| Message ID | 20231017200109.11407-1-quic_wcheng@quicinc.com |
|---|---|
| Headers | show |
| Series | Introduce QC USB SND audio offloading support | expand |
It's been a very long time since I reviewed earlier versions, and I am still lost on terminology and concepts. The explanations below should really be added as a .rst file in Documentation for reference, not just as a cover letter. > 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 "backend" is a loaded terms for ASoC. Can you clarify which part of the ascii art below is a 'backend'? > 3. Introduce XHCI interrupter support > 4. Create vendor ops for the USB SND driver > > USB | ASoC > -------------------------------------------------------------------- > | _________________________ > | |sm8250 platform card | > | |_________________________| > | | | > | ___V____ ____V____ > | |Q6USB | |Q6AFE | > | |"codec" | |"cpu" | > | |________| |_________| > | ^ ^ ^ > | | |________| > | ___V____ | > | |SOC-USB | | > ________ ________ | | | > |USB SND |<--->|QC offld|<------------>|________| | > |(card.c)| | |<---------- | > |________| |________|___ | | | > ^ ^ | | | ____________V_________ > | | | | | |APR/GLINK | > __ V_______________V_____ | | | |______________________| > |USB SND (endpoint.c) | | | | ^ > |_________________________| | | | | > ^ | | | ___________V___________ > | | | |->|audio DSP | > ___________V_____________ | | |_______________________| > |XHCI HCD |<- | > |_________________________| | > > > Adding ASoC binding layer: > soc-usb: Intention is to treat a USB port similar to a headphone jack. What is a 'port'? USB refers to "interfaces" and "endpoints". Is a "port" a 1:1 mapping to "endpoint"? Below I read "AFE port" so not sure what concepts refer to what. > 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 The asciiart above suggests that q6usb exposes a codec DAI - but the backend dailink is created by the platform card? > resources needed to initiate a playback stream using the Q6DSP. Will is capture supported? there's explicit references to "num_capture" in following patches. > 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. what about capture, e.g. for a headset? > 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: typo: platform > 0 [SM8250MTPWCD938]: sm8250 - SM8250-MTP-WCD9380-WSA8810-VA-D > SM8250-MTP-WCD9380-WSA8810-VA-DMIC How do you plan on exposing the USB PCM device? The lines above are really cryptic, and with no USB reference in any of the short/long card names it's not obvious that this card is different from the no-offload case, is it? > 1 [Audio ]: USB-Audio - USB Audio > Generic USB Audio at usb-xhci-hcd.1.auto-1.4, high speed likewise some sort of qualifier would be useful to show that card 0 and card 1 can target the same USB endpoints. > 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
On 10/17/23 15:00, Wesley Cheng wrote: > Introduce a check for if a particular PCM format is supported by the USB Introduce a helper to check if a ... > audio device connected. If the USB audio device does not have an audio > profile which can support the requested format, then notify the USB > backend. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > include/sound/soc-usb.h | 3 +++ > sound/soc/soc-usb.c | 13 +++++++++++++ > 2 files changed, 16 insertions(+) > > diff --git a/include/sound/soc-usb.h b/include/sound/soc-usb.h > index 58c686f4f7ba..c6ddc055c4cd 100644 > --- a/include/sound/soc-usb.h > +++ b/include/sound/soc-usb.h > @@ -37,6 +37,9 @@ struct snd_soc_usb { > void *priv_data; > }; > > +int snd_soc_usb_find_format(int card_idx, struct snd_pcm_hw_params *params, > + int direction); > + > int snd_soc_usb_connect(struct device *usbdev, struct snd_soc_usb_device *sdev); > int snd_soc_usb_disconnect(struct device *usbdev, struct snd_soc_usb_device *sdev); > void *snd_soc_usb_find_priv_data(struct device *usbdev); > diff --git a/sound/soc/soc-usb.c b/sound/soc/soc-usb.c > index 73b1bcc3b506..7407678a993e 100644 > --- a/sound/soc/soc-usb.c > +++ b/sound/soc/soc-usb.c > @@ -63,6 +63,19 @@ void *snd_soc_usb_find_priv_data(struct device *dev) > } > EXPORT_SYMBOL_GPL(snd_soc_usb_find_priv_data); > > +int snd_soc_usb_find_format(int card_idx, struct snd_pcm_hw_params *params, > + int direction) > +{ > + struct snd_usb_stream *as; > + > + as = snd_usb_find_suppported_substream(card_idx, params, direction); > + if (!as) > + return -EOPNOTSUPP; > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(snd_soc_usb_find_format); Is this the right way to check for formats? formats are defined within the scope of an endpoint, and those endpoints are themselves defined within the scope of an interface? I don't see a notion of endpoint here. Does this assume all endpoints are valid, or maybe the existence of a single endpoint in a device? Confused.
On 10/17/23 15:01, Wesley Cheng wrote: > The USB backend should know about which sound resources are being shared > between the ASoC and USB SND paths. This can be utilized to properly > select and maintain the offloading devices. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > sound/soc/qcom/qdsp6/q6usb.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/sound/soc/qcom/qdsp6/q6usb.c b/sound/soc/qcom/qdsp6/q6usb.c > index 329a7d4a3c01..d697cbe7f184 100644 > --- a/sound/soc/qcom/qdsp6/q6usb.c > +++ b/sound/soc/qcom/qdsp6/q6usb.c > @@ -25,10 +25,18 @@ > > #define SID_MASK 0xF > > +struct q6usb_status { > + unsigned int num_pcm; how would one know which ones are capture and which ones are playback? This really looks like a playback-only assumption, despite earlier mentions of capture supported. > + unsigned int chip_index; > + unsigned int pcm_index; > +}; > + > struct q6usb_port_data { > struct q6afe_usb_cfg usb_cfg; > struct snd_soc_usb *usb; > struct q6usb_offload priv; > + unsigned long available_card_slot; > + struct q6usb_status status[SNDRV_CARDS]; > int active_idx; > }; > > @@ -110,6 +118,14 @@ static int q6usb_alsa_connection_cb(struct snd_soc_usb *usb, > if (connected) { > /* We only track the latest USB headset plugged in */ > data->active_idx = sdev->card_idx; > + > + set_bit(sdev->card_idx, &data->available_card_slot); > + data->status[sdev->card_idx].num_pcm = sdev->num_playback; there you go... > + data->status[sdev->card_idx].chip_index = sdev->chip_idx; > + } else { > + clear_bit(sdev->card_idx, &data->available_card_slot); > + data->status[sdev->card_idx].num_pcm = 0; > + data->status[sdev->card_idx].chip_index = 0; > } > > return 0;
On 10/17/23 15:01, Wesley Cheng wrote: > Expose a kcontrol on the platform sound card, which will allow for > userspace to determine which USB card number and PCM device to offload. > This allows for userspace to potentially tag an alternate path for a > specific USB SND card and PCM device. Previously, control was absent, and > the offload path would be enabled on the last USB SND device which was > connected. This logic will continue to be applicable if no mixer input is > received for specific device selection. > > An example to configure the offload device using tinymix: > tinymix -D 0 set 'Q6USB offload SND device select' 1 0 > > The above will set the Q6AFE device token to choose offload on card#1 and > pcm#0. Device selection is made possible by setting the Q6AFE device > token. The audio DSP utilizes this parameter, and will pass this field > back to the USB offload driver within the QMI stream requests. This still begs the question on how userspace would figure what the card1 is and which endpoint is used when PCM0 is opened? Ideally userpace would not have to know anything about "Q6USB". Presumably when other vendors expose their USB offload solution, we would want a generic control name, no? Jaroslav should chime in on this one :-) > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > sound/soc/qcom/qdsp6/q6usb.c | 125 ++++++++++++++++++++++++++++++++++- > 1 file changed, 122 insertions(+), 3 deletions(-) > > diff --git a/sound/soc/qcom/qdsp6/q6usb.c b/sound/soc/qcom/qdsp6/q6usb.c > index d697cbe7f184..a95276b7d91d 100644 > --- a/sound/soc/qcom/qdsp6/q6usb.c > +++ b/sound/soc/qcom/qdsp6/q6usb.c > @@ -14,6 +14,7 @@ > #include <linux/dma-map-ops.h> > > #include <sound/pcm.h> > +#include <sound/control.h> > #include <sound/soc.h> > #include <sound/soc-usb.h> > #include <sound/pcm_params.h> > @@ -35,9 +36,12 @@ struct q6usb_port_data { > struct q6afe_usb_cfg usb_cfg; > struct snd_soc_usb *usb; > struct q6usb_offload priv; > + struct mutex mutex; missing comment on what this protects. "mutex" is really a poor choice/name if I am honest. > unsigned long available_card_slot; > struct q6usb_status status[SNDRV_CARDS]; > - int active_idx; > + bool idx_valid; > + int sel_card_idx; > + int sel_pcm_idx; > }; > +/* Build a mixer control for a UAC connector control (jack-detect) */ > +static void q6usb_connector_control_init(struct snd_soc_component *component) > +{ > + int ret; > + > + ret = snd_ctl_add(component->card->snd_card, > + snd_ctl_new1(&q6usb_offload_dev_ctrl, component)); > + if (ret < 0) > + return; that error handling does not seem terribly useful... > +} > + > static int q6usb_audio_ports_of_xlate_dai_name(struct snd_soc_component *component, > const struct of_phandle_args *args, > const char **dai_name) > @@ -115,9 +227,11 @@ static int q6usb_alsa_connection_cb(struct snd_soc_usb *usb, > > data = dev_get_drvdata(usb->component->dev); > > + mutex_lock(&data->mutex); > if (connected) { > /* We only track the latest USB headset plugged in */ > - data->active_idx = sdev->card_idx; > + if (!data->idx_valid || data->sel_card_idx < 0) > + data->sel_card_idx = sdev->card_idx; > > set_bit(sdev->card_idx, &data->available_card_slot); > data->status[sdev->card_idx].num_pcm = sdev->num_playback; > @@ -127,6 +241,7 @@ static int q6usb_alsa_connection_cb(struct snd_soc_usb *usb, > data->status[sdev->card_idx].num_pcm = 0; > data->status[sdev->card_idx].chip_index = 0; > } > + mutex_unlock(&data->mutex); > > return 0; > } > @@ -135,6 +250,8 @@ static int q6usb_component_probe(struct snd_soc_component *component) > { > struct q6usb_port_data *data = dev_get_drvdata(component->dev); > > + q6usb_connector_control_init(component); > + > data->usb = snd_soc_usb_add_port(component->dev, &data->priv, q6usb_alsa_connection_cb); > if (IS_ERR(data->usb)) { > dev_err(component->dev, "failed to add usb port\n"); > @@ -189,6 +306,8 @@ static int q6usb_dai_dev_probe(struct platform_device *pdev) > > data->priv.domain = iommu_get_domain_for_dev(&pdev->dev); > > + mutex_init(&data->mutex); > + > data->priv.dev = dev; > dev_set_drvdata(dev, data); >
Hi Pierre, On 10/17/2023 1:58 PM, Pierre-Louis Bossart wrote: > It's been a very long time since I reviewed earlier versions, and I am > still lost on terminology and concepts. The explanations below should > really be added as a .rst file in Documentation for reference, not just > as a cover letter. > Thanks for the review! Sure, maybe I can write a more comprehensive documentation that saves these details somewhere. Will add a RST documentation for material where necessary. >> 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 > > "backend" is a loaded terms for ASoC. Can you clarify which part of the > ascii art below is a 'backend'? > This would be the Q6USB entity which is the DPCM backend for this particular audio path. >> 3. Introduce XHCI interrupter support >> 4. Create vendor ops for the USB SND driver >> >> USB | ASoC >> -------------------------------------------------------------------- >> | _________________________ >> | |sm8250 platform card | >> | |_________________________| >> | | | >> | ___V____ ____V____ >> | |Q6USB | |Q6AFE | >> | |"codec" | |"cpu" | >> | |________| |_________| >> | ^ ^ ^ >> | | |________| >> | ___V____ | >> | |SOC-USB | | >> ________ ________ | | | >> |USB SND |<--->|QC offld|<------------>|________| | >> |(card.c)| | |<---------- | >> |________| |________|___ | | | >> ^ ^ | | | ____________V_________ >> | | | | | |APR/GLINK | >> __ V_______________V_____ | | | |______________________| >> |USB SND (endpoint.c) | | | | ^ >> |_________________________| | | | | >> ^ | | | ___________V___________ >> | | | |->|audio DSP | >> ___________V_____________ | | |_______________________| >> |XHCI HCD |<- | >> |_________________________| | >> >> >> Adding ASoC binding layer: >> soc-usb: Intention is to treat a USB port similar to a headphone jack. > > What is a 'port'? USB refers to "interfaces" and "endpoints". Is a > "port" a 1:1 mapping to "endpoint"? > > Below I read "AFE port" so not sure what concepts refer to what. > "Port" in this explanation refers to the USB port. So the audio device connected. You are right that a USB device can enumerate w/ multiple interfaces (ie UAC + HID + ...) so the closest relation to "port" is "interface." It is not a 1:1 mapping w/ the number of endpoints exposed by a device. "AFE port" is just something that has been termed from the audio DSP end, so that concept of port is not related to the port where USB devices are connected to. This is something that is defined within the audio DSP. >> 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 > > The asciiart above suggests that q6usb exposes a codec DAI - but the > backend dailink is created by the platform card? > That is my understanding, at least. The machine driver (sm8250.c) has an API that parses our DT node for the DAI relationships (qcom_snd_parse_of()), and seems to also create the dailinks. >> resources needed to initiate a playback stream using the Q6DSP. Will > > is capture supported? there's explicit references to "num_capture" in > following patches. > We (QCOM) do not support capture at the moment, but the num_capture was added to the soc-usb driver, which is platform independent. This is in case other vendors want to add this support, but have capture included as well. >> 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. > > what about capture, e.g. for a headset? > Not supported yet at the moment. >> 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: > > typo: platform > Thanks, will fix this. >> 0 [SM8250MTPWCD938]: sm8250 - SM8250-MTP-WCD9380-WSA8810-VA-D >> SM8250-MTP-WCD9380-WSA8810-VA-DMIC > > How do you plan on exposing the USB PCM device? > > The lines above are really cryptic, and with no USB reference in any of > the short/long card names it's not obvious that this card is different > from the no-offload case, is it? > In the end, since the offload case is handled by the audio DSP, it would have to go through the platform/machine sound card. That is the sm8250 device above. >> 1 [Audio ]: USB-Audio - USB Audio >> Generic USB Audio at usb-xhci-hcd.1.auto-1.4, high speed > > likewise some sort of qualifier would be useful to show that card 0 and > card 1 can target the same USB endpoints. > Do userspace entities look at this card string? Assuming there is only one platform card, there are situations where maybe multiple USB audio devices are connected to the same USB root hub, so offloading can happen on any one of them (not at the same time). Thanks Wesley Cheng
Hi Pierre, On 10/18/2023 6:54 AM, Pierre-Louis Bossart wrote: > > > On 10/17/23 19:25, Wesley Cheng wrote: >> Hi Pierre, >> >> On 10/17/2023 1:58 PM, Pierre-Louis Bossart wrote: >>> It's been a very long time since I reviewed earlier versions, and I am >>> still lost on terminology and concepts. The explanations below should >>> really be added as a .rst file in Documentation for reference, not just >>> as a cover letter. >>> >> >> Thanks for the review! >> >> Sure, maybe I can write a more comprehensive documentation that saves >> these details somewhere. Will add a RST documentation for material >> where necessary. >> >>>> 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 >>> >>> "backend" is a loaded terms for ASoC. Can you clarify which part of the >>> ascii art below is a 'backend'? >>> >> >> This would be the Q6USB entity which is the DPCM backend for this >> particular audio path. > > DPCM is about dailinks. Technically the q6usb entity is a codec dai > which is part of a DPCM backend dailink. >> >>>> 3. Introduce XHCI interrupter support >>>> 4. Create vendor ops for the USB SND driver >>>> >>>> USB | ASoC >>>> -------------------------------------------------------------------- >>>> | _________________________ >>>> | |sm8250 platform card | >>>> | |_________________________| >>>> | | | >>>> | ___V____ ____V____ >>>> | |Q6USB | |Q6AFE | >>>> | |"codec" | |"cpu" | >>>> | |________| |_________| >>>> | ^ ^ ^ >>>> | | |________| >>>> | ___V____ | >>>> | |SOC-USB | | >>>> ________ ________ | | | >>>> |USB SND |<--->|QC offld|<------------>|________| | >>>> |(card.c)| | |<---------- | >>>> |________| |________|___ | | | >>>> ^ ^ | | | ____________V_________ >>>> | | | | | |APR/GLINK | >>>> __ V_______________V_____ | | | |______________________| >>>> |USB SND (endpoint.c) | | | | ^ >>>> |_________________________| | | | | >>>> ^ | | | ___________V___________ >>>> | | | |->|audio DSP | >>>> ___________V_____________ | | |_______________________| >>>> |XHCI HCD |<- | >>>> |_________________________| | >>>> >>>> >>>> Adding ASoC binding layer: >>>> soc-usb: Intention is to treat a USB port similar to a headphone jack. >>> >>> What is a 'port'? USB refers to "interfaces" and "endpoints". Is a >>> "port" a 1:1 mapping to "endpoint"? >>> >>> Below I read "AFE port" so not sure what concepts refer to what. >>> >> >> "Port" in this explanation refers to the USB port. So the audio device >> connected. You are right that a USB device can enumerate w/ multiple >> interfaces (ie UAC + HID + ...) so the closest relation to "port" is >> "interface." It is not a 1:1 mapping w/ the number of endpoints exposed >> by a device. >> >> "AFE port" is just something that has been termed from the audio DSP >> end, so that concept of port is not related to the port where USB >> devices are connected to. This is something that is defined within the >> audio DSP. > > Wow. So there's a "USB port" and "AFE port". I would recommend avoiding > the same term for completely different concepts. Why not use "USB device"? > I think maybe USB interface is probably the most acceptable, since even at the USB snd level, they work based on usb_interface, not on the udev (USB device) itself. >>>> 0 [SM8250MTPWCD938]: sm8250 - SM8250-MTP-WCD9380-WSA8810-VA-D >>>> SM8250-MTP-WCD9380-WSA8810-VA-DMIC >>> >>> How do you plan on exposing the USB PCM device? >>> >>> The lines above are really cryptic, and with no USB reference in any of >>> the short/long card names it's not obvious that this card is different >>> from the no-offload case, is it? >>> >> >> In the end, since the offload case is handled by the audio DSP, it would >> have to go through the platform/machine sound card. That is the sm8250 >> device above. >> >>>> 1 [Audio ]: USB-Audio - USB Audio >>>> Generic USB Audio at usb-xhci-hcd.1.auto-1.4, >>>> high speed >>> >>> likewise some sort of qualifier would be useful to show that card 0 and >>> card 1 can target the same USB endpoints. >>> >> >> Do userspace entities look at this card string? Assuming there is only >> one platform card, there are situations where maybe multiple USB audio >> devices are connected to the same USB root hub, so offloading can happen >> on any one of them (not at the same time). > > Jaroslav cares, as measured by the changes over the years to make the > card names more self-explanatory. > > I really don't see anything in the SM8250MTPWCD938 card name that would > hint at the support of USB. If it's not in the card string, maybe this > can be added in the component string as well (amixer -Dhw:0 info). The > point is that userspace should not have to maintain an 'accept-list' of > card names but have the means to check the USB offload capability with a > vendor-neutral convention. I'll take a look at adding it into the components string. At least in that case, we'd be able to dynamically modify to say if USB offload is supported or not based on the child entries/paths that are defined in the DT node. Thanks Wesley Cheng
Hi Pierre, On 10/17/2023 3:33 PM, Pierre-Louis Bossart wrote: > > > On 10/17/23 15:00, Wesley Cheng wrote: >> Introduce a check for if a particular PCM format is supported by the USB > > Introduce a helper to check if a ... > Ack. >> audio device connected. If the USB audio device does not have an audio >> profile which can support the requested format, then notify the USB >> backend. >> >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> >> --- >> include/sound/soc-usb.h | 3 +++ >> sound/soc/soc-usb.c | 13 +++++++++++++ >> 2 files changed, 16 insertions(+) >> >> diff --git a/include/sound/soc-usb.h b/include/sound/soc-usb.h >> index 58c686f4f7ba..c6ddc055c4cd 100644 >> --- a/include/sound/soc-usb.h >> +++ b/include/sound/soc-usb.h >> @@ -37,6 +37,9 @@ struct snd_soc_usb { >> void *priv_data; >> }; >> >> +int snd_soc_usb_find_format(int card_idx, struct snd_pcm_hw_params *params, >> + int direction); >> + >> int snd_soc_usb_connect(struct device *usbdev, struct snd_soc_usb_device *sdev); >> int snd_soc_usb_disconnect(struct device *usbdev, struct snd_soc_usb_device *sdev); >> void *snd_soc_usb_find_priv_data(struct device *usbdev); >> diff --git a/sound/soc/soc-usb.c b/sound/soc/soc-usb.c >> index 73b1bcc3b506..7407678a993e 100644 >> --- a/sound/soc/soc-usb.c >> +++ b/sound/soc/soc-usb.c >> @@ -63,6 +63,19 @@ void *snd_soc_usb_find_priv_data(struct device *dev) >> } >> EXPORT_SYMBOL_GPL(snd_soc_usb_find_priv_data); >> >> +int snd_soc_usb_find_format(int card_idx, struct snd_pcm_hw_params *params, >> + int direction) >> +{ >> + struct snd_usb_stream *as; >> + >> + as = snd_usb_find_suppported_substream(card_idx, params, direction); >> + if (!as) >> + return -EOPNOTSUPP; >> + >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(snd_soc_usb_find_format); > > Is this the right way to check for formats? > > formats are defined within the scope of an endpoint, and those endpoints > are themselves defined within the scope of an interface? > > I don't see a notion of endpoint here. Does this assume all endpoints > are valid, or maybe the existence of a single endpoint in a device? > > Confused. At least in terms of USB and USB UAC, formats are defined within an audio streaming interface descriptor, which will include multiple (up to 2) USB endpoints. Those endpoints will be described w/ both an audio streaming endpoint descriptor as well as a standard USB endpoint descriptor. The audio interface/format descriptors are the ones that carry the information about what formats are supported by the USB device. So this API finds a possible USB AS streaming descriptor on the device that matches the requested one. Endpoints will be opened subsequently when the audio stream is started, and an interface is enabled by sending a SET_INTERFACE control packet on the USB bus. Thanks Wesley Cheng
Hi Pierre, On 10/17/2023 3:43 PM, Pierre-Louis Bossart wrote: > > > On 10/17/23 15:01, Wesley Cheng wrote: >> The USB backend should know about which sound resources are being shared >> between the ASoC and USB SND paths. This can be utilized to properly >> select and maintain the offloading devices. >> >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> >> --- >> sound/soc/qcom/qdsp6/q6usb.c | 16 ++++++++++++++++ >> 1 file changed, 16 insertions(+) >> >> diff --git a/sound/soc/qcom/qdsp6/q6usb.c b/sound/soc/qcom/qdsp6/q6usb.c >> index 329a7d4a3c01..d697cbe7f184 100644 >> --- a/sound/soc/qcom/qdsp6/q6usb.c >> +++ b/sound/soc/qcom/qdsp6/q6usb.c >> @@ -25,10 +25,18 @@ >> >> #define SID_MASK 0xF >> >> +struct q6usb_status { >> + unsigned int num_pcm; > > how would one know which ones are capture and which ones are playback? > > This really looks like a playback-only assumption, despite earlier > mentions of capture supported. > Yes, playback only, which is the reasoning for only having one parameter here. I will rename it though to be clearer. Thanks Wesley Cheng >> + unsigned int chip_index; >> + unsigned int pcm_index; >> +}; >> + >> struct q6usb_port_data { >> struct q6afe_usb_cfg usb_cfg; >> struct snd_soc_usb *usb; >> struct q6usb_offload priv; >> + unsigned long available_card_slot; >> + struct q6usb_status status[SNDRV_CARDS]; >> int active_idx; >> }; >> >> @@ -110,6 +118,14 @@ static int q6usb_alsa_connection_cb(struct snd_soc_usb *usb, >> if (connected) { >> /* We only track the latest USB headset plugged in */ >> data->active_idx = sdev->card_idx; >> + >> + set_bit(sdev->card_idx, &data->available_card_slot); >> + data->status[sdev->card_idx].num_pcm = sdev->num_playback; > > there you go... > >> + data->status[sdev->card_idx].chip_index = sdev->chip_idx; >> + } else { >> + clear_bit(sdev->card_idx, &data->available_card_slot); >> + data->status[sdev->card_idx].num_pcm = 0; >> + data->status[sdev->card_idx].chip_index = 0; >> } >> >> return 0;
Hi Pierre, On 10/17/2023 3:50 PM, Pierre-Louis Bossart wrote: > > > On 10/17/23 15:01, Wesley Cheng wrote: >> Expose a kcontrol on the platform sound card, which will allow for >> userspace to determine which USB card number and PCM device to offload. >> This allows for userspace to potentially tag an alternate path for a >> specific USB SND card and PCM device. Previously, control was absent, and >> the offload path would be enabled on the last USB SND device which was >> connected. This logic will continue to be applicable if no mixer input is >> received for specific device selection. >> >> An example to configure the offload device using tinymix: >> tinymix -D 0 set 'Q6USB offload SND device select' 1 0 >> >> The above will set the Q6AFE device token to choose offload on card#1 and >> pcm#0. Device selection is made possible by setting the Q6AFE device >> token. The audio DSP utilizes this parameter, and will pass this field >> back to the USB offload driver within the QMI stream requests. > > This still begs the question on how userspace would figure what the > card1 is and which endpoint is used when PCM0 is opened? > Assuming we have something maybe in the component string for card1, then maybe that will help in this case as you mentioned earlier. Again, I think my understanding of "endpoint" here is referring to the USB endpoint. However, that isn't normally how we should think about it. From the USB sound perspective, it would be the USB interface that is selected, and the USB endpoints that that interface descriptor includes (up to 2 usb eps). > Ideally userpace would not have to know anything about "Q6USB". > Presumably when other vendors expose their USB offload solution, we > would want a generic control name, no? > Hmm...initially I was keeping the sound kcontrol implementation based on a vendor specific approach. Although, it might be good to standardize it a bit. I could see if we can add this to within soc-usb so whenever we just create a soc usb device, it would also create and initialize the kcontrols as well? > Jaroslav should chime in on this one :-) > > >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> >> --- >> sound/soc/qcom/qdsp6/q6usb.c | 125 ++++++++++++++++++++++++++++++++++- >> 1 file changed, 122 insertions(+), 3 deletions(-) >> >> diff --git a/sound/soc/qcom/qdsp6/q6usb.c b/sound/soc/qcom/qdsp6/q6usb.c >> index d697cbe7f184..a95276b7d91d 100644 >> --- a/sound/soc/qcom/qdsp6/q6usb.c >> +++ b/sound/soc/qcom/qdsp6/q6usb.c >> @@ -14,6 +14,7 @@ >> #include <linux/dma-map-ops.h> >> >> #include <sound/pcm.h> >> +#include <sound/control.h> >> #include <sound/soc.h> >> #include <sound/soc-usb.h> >> #include <sound/pcm_params.h> >> @@ -35,9 +36,12 @@ struct q6usb_port_data { >> struct q6afe_usb_cfg usb_cfg; >> struct snd_soc_usb *usb; >> struct q6usb_offload priv; >> + struct mutex mutex; > > missing comment on what this protects. "mutex" is really a poor > choice/name if I am honest. > >> unsigned long available_card_slot; >> struct q6usb_status status[SNDRV_CARDS]; >> - int active_idx; >> + bool idx_valid; >> + int sel_card_idx; >> + int sel_pcm_idx; >> }; > >> +/* Build a mixer control for a UAC connector control (jack-detect) */ >> +static void q6usb_connector_control_init(struct snd_soc_component *component) >> +{ >> + int ret; >> + >> + ret = snd_ctl_add(component->card->snd_card, >> + snd_ctl_new1(&q6usb_offload_dev_ctrl, component)); >> + if (ret < 0) >> + return; > > that error handling does not seem terribly useful... > Based on your earlier comment, this might change :) Thanks Wesley Cheng
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 USB | ASoC -------------------------------------------------------------------- | _________________________ | |sm8250 platform card | | |_________________________| | | | | ___V____ ____V____ | |Q6USB | |Q6AFE | | |"codec" | |"cpu" | | |________| |_________| | ^ ^ ^ | | |________| | ___V____ | | |SOC-USB | | ________ ________ | | | |USB SND |<--->|QC offld|<------------>|________| | |(card.c)| | |<---------- | |________| |________|___ | | | ^ ^ | | | ____________V_________ | | | | | |APR/GLINK | __ V_______________V_____ | | | |______________________| |USB SND (endpoint.c) | | | | ^ |_________________________| | | | | ^ | | | ___________V___________ | | | |->|audio DSP | ___________V_____________ | | |_______________________| |XHCI HCD |<- | |_________________________| | 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 Changelog -------------------------------------------- Changes in v9: - Fixed the dt binding check issue with regards to num-hc-interrupters. Changes in v8: - Cleaned up snd_soc_usb_find_priv_data() based on Mark's feedback. Removed some of the duplicate looping code that was present on previous patches. Also renamed the API. - Integrated Mathias' suggestions on his new sideband changes: https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters - Addressed some of Mathias' fixme tags, such as: - Resetting transfer ring dequeue/enqueue pointers - Issuing stop endpoint command during ep removal - Reset ERDP properly to first segment ring during interrupter removal. (this is currently just being cleared to 0, but should be pointing to a valid segment if controller is still running. Changes in v7: - Fixed dt check error for q6usb bindings - Updated q6usb property from qcom,usb-audio-intr-num --> qcom,usb-audio-intr-idx - Removed separate DWC3 HC interrupters num property, and place limits to XHCI one. - Modified xhci_ring_to_sgtable() to use assigned IOVA/DMA address to fetch pages, as it is not ensured event ring allocated is always done in the vmalloc range. Changes in v6: - Fixed limits and description on several DT bindings (XHCI and Q6USB) - Fixed patch subjects to follow other ALSA/ASoC notations. USB SND - Addressed devices which expose multiple audio (UAC) interfaces. These devices will create a single USB sound card with multiple audio streams, and receive multiple interface probe routines. QC offload was not properly considering cases with multiple probe calls. - Renamed offload module name and kconfig to fit within the SND domain. - Renamed attach/detach endpoint API to keep the hw_params notation. Changes in v5: - Removed some unnescessary files that were included - Fixed some typos mentioned - Addressed dt-binding issues and added hc-interrupters definition to usb-xhci.yaml XHCI: - Moved secondary skip events API to xhci-ring and updated implementation - Utilized existing XHCI APIs, such as inc_deq and xhci_update_erst_dequeue() USB SND - Renamed and reworked the APIs in "sound: usb: Export USB SND APIs for modules" patch to include suggestions to utilize snd_usb_hw_params/free and to avoid generic naming. - Added a resume_cb() op for completion sake. - Addressed some locking concerns with regards to when registering for platform hooks. - Added routine to disconnect all offloaded devices during module unbind. ASoC - Replaced individual PCM parameter arguments in snd_soc_usb_connect() with new snd_soc_usb_device structure to pass along PCM info. - Modified snd_jack set report to notify HEADPHONE event, as we do not support record path. Changes in v4: - Rebased to xhci/for-usb-next - Addressed some dt-bindings comments XHCI: - Pulled in latest changes from Mathias' feature_interrupters branch: https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters - Fixed commit text and signage for the XHCI sideband/interrupter related changes - Added some logic to address the FIXME tags mentioned throughout the commits, such as handling multi segment rings and building the SGT, locking concerns, and ep cleanup operations. - Removed some fixme tags for conditions that may not be needed/addressed. - Repurposed the new endpoint stop sync API to be utilized in other places. - Fixed potential compile issue if XHCI sideband config is not defined. ASoC: - Added sound jack control into the Q6USB driver. Allows for userpsace to know when an offload capable device is connected. USB SND: - Avoided exporting _snd_pcm_hw_param_set based on Takashi's recommendation. - Split USB QMI packet header definitions into a separate commit. This is used to properly allow the QMI interface driver to parse and route QMI packets accordingly - Added a "depends on" entry when enabling QC audio offload to avoid compile time issues. Changes in v3: - Changed prefix from RFC to PATCH - Rebased entire series to usb-next - Updated copyright years XHCI: - Rebased changes on top of XHCI changes merged into usb-next, and only added changes that were still under discussion. - Added change to read in the "num-hc-interrupters" device property. ASoC: - qusb6 USB backend - Incorporated suggestions to fetch iommu information with existing APIs - Added two new sound kcontrols to fetch offload status and offload device selection. - offload status - will return the card and pcm device in use tinymix -D 0 get 1 --> 1, 0 (offload in progress on card#1 pcm#0) - device selection - set the card and pcm device to enable offload on. Ex.: tinymix -D 0 set 1 2 0 --> sets offload on card#2 pcm#0 (this should be the USB card) USB SND: - Fixed up some locking related concerns for registering platform ops. - Moved callbacks under the register_mutex, so that - Modified APIs to properly pass more information about the USB SND device, so that the Q6USB backend can build a device list/map, in order to monitor offload status and device selection. 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. Mathias Nyman (4): xhci: split free interrupter into separate remove and free parts xhci: add support to allocate several interrupters xhci: add helper to stop endpoint and wait for completion xhci: sideband: add initial api to register a sideband entity Wesley Cheng (30): usb: host: xhci-mem: Cleanup pending secondary event ring events usb: host: xhci-mem: Allow for interrupter clients to choose specific index ASoC: Add SOC USB APIs for adding an USB backend ASoC: dt-bindings: qcom,q6dsp-lpass-ports: Add USB_RX port ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp ASoC: qdsp6: q6afe: Increase APR timeout ASoC: qcom: qdsp6: Add USB backend ASoC driver for Q6 ALSA: usb-audio: Introduce USB SND platform op callbacks ALSA: usb-audio: Export USB SND APIs for modules dt-bindings: usb: xhci: Add num-hc-interrupters definition dt-bindings: usb: dwc3: Limit num-hc-interrupters definition usb: dwc3: Specify maximum number of XHCI interrupters usb: host: xhci-plat: Set XHCI max interrupters if property is present ALSA: usb-audio: qcom: Add USB QMI definitions ALSA: usb-audio: qcom: Introduce QC USB SND offloading support ALSA: usb-audio: Check for support for requested audio format ASoC: usb: Add PCM format check API for USB backend ASoC: qcom: qdsp6: Ensure PCM format is supported by USB audio device ALSA: usb-audio: Prevent starting of audio stream if in use ASoC: dt-bindings: Add Q6USB backend ASoC: dt-bindings: Update example for enabling USB offload on SM8250 ASoC: qcom: qdsp6: q6afe: Split USB AFE dev_token param into separate API ALSA: usb-audio: qcom: Populate PCM and USB chip information ASoC: qcom: qdsp6: Add support to track available USB PCM devices ASoC: qcom: qdsp6: Add SND kcontrol to select offload device ASoC: qcom: qdsp6: Add SND kcontrol for fetching offload status ASoC: qcom: qdsp6: Add headphone jack for offload connection status ALSA: usb-audio: qcom: Use card and PCM index from QMI request ALSA: usb-audio: Allow for rediscovery of connected USB SND devices ASoC: usb: Rediscover USB SND devices on USB port add .../devicetree/bindings/sound/qcom,q6usb.yaml | 55 + .../bindings/sound/qcom,sm8250.yaml | 15 + .../devicetree/bindings/usb/snps,dwc3.yaml | 4 + .../devicetree/bindings/usb/usb-xhci.yaml | 6 + drivers/usb/dwc3/core.c | 12 + drivers/usb/dwc3/core.h | 2 + drivers/usb/dwc3/host.c | 5 +- drivers/usb/host/Kconfig | 9 + drivers/usb/host/Makefile | 4 + drivers/usb/host/xhci-debugfs.c | 2 +- drivers/usb/host/xhci-mem.c | 136 +- drivers/usb/host/xhci-plat.c | 2 + drivers/usb/host/xhci-ring.c | 53 +- drivers/usb/host/xhci-sideband.c | 372 ++++ drivers/usb/host/xhci.c | 114 +- drivers/usb/host/xhci.h | 18 +- .../sound/qcom,q6dsp-lpass-ports.h | 1 + include/linux/usb/xhci-sideband.h | 67 + include/sound/q6usboffload.h | 20 + include/sound/soc-usb.h | 51 + sound/soc/Makefile | 2 +- sound/soc/qcom/Kconfig | 4 + sound/soc/qcom/qdsp6/Makefile | 1 + sound/soc/qcom/qdsp6/q6afe-dai.c | 56 + sound/soc/qcom/qdsp6/q6afe.c | 206 +- sound/soc/qcom/qdsp6/q6afe.h | 36 +- sound/soc/qcom/qdsp6/q6dsp-lpass-ports.c | 23 + sound/soc/qcom/qdsp6/q6dsp-lpass-ports.h | 1 + sound/soc/qcom/qdsp6/q6routing.c | 9 + sound/soc/qcom/qdsp6/q6usb.c | 450 ++++ sound/soc/soc-usb.c | 201 ++ sound/usb/Kconfig | 15 + sound/usb/Makefile | 2 +- sound/usb/card.c | 123 ++ sound/usb/card.h | 23 + sound/usb/endpoint.c | 1 + sound/usb/helper.c | 1 + sound/usb/pcm.c | 94 +- sound/usb/pcm.h | 11 + sound/usb/qcom/Makefile | 2 + sound/usb/qcom/qc_audio_offload.c | 1867 +++++++++++++++++ sound/usb/qcom/usb_audio_qmi_v01.c | 892 ++++++++ sound/usb/qcom/usb_audio_qmi_v01.h | 162 ++ 43 files changed, 5041 insertions(+), 89 deletions(-) create mode 100644 Documentation/devicetree/bindings/sound/qcom,q6usb.yaml create mode 100644 drivers/usb/host/xhci-sideband.c create mode 100644 include/linux/usb/xhci-sideband.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