s dmx_demux_t; +</programlisting> + +</section> +<section id="demux_directory"> +<title>Demux directory</title> + <programlisting> + /⋆ + ⋆ DMX_DIR_ENTRY(): Casts elements in the list of registered + ⋆ demuxes from the generic type struct list_head⋆ to the type dmx_demux_t + ⋆. + ⋆/ + + #define DMX_DIR_ENTRY(list) list_entry(list, dmx_demux_t, reg_list) + + int dmx_register_demux (dmx_demux_t⋆ demux); + int dmx_unregister_demux (dmx_demux_t⋆ demux); + struct list_head⋆ dmx_get_demuxes (void); +</programlisting> + </section></section> +<section id="demux_directory_api"> +<title>Demux Directory API</title> +<para>The demux directory is a Linux kernel-wide facility for registering and accessing the +MPEG-2 TS demuxes in the system. Run-time registering and unregistering of demux drivers +is possible using this API. +</para> +<para>All demux drivers in the directory implement the abstract interface dmx_demux_t. +</para> + +<section +role="subsection"><title>dmx_register_demux()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function makes a demux driver interface available to the Linux kernel. It is + usually called by the init_module() function of the kernel module that contains + the demux driver. The caller of this function is responsible for allocating + dynamic or static memory for the demux structure and for initializing its fields + before calling this function. The memory allocated for the demux structure + must not be freed before calling dmx_unregister_demux(),</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int dmx_register_demux ( dmx_demux_t ⋆demux )</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux structure.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EEXIST</para> +</entry><entry + align="char"> +<para>A demux with the same value of the id field already stored + in the directory.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSPC</para> +</entry><entry + align="char"> +<para>No space left in the directory.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>dmx_unregister_demux()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function is called to indicate that the given demux interface is no + longer available. The caller of this function is responsible for freeing the + memory of the demux structure, if it was dynamically allocated before calling + dmx_register_demux(). The cleanup_module() function of the kernel module + that contains the demux driver should call this function. Note that this function + fails if the demux is currently in use, i.e., release_demux() has not been called + for the interface.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int dmx_unregister_demux ( dmx_demux_t ⋆demux )</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux structure which is to be + unregistered.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>ENODEV</para> +</entry><entry + align="char"> +<para>The specified demux is not registered in the demux + directory.</para> +</entry> + </row><row><entry + align="char"> +<para>EBUSY</para> +</entry><entry + align="char"> +<para>The specified demux is currently in use.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>dmx_get_demuxes()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Provides the caller with the list of registered demux interfaces, using the + standard list structure defined in the include file linux/list.h. The include file + demux.h defines the macro DMX_DIR_ENTRY() for converting an element of + the generic type struct list_head* to the type dmx_demux_t*. The caller must + not free the memory of any of the elements obtained via this function call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>struct list_head ⋆dmx_get_demuxes ()</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>none</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>struct list_head *</para> +</entry><entry + align="char"> +<para>A list of demux interfaces, or NULL in the case of an + empty list.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> +<section id="demux_api"> +<title>Demux API</title> +<para>The demux API should be implemented for each demux in the system. It is used to select +the TS source of a demux and to manage the demux resources. When the demux +client allocates a resource via the demux API, it receives a pointer to the API of that +resource. +</para> +<para>Each demux receives its TS input from a DVB front-end or from memory, as set via the +demux API. In a system with more than one front-end, the API can be used to select one of +the DVB front-ends as a TS source for a demux, unless this is fixed in the HW platform. The +demux API only controls front-ends regarding their connections with demuxes; the APIs +used to set the other front-end parameters, such as tuning, are not defined in this +document. +</para> +<para>The functions that implement the abstract interface demux should be defined static or +module private and registered to the Demux Directory for external access. It is not necessary +to implement every function in the demux_t struct, however (for example, a demux interface +might support Section filtering, but not TS or PES filtering). The API client is expected to +check the value of any function pointer before calling the function: the value of NULL means +“function not available”. +</para> +<para>Whenever the functions of the demux API modify shared data, the possibilities of lost +update and race condition problems should be addressed, e.g. by protecting parts of code with +mutexes. This is especially important on multi-processor hosts. +</para> +<para>Note that functions called from a bottom half context must not sleep, at least in the 2.2.x +kernels. Even a simple memory allocation can result in a kernel thread being put to sleep if +swapping is needed. For example, the Linux kernel calls the functions of a network device +interface from a bottom half context. Thus, if a demux API function is called from network +device code, the function must not sleep. +</para> + + +<section id="kdapi_fopen"> +<title>open()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function reserves the demux for use by the caller and, if necessary, + initializes the demux. When the demux is no longer needed, the function close() + should be called. It should be possible for multiple clients to access the demux + at the same time. Thus, the function implementation should increment the + demux usage count when open() is called and decrement it when close() is + called.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int open ( demux_t⋆ demux );</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EUSERS</para> +</entry><entry + align="char"> +<para>Maximum usage count reached.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="kdapi_fclose"> +<title>close()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function reserves the demux for use by the caller and, if necessary, + initializes the demux. When the demux is no longer needed, the function close() + should be called. It should be possible for multiple clients to access the demux + at the same time. Thus, the function implementation should increment the + demux usage count when open() is called and decrement it when close() is + called.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int close(demux_t⋆ demux);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENODEV</para> +</entry><entry + align="char"> +<para>The demux was not in use.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> +<section id="kdapi_fwrite"> +<title>write()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function provides the demux driver with a memory buffer containing TS + packets. Instead of receiving TS packets from the DVB front-end, the demux + driver software will read packets from memory. Any clients of this demux + with active TS, PES or Section filters will receive filtered data via the Demux + callback API (see 0). The function returns when all the data in the buffer has + been consumed by the demux. Demux hardware typically cannot read TS from + memory. If this is the case, memory-based filtering has to be implemented + entirely in software.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int write(demux_t⋆ demux, const char⋆ buf, size_t + count);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>const char* buf</para> +</entry><entry + align="char"> +<para>Pointer to the TS data in kernel-space memory.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t length</para> +</entry><entry + align="char"> +<para>Length of the TS data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>The command is not implemented.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>allocate_ts_feed()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Allocates a new TS feed, which is used to filter the TS packets carrying a + certain PID. The TS feed normally corresponds to a hardware PID filter on the + demux chip.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int allocate_ts_feed(dmx_demux_t⋆ demux, + dmx_ts_feed_t⋆⋆ feed, dmx_ts_cb callback);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_ts_feed_t** + feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_ts_cb callback</para> +</entry><entry + align="char"> +<para>Pointer to the callback function for passing received TS + packet</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EBUSY</para> +</entry><entry + align="char"> +<para>No more TS feeds available.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>The command is not implemented.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>release_ts_feed()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Releases the resources allocated with allocate_ts_feed(). Any filtering in + progress on the TS feed should be stopped before calling this function.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int release_ts_feed(dmx_demux_t⋆ demux, + dmx_ts_feed_t⋆ feed);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t* demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_ts_feed_t* feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>allocate_section_feed()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Allocates a new section feed, i.e. a demux resource for filtering and receiving + sections. On platforms with hardware support for section filtering, a section + feed is directly mapped to the demux HW. On other platforms, TS packets are + first PID filtered in hardware and a hardware section filter then emulated in + software. The caller obtains an API pointer of type dmx_section_feed_t as an + out parameter. Using this API the caller can set filtering parameters and start + receiving sections.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int allocate_section_feed(dmx_demux_t⋆ demux, + dmx_section_feed_t ⋆⋆feed, dmx_section_cb callback);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t *demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_feed_t + **feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_cb + callback</para> +</entry><entry + align="char"> +<para>Pointer to the callback function for passing received + sections.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EBUSY</para> +</entry><entry + align="char"> +<para>No more section feeds available.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>The command is not implemented.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>release_section_feed()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Releases the resources allocated with allocate_section_feed(), including + allocated filters. Any filtering in progress on the section feed should be stopped + before calling this function.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int release_section_feed(dmx_demux_t⋆ demux, + dmx_section_feed_t ⋆feed);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>demux_t *demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_feed_t + *feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>descramble_mac_address()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function runs a descrambling algorithm on the destination MAC + address field of a DVB Datagram Section, replacing the original address + with its un-encrypted version. Otherwise, the description on the function + descramble_section_payload() applies also to this function.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int descramble_mac_address(dmx_demux_t⋆ demux, __u8 + ⋆buffer1, size_t buffer1_length, __u8 ⋆buffer2, + size_t buffer2_length, __u16 pid);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t + *demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8 *buffer1</para> +</entry><entry + align="char"> +<para>Pointer to the first byte of the section.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer1_length</para> +</entry><entry + align="char"> +<para>Length of the section data, including headers and CRC, + in buffer1.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8* buffer2</para> +</entry><entry + align="char"> +<para>Pointer to the tail of the section data, or NULL. The + pointer has a non-NULL value if the section wraps past + the end of a circular buffer.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer2_length</para> +</entry><entry + align="char"> +<para>Length of the section data, including headers and CRC, + in buffer2.</para> +</entry> + </row><row><entry + align="char"> +<para>__u16 pid</para> +</entry><entry + align="char"> +<para>The PID on which the section was received. Useful + for obtaining the descrambling key, e.g. from a DVB + Common Access facility.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>No descrambling facility available.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>descramble_section_payload()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function runs a descrambling algorithm on the payload of a DVB + Datagram Section, replacing the original payload with its un-encrypted + version. The function will be called from the demux API implementation; + the API client need not call this function directly. Section-level scrambling + algorithms are currently standardized only for DVB-RCC (return channel + over 2-directional cable TV network) systems. For all other DVB networks, + encryption schemes are likely to be proprietary to each data broadcaster. Thus, + it is expected that this function pointer will have the value of NULL (i.e., + function not available) in most demux API implementations. Nevertheless, it + should be possible to use the function pointer as a hook for dynamically adding + a “plug-in” descrambling facility to a demux driver.</para> +</entry> + </row><row><entry + align="char"> +<para>While this function is not needed with hardware-based section descrambling, + the descramble_section_payload function pointer can be used to override the + default hardware-based descrambling algorithm: if the function pointer has a + non-NULL value, the corresponding function should be used instead of any + descrambling hardware.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int descramble_section_payload(dmx_demux_t⋆ demux, + __u8 ⋆buffer1, size_t buffer1_length, __u8 ⋆buffer2, + size_t buffer2_length, __u16 pid);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t + *demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8 *buffer1</para> +</entry><entry + align="char"> +<para>Pointer to the first byte of the section.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer1_length</para> +</entry><entry + align="char"> +<para>Length of the section data, including headers and CRC, + in buffer1.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8 *buffer2</para> +</entry><entry + align="char"> +<para>Pointer to the tail of the section data, or NULL. The + pointer has a non-NULL value if the section wraps past + the end of a circular buffer.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer2_length</para> +</entry><entry + align="char"> +<para>Length of the section data, including headers and CRC, + in buffer2.</para> +</entry> + </row><row><entry + align="char"> +<para>__u16 pid</para> +</entry><entry + align="char"> +<para>The PID on which the section was received. Useful + for obtaining the descrambling key, e.g. from a DVB + Common Access facility.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>No descrambling facility available.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>add_frontend()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Registers a connectivity between a demux and a front-end, i.e., indicates that + the demux can be connected via a call to connect_frontend() to use the given + front-end as a TS source. The client of this function has to allocate dynamic or + static memory for the frontend structure and initialize its fields before calling + this function. This function is normally called during the driver initialization. + The caller must not free the memory of the frontend struct before successfully + calling remove_frontend().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int add_frontend(dmx_demux_t ⋆demux, dmx_frontend_t + ⋆frontend);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_frontend_t* + frontend</para> +</entry><entry + align="char"> +<para>Pointer to the front-end instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EEXIST</para> +</entry><entry + align="char"> +<para>A front-end with the same value of the id field already + registered.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINUSE</para> +</entry><entry + align="char"> +<para>The demux is in use.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOMEM</para> +</entry><entry + align="char"> +<para>No more front-ends can be added.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>remove_frontend()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Indicates that the given front-end, registered by a call to add_frontend(), can + no longer be connected as a TS source by this demux. The function should be + called when a front-end driver or a demux driver is removed from the system. + If the front-end is in use, the function fails with the return value of -EBUSY. + After successfully calling this function, the caller can free the memory of + the frontend struct if it was dynamically allocated before the add_frontend() + operation.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int remove_frontend(dmx_demux_t⋆ demux, + dmx_frontend_t⋆ frontend);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_frontend_t* + frontend</para> +</entry><entry + align="char"> +<para>Pointer to the front-end instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row><row><entry + align="char"> +<para>-EBUSY</para> +</entry><entry + align="char"> +<para>The front-end is in use, i.e. a call to connect_frontend() + has not been followed by a call to disconnect_frontend().</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>get_frontends()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Provides the APIs of the front-ends that have been registered for this demux. + Any of the front-ends obtained with this call can be used as a parameter for + connect_frontend().</para> +</entry> + </row><row><entry + align="char"> +<para>The include file demux.h contains the macro DMX_FE_ENTRY() for + converting an element of the generic type struct list_head* to the type + dmx_frontend_t*. The caller must not free the memory of any of the elements + obtained via this function call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>struct list_head⋆ get_frontends(dmx_demux_t⋆ demux);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t*</para> +</entry><entry + align="char"> +<para>A list of front-end interfaces, or NULL in the case of an + empty list.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>connect_frontend()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Connects the TS output of the front-end to the input of the demux. A demux + can only be connected to a front-end registered to the demux with the function + add_frontend().</para> +</entry> + </row><row><entry + align="char"> +<para>It may or may not be possible to connect multiple demuxes to the same + front-end, depending on the capabilities of the HW platform. When not used, + the front-end should be released by calling disconnect_frontend().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int connect_frontend(dmx_demux_t⋆ demux, + dmx_frontend_t⋆ frontend);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_frontend_t* + frontend</para> +</entry><entry + align="char"> +<para>Pointer to the front-end instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row><row><entry + align="char"> +<para>-EBUSY</para> +</entry><entry + align="char"> +<para>The front-end is in use.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>disconnect_frontend()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Disconnects the demux and a front-end previously connected by a + connect_frontend() call.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int disconnect_frontend(dmx_demux_t⋆ demux);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_demux_t* + demux</para> +</entry><entry + align="char"> +<para>Pointer to the demux API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> +<section id="demux_callback_api"> +<title>Demux Callback API</title> +<para>This kernel-space API comprises the callback functions that deliver filtered data to the +demux client. Unlike the other APIs, these API functions are provided by the client and called +from the demux code. +</para> +<para>The function pointers of this abstract interface are not packed into a structure as in the +other demux APIs, because the callback functions are registered and used independent +of each other. As an example, it is possible for the API client to provide several +callback functions for receiving TS packets and no callbacks for PES packets or +sections. +</para> +<para>The functions that implement the callback API need not be re-entrant: when a demux +driver calls one of these functions, the driver is not allowed to call the function again before +the original call returns. If a callback is triggered by a hardware interrupt, it is recommended +to use the Linux “bottom half” mechanism or start a tasklet instead of making the callback +function call directly from a hardware interrupt. +</para> + +<section +role="subsection"><title>dmx_ts_cb()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function, provided by the client of the demux API, is called from the + demux code. The function is only called when filtering on this TS feed has + been enabled using the start_filtering() function.</para> +</entry> + </row><row><entry + align="char"> +<para>Any TS packets that match the filter settings are copied to a circular buffer. The + filtered TS packets are delivered to the client using this callback function. The + size of the circular buffer is controlled by the circular_buffer_size parameter + of the set() function in the TS Feed API. It is expected that the buffer1 and + buffer2 callback parameters point to addresses within the circular buffer, but + other implementations are also possible. Note that the called party should not + try to free the memory the buffer1 and buffer2 parameters point to.</para> +</entry> + </row><row><entry + align="char"> +<para>When this function is called, the buffer1 parameter typically points to the + start of the first undelivered TS packet within a circular buffer. The buffer2 + buffer parameter is normally NULL, except when the received TS packets have + crossed the last address of the circular buffer and ”wrapped” to the beginning + of the buffer. In the latter case the buffer1 parameter would contain an address + within the circular buffer, while the buffer2 parameter would contain the first + address of the circular buffer.</para> +</entry> + </row><row><entry + align="char"> +<para>The number of bytes delivered with this function (i.e. buffer1_length + + buffer2_length) is usually equal to the value of callback_length parameter + given in the set() function, with one exception: if a timeout occurs before + receiving callback_length bytes of TS data, any undelivered packets are + immediately delivered to the client by calling this function. The timeout + duration is controlled by the set() function in the TS Feed API.</para> +</entry> + </row><row><entry + align="char"> +<para>If a TS packet is received with errors that could not be fixed by the TS-level + forward error correction (FEC), the Transport_error_indicator flag of the TS + packet header should be set. The TS packet should not be discarded, as + the error can possibly be corrected by a higher layer protocol. If the called + party is slow in processing the callback, it is possible that the circular buffer + eventually fills up. If this happens, the demux driver should discard any TS + packets received while the buffer is full. The error should be indicated to the + client on the next callback by setting the success parameter to the value of + DMX_OVERRUN_ERROR.</para> +</entry> + </row><row><entry + align="char"> +<para>The type of data returned to the callback can be selected by the new + function int (*set_type) (struct dmx_ts_feed_s* feed, int type, dmx_ts_pes_t + pes_type) which is part of the dmx_ts_feed_s struct (also cf. to the + include file ost/demux.h) The type parameter decides if the raw TS packet + (TS_PACKET) or just the payload (TS_PACKET—TS_PAYLOAD_ONLY) + should be returned. If additionally the TS_DECODER bit is set the stream + will also be sent to the hardware MPEG decoder. In this case, the second + flag decides as what kind of data the stream should be interpreted. The + possible choices are one of DMX_TS_PES_AUDIO, DMX_TS_PES_VIDEO, + DMX_TS_PES_TELETEXT, DMX_TS_PES_SUBTITLE, + DMX_TS_PES_PCR, or DMX_TS_PES_OTHER.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int dmx_ts_cb(__u8⋆ buffer1, size_t buffer1_length, + __u8⋆ buffer2, size_t buffer2_length, dmx_ts_feed_t⋆ + source, dmx_success_t success);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>__u8* buffer1</para> +</entry><entry + align="char"> +<para>Pointer to the start of the filtered TS packets.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer1_length</para> +</entry><entry + align="char"> +<para>Length of the TS data in buffer1.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8* buffer2</para> +</entry><entry + align="char"> +<para>Pointer to the tail of the filtered TS packets, or NULL.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer2_length</para> +</entry><entry + align="char"> +<para>Length of the TS data in buffer2.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_ts_feed_t* + source</para> +</entry><entry + align="char"> +<para>Indicates which TS feed is the source of the callback.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_success_t + success</para> +</entry><entry + align="char"> +<para>Indicates if there was an error in TS reception.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>Continue filtering.</para> +</entry> + </row><row><entry + align="char"> +<para>-1</para> +</entry><entry + align="char"> +<para>Stop filtering - has the same effect as a call to + stop_filtering() on the TS Feed API.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>dmx_section_cb()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function, provided by the client of the demux API, is called from the + demux code. The function is only called when filtering of sections has been + enabled using the function start_filtering() of the section feed API. When the + demux driver has received a complete section that matches at least one section + filter, the client is notified via this callback function. Normally this function is + called for each received section; however, it is also possible to deliver multiple + sections with one callback, for example when the system load is high. If an + error occurs while receiving a section, this function should be called with + the corresponding error type set in the success field, whether or not there is + data to deliver. The Section Feed implementation should maintain a circular + buffer for received sections. However, this is not necessary if the Section Feed + API is implemented as a client of the TS Feed API, because the TS Feed + implementation then buffers the received data. The size of the circular buffer + can be configured using the set() function in the Section Feed API. If there + is no room in the circular buffer when a new section is received, the section + must be discarded. If this happens, the value of the success parameter should + be DMX_OVERRUN_ERROR on the next callback.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int dmx_section_cb(__u8⋆ buffer1, size_t + buffer1_length, __u8⋆ buffer2, size_t + buffer2_length, dmx_section_filter_t⋆ source, + dmx_success_t success);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>__u8* buffer1</para> +</entry><entry + align="char"> +<para>Pointer to the start of the filtered section, e.g. within the + circular buffer of the demux driver.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer1_length</para> +</entry><entry + align="char"> +<para>Length of the filtered section data in buffer1, including + headers and CRC.</para> +</entry> + </row><row><entry + align="char"> +<para>__u8* buffer2</para> +</entry><entry + align="char"> +<para>Pointer to the tail of the filtered section data, or NULL. + Useful to handle the wrapping of a circular buffer.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t buffer2_length</para> +</entry><entry + align="char"> +<para>Length of the filtered section data in buffer2, including + headers and CRC.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_filter_t* + filter</para> +</entry><entry + align="char"> +<para>Indicates the filter that triggered the callback.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_success_t + success</para> +</entry><entry + align="char"> +<para>Indicates if there was an error in section reception.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>Continue filtering.</para> +</entry> + </row><row><entry + align="char"> +<para>-1</para> +</entry><entry + align="char"> +<para>Stop filtering - has the same effect as a call to + stop_filtering() on the Section Feed API.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> +<section id="ts_feed_api"> +<title>TS Feed API</title> +<para>A TS feed is typically mapped to a hardware PID filter on the demux chip. +Using this API, the client can set the filtering properties to start/stop filtering TS +packets on a particular TS feed. The API is defined as an abstract interface of the type +dmx_ts_feed_t. +</para> +<para>The functions that implement the interface should be defined static or module private. The +client can get the handle of a TS feed API by calling the function allocate_ts_feed() in the +demux API. +</para> + +<section +role="subsection"><title>set()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function sets the parameters of a TS feed. Any filtering in progress on the + TS feed must be stopped before calling this function.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int set ( dmx_ts_feed_t⋆ feed, __u16 pid, size_t + callback_length, size_t circular_buffer_size, int + descramble, struct timespec timeout);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_ts_feed_t* feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>__u16 pid</para> +</entry><entry + align="char"> +<para>PID value to filter. Only the TS packets carrying the + specified PID will be passed to the API client.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t + callback_length</para> +</entry><entry + align="char"> +<para>Number of bytes to deliver with each call to the + dmx_ts_cb() callback function. The value of this + parameter should be a multiple of 188.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t + circular_buffer_size</para> +</entry><entry + align="char"> +<para>Size of the circular buffer for the filtered TS packets.</para> +</entry> + </row><row><entry + align="char"> +<para>int descramble</para> +</entry><entry + align="char"> +<para>If non-zero, descramble the filtered TS packets.</para> +</entry> + </row><row><entry + align="char"> +<para>struct timespec + timeout</para> +</entry><entry + align="char"> +<para>Maximum time to wait before delivering received TS + packets to the client.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOMEM</para> +</entry><entry + align="char"> +<para>Not enough memory for the requested buffer size.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>No descrambling facility available for TS.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>start_filtering()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Starts filtering TS packets on this TS feed, according to its settings. The PID + value to filter can be set by the API client. All matching TS packets are + delivered asynchronously to the client, using the callback function registered + with allocate_ts_feed().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int start_filtering(dmx_ts_feed_t⋆ feed);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_ts_feed_t* feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>stop_filtering()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Stops filtering TS packets on this TS feed.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int stop_filtering(dmx_ts_feed_t⋆ feed);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_ts_feed_t* feed</para> +</entry><entry + align="char"> +<para>Pointer to the TS feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + </section></section> +<section id="section_feed_api"> +<title>Section Feed API</title> +<para>A section feed is a resource consisting of a PID filter and a set of section filters. Using this +API, the client can set the properties of a section feed and to start/stop filtering. The API is +defined as an abstract interface of the type dmx_section_feed_t. The functions that implement +the interface should be defined static or module private. The client can get the handle of +a section feed API by calling the function allocate_section_feed() in the demux +API. +</para> +<para>On demux platforms that provide section filtering in hardware, the Section Feed API +implementation provides a software wrapper for the demux hardware. Other platforms may +support only PID filtering in hardware, requiring that TS packets are converted to sections in +software. In the latter case the Section Feed API implementation can be a client of the TS +Feed API. +</para> + +</section> +<section id="kdapi_set"> +<title>set()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function sets the parameters of a section feed. Any filtering in progress on + the section feed must be stopped before calling this function. If descrambling + is enabled, the payload_scrambling_control and address_scrambling_control + fields of received DVB datagram sections should be observed. If either one is + non-zero, the section should be descrambled either in hardware or using the + functions descramble_mac_address() and descramble_section_payload() of the + demux API. Note that according to the MPEG-2 Systems specification, only + the payloads of private sections can be scrambled while the rest of the section + data must be sent in the clear.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int set(dmx_section_feed_t⋆ feed, __u16 pid, size_t + circular_buffer_size, int descramble, int + check_crc);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>__u16 pid</para> +</entry><entry + align="char"> +<para>PID value to filter; only the TS packets carrying the + specified PID will be accepted.</para> +</entry> + </row><row><entry + align="char"> +<para>size_t + circular_buffer_size</para> +</entry><entry + align="char"> +<para>Size of the circular buffer for filtered sections.</para> +</entry> + </row><row><entry + align="char"> +<para>int descramble</para> +</entry><entry + align="char"> +<para>If non-zero, descramble any sections that are scrambled.</para> +</entry> + </row><row><entry + align="char"> +<para>int check_crc</para> +</entry><entry + align="char"> +<para>If non-zero, check the CRC values of filtered sections.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOMEM</para> +</entry><entry + align="char"> +<para>Not enough memory for the requested buffer size.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSYS</para> +</entry><entry + align="char"> +<para>No descrambling facility available for sections.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameters.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>allocate_filter()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function is used to allocate a section filter on the demux. It should only be + called when no filtering is in progress on this section feed. If a filter cannot be + allocated, the function fails with -ENOSPC. See in section ?? for the format of + the section filter.</para> +</entry> + </row><row><entry + align="char"> +<para>The bitfields filter_mask and filter_value should only be modified when no + filtering is in progress on this section feed. filter_mask controls which bits of + filter_value are compared with the section headers/payload. On a binary value + of 1 in filter_mask, the corresponding bits are compared. The filter only accepts + sections that are equal to filter_value in all the tested bit positions. Any changes + to the values of filter_mask and filter_value are guaranteed to take effect only + when the start_filtering() function is called next time. The parent pointer in + the struct is initialized by the API implementation to the value of the feed + parameter. The priv pointer is not used by the API implementation, and can + thus be freely utilized by the caller of this function. Any data pointed to by the + priv pointer is available to the recipient of the dmx_section_cb() function call.</para> +</entry> + </row><row><entry + align="char"> +<para>While the maximum section filter length (DMX_MAX_FILTER_SIZE) is + currently set at 16 bytes, hardware filters of that size are not available on all + platforms. Therefore, section filtering will often take place first in hardware, + followed by filtering in software for the header bytes that were not covered + by a hardware filter. The filter_mask field can be checked to determine how + many bytes of the section filter are actually used, and if the hardware filter will + suffice. Additionally, software-only section filters can optionally be allocated + to clients when all hardware section filters are in use. Note that on most demux + hardware it is not possible to filter on the section_length field of the section + header – thus this field is ignored, even though it is included in filter_value and + filter_mask fields.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int allocate_filter(dmx_section_feed_t⋆ feed, + dmx_section_filter_t⋆⋆ filter);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_filter_t** + filter</para> +</entry><entry + align="char"> +<para>Pointer to the allocated filter.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENOSPC</para> +</entry><entry + align="char"> +<para>No filters of given type and length available.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameters.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>release_filter()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>This function releases all the resources of a previously allocated section filter. + The function should not be called while filtering is in progress on this section + feed. After calling this function, the caller should not try to dereference the + filter pointer.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int release_filter ( dmx_section_feed_t⋆ feed, + dmx_section_filter_t⋆ filter);</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row><row><entry + align="char"> +<para>dmx_section_filter_t* + filter</para> +</entry><entry + align="char"> +<para>I/O Pointer to the instance data of a section filter.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-ENODEV</para> +</entry><entry + align="char"> +<para>No such filter allocated.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>start_filtering()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Starts filtering sections on this section feed, according to its settings. Sections + are first filtered based on their PID and then matched with the section + filters allocated for this feed. If the section matches the PID filter and + at least one section filter, it is delivered to the API client. The section + is delivered asynchronously using the callback function registered with + allocate_section_feed().</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int start_filtering ( dmx_section_feed_t⋆ feed );</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section><section +role="subsection"><title>stop_filtering()</title> +<para>DESCRIPTION +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>Stops filtering sections on this section feed. Note that any changes to the + filtering parameters (filter_value, filter_mask, etc.) should only be made when + filtering is stopped.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>SYNOPSIS +</para> +<informaltable><tgroup cols="1"><tbody><row><entry + align="char"> +<para>int stop_filtering ( dmx_section_feed_t⋆ feed );</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>PARAMETERS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>dmx_section_feed_t* + feed</para> +</entry><entry + align="char"> +<para>Pointer to the section feed API and instance data.</para> +</entry> + </row></tbody></tgroup></informaltable> +<para>RETURNS +</para> +<informaltable><tgroup cols="2"><tbody><row><entry + align="char"> +<para>0</para> +</entry><entry + align="char"> +<para>The function was completed without errors.</para> +</entry> + </row><row><entry + align="char"> +<para>-EINVAL</para> +</entry><entry + align="char"> +<para>Bad parameter.</para> +</entry> + </row></tbody></tgroup></informaltable> + +</section> |