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.
Signed-off-by: Takashi Iwai tiwai@suse.de --- include/sound/pcm.h | 38 +++++++++++++++++++++++++++++++++----- sound/core/pcm_lib.c | 26 +++++++++++++++++++++++++- 2 files changed, 58 insertions(+), 6 deletions(-)
diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 173c6a6ebf35..e3a7269824c7 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -1090,34 +1090,62 @@ void snd_pcm_playback_silence(struct snd_pcm_substream *substream, snd_pcm_ufram 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); }
extern const struct snd_pcm_hw_constraint_list snd_pcm_known_rates; diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 094447ae8486..4ad8f5aee74f 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -2003,6 +2003,15 @@ static int default_write_copy(struct snd_pcm_substream *substream, return 0; }
+/* default copy_kernel ops for write */ +static int default_write_copy_kernel(struct snd_pcm_substream *substream, + int channel, unsigned long hwoff, + void *buf, unsigned long bytes) +{ + memcpy(get_dma_ptr(substream->runtime, channel, hwoff), buf, bytes); + return 0; +} + /* fill silence instead of copy data; called as a transfer helper * from __snd_pcm_lib_write() or directly from noninterleaved_copy() when * a NULL buffer is passed @@ -2036,6 +2045,15 @@ static int default_read_copy(struct snd_pcm_substream *substream, return 0; }
+/* default copy_kernel ops for read */ +static int default_read_copy_kernel(struct snd_pcm_substream *substream, + int channel, unsigned long hwoff, + void *buf, unsigned long bytes) +{ + memcpy(buf, get_dma_ptr(substream->runtime, channel, hwoff), bytes); + return 0; +} + /* call transfer function with the converted pointers and sizes; * for interleaved mode, it's one shot for all samples */ @@ -2119,7 +2137,7 @@ static int pcm_accessible_state(struct snd_pcm_runtime *runtime) /* the common loop for read/write data */ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream, void *data, bool interleaved, - snd_pcm_uframes_t size) + snd_pcm_uframes_t size, bool in_kernel) { struct snd_pcm_runtime *runtime = substream->runtime; snd_pcm_uframes_t xfer = 0; @@ -2152,6 +2170,12 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream, transfer = fill_silence; else return -EINVAL; + } else if (in_kernel) { + if (substream->ops->copy_kernel) + transfer = substream->ops->copy_kernel; + else + transfer = is_playback ? + default_write_copy_kernel : default_read_copy_kernel; } else { if (substream->ops->copy_user) transfer = (pcm_transfer_f)substream->ops->copy_user;