Message ID | 20240829194105.1504814-1-quic_wcheng@quicinc.com |
---|---|
Headers | show |
Series | Introduce QC USB SND audio offloading support | expand |
On 8/29/24 21:40, Wesley Cheng wrote: > Some vendor modules will utilize useful parsing and endpoint management > APIs to start audio playback/capture. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
On 8/29/24 21:40, Wesley Cheng wrote: > Allow for checks on a specific USB audio device to see if a requested PCM > format is supported. This is needed for support when playback is > initiated by the ASoC USB backend path. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
On 8/29/24 21:40, Wesley Cheng wrote: > USB SND needs to know how the USB offload path is being routed. This would > allow for applications to open the corresponding sound card and pcm device > when it wants to take the audio offload path. This callback should return > the mapped indexes based on the USB SND device information. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> > diff --git a/include/sound/soc-usb.h b/include/sound/soc-usb.h > index 5c788cbfa82e..86876098a2b7 100644 > --- a/include/sound/soc-usb.h > +++ b/include/sound/soc-usb.h > @@ -36,6 +36,7 @@ struct snd_soc_usb_device { > * @list - list head for SND SOC struct list > * @component - reference to ASoC component > * @connection_status_cb - callback to notify connection events > + * @update_offload_route_info - callback to fetch mapped ASoC device nit-pick: explain that 'route' refers to the (card, device) pair and isn't related to the concept of DAPM route. > * @priv_data - driver data > **/ > struct snd_soc_usb { > @@ -44,6 +45,9 @@ struct snd_soc_usb { > int (*connection_status_cb)(struct snd_soc_usb *usb, > struct snd_soc_usb_device *sdev, > bool connected); > + int (*update_offload_route_info)(struct snd_soc_component *component, > + int card, int pcm, int direction, > + long *route); nit-pick: also explain the format used for the (card, device) pair stored in the long > void *priv_data; > }; > > @@ -59,6 +63,8 @@ void *snd_soc_usb_find_priv_data(struct device *dev); > int snd_soc_usb_setup_offload_jack(struct snd_soc_component *component, > struct snd_soc_jack *jack); > int snd_soc_usb_disable_offload_jack(struct snd_soc_component *component); > +int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm, > + int direction, long *route); > > struct snd_soc_usb *snd_soc_usb_allocate_port(struct snd_soc_component *component, > void *data); > @@ -101,6 +107,12 @@ static inline int snd_soc_usb_disable_offload_jack(struct snd_soc_component *com > return 0; > } > > +static int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm, > + int direction, long *route) > +{ > + return -ENODEV; > +} > + > static inline struct snd_soc_usb * > snd_soc_usb_allocate_port(struct snd_soc_component *component, void *data) > { > diff --git a/sound/soc/soc-usb.c b/sound/soc/soc-usb.c > index 3d5354298206..de249e8a28cb 100644 > --- a/sound/soc/soc-usb.c > +++ b/sound/soc/soc-usb.c > @@ -117,6 +117,37 @@ int snd_soc_usb_disable_offload_jack(struct snd_soc_component *component) > } > EXPORT_SYMBOL_GPL(snd_soc_usb_disable_offload_jack); > > +/** > + * snd_soc_usb_update_offload_route - Find active USB offload path > + * @dev - USB device to get offload status > + * @card - USB card index > + * @pcm - USB PCM device index > + * @direction - playback or capture direction > + * @route - pointer to route output array > + * > + * Fetch the current status for the USB SND card and PCM device indexes > + * specified. > + */ > +int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm, > + int direction, long *route) > +{ > + struct snd_soc_usb *ctx; > + int ret; > + > + ctx = snd_soc_find_usb_ctx(dev); > + if (!ctx) > + return -ENODEV; > + > + mutex_lock(&ctx_mutex); > + if (ctx && ctx->update_offload_route_info) > + ret = ctx->update_offload_route_info(ctx->component, card, pcm, > + direction, route); > + mutex_unlock(&ctx_mutex); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(snd_soc_usb_update_offload_route); > + > /** > * snd_soc_usb_find_priv_data() - Retrieve private data stored > * @dev: device reference
> diff --git a/Documentation/sound/soc/index.rst b/Documentation/sound/soc/index.rst > index e57df2dab2fd..8bed8f8f48da 100644 > --- a/Documentation/sound/soc/index.rst > +++ b/Documentation/sound/soc/index.rst > @@ -18,3 +18,4 @@ The documentation is spilt into the following sections:- > jack > dpcm > codec-to-codec > + usb > diff --git a/Documentation/sound/soc/usb.rst b/Documentation/sound/soc/usb.rst > new file mode 100644 > index 000000000000..bd3d9eb86b07 > --- /dev/null > +++ b/Documentation/sound/soc/usb.rst > @@ -0,0 +1,429 @@ > +================ > +ASoC USB support > +================ > + > +Overview > +======== > +In order to leverage the existing USB sound device support in ALSA, the > +ASoC USB APIs are introduced to allow for the entities to communicate > +with one another. nit-pick: entities is rather vague and an overloaded term in USB audio. Maybe "allow the subsystems to exchange configuration information" > +One potential use case would be to support USB audio offloading, which is > +an implementation that allows for an external DSP on the SoC to handle the nit-pick: not sure about the reference to an 'external DSP'. "external" would usually to a stand-alone device and there's no real need for DSP capabilities for USB offload, e.g. a regular embedded core would do just fine. maybe "allows for an alternate power-optimized path in the audio subsystem to handle the transfer of audio data over the USB bus" > +transfer of audio data over the USB bus. This would let the main > +processor to stay in lower power modes for longer duration. The following > +is an example design of how the ASoC and ALSA pieces can be connected > +together to achieve this: > + int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm, > + int direction, long *route) > +.. > + > + - ``dev``: USB device to look up offload path mapping > + - ``card``: USB sound card index > + - ``pcm``: USB sound PCM device index > + - ``direction``: direction to fetch offload routing information > + - ``route``: mapping of sound card and pcm indexes for the offload path nit-pick: again explain how the card and pcm indices are handled. > +-------------------------------- > +USB devices can be hotplugged into the USB root hub at any point in time. "root hub" really? Is this really required? I would think the entire framework would work just fine if the device is connected to any hub at any level, not just "the" root hub.
On 8/29/24 21:40, Wesley Cheng wrote: > Create a USB BE component that will register a new USB port to the ASoC USB > framework. This will handle determination on if the requested audio > profile is supported by the USB device currently selected. > > Check for if the PCM format is supported during the hw_params callback. If > the profile is not supported then the userspace ALSA entity will receive an > error, and can take further action. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > include/sound/q6usboffload.h | 20 +++ > sound/soc/qcom/Kconfig | 10 ++ > sound/soc/qcom/qdsp6/Makefile | 1 + > sound/soc/qcom/qdsp6/q6usb.c | 246 ++++++++++++++++++++++++++++++++++ > 4 files changed, 277 insertions(+) > create mode 100644 include/sound/q6usboffload.h > create mode 100644 sound/soc/qcom/qdsp6/q6usb.c > > diff --git a/include/sound/q6usboffload.h b/include/sound/q6usboffload.h > new file mode 100644 > index 000000000000..49ab2c34b84c > --- /dev/null > +++ b/include/sound/q6usboffload.h > @@ -0,0 +1,20 @@ > +/* SPDX-License-Identifier: GPL-2.0 > + * > + * linux/sound/q6usboffload.h -- QDSP6 USB offload not sure about the linux/ prefix? > + * > + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved. > + */ > + > +/** > + * struct q6usb_offload > + * @dev - dev handle to usb be > + * @sid - streamID for iommu > + * @intr_num - usb interrupter number > + * @domain - allocated iommu domain > + **/ > +struct q6usb_offload { > + struct device *dev; > + long long sid; > + u16 intr_num; > + struct iommu_domain *domain; > +}; consider reordering to avoid holes/alignment issues, e.g. all pointers first, then long long then u16 > +static int q6usb_hw_params(struct snd_pcm_substream *substream, > + struct snd_pcm_hw_params *params, > + struct snd_soc_dai *dai) > +{ > + struct q6usb_port_data *data = dev_get_drvdata(dai->dev); > + struct snd_soc_pcm_runtime *rtd = substream->private_data; > + struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(rtd, 0); > + int direction = substream->stream; > + struct q6afe_port *q6usb_afe; > + struct snd_soc_usb_device *sdev; > + int ret = -EINVAL; > + > + mutex_lock(&data->mutex); > + > + /* No active chip index */ > + if (list_empty(&data->devices)) > + goto out; -ENODEV for the default return value>? > + > + sdev = list_last_entry(&data->devices, struct snd_soc_usb_device, list); > + > + ret = snd_soc_usb_find_supported_format(sdev->chip_idx, params, direction); > + if (ret < 0) > + goto out; > + > + q6usb_afe = q6afe_port_get_from_id(cpu_dai->dev, USB_RX); > + if (IS_ERR(q6usb_afe)) > + goto out; > + > + /* Notify audio DSP about the devices being offloaded */ > + ret = afe_port_send_usb_dev_param(q6usb_afe, sdev->card_idx, > + sdev->ppcm_idx[sdev->num_playback - 1]); don't you need a symmetrical notification upon hw_free()? Also what happens if there are multiple calls to hw_params, which is quite legit in ALSA/ASoC?
On 8/29/24 21:40, Wesley Cheng wrote: > Within the UAC descriptor, there is information describing the size of a > sample (bSubframeSize/bSubslotSize) and the number of relevant bits > (bBitResolution). Currently, fmt_bits carries only the bit resolution, > however, some offloading entities may also require the overall size of the > sample. Save this information in a separate parameter, as depending on the > UAC format type, the sample size can not easily be decoded from other > existing parameters. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > sound/usb/card.h | 1 + > sound/usb/format.c | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/sound/usb/card.h b/sound/usb/card.h > index 23d9e6fc69e7..15cda1730076 100644 > --- a/sound/usb/card.h > +++ b/sound/usb/card.h > @@ -15,6 +15,7 @@ struct audioformat { > unsigned int channels; /* # channels */ > unsigned int fmt_type; /* USB audio format type (1-3) */ > unsigned int fmt_bits; /* number of significant bits */ > + unsigned int fmt_sz; /* overall audio sub frame/slot size */ > unsigned int frame_size; /* samples per frame for non-audio */ > unsigned char iface; /* interface number */ > unsigned char altsetting; /* corresponding alternate setting */ > diff --git a/sound/usb/format.c b/sound/usb/format.c > index 3b45d0ee7693..5fde543536a8 100644 > --- a/sound/usb/format.c > +++ b/sound/usb/format.c > @@ -80,6 +80,7 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip, > } > > fp->fmt_bits = sample_width; > + fp->fmt_sz = sample_bytes; > > if ((pcm_formats == 0) && > (format == 0 || format == (1 << UAC_FORMAT_TYPE_I_UNDEFINED))) { Should this patch be added first? I mean, I don't see any dependency on USB offload I am actually confused as to how the regular USB audio path deals with format, this must be inferred somewhere from the fmt_bits. Probably a question for Takashi :-)
On 8/29/24 21:40, Wesley Cheng wrote: > With USB audio offloading, an audio session is started from the ASoC > platform sound card and PCM devices. Likewise, the USB SND path is still > readily available for use, in case the non-offload path is desired. In > order to prevent the two entities from attempting to use the USB bus, > introduce a flag that determines when either paths are in use. > > If a PCM device is already in use, the check will return an error to > userspace notifying that the stream is currently busy. This ensures that > only one path is using the USB substream. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> I would also move this patch earlier in the series since it has no dependency on USB offload really, and if somehow it breaks USB audio regular paths we'd want to know early for bisection. > --- > sound/usb/card.h | 1 + > sound/usb/pcm.c | 29 ++++++++++++++++++++++++++--- > 2 files changed, 27 insertions(+), 3 deletions(-) > > diff --git a/sound/usb/card.h b/sound/usb/card.h > index 15cda1730076..d8b8522e1613 100644 > --- a/sound/usb/card.h > +++ b/sound/usb/card.h > @@ -165,6 +165,7 @@ struct snd_usb_substream { > unsigned int pkt_offset_adj; /* Bytes to drop from beginning of packets (for non-compliant devices) */ > unsigned int stream_offset_adj; /* Bytes to drop from beginning of stream (for non-compliant devices) */ > > + unsigned int opened:1; /* pcm device opened */ > unsigned int running: 1; /* running status */ > unsigned int period_elapsed_pending; /* delay period handling */ > > diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c > index 18467da6fd9e..b24ee38fad72 100644 > --- a/sound/usb/pcm.c > +++ b/sound/usb/pcm.c > @@ -1241,8 +1241,17 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream) > struct snd_usb_stream *as = snd_pcm_substream_chip(substream); > struct snd_pcm_runtime *runtime = substream->runtime; > struct snd_usb_substream *subs = &as->substream[direction]; > + struct snd_usb_audio *chip = subs->stream->chip; > int ret; > > + mutex_lock(&chip->mutex); > + if (subs->opened) { > + mutex_unlock(&chip->mutex); > + return -EBUSY; > + } > + subs->opened = 1; > + mutex_unlock(&chip->mutex); > + > runtime->hw = snd_usb_hardware; > /* need an explicit sync to catch applptr update in low-latency mode */ > if (direction == SNDRV_PCM_STREAM_PLAYBACK && > @@ -1259,13 +1268,23 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream) > > ret = setup_hw_info(runtime, subs); > if (ret < 0) > - return ret; > + goto err_open; > ret = snd_usb_autoresume(subs->stream->chip); > if (ret < 0) > - return ret; > + goto err_open; > ret = snd_media_stream_init(subs, as->pcm, direction); > if (ret < 0) > - snd_usb_autosuspend(subs->stream->chip); > + goto err_resume; > + > + return 0; > + > +err_resume: > + snd_usb_autosuspend(subs->stream->chip); > +err_open: > + mutex_lock(&chip->mutex); > + subs->opened = 0; > + mutex_unlock(&chip->mutex); > + > return ret; > } > > @@ -1274,6 +1293,7 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream) > int direction = substream->stream; > struct snd_usb_stream *as = snd_pcm_substream_chip(substream); > struct snd_usb_substream *subs = &as->substream[direction]; > + struct snd_usb_audio *chip = subs->stream->chip; > int ret; > > snd_media_stop_pipeline(subs); > @@ -1287,6 +1307,9 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream) > > subs->pcm_substream = NULL; > snd_usb_autosuspend(subs->stream->chip); > + mutex_lock(&chip->mutex); > + subs->opened = 0; > + mutex_unlock(&chip->mutex); > > return 0; > }
On 8/29/24 21:41, Wesley Cheng wrote: > Add proper checks and updates to the USB substream once receiving a USB QMI > stream enable request. If the substream is already in use from the non > offload path, reject the stream enable request. In addition, update the > USB substream opened parameter when enabling the offload path, so the > non offload path can be blocked. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > sound/usb/qcom/qc_audio_offload.c | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) > > diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c > index e9f2fd6bbb41..0bd533f539e4 100644 > --- a/sound/usb/qcom/qc_audio_offload.c > +++ b/sound/usb/qcom/qc_audio_offload.c > @@ -1482,12 +1482,17 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle, > goto response; > } > > + mutex_lock(&chip->mutex); > if (req_msg->enable) { > - if (info_idx < 0 || chip->system_suspend) { > + if (info_idx < 0 || chip->system_suspend || subs->opened) { > ret = -EBUSY; > + mutex_unlock(&chip->mutex); > + > goto response; > } > + subs->opened = 1; > } > + mutex_unlock(&chip->mutex); > > if (req_msg->service_interval_valid) { > ret = get_data_interval_from_si(subs, > @@ -1509,6 +1514,11 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle, > if (!ret) > ret = prepare_qmi_response(subs, req_msg, &resp, > info_idx); > + if (ret < 0) { > + mutex_lock(&chip->mutex); > + subs->opened = 0; > + mutex_unlock(&chip->mutex); > + } > } else { > info = &uadev[pcm_card_num].info[info_idx]; > if (info->data_ep_pipe) { > @@ -1532,6 +1542,9 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle, > } > > disable_audio_stream(subs); > + mutex_lock(&chip->mutex); > + subs->opened = 0; > + mutex_unlock(&chip->mutex); > } > This sounds ok but I wonder why all this needs to be done in Qualcomm-specific layers instead of soc-usb?
On 8/29/24 21:41, Wesley Cheng wrote: > In order to allow userspace/applications know about USB offloading status, > expose a sound kcontrol that fetches information about which sound card > and PCM index the USB device is mapped to for supporting offloading. In > the USB audio offloading framework, the ASoC BE DAI link is the entity > responsible for registering to the SOC USB layer. > > It is expected for the USB SND offloading driver to add the kcontrol to the > sound card associated with the USB audio device. An example output would > look like: this is very odd, the offloading driver adds a control to another card? That seems like a rather important layering violation. I thought it was done the other way, the USB audio card created a control that would point to the other card/device. > > tinymix -D 1 get 'USB Offload Playback Route PCM#0' > -1, -1 (range -1->255) > > This example signifies that there is no mapped ASoC path available for the > USB SND device. but that control would not even exist if the ASoC-based driver isn't probed. It's become really hard to follow, I've been on all this for 1.5hrs and losing track of the design. > tinymix -D 1 get 'USB Offload Playback Route PCM#0' > 0, 0 (range -1->255) > > This example signifies that the offload path is available over ASoC sound > card index#0 and PCM device#0. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > sound/usb/Kconfig | 10 +++ > sound/usb/Makefile | 2 + > sound/usb/mixer_usb_offload.c | 102 ++++++++++++++++++++++++++++++ > sound/usb/mixer_usb_offload.h | 17 +++++ > sound/usb/qcom/Makefile | 2 +- > sound/usb/qcom/qc_audio_offload.c | 2 + > 6 files changed, 134 insertions(+), 1 deletion(-) > create mode 100644 sound/usb/mixer_usb_offload.c > create mode 100644 sound/usb/mixer_usb_offload.h > > diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig > index 5cc3eaf53e6b..e3fbf9541d0b 100644 > --- a/sound/usb/Kconfig > +++ b/sound/usb/Kconfig > @@ -176,10 +176,20 @@ config SND_BCD2000 > To compile this driver as a module, choose M here: the module > will be called snd-bcd2000. > > +config SND_USB_OFFLOAD_MIXER > + tristate "USB Audio Offload mixer control" > + help > + Say Y to enable the USB audio offloading mixer controls. This > + exposes an USB offload capable kcontrol to signal to applications > + about which platform sound card can support USB audio offload. > + The returning values specify the mapped ASoC card and PCM device > + the USB audio device is associated to. > + > config SND_USB_AUDIO_QMI > tristate "Qualcomm Audio Offload driver" > depends on QCOM_QMI_HELPERS && SND_USB_AUDIO && USB_XHCI_SIDEBAND && SND_SOC_USB > select SND_PCM > + select SND_USB_OFFLOAD_MIXER > help > Say Y here to enable the Qualcomm USB audio offloading feature. > > diff --git a/sound/usb/Makefile b/sound/usb/Makefile > index 54a06a2f73ca..2f19f854944c 100644 > --- a/sound/usb/Makefile > +++ b/sound/usb/Makefile > @@ -36,3 +36,5 @@ obj-$(CONFIG_SND_USB_US122L) += snd-usbmidi-lib.o > > obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/ bcd2000/ qcom/ > obj-$(CONFIG_SND_USB_LINE6) += line6/ > + > +obj-$(CONFIG_SND_USB_OFFLOAD_MIXER) += mixer_usb_offload.o > diff --git a/sound/usb/mixer_usb_offload.c b/sound/usb/mixer_usb_offload.c > new file mode 100644 > index 000000000000..16e2fd634684 > --- /dev/null > +++ b/sound/usb/mixer_usb_offload.c > @@ -0,0 +1,102 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved. > + */ > + > +#include <linux/usb.h> > + > +#include <sound/core.h> > +#include <sound/control.h> > +#include <sound/soc-usb.h> > + > +#include "usbaudio.h" > +#include "card.h" > +#include "helper.h" > +#include "mixer.h" > + > +#include "mixer_usb_offload.h" > + > +#define PCM_IDX(n) ((n) & 0xffff) > +#define CARD_IDX(n) ((n) >> 16) > + > +static int > +snd_usb_offload_route_get(struct snd_kcontrol *kcontrol, > + struct snd_ctl_elem_value *ucontrol) > +{ > + struct device *sysdev = snd_kcontrol_chip(kcontrol); > + int ret; > + > + ret = snd_soc_usb_update_offload_route(sysdev, > + CARD_IDX(kcontrol->private_value), > + PCM_IDX(kcontrol->private_value), > + SNDRV_PCM_STREAM_PLAYBACK, > + ucontrol->value.integer.value); > + if (ret < 0) { > + ucontrol->value.integer.value[0] = -1; > + ucontrol->value.integer.value[1] = -1; > + } > + > + return 0; > +} > + > +static int snd_usb_offload_route_info(struct snd_kcontrol *kcontrol, > + struct snd_ctl_elem_info *uinfo) > +{ > + uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; > + uinfo->count = 2; > + uinfo->value.integer.min = -1; > + /* Arbitrary max value, as there is no 'limit' on number of PCM devices */ > + uinfo->value.integer.max = 0xff; > + > + return 0; > +} > + > +static struct snd_kcontrol_new snd_usb_offload_mapped_ctl = { > + .iface = SNDRV_CTL_ELEM_IFACE_CARD, > + .access = SNDRV_CTL_ELEM_ACCESS_READ, > + .info = snd_usb_offload_route_info, > + .get = snd_usb_offload_route_get, > +}; > + > +/** > + * snd_usb_offload_create_ctl() - Add USB offload bounded mixer > + * @chip - USB SND chip device > + * > + * Creates a sound control for a USB audio device, so that applications can > + * query for if there is an available USB audio offload path, and which > + * card is managing it. > + */ > +int snd_usb_offload_create_ctl(struct snd_usb_audio *chip) > +{ > + struct usb_device *udev = chip->dev; > + struct snd_kcontrol_new *chip_kctl; > + struct snd_usb_substream *subs; > + struct snd_usb_stream *as; > + char ctl_name[37]; > + int ret; > + > + list_for_each_entry(as, &chip->pcm_list, list) { > + subs = &as->substream[SNDRV_PCM_STREAM_PLAYBACK]; > + if (!subs->ep_num) > + continue; > + > + chip_kctl = &snd_usb_offload_mapped_ctl; > + chip_kctl->count = 1; > + /* > + * Store the associated USB SND card number and PCM index for > + * the kctl. > + */ > + chip_kctl->private_value = as->pcm_index | > + chip->card->number << 16; > + sprintf(ctl_name, "USB Offload Playback Route PCM#%d", > + as->pcm_index); > + chip_kctl->name = ctl_name; > + ret = snd_ctl_add(chip->card, snd_ctl_new1(chip_kctl, > + udev->bus->sysdev)); > + if (ret < 0) > + break; > + } > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(snd_usb_offload_create_ctl); > diff --git a/sound/usb/mixer_usb_offload.h b/sound/usb/mixer_usb_offload.h > new file mode 100644 > index 000000000000..3f6e2a8b19c8 > --- /dev/null > +++ b/sound/usb/mixer_usb_offload.h > @@ -0,0 +1,17 @@ > +/* SPDX-License-Identifier: GPL-2.0 > + * > + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved. > + */ > + > +#ifndef __USB_OFFLOAD_MIXER_H > +#define __USB_OFFLOAD_MIXER_H > + > +#if IS_ENABLED(CONFIG_SND_USB_OFFLOAD_MIXER) > +int snd_usb_offload_create_ctl(struct snd_usb_audio *chip); > +#else > +static inline int snd_usb_offload_create_ctl(struct snd_usb_audio *chip) > +{ > + return 0; > +} > +#endif > +#endif /* __USB_OFFLOAD_MIXER_H */ > diff --git a/sound/usb/qcom/Makefile b/sound/usb/qcom/Makefile > index a81c9b28d484..4005e8391ab9 100644 > --- a/sound/usb/qcom/Makefile > +++ b/sound/usb/qcom/Makefile > @@ -1,2 +1,2 @@ > snd-usb-audio-qmi-objs := usb_audio_qmi_v01.o qc_audio_offload.o > -obj-$(CONFIG_SND_USB_AUDIO_QMI) += snd-usb-audio-qmi.o > \ No newline at end of file > +obj-$(CONFIG_SND_USB_AUDIO_QMI) += snd-usb-audio-qmi.o > diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c > index a7ad15404fd1..5b9262a116be 100644 > --- a/sound/usb/qcom/qc_audio_offload.c > +++ b/sound/usb/qcom/qc_audio_offload.c > @@ -36,6 +36,7 @@ > #include "../helper.h" > #include "../pcm.h" > #include "../power.h" > +#include "../mixer_usb_offload.h" > > #include "usb_audio_qmi_v01.h" > > @@ -1703,6 +1704,7 @@ static void qc_usb_audio_offload_probe(struct snd_usb_audio *chip) > sdev->card_idx = chip->card->number; > sdev->chip_idx = chip->index; > > + snd_usb_offload_create_ctl(chip); > snd_soc_usb_connect(usb_get_usb_backend(udev), sdev); > } >
On 8/30/2024 2:03 AM, Pierre-Louis Bossart wrote: >> diff --git a/Documentation/sound/soc/index.rst b/Documentation/sound/soc/index.rst >> index e57df2dab2fd..8bed8f8f48da 100644 >> --- a/Documentation/sound/soc/index.rst >> +++ b/Documentation/sound/soc/index.rst >> @@ -18,3 +18,4 @@ The documentation is spilt into the following sections:- >> jack >> dpcm >> codec-to-codec >> + usb >> diff --git a/Documentation/sound/soc/usb.rst b/Documentation/sound/soc/usb.rst >> new file mode 100644 >> index 000000000000..bd3d9eb86b07 >> --- /dev/null >> +++ b/Documentation/sound/soc/usb.rst >> @@ -0,0 +1,429 @@ >> +================ >> +ASoC USB support >> +================ >> + >> +Overview >> +======== >> +In order to leverage the existing USB sound device support in ALSA, the >> +ASoC USB APIs are introduced to allow for the entities to communicate >> +with one another. > nit-pick: entities is rather vague and an overloaded term in USB audio. > Maybe "allow the subsystems to exchange configuration information" Sure, will make that change. >> +One potential use case would be to support USB audio offloading, which is >> +an implementation that allows for an external DSP on the SoC to handle the > nit-pick: not sure about the reference to an 'external DSP'. "external" > would usually to a stand-alone device and there's no real need for DSP > capabilities for USB offload, e.g. a regular embedded core would do just > fine. > > maybe "allows for an alternate power-optimized path in the audio > subsystem to handle the transfer of audio data over the USB bus" Yeah, I guess external doesn't make sense, its just another core within the SoC. >> +transfer of audio data over the USB bus. This would let the main >> +processor to stay in lower power modes for longer duration. The following >> +is an example design of how the ASoC and ALSA pieces can be connected >> +together to achieve this: >> + int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm, >> + int direction, long *route) >> +.. >> + >> + - ``dev``: USB device to look up offload path mapping >> + - ``card``: USB sound card index >> + - ``pcm``: USB sound PCM device index >> + - ``direction``: direction to fetch offload routing information >> + - ``route``: mapping of sound card and pcm indexes for the offload path > nit-pick: again explain how the card and pcm indices are handled. > Will do. >> +-------------------------------- >> +USB devices can be hotplugged into the USB root hub at any point in time. > "root hub" really? > > Is this really required? I would think the entire framework would work > just fine if the device is connected to any hub at any level, not just > "the" root hub. Yes, you're right. Will clarify this as well. My test set up for this involves doing audio transfers on multiple devices over an external 4port USB hub. Thanks Wesley Cheng >
Hi Pierre, On 8/30/2024 2:21 AM, Pierre-Louis Bossart wrote: > > On 8/29/24 21:40, Wesley Cheng wrote: >> Create a USB BE component that will register a new USB port to the ASoC USB >> framework. This will handle determination on if the requested audio >> profile is supported by the USB device currently selected. >> >> Check for if the PCM format is supported during the hw_params callback. If >> the profile is not supported then the userspace ALSA entity will receive an >> error, and can take further action. >> >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> >> --- >> include/sound/q6usboffload.h | 20 +++ >> sound/soc/qcom/Kconfig | 10 ++ >> sound/soc/qcom/qdsp6/Makefile | 1 + >> sound/soc/qcom/qdsp6/q6usb.c | 246 ++++++++++++++++++++++++++++++++++ >> 4 files changed, 277 insertions(+) >> create mode 100644 include/sound/q6usboffload.h >> create mode 100644 sound/soc/qcom/qdsp6/q6usb.c >> >> diff --git a/include/sound/q6usboffload.h b/include/sound/q6usboffload.h >> new file mode 100644 >> index 000000000000..49ab2c34b84c >> --- /dev/null >> +++ b/include/sound/q6usboffload.h >> @@ -0,0 +1,20 @@ >> +/* SPDX-License-Identifier: GPL-2.0 >> + * >> + * linux/sound/q6usboffload.h -- QDSP6 USB offload > not sure about the linux/ prefix? > >> + * >> + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved. >> + */ >> + >> +/** >> + * struct q6usb_offload >> + * @dev - dev handle to usb be >> + * @sid - streamID for iommu >> + * @intr_num - usb interrupter number >> + * @domain - allocated iommu domain >> + **/ >> +struct q6usb_offload { >> + struct device *dev; >> + long long sid; >> + u16 intr_num; >> + struct iommu_domain *domain; >> +}; > consider reordering to avoid holes/alignment issues, e.g. all pointers > first, then long long then u16 > Will fix these. >> +static int q6usb_hw_params(struct snd_pcm_substream *substream, >> + struct snd_pcm_hw_params *params, >> + struct snd_soc_dai *dai) >> +{ >> + struct q6usb_port_data *data = dev_get_drvdata(dai->dev); >> + struct snd_soc_pcm_runtime *rtd = substream->private_data; >> + struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(rtd, 0); >> + int direction = substream->stream; >> + struct q6afe_port *q6usb_afe; >> + struct snd_soc_usb_device *sdev; >> + int ret = -EINVAL; >> + >> + mutex_lock(&data->mutex); >> + >> + /* No active chip index */ >> + if (list_empty(&data->devices)) >> + goto out; > -ENODEV for the default return value>? Sure. >> + >> + sdev = list_last_entry(&data->devices, struct snd_soc_usb_device, list); >> + >> + ret = snd_soc_usb_find_supported_format(sdev->chip_idx, params, direction); >> + if (ret < 0) >> + goto out; >> + >> + q6usb_afe = q6afe_port_get_from_id(cpu_dai->dev, USB_RX); >> + if (IS_ERR(q6usb_afe)) >> + goto out; >> + >> + /* Notify audio DSP about the devices being offloaded */ >> + ret = afe_port_send_usb_dev_param(q6usb_afe, sdev->card_idx, >> + sdev->ppcm_idx[sdev->num_playback - 1]); > don't you need a symmetrical notification upon hw_free()? > > Also what happens if there are multiple calls to hw_params, which is > quite legit in ALSA/ASoC? The afe_port_send_usb_dev_param() is meant to just update the device selected for offload on the audio DSP end, and this won't be referenced until our Q6AFE DAI sends the port start command in its prepare() callback. Don't think we need to handle anything specific in the hw_free() case. As long as the hw_params() callback is called before any audio session is started, then we'll ensure that the device selected is always updated to the audio DSP. Thanks Wesley Cheng
Hi Pierre, On 8/30/2024 2:45 AM, Pierre-Louis Bossart wrote: > > On 8/29/24 21:40, Wesley Cheng wrote: >> With USB audio offloading, an audio session is started from the ASoC >> platform sound card and PCM devices. Likewise, the USB SND path is still >> readily available for use, in case the non-offload path is desired. In >> order to prevent the two entities from attempting to use the USB bus, >> introduce a flag that determines when either paths are in use. >> >> If a PCM device is already in use, the check will return an error to >> userspace notifying that the stream is currently busy. This ensures that >> only one path is using the USB substream. >> >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> > > I would also move this patch earlier in the series since it has no > dependency on USB offload really, and if somehow it breaks USB audio > regular paths we'd want to know early for bisection. Sure I'll re-order this earlier since I'm going to send out another rev. Thanks Wesley Cheng > >> --- >> sound/usb/card.h | 1 + >> sound/usb/pcm.c | 29 ++++++++++++++++++++++++++--- >> 2 files changed, 27 insertions(+), 3 deletions(-) >> >> diff --git a/sound/usb/card.h b/sound/usb/card.h >> index 15cda1730076..d8b8522e1613 100644 >> --- a/sound/usb/card.h >> +++ b/sound/usb/card.h >> @@ -165,6 +165,7 @@ struct snd_usb_substream { >> unsigned int pkt_offset_adj; /* Bytes to drop from beginning of packets (for non-compliant devices) */ >> unsigned int stream_offset_adj; /* Bytes to drop from beginning of stream (for non-compliant devices) */ >> >> + unsigned int opened:1; /* pcm device opened */ >> unsigned int running: 1; /* running status */ >> unsigned int period_elapsed_pending; /* delay period handling */ >> >> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c >> index 18467da6fd9e..b24ee38fad72 100644 >> --- a/sound/usb/pcm.c >> +++ b/sound/usb/pcm.c >> @@ -1241,8 +1241,17 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream) >> struct snd_usb_stream *as = snd_pcm_substream_chip(substream); >> struct snd_pcm_runtime *runtime = substream->runtime; >> struct snd_usb_substream *subs = &as->substream[direction]; >> + struct snd_usb_audio *chip = subs->stream->chip; >> int ret; >> >> + mutex_lock(&chip->mutex); >> + if (subs->opened) { >> + mutex_unlock(&chip->mutex); >> + return -EBUSY; >> + } >> + subs->opened = 1; >> + mutex_unlock(&chip->mutex); >> + >> runtime->hw = snd_usb_hardware; >> /* need an explicit sync to catch applptr update in low-latency mode */ >> if (direction == SNDRV_PCM_STREAM_PLAYBACK && >> @@ -1259,13 +1268,23 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream) >> >> ret = setup_hw_info(runtime, subs); >> if (ret < 0) >> - return ret; >> + goto err_open; >> ret = snd_usb_autoresume(subs->stream->chip); >> if (ret < 0) >> - return ret; >> + goto err_open; >> ret = snd_media_stream_init(subs, as->pcm, direction); >> if (ret < 0) >> - snd_usb_autosuspend(subs->stream->chip); >> + goto err_resume; >> + >> + return 0; >> + >> +err_resume: >> + snd_usb_autosuspend(subs->stream->chip); >> +err_open: >> + mutex_lock(&chip->mutex); >> + subs->opened = 0; >> + mutex_unlock(&chip->mutex); >> + >> return ret; >> } >> >> @@ -1274,6 +1293,7 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream) >> int direction = substream->stream; >> struct snd_usb_stream *as = snd_pcm_substream_chip(substream); >> struct snd_usb_substream *subs = &as->substream[direction]; >> + struct snd_usb_audio *chip = subs->stream->chip; >> int ret; >> >> snd_media_stop_pipeline(subs); >> @@ -1287,6 +1307,9 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream) >> >> subs->pcm_substream = NULL; >> snd_usb_autosuspend(subs->stream->chip); >> + mutex_lock(&chip->mutex); >> + subs->opened = 0; >> + mutex_unlock(&chip->mutex); >> >> return 0; >> }
Hi Pierre, On 8/30/2024 2:55 AM, Pierre-Louis Bossart wrote: > > On 8/29/24 21:41, Wesley Cheng wrote: >> Add proper checks and updates to the USB substream once receiving a USB QMI >> stream enable request. If the substream is already in use from the non >> offload path, reject the stream enable request. In addition, update the >> USB substream opened parameter when enabling the offload path, so the >> non offload path can be blocked. >> >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> >> --- >> sound/usb/qcom/qc_audio_offload.c | 15 ++++++++++++++- >> 1 file changed, 14 insertions(+), 1 deletion(-) >> >> diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c >> index e9f2fd6bbb41..0bd533f539e4 100644 >> --- a/sound/usb/qcom/qc_audio_offload.c >> +++ b/sound/usb/qcom/qc_audio_offload.c >> @@ -1482,12 +1482,17 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle, >> goto response; >> } >> >> + mutex_lock(&chip->mutex); >> if (req_msg->enable) { >> - if (info_idx < 0 || chip->system_suspend) { >> + if (info_idx < 0 || chip->system_suspend || subs->opened) { >> ret = -EBUSY; >> + mutex_unlock(&chip->mutex); >> + >> goto response; >> } >> + subs->opened = 1; >> } >> + mutex_unlock(&chip->mutex); >> >> if (req_msg->service_interval_valid) { >> ret = get_data_interval_from_si(subs, >> @@ -1509,6 +1514,11 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle, >> if (!ret) >> ret = prepare_qmi_response(subs, req_msg, &resp, >> info_idx); >> + if (ret < 0) { >> + mutex_lock(&chip->mutex); >> + subs->opened = 0; >> + mutex_unlock(&chip->mutex); >> + } >> } else { >> info = &uadev[pcm_card_num].info[info_idx]; >> if (info->data_ep_pipe) { >> @@ -1532,6 +1542,9 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle, >> } >> >> disable_audio_stream(subs); >> + mutex_lock(&chip->mutex); >> + subs->opened = 0; >> + mutex_unlock(&chip->mutex); >> } >> > > This sounds ok but I wonder why all this needs to be done in > Qualcomm-specific layers instead of soc-usb? > This is to prevent conflicts within the non-offload/legacy USB SND path and the USB SND offload vendor driver. Don't think we need to involve anything with ASoC in these checks. Thanks Wesley Cheng
Hi Pierre, On 8/30/2024 3:05 AM, Pierre-Louis Bossart wrote: > > On 8/29/24 21:41, Wesley Cheng wrote: >> In order to allow userspace/applications know about USB offloading status, >> expose a sound kcontrol that fetches information about which sound card >> and PCM index the USB device is mapped to for supporting offloading. In >> the USB audio offloading framework, the ASoC BE DAI link is the entity >> responsible for registering to the SOC USB layer. >> >> It is expected for the USB SND offloading driver to add the kcontrol to the >> sound card associated with the USB audio device. An example output would >> look like: > this is very odd, the offloading driver adds a control to another card? > > That seems like a rather important layering violation. > > I thought it was done the other way, the USB audio card created a > control that would point to the other card/device. The USB SND offloading vendor driver (qc_audio_offload), which technically co-exists with USB SND core, is the entity that will add the offload kcontrol to the USB audio device's sound card. Initially, I had the kcontrol creation as part of the USB SND mixer, but I believe Takashi preferred if the vendor driver did it instead. > >> tinymix -D 1 get 'USB Offload Playback Route PCM#0' >> -1, -1 (range -1->255) >> >> This example signifies that there is no mapped ASoC path available for the >> USB SND device. > but that control would not even exist if the ASoC-based driver isn't probed. > > It's become really hard to follow, I've been on all this for 1.5hrs and > losing track of the design. Hence why it probably is a good idea to leave it within the USB offload vendor driver. There are checks to ensure that the ASoC based driver is probed/available before the kcontrols are created for a device. If there are devices that were identified before the ASoC components were probed, then the snd_usb_rediscover_devices() is triggered as part of soc-usb, and that would call the connect_cb() callback to the USB SND vendor offload driver to create the kcontrol. Thanks Wesley Cheng >> tinymix -D 1 get 'USB Offload Playback Route PCM#0' >> 0, 0 (range -1->255) >> >> This example signifies that the offload path is available over ASoC sound >> card index#0 and PCM device#0. >> >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> >> --- >> sound/usb/Kconfig | 10 +++ >> sound/usb/Makefile | 2 + >> sound/usb/mixer_usb_offload.c | 102 ++++++++++++++++++++++++++++++ >> sound/usb/mixer_usb_offload.h | 17 +++++ >> sound/usb/qcom/Makefile | 2 +- >> sound/usb/qcom/qc_audio_offload.c | 2 + >> 6 files changed, 134 insertions(+), 1 deletion(-) >> create mode 100644 sound/usb/mixer_usb_offload.c >> create mode 100644 sound/usb/mixer_usb_offload.h >> >> diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig >> index 5cc3eaf53e6b..e3fbf9541d0b 100644 >> --- a/sound/usb/Kconfig >> +++ b/sound/usb/Kconfig >> @@ -176,10 +176,20 @@ config SND_BCD2000 >> To compile this driver as a module, choose M here: the module >> will be called snd-bcd2000. >> >> +config SND_USB_OFFLOAD_MIXER >> + tristate "USB Audio Offload mixer control" >> + help >> + Say Y to enable the USB audio offloading mixer controls. This >> + exposes an USB offload capable kcontrol to signal to applications >> + about which platform sound card can support USB audio offload. >> + The returning values specify the mapped ASoC card and PCM device >> + the USB audio device is associated to. >> + >> config SND_USB_AUDIO_QMI >> tristate "Qualcomm Audio Offload driver" >> depends on QCOM_QMI_HELPERS && SND_USB_AUDIO && USB_XHCI_SIDEBAND && SND_SOC_USB >> select SND_PCM >> + select SND_USB_OFFLOAD_MIXER >> help >> Say Y here to enable the Qualcomm USB audio offloading feature. >> >> diff --git a/sound/usb/Makefile b/sound/usb/Makefile >> index 54a06a2f73ca..2f19f854944c 100644 >> --- a/sound/usb/Makefile >> +++ b/sound/usb/Makefile >> @@ -36,3 +36,5 @@ obj-$(CONFIG_SND_USB_US122L) += snd-usbmidi-lib.o >> >> obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/ bcd2000/ qcom/ >> obj-$(CONFIG_SND_USB_LINE6) += line6/ >> + >> +obj-$(CONFIG_SND_USB_OFFLOAD_MIXER) += mixer_usb_offload.o >> diff --git a/sound/usb/mixer_usb_offload.c b/sound/usb/mixer_usb_offload.c >> new file mode 100644 >> index 000000000000..16e2fd634684 >> --- /dev/null >> +++ b/sound/usb/mixer_usb_offload.c >> @@ -0,0 +1,102 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved. >> + */ >> + >> +#include <linux/usb.h> >> + >> +#include <sound/core.h> >> +#include <sound/control.h> >> +#include <sound/soc-usb.h> >> + >> +#include "usbaudio.h" >> +#include "card.h" >> +#include "helper.h" >> +#include "mixer.h" >> + >> +#include "mixer_usb_offload.h" >> + >> +#define PCM_IDX(n) ((n) & 0xffff) >> +#define CARD_IDX(n) ((n) >> 16) >> + >> +static int >> +snd_usb_offload_route_get(struct snd_kcontrol *kcontrol, >> + struct snd_ctl_elem_value *ucontrol) >> +{ >> + struct device *sysdev = snd_kcontrol_chip(kcontrol); >> + int ret; >> + >> + ret = snd_soc_usb_update_offload_route(sysdev, >> + CARD_IDX(kcontrol->private_value), >> + PCM_IDX(kcontrol->private_value), >> + SNDRV_PCM_STREAM_PLAYBACK, >> + ucontrol->value.integer.value); >> + if (ret < 0) { >> + ucontrol->value.integer.value[0] = -1; >> + ucontrol->value.integer.value[1] = -1; >> + } >> + >> + return 0; >> +} >> + >> +static int snd_usb_offload_route_info(struct snd_kcontrol *kcontrol, >> + struct snd_ctl_elem_info *uinfo) >> +{ >> + uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; >> + uinfo->count = 2; >> + uinfo->value.integer.min = -1; >> + /* Arbitrary max value, as there is no 'limit' on number of PCM devices */ >> + uinfo->value.integer.max = 0xff; >> + >> + return 0; >> +} >> + >> +static struct snd_kcontrol_new snd_usb_offload_mapped_ctl = { >> + .iface = SNDRV_CTL_ELEM_IFACE_CARD, >> + .access = SNDRV_CTL_ELEM_ACCESS_READ, >> + .info = snd_usb_offload_route_info, >> + .get = snd_usb_offload_route_get, >> +}; >> + >> +/** >> + * snd_usb_offload_create_ctl() - Add USB offload bounded mixer >> + * @chip - USB SND chip device >> + * >> + * Creates a sound control for a USB audio device, so that applications can >> + * query for if there is an available USB audio offload path, and which >> + * card is managing it. >> + */ >> +int snd_usb_offload_create_ctl(struct snd_usb_audio *chip) >> +{ >> + struct usb_device *udev = chip->dev; >> + struct snd_kcontrol_new *chip_kctl; >> + struct snd_usb_substream *subs; >> + struct snd_usb_stream *as; >> + char ctl_name[37]; >> + int ret; >> + >> + list_for_each_entry(as, &chip->pcm_list, list) { >> + subs = &as->substream[SNDRV_PCM_STREAM_PLAYBACK]; >> + if (!subs->ep_num) >> + continue; >> + >> + chip_kctl = &snd_usb_offload_mapped_ctl; >> + chip_kctl->count = 1; >> + /* >> + * Store the associated USB SND card number and PCM index for >> + * the kctl. >> + */ >> + chip_kctl->private_value = as->pcm_index | >> + chip->card->number << 16; >> + sprintf(ctl_name, "USB Offload Playback Route PCM#%d", >> + as->pcm_index); >> + chip_kctl->name = ctl_name; >> + ret = snd_ctl_add(chip->card, snd_ctl_new1(chip_kctl, >> + udev->bus->sysdev)); >> + if (ret < 0) >> + break; >> + } >> + >> + return ret; >> +} >> +EXPORT_SYMBOL_GPL(snd_usb_offload_create_ctl); >> diff --git a/sound/usb/mixer_usb_offload.h b/sound/usb/mixer_usb_offload.h >> new file mode 100644 >> index 000000000000..3f6e2a8b19c8 >> --- /dev/null >> +++ b/sound/usb/mixer_usb_offload.h >> @@ -0,0 +1,17 @@ >> +/* SPDX-License-Identifier: GPL-2.0 >> + * >> + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved. >> + */ >> + >> +#ifndef __USB_OFFLOAD_MIXER_H >> +#define __USB_OFFLOAD_MIXER_H >> + >> +#if IS_ENABLED(CONFIG_SND_USB_OFFLOAD_MIXER) >> +int snd_usb_offload_create_ctl(struct snd_usb_audio *chip); >> +#else >> +static inline int snd_usb_offload_create_ctl(struct snd_usb_audio *chip) >> +{ >> + return 0; >> +} >> +#endif >> +#endif /* __USB_OFFLOAD_MIXER_H */ >> diff --git a/sound/usb/qcom/Makefile b/sound/usb/qcom/Makefile >> index a81c9b28d484..4005e8391ab9 100644 >> --- a/sound/usb/qcom/Makefile >> +++ b/sound/usb/qcom/Makefile >> @@ -1,2 +1,2 @@ >> snd-usb-audio-qmi-objs := usb_audio_qmi_v01.o qc_audio_offload.o >> -obj-$(CONFIG_SND_USB_AUDIO_QMI) += snd-usb-audio-qmi.o >> \ No newline at end of file >> +obj-$(CONFIG_SND_USB_AUDIO_QMI) += snd-usb-audio-qmi.o >> diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c >> index a7ad15404fd1..5b9262a116be 100644 >> --- a/sound/usb/qcom/qc_audio_offload.c >> +++ b/sound/usb/qcom/qc_audio_offload.c >> @@ -36,6 +36,7 @@ >> #include "../helper.h" >> #include "../pcm.h" >> #include "../power.h" >> +#include "../mixer_usb_offload.h" >> >> #include "usb_audio_qmi_v01.h" >> >> @@ -1703,6 +1704,7 @@ static void qc_usb_audio_offload_probe(struct snd_usb_audio *chip) >> sdev->card_idx = chip->card->number; >> sdev->chip_idx = chip->index; >> >> + snd_usb_offload_create_ctl(chip); >> snd_soc_usb_connect(usb_get_usb_backend(udev), sdev); >> } >>