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      1 /* Copyright 2017 The Chromium OS Authors. All rights reserved.
      2  * Use of this source code is governed by a BSD-style license that can be
      3  * found in the LICENSE file.
      4  *
      5  * `dev_io` Handles playback to and capture from open devices.  It runs only on
      6  * the audio thread.
      7  */
      8 
      9 #ifndef DEV_IO_H_
     10 #define DEV_IO_H_
     11 
     12 #include "cras_iodev.h"
     13 #include "cras_types.h"
     14 #include "polled_interval_checker.h"
     15 
     16 /*
     17  * Open input/output devices.
     18  *    dev - The device.
     19  *    wake_ts - When callback is needed to avoid xrun.
     20  *    last_non_empty_ts - The last time we know the device played/captured
     21  *        non-empty (zero) audio.
     22  *    coarse_rate_adjust - Hack for when the sample rate needs heavy correction.
     23  */
     24 struct open_dev {
     25 	struct cras_iodev *dev;
     26 	struct timespec wake_ts;
     27 	struct polled_interval *non_empty_check_pi;
     28 	struct polled_interval *empty_pi;
     29 	int coarse_rate_adjust;
     30 	struct open_dev *prev, *next;
     31 };
     32 
     33 /*
     34  * Fetches streams from each device in `odev_list`.
     35  *    odev_list - The list of open devices.
     36  */
     37 void dev_io_playback_fetch(struct open_dev *odev_list);
     38 
     39 /*
     40  * Writes the samples fetched from the streams to the playback devices.
     41  *    odev_list - The list of open devices.  Devices will be removed when
     42  *                writing returns an error.
     43  */
     44 int dev_io_playback_write(struct open_dev **odevs,
     45 			  struct cras_fmt_conv *output_converter);
     46 
     47 /* Only public for testing. */
     48 int write_output_samples(struct open_dev **odevs,
     49 			 struct open_dev *adev,
     50 			 struct cras_fmt_conv *output_converter);
     51 
     52 /*
     53  * Captures samples from each device in the list.
     54  *    list - Pointer to the list of input devices.  Devices that fail to read
     55  *           will be removed from the list.
     56  */
     57 int dev_io_capture(struct open_dev **list);
     58 
     59 /*
     60  * Send samples that have been captured to their streams.
     61  */
     62 int dev_io_send_captured_samples(struct open_dev *idev_list);
     63 
     64 /* Reads and/or writes audio samples from/to the devices. */
     65 void dev_io_run(struct open_dev **odevs, struct open_dev **idevs,
     66 		struct cras_fmt_conv *output_converter);
     67 
     68 /*
     69  * Fills min_ts with the next time the system should wake to service input.
     70  * Returns the number of devices waiting.
     71  */
     72 int dev_io_next_input_wake(struct open_dev **idevs, struct timespec *min_ts);
     73 
     74 /*
     75  * Removes a device from a list of devices.
     76  *    odev_list - A pointer to the list to modify.
     77  *    dev_to_rm - Find this device in the list and remove it.
     78  */
     79 void dev_io_rm_open_dev(struct open_dev **odev_list,
     80 			struct open_dev *dev_to_rm);
     81 
     82 /* Returns a pointer to an open_dev if it is in the list, otherwise NULL. */
     83 struct open_dev *dev_io_find_open_dev(struct open_dev *odev_list,
     84                                       const struct cras_iodev *dev);
     85 
     86 /* Remove a stream from the provided list of devices. */
     87 int dev_io_remove_stream(struct open_dev **dev_list,
     88 			 struct cras_rstream *stream,
     89 			 struct cras_iodev *dev);
     90 
     91 #endif /* DEV_IO_H_ */
     92