alsa-utils/axfer/xfer-libasound.h
Takashi Sakamoto cd211d8c22 axfer: add a common interface of waiter for I/O event notification
There're several types of system calls for multiplexed I/O. They're used to
receive notifications of I/O events. Typically, userspace applications call
them against file descriptor to yield CPU. When I/O is enabled on any of
the descriptors, a task of the application is rescheduled, then the
application execute I/O calls.

This commit adds a common interface for this type of system calls, named as
'waiter'. This is expected to be used with non-blocking file operation and
operations on mapped page frame.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-11-13 12:04:48 +01:00

78 lines
1.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
//
// xfer-libasound.h - a header for receiver/transmitter of frames by alsa-lib.
//
// Copyright (c) 2018 Takashi Sakamoto <o-takashi@sakamocchi.jp>
//
// Licensed under the terms of the GNU General Public License, version 2.
#ifndef __ALSA_UTILS_AXFER_XFER_LIBASOUND__H_
#define __ALSA_UTILS_AXFER_XFER_LIBASOUND__H_
#include "xfer.h"
#include "waiter.h"
#define logging(state, ...) \
snd_output_printf(state->log, __VA_ARGS__)
struct xfer_libasound_ops;
struct libasound_state {
snd_pcm_t *handle;
snd_output_t *log;
snd_pcm_hw_params_t *hw_params;
snd_pcm_sw_params_t *sw_params;
const struct xfer_libasound_ops *ops;
void *private_data;
bool verbose;
char *node_literal;
unsigned int msec_per_period;
unsigned int msec_per_buffer;
unsigned int frames_per_period;
unsigned int frames_per_buffer;
unsigned int msec_for_avail_min;
unsigned int msec_for_start_threshold;
unsigned int msec_for_stop_threshold;
bool finish_at_xrun:1;
bool nonblock:1;
bool mmap:1;
bool test_nowait:1;
bool no_auto_resample:1;
bool no_auto_channels:1;
bool no_auto_format:1;
bool no_softvol:1;
bool use_waiter:1;
enum waiter_type waiter_type;
struct waiter_context *waiter;
};
// For internal use in 'libasound' module.
struct xfer_libasound_ops {
int (*pre_process)(struct libasound_state *state);
int (*process_frames)(struct libasound_state *state,
unsigned int *frame_count,
struct mapper_context *mapper,
struct container_context *cntrs);
void (*post_process)(struct libasound_state *state);
unsigned int private_size;
};
int xfer_libasound_wait_event(struct libasound_state *state, int timeout_msec,
unsigned short *revents);
extern const struct xfer_libasound_ops xfer_libasound_irq_rw_ops;
extern const struct xfer_libasound_ops xfer_libasound_irq_mmap_r_ops;
extern const struct xfer_libasound_ops xfer_libasound_irq_mmap_w_ops;
#endif