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Commit 5469306a authored by Jaroslav Kysela's avatar Jaroslav Kysela
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ALSA CVS update - Takashi Iwai <tiwai@suse.de> 

Documentation
changed the description of the buffer allocation routines
for the new designed functions.
parent cd37e0d6
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Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
View file @ 5469306a
......@@ -18,8 +18,8 @@
</affiliation>
</author>
<date>Mar. 26, 2003</date>
<edition>0.3</edition>
<date>Mar. 6, 2004</date>
<edition>0.3.1</edition>
<abstract>
<para>
......@@ -30,7 +30,7 @@
<legalnotice>
<para>
Copyright (c) 2002, 2003 Takashi Iwai <email>tiwai@suse.de</email>
Copyright (c) 2002-2004 Takashi Iwai <email>tiwai@suse.de</email>
</para>
<para>
......@@ -111,18 +111,18 @@
<para>
One is the the trees provided as a tarball or via cvs from the
ALSA's ftp site, and another is the 2.5 (or later) Linux kernel
ALSA's ftp site, and another is the 2.6 (or later) Linux kernel
tree. To synchronize both, the ALSA driver tree is split to
two different trees: alsa-kernel and alsa-driver. The former
contains purely the source codes for the Linux 2.5 (or later)
tree. This tree is designed only for compilation on 2.5 or
contains purely the source codes for the Linux 2.6 (or later)
tree. This tree is designed only for compilation on 2.6 or
later environment. The latter, alsa-driver, contains many subtle
files for compiling the ALSA driver on the outside of Linux
kernel like configure script, the wrapper functions for older,
2.2 and 2.4 kernels, to adapt the latest kernel API,
and additional drivers which are still in development or in
tests. The drivers in alsa-driver tree will be moved to
alsa-kernel (eventually 2.5 kernel tree) once when they are
alsa-kernel (eventually 2.6 kernel tree) once when they are
finished and confirmed to work fine.
</para>
......@@ -346,7 +346,7 @@
<section id="file-tree-oss-directory">
<title>oss directory</title>
<para>
The OSS/Lite source files are stored here on Linux 2.5 (or
The OSS/Lite source files are stored here on Linux 2.6 (or
later) tree. (In the ALSA driver tarball, it's empty, of course :)
</para>
</section>
......@@ -1815,7 +1815,7 @@
<para>
Oh, one thing was forgotten. If you have no exported symbols,
you need to declare it on 2.2 or 2.4 kernels (on 2.5 kernels
you need to declare it on 2.2 or 2.4 kernels (on 2.6 kernels
it's not necessary, though).
<informalexample>
......@@ -2075,7 +2075,8 @@
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
&snd_mychip_capture_ops);
/* pre-allocation of buffers */
snd_pcm_lib_preallocate_pci_pages_for_all(chip->pci, pcm,
snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
snd_dma_pci_data(chip->pci),
64*1024, 64*1024);
return 0;
}
......@@ -2202,7 +2203,8 @@
<informalexample>
<programlisting>
<![CDATA[
snd_pcm_lib_preallocate_pci_pages_for_all(chip->pci, pcm,
snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
snd_dma_pci_data(chip->pci),
64*1024, 64*1024);
]]>
</programlisting>
......@@ -4724,7 +4726,8 @@ struct _snd_pcm_runtime {
<informalexample>
<programlisting>
<![CDATA[
snd_pcm_lib_preallocate_pci_pages_for_all(pci, pcm, size, max);
snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
snd_dma_pci_data(pci), size, max);
]]>
</programlisting>
</informalexample>
......@@ -4734,8 +4737,25 @@ struct _snd_pcm_runtime {
size to be changed via <filename>prealloc</filename> proc file.
The allocator will try to get as the large area as possible
within the given size.
There are different versions of pre-allocator for different
buses.
</para>
<para>
The second argument (type) and the third argument (device pointer)
are dependent on the bus.
In the case of ISA bus, pass <function>snd_dma_isa_data()</function>
as the third argument with <constant>SNDRV_DMA_TYPE_DEV</constant> type.
For the continuous buffer unrelated to the bus can be pre-allocated
with <constant>SNDRV_DMA_TYPE_CONTINUOUS</constant> type and the
<function>snd_dma_continuous_data(GFP_KERNEL)</function> device pointer,
whereh <constant>GFP_KERNEL</constant> is the kernel allocation flag to
use. For the SBUS, <constant>SNDRV_DMA_TYPE_SBUS</constant> and
<function>snd_dma_sbus_data(sbus_dev)</function> are used instead.
For the PCI scatter-gather buffers, use
<constant>SNDRV_DMA_TYPE_DEV_SG</constant> with
<function>snd_dma_pci_data(pci)</function>
(see the section
<link linkend="buffer-and-memory-non-contiguous"><citetitle>Non-Contiguous Buffers
</citetitle></link>).
</para>
<para>
......@@ -4942,11 +4962,13 @@ struct _snd_pcm_runtime {
<para>
For creating the SG-buffer handler, call
<function>snd_pcm_lib_preallocate_sg_pages()</function> or
<function>snd_pcm_lib_preallocate_sg_pages_for_all()</function>
<function>snd_pcm_lib_preallocate_pages()</function> or
<function>snd_pcm_lib_preallocate_pages_for_all()</function>
with <constant>SNDRV_DMA_TYPE_DEV_SG</constant>
in the PCM constructor like other PCI pre-allocator.
You need to pass the
<structname>pci_dev</structname> struct pointer of the chip.
You need to pass the <function>snd_dma_pci_data(pci)</function>,
where pci is the struct <structname>pci_dev</structname> pointer
of the chip as well.
The <type>snd_sg_buf_t</type> instance is created as
substream-&gt;dma_private. You can cast
the pointer like:
......@@ -5280,7 +5302,7 @@ struct _snd_pcm_runtime {
</para>
<para>
For keeping the readability of 2.5 source code, it's recommended to
For keeping the readability of 2.6 source code, it's recommended to
separate the above ifdef condition as the patch file in alsa-driver
directory.
See <filename>alsa-driver/pci/ali5451.c</filename> for example.
......@@ -5612,7 +5634,7 @@ struct _snd_pcm_runtime {
tree. Then the driver is evaluated, audited and tested
by developers and users. After a certain time, the driver
will go to alsa-kernel tree and eventually integrated into
Linux 2.5 tree.
Linux 2.6 tree.
</para>
<para>
......@@ -5648,61 +5670,44 @@ struct _snd_pcm_runtime {
<listitem>
<para>
Modify alsa-driver/acore/Makefile
Create the Kconfig entry
</para>
<para>
Here define the dependent modules.
Add the new entry of Kconfig for your xyz driver.
<informalexample>
<programlisting>
<![CDATA[
obj-$(CONFIG_SND_XYZ) += snd.o ...
config SND_BT87X
tristate "Foobar XYX"
depends on SND
select SND_PCM
help
Say 'Y' or 'M' to include support for Foobar XYZ soundcard.
]]>
</programlisting>
</informalexample>
If the driver supports PCM, snd-pcm.o,
snd-timer.o and snd-page-alloc.o
will be needed.
</para>
<para>
For rawmidi, snd-rawmidi.o is needed in addition.
The MIDI stuff is also related to the sequencer.
You'll need to modify alsa-driver/acore/seq/Makefile.
the line, select SND_PCM, specifies that the driver xyz supports
PCM. In addition to SND_PCM, the following components are
supported for select command:
SND_RAWMIDI, SND_TIMER, SND_HWDEP, SND_MPU401_UART,
SND_OPL3_LIB, SND_OPL4_LIB, SND_VX_LIB, SND_AC97_CODEC.
Add the select command for each supported component.
</para>
<para>
For OPL3, snd-hwdep.o is needed, too.
It's involved with the sequencer, and as well as rawmidi,
you'll need to modify alsa-driver/acore/seq/Makefile
and acore/seq/instr/Makefile in addition.
Also, a new entry is necessary in
alsa-driver/drivers/opl3/Makefile.
Note that some selections imply the lowlevel selections.
For example, PCM includes TIMER, MPU401_UART includes RAWMIDI,
AC97_CODEC includes PCM, and OPL3_LIB includes HWDEP.
You don't need to give the lowlevel selections again.
</para>
</listitem>
<listitem>
<para>
Modify alsa-driver/utils/Modules.dep
For the details of Kconfig script, refer to the kbuild
documentation.
</para>
<para>
Add the module definition for configure, here.
The beginning of the line must be a vertical bar, following
the card module name (snd-xyz) and the list of its all
dependent modules.
<informalexample>
<programlisting>
<![CDATA[
%dir linux/sound/pci
|snd-azt3328 snd-pcm snd-mpu401-uart snd-opl3-lib snd-opl3-synth
|snd-xyz snd-pcm ...
]]>
</programlisting>
</informalexample>
</para>
</listitem>
<listitem>
......@@ -5730,7 +5735,7 @@ struct _snd_pcm_runtime {
<informalexample>
<programlisting>
<![CDATA[
extra-subdir-y := pdplus vx222 xyz
obj-$(CONFIG_SND) += xyz/
]]>
</programlisting>
</informalexample>
......@@ -5745,13 +5750,13 @@ struct _snd_pcm_runtime {
<title>Sample Makefile for a driver xyz</title>
<programlisting>
<![CDATA[
TOPDIR = ../..
ifndef SND_TOPDIR
SND_TOPDIR=../..
endif
include $(TOPDIR)/toplevel.config
include $(TOPDIR)/Makefile.conf
TOPDIR = $(MAINSRCDIR)
snd-xyz-objs := xyz.o abc.o def.o
obj-$(CONFIG_SND_XYZ) += snd-xyz.o
......@@ -5765,7 +5770,7 @@ struct _snd_pcm_runtime {
<listitem>
<para>
Modify alsa-driver/acore/Makefile
Create the Kconfig entry
</para>
<para>
......@@ -5773,23 +5778,6 @@ struct _snd_pcm_runtime {
</para>
</listitem>
<listitem>
<para>
Modify alsa-driver/utils/Modules.dep
</para>
<para>
<informalexample>
<programlisting>
<![CDATA[
%dir linux/sound/pci/xyz
|snd-xyz snd-pcm ...
]]>
</programlisting>
</informalexample>
</para>
</listitem>
<listitem>
<para>
Run cvscompile script to re-generate the configure script and
......
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