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author | Takashi Iwai <tiwai@suse.de> | 2017-05-24 18:23:20 +0200 |
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committer | Takashi Iwai <tiwai@suse.de> | 2017-06-02 19:38:24 +0200 |
commit | 68541213720df9bb7904cc1fecab563d424849ae (patch) | |
tree | e8d3036ac6fe85d3e0b43bfa0dec7f16ee315127 /include | |
parent | a9cd29e79965f0f769d13edcf2e9adb389698e7b (diff) | |
download | linux-68541213720df9bb7904cc1fecab563d424849ae.tar.bz2 |
ALSA: pcm: Direct in-kernel read/write support
Now all materials are ready, let's allow the direct in-kernel
read/write, i.e. a kernel-space buffer is passed for read or write,
instead of the normal user-space buffer. This feature is used by OSS
layer and UAC1 driver, for example.
The __snd_pcm_lib_xfer() takes in_kernel argument that indicates the
in-kernel buffer copy. When this flag is set, another transfer code
is used. It's either via copy_kernel PCM ops or the normal memcpy(),
depending on the driver setup.
As external API, snd_pcm_kernel_read(), *_write() and other variants
are provided.
That's all. This support is really simple because of the code
refactoring until now.
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include')
-rw-r--r-- | include/sound/pcm.h | 38 |
1 files changed, 33 insertions, 5 deletions
diff --git a/include/sound/pcm.h b/include/sound/pcm.h index db649083c76d..c24f85f12b71 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -1074,34 +1074,62 @@ int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream, void snd_pcm_period_elapsed(struct snd_pcm_substream *substream); snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream, void *buf, bool interleaved, - snd_pcm_uframes_t frames); + snd_pcm_uframes_t frames, bool in_kernel); static inline snd_pcm_sframes_t snd_pcm_lib_write(struct snd_pcm_substream *substream, const void __user *buf, snd_pcm_uframes_t frames) { - return __snd_pcm_lib_xfer(substream, (void *)buf, true, frames); + return __snd_pcm_lib_xfer(substream, (void *)buf, true, frames, false); } static inline snd_pcm_sframes_t snd_pcm_lib_read(struct snd_pcm_substream *substream, void __user *buf, snd_pcm_uframes_t frames) { - return __snd_pcm_lib_xfer(substream, (void *)buf, true, frames); + return __snd_pcm_lib_xfer(substream, (void *)buf, true, frames, false); } static inline snd_pcm_sframes_t snd_pcm_lib_writev(struct snd_pcm_substream *substream, void __user **bufs, snd_pcm_uframes_t frames) { - return __snd_pcm_lib_xfer(substream, (void *)bufs, false, frames); + return __snd_pcm_lib_xfer(substream, (void *)bufs, false, frames, false); } static inline snd_pcm_sframes_t snd_pcm_lib_readv(struct snd_pcm_substream *substream, void __user **bufs, snd_pcm_uframes_t frames) { - return __snd_pcm_lib_xfer(substream, (void *)bufs, false, frames); + return __snd_pcm_lib_xfer(substream, (void *)bufs, false, frames, false); +} + +static inline snd_pcm_sframes_t +snd_pcm_kernel_write(struct snd_pcm_substream *substream, + const void *buf, snd_pcm_uframes_t frames) +{ + return __snd_pcm_lib_xfer(substream, (void *)buf, true, frames, true); +} + +static inline snd_pcm_sframes_t +snd_pcm_kernel_read(struct snd_pcm_substream *substream, + void *buf, snd_pcm_uframes_t frames) +{ + return __snd_pcm_lib_xfer(substream, buf, true, frames, true); +} + +static inline snd_pcm_sframes_t +snd_pcm_kernel_writev(struct snd_pcm_substream *substream, + void **bufs, snd_pcm_uframes_t frames) +{ + return __snd_pcm_lib_xfer(substream, bufs, false, frames, true); +} + +static inline snd_pcm_sframes_t +snd_pcm_kernel_readv(struct snd_pcm_substream *substream, + void **bufs, snd_pcm_uframes_t frames) +{ + return __snd_pcm_lib_xfer(substream, bufs, false, frames, true); } int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime); |