On Asymmetric multiprocessor, there is Cortex-A core and Cortex-M core, Linux is running on A core, RTOS is running on M core. The audio hardware device can be controlled by Cortex-M device, So audio playback/capture can be handled by M core.
Rpmsg is the interface for sending and receiving msg to and from M core, that we can create a virtual sound on Cortex-A core side.
A core will tell the Cortex-M core sound format/rate/channel, where is the data buffer, what is the period size, when to start, when to stop and when suspend or resume happen, each of this behavior there is defined rpmsg command.
Especially we designed the low power audio case, that is to allocate a large buffer and fill the data, then Cortex-A core can go to sleep mode, Cortex-M core continue to play the sound, when the buffer is consumed, Cortex-M core will trigger the Cortex-A core to wakeup to fill data.
changes in v4: - remove the sound card node, merge the property to cpu dai node according to Rob's comments. - sound card device will be registered by cpu dai driver. - Fix do_div issue reported by kernel test robot
changes in v3: - add local refcount for clk enablement in hw_params() - update the document according Rob's comments
changes in v2: - update codes and comments according to Mark's comments
Shengjiu Wang (6): ASoC: soc-component: Add snd_soc_pcm_component_ack ASoC: fsl_rpmsg: Add CPU DAI driver for audio base on rpmsg ASoC: dt-bindings: fsl_rpmsg: Add binding doc for rpmsg cpu dai driver ASoC: imx-audio-rpmsg: Add rpmsg_driver for audio channel ASoC: imx-pcm-rpmsg: Add platform driver for audio base on rpmsg ASoC: imx-rpmsg: Add machine driver for audio base on rpmsg
.../devicetree/bindings/sound/fsl,rpmsg.yaml | 118 +++ include/sound/soc-component.h | 3 + sound/soc/fsl/Kconfig | 28 + sound/soc/fsl/Makefile | 6 + sound/soc/fsl/fsl_rpmsg.c | 283 ++++++ sound/soc/fsl/fsl_rpmsg.h | 42 + sound/soc/fsl/imx-audio-rpmsg.c | 151 +++ sound/soc/fsl/imx-pcm-rpmsg.c | 919 ++++++++++++++++++ sound/soc/fsl/imx-pcm-rpmsg.h | 512 ++++++++++ sound/soc/fsl/imx-rpmsg.c | 127 +++ sound/soc/soc-component.c | 14 + sound/soc/soc-pcm.c | 2 + 12 files changed, 2205 insertions(+) create mode 100644 Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml create mode 100644 sound/soc/fsl/fsl_rpmsg.c create mode 100644 sound/soc/fsl/fsl_rpmsg.h create mode 100644 sound/soc/fsl/imx-audio-rpmsg.c create mode 100644 sound/soc/fsl/imx-pcm-rpmsg.c create mode 100644 sound/soc/fsl/imx-pcm-rpmsg.h create mode 100644 sound/soc/fsl/imx-rpmsg.c