// SPDX-License-Identifier: GPL-2.0-or-later /* */ #include <linux/gfp.h> #include <linux/init.h> #include <linux/ratelimit.h> #include <linux/usb.h> #include <linux/usb/audio.h> #include <linux/slab.h> #include <sound/core.h> #include <sound/pcm.h> #include <sound/pcm_params.h> #include "usbaudio.h" #include "helper.h" #include "card.h" #include "endpoint.h" #include "pcm.h" #include "clock.h" #include "quirks.h" enum { … }; /* interface refcounting */ struct snd_usb_iface_ref { … }; /* clock refcounting */ struct snd_usb_clock_ref { … }; /* * snd_usb_endpoint is a model that abstracts everything related to an * USB endpoint and its streaming. * * There are functions to activate and deactivate the streaming URBs and * optional callbacks to let the pcm logic handle the actual content of the * packets for playback and record. Thus, the bus streaming and the audio * handlers are fully decoupled. * * There are two different types of endpoints in audio applications. * * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both * inbound and outbound traffic. * * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and * expect the payload to carry Q10.14 / Q16.16 formatted sync information * (3 or 4 bytes). * * Each endpoint has to be configured prior to being used by calling * snd_usb_endpoint_set_params(). * * The model incorporates a reference counting, so that multiple users * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and * only the first user will effectively start the URBs, and only the last * one to stop it will tear the URBs down again. */ /* * convert a sampling rate into our full speed format (fs/1000 in Q16.16) * this will overflow at approx 524 kHz */ static inline unsigned get_usb_full_speed_rate(unsigned int rate) { … } /* * convert a sampling rate into USB high speed format (fs/8000 in Q16.16) * this will overflow at approx 4 MHz */ static inline unsigned get_usb_high_speed_rate(unsigned int rate) { … } /* * release a urb data */ static void release_urb_ctx(struct snd_urb_ctx *u) { … } static const char *usb_error_string(int err) { … } static inline bool ep_state_running(struct snd_usb_endpoint *ep) { … } static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new) { … } /** * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type * * @ep: The snd_usb_endpoint * * Determine whether an endpoint is driven by an implicit feedback * data endpoint source. */ int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep) { … } /* * Return the number of samples to be sent in the next packet * for streaming based on information derived from sync endpoints * * This won't be used for implicit feedback which takes the packet size * returned from the sync source */ static int slave_next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail) { … } /* * Return the number of samples to be sent in the next packet * for adaptive and synchronous endpoints */ static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail) { … } /* * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent * in the next packet * * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN * Exception: @avail = 0 for skipping the check. */ int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep, struct snd_urb_ctx *ctx, int idx, unsigned int avail) { … } static void call_retire_callback(struct snd_usb_endpoint *ep, struct urb *urb) { … } static void retire_outbound_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *urb_ctx) { … } static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, struct snd_usb_endpoint *sender, const struct urb *urb); static void retire_inbound_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *urb_ctx) { … } static inline bool has_tx_length_quirk(struct snd_usb_audio *chip) { … } static void prepare_silent_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *ctx) { … } /* * Prepare a PLAYBACK urb for submission to the bus. */ static int prepare_outbound_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *ctx, bool in_stream_lock) { … } /* * Prepare a CAPTURE or SYNC urb for submission to the bus. */ static int prepare_inbound_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *urb_ctx) { … } /* notify an error as XRUN to the assigned PCM data substream */ static void notify_xrun(struct snd_usb_endpoint *ep) { … } static struct snd_usb_packet_info * next_packet_fifo_enqueue(struct snd_usb_endpoint *ep) { … } static struct snd_usb_packet_info * next_packet_fifo_dequeue(struct snd_usb_endpoint *ep) { … } static void push_back_to_ready_list(struct snd_usb_endpoint *ep, struct snd_urb_ctx *ctx) { … } /* * Send output urbs that have been prepared previously. URBs are dequeued * from ep->ready_playback_urbs and in case there aren't any available * or there are no packets that have been prepared, this function does * nothing. * * The reason why the functionality of sending and preparing URBs is separated * is that host controllers don't guarantee the order in which they return * inbound and outbound packets to their submitters. * * This function is used both for implicit feedback endpoints and in low- * latency playback mode. */ int snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep, bool in_stream_lock) { … } /* * complete callback for urbs */ static void snd_complete_urb(struct urb *urb) { … } /* * Find or create a refcount object for the given interface * * The objects are released altogether in snd_usb_endpoint_free_all() */ static struct snd_usb_iface_ref * iface_ref_find(struct snd_usb_audio *chip, int iface) { … } /* Similarly, a refcount object for clock */ static struct snd_usb_clock_ref * clock_ref_find(struct snd_usb_audio *chip, int clock) { … } /* * Get the existing endpoint object corresponding EP * Returns NULL if not present. */ struct snd_usb_endpoint * snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num) { … } #define ep_type_name(type) … /** * snd_usb_add_endpoint: Add an endpoint to an USB audio chip * * @chip: The chip * @ep_num: The number of the endpoint to use * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC * * If the requested endpoint has not been added to the given chip before, * a new instance is created. * * Returns zero on success or a negative error code. * * New endpoints will be added to chip->ep_list and freed by * calling snd_usb_endpoint_free_all(). * * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that * bNumEndpoints > 1 beforehand. */ int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type) { … } /* Set up syncinterval and maxsyncsize for a sync EP */ static void endpoint_set_syncinterval(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { … } static bool endpoint_compatible(struct snd_usb_endpoint *ep, const struct audioformat *fp, const struct snd_pcm_hw_params *params) { … } /* * Check whether the given fp and hw params are compatible with the current * setup of the target EP for implicit feedback sync */ bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep, const struct audioformat *fp, const struct snd_pcm_hw_params *params) { … } /* * snd_usb_endpoint_open: Open the endpoint * * Called from hw_params to assign the endpoint to the substream. * It's reference-counted, and only the first opener is allowed to set up * arbitrary parameters. The later opener must be compatible with the * former opened parameters. * The endpoint needs to be closed via snd_usb_endpoint_close() later. * * Note that this function doesn't configure the endpoint. The substream * needs to set it up later via snd_usb_endpoint_set_params() and * snd_usb_endpoint_prepare(). */ struct snd_usb_endpoint * snd_usb_endpoint_open(struct snd_usb_audio *chip, const struct audioformat *fp, const struct snd_pcm_hw_params *params, bool is_sync_ep, bool fixed_rate) { … } /* * snd_usb_endpoint_set_sync: Link data and sync endpoints * * Pass NULL to sync_ep to unlink again */ void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip, struct snd_usb_endpoint *data_ep, struct snd_usb_endpoint *sync_ep) { … } /* * Set data endpoint callbacks and the assigned data stream * * Called at PCM trigger and cleanups. * Pass NULL to deactivate each callback. */ void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep, int (*prepare)(struct snd_usb_substream *subs, struct urb *urb, bool in_stream_lock), void (*retire)(struct snd_usb_substream *subs, struct urb *urb), struct snd_usb_substream *data_subs) { … } static int endpoint_set_interface(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep, bool set) { … } /* * snd_usb_endpoint_close: Close the endpoint * * Unreference the already opened endpoint via snd_usb_endpoint_open(). */ void snd_usb_endpoint_close(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { … } /* Prepare for suspening EP, called from the main suspend handler */ void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep) { … } /* * wait until all urbs are processed. */ static int wait_clear_urbs(struct snd_usb_endpoint *ep) { … } /* sync the pending stop operation; * this function itself doesn't trigger the stop operation */ void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep) { … } /* * Stop active urbs * * This function moves the EP to STOPPING state if it's being RUNNING. */ static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending) { … } /* * release an endpoint's urbs */ static int release_urbs(struct snd_usb_endpoint *ep, bool force) { … } /* * configure a data endpoint */ static int data_ep_set_params(struct snd_usb_endpoint *ep) { … } /* * configure a sync endpoint */ static int sync_ep_set_params(struct snd_usb_endpoint *ep) { … } /* update the rate of the referred clock; return the actual rate */ static int update_clock_ref_rate(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { … } /* * snd_usb_endpoint_set_params: configure an snd_usb_endpoint * * It's called either from hw_params callback. * Determine the number of URBs to be used on this endpoint. * An endpoint must be configured before it can be started. * An endpoint that is already running can not be reconfigured. */ int snd_usb_endpoint_set_params(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { … } static int init_sample_rate(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { … } /* * snd_usb_endpoint_prepare: Prepare the endpoint * * This function sets up the EP to be fully usable state. * It's called either from prepare callback. * The function checks need_setup flag, and performs nothing unless needed, * so it's safe to call this multiple times. * * This returns zero if unchanged, 1 if the configuration has changed, * or a negative error code. */ int snd_usb_endpoint_prepare(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { … } /* get the current rate set to the given clock by any endpoint */ int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock) { … } /** * snd_usb_endpoint_start: start an snd_usb_endpoint * * @ep: the endpoint to start * * A call to this function will increment the running count of the endpoint. * In case it is not already running, the URBs for this endpoint will be * submitted. Otherwise, this function does nothing. * * Must be balanced to calls of snd_usb_endpoint_stop(). * * Returns an error if the URB submission failed, 0 in all other cases. */ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep) { … } /** * snd_usb_endpoint_stop: stop an snd_usb_endpoint * * @ep: the endpoint to stop (may be NULL) * @keep_pending: keep in-flight URBs * * A call to this function will decrement the running count of the endpoint. * In case the last user has requested the endpoint stop, the URBs will * actually be deactivated. * * Must be balanced to calls of snd_usb_endpoint_start(). * * The caller needs to synchronize the pending stop operation via * snd_usb_endpoint_sync_pending_stop(). */ void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending) { … } /** * snd_usb_endpoint_release: Tear down an snd_usb_endpoint * * @ep: the endpoint to release * * This function does not care for the endpoint's running count but will tear * down all the streaming URBs immediately. */ void snd_usb_endpoint_release(struct snd_usb_endpoint *ep) { … } /** * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint * @chip: The chip * * This free all endpoints and those resources */ void snd_usb_endpoint_free_all(struct snd_usb_audio *chip) { … } /* * snd_usb_handle_sync_urb: parse an USB sync packet * * @ep: the endpoint to handle the packet * @sender: the sending endpoint * @urb: the received packet * * This function is called from the context of an endpoint that received * the packet and is used to let another endpoint object handle the payload. */ static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, struct snd_usb_endpoint *sender, const struct urb *urb) { … }
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