| Message ID | 20230126031424.14582-1-quic_wcheng@quicinc.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce QC USB SND audio offloading support | expand |
On 26.1.2023 5.14, Wesley Cheng wrote: > Changes in v2: > > XHCI: > - Replaced XHCI and HCD changes with Mathias' XHCI interrupter changes > in his tree: > https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters > I'll submit the first three patches from that branch myself to usb-next, might modify them slightly. Just need to make sure they don't cause regression. Those are changes I want done anyway. > Adjustments made to Mathias' changes: > - Created xhci-intr.h to export/expose interrupter APIs versus exposing xhci.h. > Moved dependent structures to this file as well. (so clients can parse out > information from "struct xhci_interrupter") > - Added some basic locking when requesting interrupters. > - Fixed up some sanity checks. > - Removed clearing of the ERSTBA during freeing of the interrupter. (pending > issue where SMMU fault occurs if DMA addr returned is 64b - TODO) Was this solvable by first clearing high 32 bits and then low 32 bits? Thanks Mathias
This version has lots of improvements, but I am concerned about hard-coded ops/callbacks that look racy and assume dependencies between driver probes. How does this work if the probe is delayed on one side for some reason? What happens is a driver is 'blacklisted' and manually added later? The code has to deal with this sort of known unknowns. I also still have a bit of heartburn with the notion that there would be a completely separate card with all the control for volume/mute/etc having to be duplicated. It's still a lot of good work so thanks for sharing and pushing for this capability.
Hi Mathias, On 1/26/2023 1:23 AM, Mathias Nyman wrote: > On 26.1.2023 5.14, Wesley Cheng wrote: >> Changes in v2: >> >> XHCI: >> - Replaced XHCI and HCD changes with Mathias' XHCI interrupter changes >> in his tree: >> https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters >> >> > > I'll submit the first three patches from that branch myself to usb-next, > might modify > them slightly. > Just need to make sure they don't cause regression. Those are changes I > want done anyway. > Sounds good! Thanks! >> Adjustments made to Mathias' changes: >> - Created xhci-intr.h to export/expose interrupter APIs versus >> exposing xhci.h. Do you think using the xhci-intr.h is a viable solution for class drivers to request for a secondary interrupter? >> Moved dependent structures to this file as well. (so clients can >> parse out >> information from "struct xhci_interrupter") >> - Added some basic locking when requesting interrupters. >> - Fixed up some sanity checks. >> - Removed clearing of the ERSTBA during freeing of the interrupter. >> (pending >> issue where SMMU fault occurs if DMA addr returned is 64b - TODO) > > Was this solvable by first clearing high 32 bits and then low 32 bits? > During the freeing of the secondary interrupter, the SMMU fault wasn't resolvable with clearing the high bits first. This does somewhat give me the notion that the xHC is attempting to access the event ring base address every time the ERSTBA is written. I believe the hi-lo write didn't work, as this time we are zero'ing out the base address. (SMMU FAR=0x0) As stated in Table 5-40 in the XHCI spec, when we write a 0 to the secondary interrupter ERSTSZ, it should disable that event ring. In this case, do we really need to explicitly clear the base address register? If I don't clear the ERSTBA (during free), then I don't see a SMMU fault even after the event ring has been freed. (ie event ring memory has been unmapped from the SMMU) So this should mean the xHC hasn't attempted to access that unmapped region for the memory address stored in the ERSTBA. Likewise, we'll write the ERSTBA again during the alloc phase to a valid and mapped address. Thanks Wesley Cheng
Changes in v2: XHCI: - Replaced XHCI and HCD changes with Mathias' XHCI interrupter changes in his tree: https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters Adjustments made to Mathias' changes: - Created xhci-intr.h to export/expose interrupter APIs versus exposing xhci.h. Moved dependent structures to this file as well. (so clients can parse out information from "struct xhci_interrupter") - Added some basic locking when requesting interrupters. - Fixed up some sanity checks. - Removed clearing of the ERSTBA during freeing of the interrupter. (pending issue where SMMU fault occurs if DMA addr returned is 64b - TODO) - Clean up pending events in the XHCI secondary interrupter. While testing USB bus suspend, it was seen that on bus resume, the xHCI HC would run into a command timeout. - Added offloading APIs to xHCI to fetch transfer and event ring information. ASoC: - Modified soc-usb to allow for multiple USB port additions. For this to work, the USB offload driver has to have a reference to the USB backend by adding a "usb-soc-be" DT entry to the device saved into XHCI sysdev. - Created separate dt-bindings for defining USB_RX port. - Increased APR timeout to accommodate the situation where the AFE port start command could be delayed due to having to issue a USB bus resume while handling the QMI stream start command. USB SND: - Added a platform ops during usb_audio_suspend(). This allows for the USB offload driver to halt the audio stream when system enters PM suspend. This ensures the audio DSP is not issuing transfers on the USB bus. - Do not override platform ops if they are already populated. - Introduce a shared status variable between the USB offload and USB SND layers, to ensure that only one path is active at a time. If the USB bus is occupied, then userspace is notified that the path is busy. Several Qualcomm based chipsets can support USB audio offloading to a dedicated audio DSP, which can take over issuing transfers to the USB host controller. The intention is to reduce the load on the main processors in the SoC, and allow them to be placed into lower power modes. There are several parts to this design: 1. Adding ASoC binding layer 2. Create a USB backend for Q6DSP 3. Introduce XHCI interrupter support 4. Create vendor ops for the USB SND driver Adding ASoC binding layer: soc-usb: Intention is to treat a USB port similar to a headphone jack. The port is always present on the device, but cable/pin status can be enabled/disabled. Expose mechanisms for USB backend ASoC drivers to communicate with USB SND. Create a USB backend for Q6DSP: q6usb: Basic backend driver that will be responsible for maintaining the resources needed to initiate a playback stream using the Q6DSP. Will be the entity that checks to make sure the connected USB audio device supports the requested PCM format. If it does not, the PCM open call will fail, and userpsace ALSA can take action accordingly. Introduce XHCI interrupter support: XHCI HCD supports multiple interrupters, which allows for events to be routed to different event rings. This is determined by "Interrupter Target" field specified in Section "6.4.1.1 Normal TRB" of the XHCI specification. Events in the offloading case will be routed to an event ring that is assigned to the audio DSP. Create vendor ops for the USB SND driver: qc_audio_offload: This particular driver has several components associated with it: - QMI stream request handler - XHCI interrupter and resource management - audio DSP memory management When the audio DSP wants to enable a playback stream, the request is first received by the ASoC platform sound card. Depending on the selected route, ASoC will bring up the individual DAIs in the path. The Q6USB backend DAI will send an AFE port start command (with enabling the USB playback path), and the audio DSP will handle the request accordingly. Part of the AFE USB port start handling will have an exchange of control messages using the QMI protocol. The qc_audio_offload driver will populate the buffer information: - Event ring base address - EP transfer ring base address and pass it along to the audio DSP. All endpoint management will now be handed over to the DSP, and the main processor is not involved in transfers. Overall, implementing this feature will still expose separate sound card and PCM devices for both the platorm card and USB audio device: 0 [SM8250MTPWCD938]: sm8250 - SM8250-MTP-WCD9380-WSA8810-VA-D SM8250-MTP-WCD9380-WSA8810-VA-DMIC 1 [Audio ]: USB-Audio - USB Audio Generic USB Audio at usb-xhci-hcd.1.auto-1.4, high speed This is to ensure that userspace ALSA entities can decide which route to take when executing the audio playback. In the above, if card#1 is selected, then USB audio data will take the legacy path over the USB PCM drivers, etc... This feature was validated using: - tinymix: set/enable the multimedia path to route to USB backend - tinyplay: issue playback on platform card Mathias Nyman (4): xhci: fix event ring segment table related masks and variables in header xhci: remove xhci_test_trb_in_td_math early development check xhci: Refactor interrupter code for initial multi interrupter support. xhci: Add support to allocate several interrupters Wesley Cheng (18): usb: xhci: Add XHCI APIs to support USB offloading usb: host: xhci-mem: Cleanup pending secondary event ring events ASoC: Add SOC USB APIs for adding an USB backend ASoC: dt-bindings: Add USB_RX port ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp ASoC: qdsp6: q6afe: Increase APR timeout ASoC: qcom: Add USB backend ASoC driver for Q6 sound: usb: card: Introduce USB SND platform op callbacks sound: usb: Export USB SND APIs for modules dt-bindings: usb: dwc3: Add snps,num-hc-interrupters definition usb: dwc3: Add DT parameter to specify maximum number of interrupters sound: usb: Introduce QC USB SND offloading support sound: usb: card: Check for support for requested audio format sound: soc: soc-usb: Add PCM format check API for USB backend sound: soc: qcom: qusb6: Ensure PCM format is supported by USB audio device sound: usb: Prevent starting of audio stream if in use ASoC: dt-bindings: Add Q6USB backend bindings ASoC: dt-bindings: Update example for enabling USB offload on SM8250 .../bindings/sound/qcom,q6usb-dais.yaml | 55 + .../bindings/sound/qcom,sm8250.yaml | 13 + .../devicetree/bindings/usb/snps,dwc3.yaml | 12 + drivers/usb/dwc3/core.c | 12 + drivers/usb/dwc3/core.h | 2 + drivers/usb/dwc3/host.c | 5 +- drivers/usb/host/xhci-debugfs.c | 2 +- drivers/usb/host/xhci-mem.c | 471 +++-- drivers/usb/host/xhci-ring.c | 68 +- drivers/usb/host/xhci.c | 199 +- drivers/usb/host/xhci.h | 81 +- .../sound/qcom,q6dsp-lpass-ports.h | 1 + include/linux/usb/xhci-intr.h | 94 + include/sound/pcm_params.h | 4 + include/sound/q6usboffload.h | 20 + include/sound/soc-usb.h | 36 + sound/core/oss/pcm_oss.c | 58 - sound/core/pcm_lib.c | 65 + sound/soc/Makefile | 2 +- sound/soc/qcom/Kconfig | 4 + sound/soc/qcom/qdsp6/Makefile | 1 + sound/soc/qcom/qdsp6/q6afe-dai.c | 48 + sound/soc/qcom/qdsp6/q6afe.c | 185 +- sound/soc/qcom/qdsp6/q6afe.h | 46 +- sound/soc/qcom/qdsp6/q6dsp-lpass-ports.c | 23 + sound/soc/qcom/qdsp6/q6dsp-lpass-ports.h | 1 + sound/soc/qcom/qdsp6/q6routing.c | 8 + sound/soc/qcom/qdsp6/q6usb.c | 234 +++ sound/soc/soc-usb.c | 215 ++ sound/usb/Kconfig | 14 + sound/usb/Makefile | 2 +- sound/usb/card.c | 58 + sound/usb/card.h | 29 + sound/usb/endpoint.c | 2 + sound/usb/helper.c | 1 + sound/usb/pcm.c | 28 +- sound/usb/pcm.h | 12 + sound/usb/qcom/Makefile | 2 + sound/usb/qcom/qc_audio_offload.c | 1789 +++++++++++++++++ sound/usb/qcom/usb_audio_qmi_v01.c | 892 ++++++++ sound/usb/qcom/usb_audio_qmi_v01.h | 162 ++ 41 files changed, 4546 insertions(+), 410 deletions(-) create mode 100644 Documentation/devicetree/bindings/sound/qcom,q6usb-dais.yaml create mode 100644 include/linux/usb/xhci-intr.h create mode 100644 include/sound/q6usboffload.h create mode 100644 include/sound/soc-usb.h create mode 100644 sound/soc/qcom/qdsp6/q6usb.c create mode 100644 sound/soc/soc-usb.c create mode 100644 sound/usb/qcom/Makefile create mode 100644 sound/usb/qcom/qc_audio_offload.c create mode 100644 sound/usb/qcom/usb_audio_qmi_v01.c create mode 100644 sound/usb/qcom/usb_audio_qmi_v01.h