It is better to keep the documentation overview at the header file,
as this makes easier for developers to remember to fix when needed.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
---
As suggested during the KS Workshop, the best is to use the !P meta-tag , and keep
the documentation overview at the header file.
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 “function is 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.</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
- “bottom half” 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>
diff --git a/drivers/media/dvb-core/demux.h b/drivers/media/dvb-core/demux.h
index ccc1f43cb9a9..f8014aabf37b 100644
--- a/drivers/media/dvb-core/demux.h
+++ b/drivers/media/dvb-core/demux.h
@@ -32,6 +32,49 @@
#include <linux/time.h>
#include <linux/dvb/dmx.h>
+/**
+ * DOC: Digital TV Demux API
+ *
+ * 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 demux.h and located in
+ * drivers/media/dvb-core.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * 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
+ * &dmx_demux. 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 function is not available.
+ *
+ * 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.
+ *
+ * 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.
+ */
+
/*
* Common definitions
*/
@@ -187,8 +230,28 @@ struct dmx_section_feed {
int (*stop_filtering)(struct dmx_section_feed *feed);
};
-/*
- * Callback functions
+/**
+ * DOC: Demux Callback API
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * This mechanism is implemented by dmx_ts_cb() and dmx_section_cb()
+ * callbacks.
*/
/**
--
2.4.3
--
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