213 lines
9.6 KiB
Plaintext
213 lines
9.6 KiB
Plaintext
|
|
$Id$
|
|
Mike Isely <isely@pobox.com>
|
|
|
|
pvrusb2 driver
|
|
|
|
Background:
|
|
|
|
This driver is intended for the "Hauppauge WinTV PVR USB 2.0", which
|
|
is a USB 2.0 hosted TV Tuner. This driver is a work in progress.
|
|
Its history started with the reverse-engineering effort by Björn
|
|
Danielsson <pvrusb2@dax.nu> whose web page can be found here:
|
|
|
|
http://pvrusb2.dax.nu/
|
|
|
|
From there Aurelien Alleaume <slts@free.fr> began an effort to
|
|
create a video4linux compatible driver. I began with Aurelien's
|
|
last known snapshot and evolved the driver to the state it is in
|
|
here.
|
|
|
|
More information on this driver can be found at:
|
|
|
|
http://www.isely.net/pvrusb2.html
|
|
|
|
|
|
This driver has a strong separation of layers. They are very
|
|
roughly:
|
|
|
|
1a. Low level wire-protocol implementation with the device.
|
|
|
|
1b. I2C adaptor implementation and corresponding I2C client drivers
|
|
implemented elsewhere in V4L.
|
|
|
|
1c. High level hardware driver implementation which coordinates all
|
|
activities that ensure correct operation of the device.
|
|
|
|
2. A "context" layer which manages instancing of driver, setup,
|
|
tear-down, arbitration, and interaction with high level
|
|
interfaces appropriately as devices are hotplugged in the
|
|
system.
|
|
|
|
3. High level interfaces which glue the driver to various published
|
|
Linux APIs (V4L, sysfs, maybe DVB in the future).
|
|
|
|
The most important shearing layer is between the top 2 layers. A
|
|
lot of work went into the driver to ensure that any kind of
|
|
conceivable API can be laid on top of the core driver. (Yes, the
|
|
driver internally leverages V4L to do its work but that really has
|
|
nothing to do with the API published by the driver to the outside
|
|
world.) The architecture allows for different APIs to
|
|
simultaneously access the driver. I have a strong sense of fairness
|
|
about APIs and also feel that it is a good design principle to keep
|
|
implementation and interface isolated from each other. Thus while
|
|
right now the V4L high level interface is the most complete, the
|
|
sysfs high level interface will work equally well for similar
|
|
functions, and there's no reason I see right now why it shouldn't be
|
|
possible to produce a DVB high level interface that can sit right
|
|
alongside V4L.
|
|
|
|
NOTE: Complete documentation on the pvrusb2 driver is contained in
|
|
the html files within the doc directory; these are exactly the same
|
|
as what is on the web site at the time. Browse those files
|
|
(especially the FAQ) before asking questions.
|
|
|
|
|
|
Building
|
|
|
|
To build these modules essentially amounts to just running "Make",
|
|
but you need the kernel source tree nearby and you will likely also
|
|
want to set a few controlling environment variables first in order
|
|
to link things up with that source tree. Please see the Makefile
|
|
here for comments that explain how to do that.
|
|
|
|
|
|
Source file list / functional overview:
|
|
|
|
(Note: The term "module" used below generally refers to loosely
|
|
defined functional units within the pvrusb2 driver and bears no
|
|
relation to the Linux kernel's concept of a loadable module.)
|
|
|
|
pvrusb2-audio.[ch] - This is glue logic that resides between this
|
|
driver and the msp3400.ko I2C client driver (which is found
|
|
elsewhere in V4L).
|
|
|
|
pvrusb2-context.[ch] - This module implements the context for an
|
|
instance of the driver. Everything else eventually ties back to
|
|
or is otherwise instanced within the data structures implemented
|
|
here. Hotplugging is ultimately coordinated here. All high level
|
|
interfaces tie into the driver through this module. This module
|
|
helps arbitrate each interface's access to the actual driver core,
|
|
and is designed to allow concurrent access through multiple
|
|
instances of multiple interfaces (thus you can for example change
|
|
the tuner's frequency through sysfs while simultaneously streaming
|
|
video through V4L out to an instance of mplayer).
|
|
|
|
pvrusb2-debug.h - This header defines a printk() wrapper and a mask
|
|
of debugging bit definitions for the various kinds of debug
|
|
messages that can be enabled within the driver.
|
|
|
|
pvrusb2-debugifc.[ch] - This module implements a crude command line
|
|
oriented debug interface into the driver. Aside from being part
|
|
of the process for implementing manual firmware extraction (see
|
|
the pvrusb2 web site mentioned earlier), probably I'm the only one
|
|
who has ever used this. It is mainly a debugging aid.
|
|
|
|
pvrusb2-eeprom.[ch] - This is glue logic that resides between this
|
|
driver the tveeprom.ko module, which is itself implemented
|
|
elsewhere in V4L.
|
|
|
|
pvrusb2-encoder.[ch] - This module implements all protocol needed to
|
|
interact with the Conexant mpeg2 encoder chip within the pvrusb2
|
|
device. It is a crude echo of corresponding logic in ivtv,
|
|
however the design goals (strict isolation) and physical layer
|
|
(proxy through USB instead of PCI) are enough different that this
|
|
implementation had to be completely different.
|
|
|
|
pvrusb2-hdw-internal.h - This header defines the core data structure
|
|
in the driver used to track ALL internal state related to control
|
|
of the hardware. Nobody outside of the core hardware-handling
|
|
modules should have any business using this header. All external
|
|
access to the driver should be through one of the high level
|
|
interfaces (e.g. V4L, sysfs, etc), and in fact even those high
|
|
level interfaces are restricted to the API defined in
|
|
pvrusb2-hdw.h and NOT this header.
|
|
|
|
pvrusb2-hdw.h - This header defines the full internal API for
|
|
controlling the hardware. High level interfaces (e.g. V4L, sysfs)
|
|
will work through here.
|
|
|
|
pvrusb2-hdw.c - This module implements all the various bits of logic
|
|
that handle overall control of a specific pvrusb2 device.
|
|
(Policy, instantiation, and arbitration of pvrusb2 devices fall
|
|
within the jurisdiction of pvrusb-context not here).
|
|
|
|
pvrusb2-i2c-chips-*.c - These modules implement the glue logic to
|
|
tie together and configure various I2C modules as they attach to
|
|
the I2C bus. There are two versions of this file. The "v4l2"
|
|
version is intended to be used in-tree alongside V4L, where we
|
|
implement just the logic that makes sense for a pure V4L
|
|
environment. The "all" version is intended for use outside of
|
|
V4L, where we might encounter other possibly "challenging" modules
|
|
from ivtv or older kernel snapshots (or even the support modules
|
|
in the standalone snapshot).
|
|
|
|
pvrusb2-i2c-cmd-v4l1.[ch] - This module implements generic V4L1
|
|
compatible commands to the I2C modules. It is here where state
|
|
changes inside the pvrusb2 driver are translated into V4L1
|
|
commands that are in turn send to the various I2C modules.
|
|
|
|
pvrusb2-i2c-cmd-v4l2.[ch] - This module implements generic V4L2
|
|
compatible commands to the I2C modules. It is here where state
|
|
changes inside the pvrusb2 driver are translated into V4L2
|
|
commands that are in turn send to the various I2C modules.
|
|
|
|
pvrusb2-i2c-core.[ch] - This module provides an implementation of a
|
|
kernel-friendly I2C adaptor driver, through which other external
|
|
I2C client drivers (e.g. msp3400, tuner, lirc) may connect and
|
|
operate corresponding chips within the the pvrusb2 device. It is
|
|
through here that other V4L modules can reach into this driver to
|
|
operate specific pieces (and those modules are in turn driven by
|
|
glue logic which is coordinated by pvrusb2-hdw, doled out by
|
|
pvrusb2-context, and then ultimately made available to users
|
|
through one of the high level interfaces).
|
|
|
|
pvrusb2-io.[ch] - This module implements a very low level ring of
|
|
transfer buffers, required in order to stream data from the
|
|
device. This module is *very* low level. It only operates the
|
|
buffers and makes no attempt to define any policy or mechanism for
|
|
how such buffers might be used.
|
|
|
|
pvrusb2-ioread.[ch] - This module layers on top of pvrusb2-io.[ch]
|
|
to provide a streaming API usable by a read() system call style of
|
|
I/O. Right now this is the only layer on top of pvrusb2-io.[ch],
|
|
however the underlying architecture here was intended to allow for
|
|
other styles of I/O to be implemented with additonal modules, like
|
|
mmap()'ed buffers or something even more exotic.
|
|
|
|
pvrusb2-main.c - This is the top level of the driver. Module level
|
|
and USB core entry points are here. This is our "main".
|
|
|
|
pvrusb2-sysfs.[ch] - This is the high level interface which ties the
|
|
pvrusb2 driver into sysfs. Through this interface you can do
|
|
everything with the driver except actually stream data.
|
|
|
|
pvrusb2-tuner.[ch] - This is glue logic that resides between this
|
|
driver and the tuner.ko I2C client driver (which is found
|
|
elsewhere in V4L).
|
|
|
|
pvrusb2-util.h - This header defines some common macros used
|
|
throughout the driver. These macros are not really specific to
|
|
the driver, but they had to go somewhere.
|
|
|
|
pvrusb2-v4l2.[ch] - This is the high level interface which ties the
|
|
pvrusb2 driver into video4linux. It is through here that V4L
|
|
applications can open and operate the driver in the usual V4L
|
|
ways. Note that **ALL** V4L functionality is published only
|
|
through here and nowhere else.
|
|
|
|
pvrusb2-video-*.[ch] - This is glue logic that resides between this
|
|
driver and the saa711x.ko I2C client driver (which is found
|
|
elsewhere in V4L). Note that saa711x.ko used to be known as
|
|
saa7115.ko in ivtv. There are two versions of this; one is
|
|
selected depending on the particular saa711[5x].ko that is found.
|
|
|
|
pvrusb2.h - This header contains compile time tunable parameters
|
|
(and at the moment the driver has very little that needs to be
|
|
tuned).
|
|
|
|
|
|
-Mike Isely
|
|
isely@pobox.com
|
|
|