2  * SPDX-License-Identifier: BSD-2-Clause
41 struct config {  struct
63  * example, a 24-bit sample will be represented with 3 bytes. If you're porting
64  * an audio application from Linux, you should be aware that 24-bit samples on
67  * number_of_fragments - 1 late. That's called jitter tolerance.
84 oss_init(struct config *config)  in oss_init()  argument
89 	if ((config->fd = open(config->device, config->mode)) < 0)  in oss_init()
90 		err(1, "Error opening the device %s", config->device);  in oss_init()
93 	if (ioctl(config->fd, SNDCTL_ENGINEINFO, &config->audio_info) < 0)  in oss_init()
97 	if (ioctl(config->fd, SNDCTL_DSP_GETCAPS, &config->audio_info.caps) < 0)  in oss_init()
101 	if (!(config->audio_info.caps & PCM_CAP_TRIGGER))  in oss_init()
105 	if (config->mmap) {  in oss_init()
106 		if (!(config->audio_info.caps & PCM_CAP_MMAP))  in oss_init()
109 		if (ioctl(config->fd, SNDCTL_DSP_COOKEDMODE, &tmp) < 0)  in oss_init()
114 	if (ioctl(config->fd, SNDCTL_DSP_SETFMT, &config->format) < 0)  in oss_init()
118 	if (ioctl(config->fd, SNDCTL_DSP_CHANNELS, &config->audio_info.max_channels) < 0)  in oss_init()
122 	if (ioctl(config->fd, SNDCTL_DSP_SPEED, &config->sample_rate) < 0)  in oss_init()
126 	switch (config->format) {  in oss_init()
129 		config->sample_size = 1;  in oss_init()
135 		config->sample_size = 2;  in oss_init()
141 		config->sample_size = 3;  in oss_init()
149 		config->sample_size = 4;  in oss_init()
152 		errx(1, "Invalid audio format %d", config->format);  in oss_init()
161 	 * - For each sound(4)-created channel, there is a software-facing  in oss_init()
162 	 *   buffer, and a hardware-facing one.  in oss_init()
163 	 * - The sizes of the buffers can be listed in the console with "sndctl  in oss_init()
165 	 * - OSS ioctls only concern software-facing buffer fragments, not  in oss_init()
173 	 * It is bound to do so at a fixed time frame, to avoid under- and  in oss_init()
176 	config->buffer_info.fragments = 2;  in oss_init()
177 	tmp = size2exp(config->sample_size * config->audio_info.max_channels);  in oss_init()
178 	tmp = ((config->buffer_info.fragments) << 16) | tmp;  in oss_init()
179 	if (ioctl(config->fd, SNDCTL_DSP_SETFRAGMENT, &tmp) < 0)  in oss_init()
183 	if ((config->mode & O_ACCMODE) == O_RDONLY)  in oss_init()
185 	if (ioctl(config->fd, request, &config->buffer_info) < 0)  in oss_init()
187 	if (config->buffer_info.fragments < 1)  in oss_init()
188 		config->buffer_info.fragments = config->buffer_info.fragstotal;  in oss_init()
189 	if (config->buffer_info.bytes < 1)  in oss_init()
190 		config->buffer_info.bytes = config->buffer_info.fragstotal * config->buffer_info.fragsize;  in oss_init()
191 	if (config->buffer_info.bytes < 1) {  in oss_init()
193 		    config->buffer_info.bytes);  in oss_init()
195 	config->sample_count = config->buffer_info.bytes / config->sample_size;  in oss_init()
196 	config->chsamples = config->sample_count / config->audio_info.max_channels;  in oss_init()
197 	config->buf = malloc(config->buffer_info.bytes);  in oss_init()
201 	    config->buffer_info.bytes, config->buffer_info.fragments,  in oss_init()
202 	    config->buffer_info.fragsize, config->buffer_info.fragstotal,  in oss_init()
203 	    config->sample_count);  in oss_init()
206 	switch (config->mode & O_ACCMODE) {  in oss_init()
217 		errx(1, "Invalid mode %d", config->mode);  in oss_init()
220 	if (ioctl(config->fd, SNDCTL_DSP_SETTRIGGER, &tmp) < 0)  in oss_init()