Work in progress to enable usb audio offload on sm8350

Change-Id: I1e33718e22b2fd46f1ca06dbc320e99755e9cd46

If the vendor USB offload class driver is not ready/initialized before USB
SND discovers attached devices, utilize snd_usb_rediscover_devices() to
find all currently attached devices, so that the ASoC entities are notified
on available USB audio devices.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

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:

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.

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.

The USB offload kcontrol will be added in addition to the existing
kcontrols identified by the USB SND mixer.  The kcontrols used to modify
the USB audio device specific parameters are still valid and expected to be
used.  These parameters are not mirrored to the ASoC subsystem.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

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>

Several Qualcomm SoCs have a dedicated audio DSP, which has the ability to
support USB sound devices.  This vendor driver will implement the required
handshaking with the DSP, in order to pass along required resources that
will be utilized by the DSP's USB SW.  The communication channel used for
this handshaking will be using the QMI protocol.  Required resources
include:
- Allocated secondary event ring address
- EP transfer ring address
- Interrupter number

The above information will allow for the audio DSP to execute USB transfers
over the USB bus.  It will also be able to support devices that have an
implicit feedback and sync endpoint as well.  Offloading these data
transfers will allow the main/applications processor to enter lower CPU
power modes, and sustain a longer duration in those modes.

Audio offloading is initiated with the following sequence:
1. Userspace configures to route audio playback to USB backend and starts
playback on the platform soundcard.
2. The Q6DSP AFE will communicate to the audio DSP to start the USB AFE
port.
3. This results in a QMI packet with a STREAM enable command.
4. The QC audio offload driver will fetch the required resources, and pass
this information as part of the QMI response to the STREAM enable command.
5. Once the QMI response is received the audio DSP will start queuing data
on the USB bus.

As part of step#2, the audio DSP is aware of the USB SND card and pcm
device index that is being selected, and is communicated as part of the QMI
request received by QC audio offload.  These indices will be used to handle
the stream enable QMI request.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

The Qualcomm USB audio offload driver utilizes the QMI protocol to
communicate with the audio DSP.  Add the necessary QMI header and field
definitions, so the QMI interface driver is able to route the QMI packet
received to the USB audio offload driver.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

The USB SND path may need to know how the USB offload path is routed, so
that applications can open the proper sound card and PCM device.  The
implementation for the QC ASoC design has a "USB Mixer" kcontrol for each
possible FE (Q6ASM) DAI, which can be utilized to know which front end link
is enabled.

When an application/userspace queries for the mapped offload devices, the
logic will lookup the USB mixer status though the following path:

MultiMedia* <-> MM_DL* <-> USB Mixer*

The "USB Mixer" is a DAPM widget, and the q6routing entity will set the
DAPM connect status accordingly if the USB mixer is enabled.  If enabled,
the Q6USB backend link can fetch the PCM device number from the FE DAI
link (Multimedia*).  With respects to the card number, that is
straightforward, as the ASoC components have direct references to the ASoC
platform sound card.

An example output can be shown below:

Number of controls: 9
name                                    value
Capture Channel Map                     0, 0 (range 0->36)
Playback Channel Map                    0, 0 (range 0->36)
Headset Capture Switch                  On
Headset Capture Volume                  1 (range 0->4)
Sidetone Playback Switch                On
Sidetone Playback Volume                4096 (range 0->8192)
Headset Playback Switch                 On
Headset Playback Volume                 20, 20 (range 0->24)
USB Offload Playback Route PCM#0        0, 1 (range -1->255)

The "USB Offload Playback Route PCM#*" kcontrol will signify the
corresponding card and pcm device it is offload to. (card#0 pcm - device#1)
If the USB SND device supports multiple audio interfaces, then it will
contain several PCM streams, hence in those situations, it is expected
that there will be multiple playback route kcontrols created.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

The headphone jack framework has a well defined infrastructure for
notifying userspace entities through input devices.  Expose a jack device
that carries information about if an offload capable device is connected.
Applications can further identify specific offloading information through
other SND kcontrols.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

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>

For USB offloading situations, the AFE port start command will result in a
QMI handshake between the Q6DSP and the main processor.  Depending on if
the USB bus is suspended, this routine would require more time to complete,
as resuming the USB bus has some overhead associated with it.  Increase the
timeout to 3s to allow for sufficient time for the USB QMI stream enable
handshake to complete.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

The QC ADSP is able to support USB playback endpoints, so that the main
application processor can be placed into lower CPU power modes.  This adds
the required AFE port configurations and port start command to start an
audio session.

Specifically, the QC ADSP can support all potential endpoints that are
exposed by the audio data interface.  This includes isochronous data
endpoints, in either synchronous mode or asynchronous mode. In the latter
case both implicit or explicit feedback endpoints are supported.  The size
of audio samples sent per USB frame (microframe) will be adjusted based on
information received on the feedback endpoint.

Some pre-requisites are needed before issuing the AFE port start command,
such as setting the USB AFE dev_token.  This carries information about the
available USB SND cards and PCM devices that have been discovered on the
USB bus.  The dev_token field is used by the audio DSP to notify the USB
offload driver of which card and PCM index to enable playback on.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Add an example on enabling of USB offload for the Q6DSP.  The routing can
be done by the mixer, which can pass the multimedia stream to the USB
backend.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Q6DSP supports handling of USB playback audio data if USB audio offloading
is enabled.  Add a new definition for the USB_RX AFE port, which is
referenced when the AFE port is started.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

With the introduction of the soc-usb driver, add documentation highlighting
details on how to utilize the new driver and how it interacts with
different components in USB SND and ASoC.  It provides examples on how to
implement the drivers that will need to be introduced in order to enable
USB audio offloading.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

In case the USB backend device has not been initialized/probed, USB SND
device connections can still occur.  When the USB backend is eventually
made available, previous USB SND device connections are not communicated to
the USB backend.  Call snd_usb_rediscover_devices() to generate the connect
callbacks for all USB SND devices connected.  This will allow for the USB
backend to be updated with the current set of devices available.

The chip array entries are all populated and removed while under the
register_mutex, so going over potential race conditions:

Thread#1:
  q6usb_component_probe()
    --> snd_soc_usb_add_port()
      --> snd_usb_rediscover_devices()
        --> mutex_lock(register_mutex)

Thread#2
  --> usb_audio_disconnect()
    --> mutex_lock(register_mutex)

So either thread#1 or thread#2 will complete first.  If

Thread#1 completes before thread#2:
  SOC USB will notify DPCM backend of the device connection.  Shortly
  after, once thread#2 runs, we will get a disconnect event for the
  connected device.

Thread#2 completes before thread#1:
  Then during snd_usb_rediscover_devices() it won't notify of any
  connection for that particular chip index.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

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.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Expose API for creation of a jack control for notifying of available
devices that are plugged in/discovered, and that support offloading.  This
allows for control names to be standardized across implementations of USB
audio offloading.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Introduce a helper to check if a particular PCM format is supported by the
USB 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.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Some platforms may have support for offloading USB audio devices to a
dedicated audio DSP.  Introduce a set of APIs that allow for management of
USB sound card and PCM devices enumerated by the USB SND class driver.
This allows for the ASoC components to be aware of what USB devices are
available for offloading.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

In case of notifying SND platform drivers of connection events, some of
these use cases, such as offloading, require an ASoC USB backend device to
be initialized before the events can be handled.  If the USB backend device
has not yet been probed, this leads to missing initial USB audio device
connection events.

Expose an API that traverses the usb_chip array for connected devices, and
to call the respective connection callback registered to the SND platform
driver.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Allow for different platforms to be notified on USB SND connect/disconnect
sequences.  This allows for platform USB SND modules to properly initialize
and populate internal structures with references to the USB SND chip
device.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

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.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

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.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

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.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Some vendor modules will utilize useful parsing and endpoint management
APIs to start audio playback/capture.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Add an USB jack type, in order to support notifying of a valid USB audio
device.  Since USB audio devices can have a slew of different
configurations that reach beyond the basic headset and headphone use cases,
classify these devices differently.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Allow for the DWC3 host driver to pass along XHCI property that defines
how many interrupters to allocate.  This is in relation for the number of
event rings that can be potentially used by other processors within the
system.

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

In the case of handling a USB bus reset, the xhci_discover_or_reset_device
can run without first notifying the xHCI sideband client driver to stop or
prevent the use of the transfer ring.  It was seen that when a bus reset
situation happened, the USB offload driver was attempting to fetch the xHCI
transfer ring information, which was already freed.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Some platforms may want to limit the number of XHCI interrupters allocated.
This is passed to xhci-plat as a device property.  Ensure that this is read
and the max_interrupters field is set.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Some clients may operate only on a specific XHCI interrupter instance.
Allow for the associated class driver to request for the interrupter that
it requires.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

As part of xHCI bus suspend, the xHCI is halted.  However, if there are
pending events in the secondary event ring, it is observed that the xHCI
controller stops responding to further commands upon host or device
initiated bus resume.  Iterate through all pending events and update the
dequeue pointer to the beginning of the event ring.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Introduce XHCI sideband, which manages the USB endpoints being requested by
a client driver.  This is used for when client drivers are attempting to
offload USB endpoints to another entity for handling USB transfers.  XHCI
sec intr will allow for drivers to fetch the required information about the
transfer ring, so the user can submit transfers independently.  Expose the
required APIs for drivers to register and request for a USB endpoint and to
manage XHCI secondary interrupters.

Driver renaming, multiple ring segment page linking, proper endpoint clean
up, and allowing module compilation added by Wesley Cheng to complete
original concept code by Mathias Nyman.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Co-developed-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>

Nothing prevents a broken HC from claiming that an endpoint is Running
and repeatedly rejecting Stop Endpoint with Context State Error.

Avoid infinite retries and give back cancelled TDs.

No such cases known so far, but HCs have bugs.

Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250311154551.4035726-4-mathias.nyman@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When the device stalls an endpoint, current TD is assigned -EPIPE
status and Reset Endpoint is queued. If a Stop Endpoint is pending
at the time, it will run before Reset Endpoint and fail due to the
stall. Its handler will change TD's status to -EPROTO before Reset
Endpoint handler runs and initiates giveback.

Check if the stall has already been handled and don't try to do it
again. Since xhci_handle_halted_endpoint() performs this check too,
not overwriting td->status is the only difference.

I haven't seen this case yet, but I have seen a related one where
the xHC has already executed Reset Endpoint, EP Context state is
now Stopped and EP_HALTED is set. If the xHC took a bit longer to
execute Reset Endpoint, said case would become this one.

Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250311154551.4035726-3-mathias.nyman@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

If EP_STALLED flag is set in xhci_urb_dequeue(), without EP_HALTED or
SET_DEQ_PENDING flags, then the endpoint is in stopped state and the
cancelled URB can be given back immediately withouth queueing
a 'stop endpoint' command.

Without this change the cancelled URB would eventually be given back
in the 'context state error' completion path of the 'stop endpoint'
command. This is not optimal.

For this improvement to work the EP_STALLED flag must be cleared with
xhci lock held.

Suggested-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250311154551.4035726-2-mathias.nyman@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Resolves the merge conflict with:
	drivers/usb/typec/ucsi/ucsi_acpi.c

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge tag 'kbuild-fixes-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Use the specified $(LD) when building userprogs with Clang

 - Pass the correct target triple when compile-testing UAPI headers
   with Clang

 - Fix pacman-pkg build error with KBUILD_OUTPUT

* tag 'kbuild-fixes-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: install-extmod-build: Fix build when specifying KBUILD_OUTPUT
  docs: Kconfig: fix defconfig description
  kbuild: hdrcheck: fix cross build with clang
  kbuild: userprogs: use correct lld when linking through clang

Pull USB fixes from Greg KH:
 "Here are some small USB driver fixes for some reported issues. These
  contain:

   - typec driver fixes

   - dwc3 driver fixes

   - xhci driver fixes

   - renesas controller fixes

   - gadget driver fixes

   - a new USB quirk added

  All of these have been in linux-next with no reported issues"

* tag 'usb-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: typec: ucsi: Fix NULL pointer access
  usb: quirks: Add DELAY_INIT and NO_LPM for Prolific Mass Storage Card Reader
  usb: xhci: Fix host controllers "dying" after suspend and resume
  usb: dwc3: Set SUSPENDENABLE soon after phy init
  usb: hub: lack of clearing xHC resources
  usb: renesas_usbhs: Flush the notify_hotplug_work
  usb: renesas_usbhs: Use devm_usb_get_phy()
  usb: renesas_usbhs: Call clk_put()
  usb: dwc3: gadget: Prevent irq storm when TH re-executes
  usb: gadget: Check bmAttributes only if configuration is valid
  xhci: Restrict USB4 tunnel detection for USB3 devices to Intel hosts
  usb: xhci: Enable the TRB overfetch quirk on VIA VL805
  usb: gadget: Fix setting self-powered state on suspend
  usb: typec: ucsi: increase timeout for PPM reset operations
  acpi: typec: ucsi: Introduce a ->poll_cci method
  usb: typec: tcpci_rt1711h: Unmask alert interrupts to fix functionality
  usb: gadget: Set self-powered based on MaxPower and bmAttributes
  usb: gadget: u_ether: Set is_suspend flag if remote wakeup fails
  usb: atm: cxacru: fix a flaw in existing endpoint checks

Merge tag 'driver-core-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fix from Greg KH:
 "Here is a single driver core fix that resolves a reported memory leak.

  It's been in linux-next for 2 weeks now with no reported problems"

* tag 'driver-core-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  drivers: core: fix device leak in __fw_devlink_relax_cycles()