[media] demux.h: move documentation overview from device-drivers.tmpl

It is better to keep the documentation overview at the header file,
as this makes easier for developers to remember to fix when needed.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

1 files changed, 6 insertions, 65 deletions

diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl
index 42a2d8593e39..c2bc8f779a9b 100644
--- a/Documentation/DocBook/device-drivers.tmpl
+++ b/Documentation/DocBook/device-drivers.tmpl
@@ -243,71 +243,12 @@ X!Isound/sound_firmware.c
 !Idrivers/media/dvb-core/dvb_math.h
 !Idrivers/media/dvb-core/dvb_ringbuffer.h
 !Idrivers/media/dvb-core/dvbdev.h
-	<sect1><title>Digital TV 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 Digital TV
-	    device driver writers. The header file for this API is named
-	    <constant>demux.h</constant> and located in
-	    <constant>drivers/media/dvb-core</constant>.</para>
-
-	<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 this 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 to 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
-	core for external access. It is not necessary to implement every
-	function in the struct <constant>dmx_demux</constant>. For example,
-	a demux interface might support Section filtering, but not PES
-	filtering. The API client is expected to check the value of any
-	function pointer before calling the function: the value of NULL means
-	that the &#8220;function is not available&#8221;.</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.</para>
-	<para>Note that functions called from a bottom half context must not
-	sleep. Even a simple memory allocation without using GFP_ATOMIC 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>
-    </sect1>
-
-    <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 DVB
-	kABIs, these 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
-	&#8220;bottom half&#8221; mechanism or start a tasklet instead of
-	making the callback function call directly from a hardware
-	interrupt.</para>
-	<para>This mechanism is implemented by
-	<link linkend='API-dmx-ts-cb'>dmx_ts_cb()</link> and
-	<link linkend='API-dmx-section-cb'>dmx_section_cb()</link>.</para>
-    </section>
-
+     <sect1><title>Digital TV Demux API</title>
+!Pdrivers/media/dvb-core/demux.h Digital TV Demux API
+     </sect1>
+     <sect1><title>Demux Callback API</title>
+!Pdrivers/media/dvb-core/demux.h Demux Callback API
+     </sect1>
 !Idrivers/media/dvb-core/demux.h
     </sect1>
     <sect1><title>Remote Controller devices</title>