On Tue, 29 Aug 2023 23:06:43 +0200, Wesley Cheng wrote: > > Several Qualcomm SoCs have a dedicated audio DSP, which has the ability to > support USB sound devices. This vendor driver will implement the required > handshaking with the DSP, in order to pass along required resources that > will be utilized by the DSP's USB SW. The communication channel used for > this handshaking will be using the QMI protocol. Required resources > include: > - Allocated secondary event ring address > - EP transfer ring address > - Interrupter number > > The above information will allow for the audio DSP to execute USB transfers > over the USB bus. It will also be able to support devices that have an > implicit feedback and sync endpoint as well. Offloading these data > transfers will allow the main/applications processor to enter lower CPU > power modes, and sustain a longer duration in those modes. > > Audio offloading is initiated with the following sequence: > 1. Userspace configures to route audio playback to USB backend and starts > playback on the platform soundcard. > 2. The Q6DSP AFE will communicate to the audio DSP to start the USB AFE > port. > 3. This results in a QMI packet with a STREAM enable command. > 4. The QC audio offload driver will fetch the required resources, and pass > this information as part of the QMI response to the STREAM enable command. > 5. Once the QMI response is received the audio DSP will start queuing data > on the USB bus. > > Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx> > --- > sound/usb/Kconfig | 15 + > sound/usb/Makefile | 2 +- > sound/usb/qcom/Makefile | 2 + > sound/usb/qcom/qc_audio_offload.c | 1813 +++++++++++++++++++++++++++++ > 4 files changed, 1831 insertions(+), 1 deletion(-) > create mode 100644 sound/usb/qcom/Makefile > create mode 100644 sound/usb/qcom/qc_audio_offload.c > > diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig > index 4a9569a3a39a..da5838656baa 100644 > --- a/sound/usb/Kconfig > +++ b/sound/usb/Kconfig > @@ -176,6 +176,21 @@ config SND_BCD2000 > To compile this driver as a module, choose M here: the module > will be called snd-bcd2000. > > +config QC_USB_AUDIO_OFFLOAD Keep SND_ prefix for consistency. And, at best, align with the module name. > + tristate "Qualcomm Audio Offload driver" > + depends on QCOM_QMI_HELPERS && SND_USB_AUDIO && USB_XHCI_SIDEBAND > + select SND_PCM > + help > + Say Y here to enable the Qualcomm USB audio offloading feature. > + > + This module sets up the required QMI stream enable/disable > + responses to requests generated by the audio DSP. It passes the > + USB transfer resource references, so that the audio DSP can issue > + USB transfers to the host controller. > + > + To compile this driver as a module, choose M here: the module > + will be called qc-audio-offload. Hmm, you renamed it differently, no? In the below: > --- /dev/null > +++ b/sound/usb/qcom/Makefile > @@ -0,0 +1,2 @@ > +snd-usb-audio-qmi-objs := usb_audio_qmi_v01.o qc_audio_offload.o > +obj-$(CONFIG_QC_USB_AUDIO_OFFLOAD) += snd-usb-audio-qmi.o ... it's called snd-usb-audio-qmi. thanks, Takashi
