1 // SPDX-License-Identifier: GPL-2.0
3 * sound.c - Sound component for Mostcore
5 * Copyright (C) 2015 Microchip Technology Germany II GmbH & Co. KG
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 #include <linux/module.h>
11 #include <linux/printk.h>
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <sound/core.h>
15 #include <sound/pcm.h>
16 #include <sound/pcm_params.h>
17 #include <linux/sched.h>
18 #include <linux/kthread.h>
19 #include <most/core.h>
21 #define DRIVER_NAME "sound"
23 static struct list_head dev_list;
24 static struct core_component comp;
27 * struct channel - private structure to keep channel specific data
28 * @substream: stores the substream structure
29 * @iface: interface for which the channel belongs to
30 * @cfg: channel configuration
31 * @card: registered sound card
32 * @list: list for private use
34 * @period_pos: current period position (ring buffer)
35 * @buffer_pos: current buffer position (ring buffer)
36 * @is_stream_running: identifies whether a stream is running or not
37 * @opened: set when the stream is opened
38 * @playback_task: playback thread
39 * @playback_waitq: waitq used by playback thread
42 struct snd_pcm_substream *substream;
43 struct snd_pcm_hardware pcm_hardware;
44 struct most_interface *iface;
45 struct most_channel_config *cfg;
46 struct snd_card *card;
47 struct list_head list;
49 unsigned int period_pos;
50 unsigned int buffer_pos;
51 bool is_stream_running;
53 struct task_struct *playback_task;
54 wait_queue_head_t playback_waitq;
56 void (*copy_fn)(void *alsa, void *most, unsigned int bytes);
59 #define MOST_PCM_INFO (SNDRV_PCM_INFO_MMAP | \
60 SNDRV_PCM_INFO_MMAP_VALID | \
61 SNDRV_PCM_INFO_BATCH | \
62 SNDRV_PCM_INFO_INTERLEAVED | \
63 SNDRV_PCM_INFO_BLOCK_TRANSFER)
65 #define swap16(val) ( \
66 (((u16)(val) << 8) & (u16)0xFF00) | \
67 (((u16)(val) >> 8) & (u16)0x00FF))
69 #define swap32(val) ( \
70 (((u32)(val) << 24) & (u32)0xFF000000) | \
71 (((u32)(val) << 8) & (u32)0x00FF0000) | \
72 (((u32)(val) >> 8) & (u32)0x0000FF00) | \
73 (((u32)(val) >> 24) & (u32)0x000000FF))
75 static void swap_copy16(u16 *dest, const u16 *source, unsigned int bytes)
79 while (i < (bytes / 2)) {
80 dest[i] = swap16(source[i]);
85 static void swap_copy24(u8 *dest, const u8 *source, unsigned int bytes)
89 while (i < bytes - 2) {
90 dest[i] = source[i + 2];
91 dest[i + 1] = source[i + 1];
92 dest[i + 2] = source[i];
97 static void swap_copy32(u32 *dest, const u32 *source, unsigned int bytes)
101 while (i < bytes / 4) {
102 dest[i] = swap32(source[i]);
107 static void alsa_to_most_memcpy(void *alsa, void *most, unsigned int bytes)
109 memcpy(most, alsa, bytes);
112 static void alsa_to_most_copy16(void *alsa, void *most, unsigned int bytes)
114 swap_copy16(most, alsa, bytes);
117 static void alsa_to_most_copy24(void *alsa, void *most, unsigned int bytes)
119 swap_copy24(most, alsa, bytes);
122 static void alsa_to_most_copy32(void *alsa, void *most, unsigned int bytes)
124 swap_copy32(most, alsa, bytes);
127 static void most_to_alsa_memcpy(void *alsa, void *most, unsigned int bytes)
129 memcpy(alsa, most, bytes);
132 static void most_to_alsa_copy16(void *alsa, void *most, unsigned int bytes)
134 swap_copy16(alsa, most, bytes);
137 static void most_to_alsa_copy24(void *alsa, void *most, unsigned int bytes)
139 swap_copy24(alsa, most, bytes);
142 static void most_to_alsa_copy32(void *alsa, void *most, unsigned int bytes)
144 swap_copy32(alsa, most, bytes);
148 * get_channel - get pointer to channel
149 * @iface: interface structure
150 * @channel_id: channel ID
152 * This traverses the channel list and returns the channel matching the
155 * Returns pointer to channel on success or NULL otherwise.
157 static struct channel *get_channel(struct most_interface *iface,
160 struct channel *channel, *tmp;
162 list_for_each_entry_safe(channel, tmp, &dev_list, list) {
163 if ((channel->iface == iface) && (channel->id == channel_id))
171 * copy_data - implements data copying function
173 * @mbo: MBO from core
175 * Copy data from/to ring buffer to/from MBO and update the buffer position
177 static bool copy_data(struct channel *channel, struct mbo *mbo)
179 struct snd_pcm_runtime *const runtime = channel->substream->runtime;
180 unsigned int const frame_bytes = channel->cfg->subbuffer_size;
181 unsigned int const buffer_size = runtime->buffer_size;
185 if (channel->cfg->direction & MOST_CH_RX)
186 frames = mbo->processed_length / frame_bytes;
188 frames = mbo->buffer_length / frame_bytes;
189 fr0 = min(buffer_size - channel->buffer_pos, frames);
191 channel->copy_fn(runtime->dma_area + channel->buffer_pos * frame_bytes,
196 /* wrap around at end of ring buffer */
197 channel->copy_fn(runtime->dma_area,
198 mbo->virt_address + fr0 * frame_bytes,
199 (frames - fr0) * frame_bytes);
202 channel->buffer_pos += frames;
203 if (channel->buffer_pos >= buffer_size)
204 channel->buffer_pos -= buffer_size;
205 channel->period_pos += frames;
206 if (channel->period_pos >= runtime->period_size) {
207 channel->period_pos -= runtime->period_size;
215 * playback_thread - function implements the playback thread
216 * @data: private data
218 * Thread which does the playback functionality in a loop. It waits for a free
219 * MBO from mostcore for a particular channel and copy the data from ring buffer
220 * to MBO. Submit the MBO back to mostcore, after copying the data.
222 * Returns 0 on success or error code otherwise.
224 static int playback_thread(void *data)
226 struct channel *const channel = data;
228 while (!kthread_should_stop()) {
229 struct mbo *mbo = NULL;
230 bool period_elapsed = false;
232 wait_event_interruptible(
233 channel->playback_waitq,
234 kthread_should_stop() ||
235 (channel->is_stream_running &&
236 (mbo = most_get_mbo(channel->iface, channel->id,
241 if (channel->is_stream_running)
242 period_elapsed = copy_data(channel, mbo);
244 memset(mbo->virt_address, 0, mbo->buffer_length);
246 most_submit_mbo(mbo);
248 snd_pcm_period_elapsed(channel->substream);
255 * pcm_open - implements open callback function for PCM middle layer
256 * @substream: pointer to ALSA PCM substream
258 * This is called when a PCM substream is opened. At least, the function should
259 * initialize the runtime->hw record.
261 * Returns 0 on success or error code otherwise.
263 static int pcm_open(struct snd_pcm_substream *substream)
265 struct channel *channel = substream->private_data;
266 struct snd_pcm_runtime *runtime = substream->runtime;
267 struct most_channel_config *cfg = channel->cfg;
269 channel->substream = substream;
271 if (cfg->direction == MOST_CH_TX) {
272 channel->playback_task = kthread_run(playback_thread, channel,
273 "most_audio_playback");
274 if (IS_ERR(channel->playback_task)) {
275 pr_err("Couldn't start thread\n");
276 return PTR_ERR(channel->playback_task);
280 if (most_start_channel(channel->iface, channel->id, &comp)) {
281 pr_err("most_start_channel() failed!\n");
282 if (cfg->direction == MOST_CH_TX)
283 kthread_stop(channel->playback_task);
287 runtime->hw = channel->pcm_hardware;
292 * pcm_close - implements close callback function for PCM middle layer
293 * @substream: sub-stream pointer
295 * Obviously, this is called when a PCM substream is closed. Any private
296 * instance for a PCM substream allocated in the open callback will be
299 * Returns 0 on success or error code otherwise.
301 static int pcm_close(struct snd_pcm_substream *substream)
303 struct channel *channel = substream->private_data;
305 if (channel->cfg->direction == MOST_CH_TX)
306 kthread_stop(channel->playback_task);
307 most_stop_channel(channel->iface, channel->id, &comp);
313 * pcm_hw_params - implements hw_params callback function for PCM middle layer
314 * @substream: sub-stream pointer
315 * @hw_params: contains the hardware parameters set by the application
317 * This is called when the hardware parameters is set by the application, that
318 * is, once when the buffer size, the period size, the format, etc. are defined
319 * for the PCM substream. Many hardware setups should be done is this callback,
320 * including the allocation of buffers.
322 * Returns 0 on success or error code otherwise.
324 static int pcm_hw_params(struct snd_pcm_substream *substream,
325 struct snd_pcm_hw_params *hw_params)
327 struct channel *channel = substream->private_data;
329 if ((params_channels(hw_params) > channel->pcm_hardware.channels_max) ||
330 (params_channels(hw_params) < channel->pcm_hardware.channels_min)) {
331 pr_err("Requested number of channels not supported.\n");
334 return snd_pcm_lib_alloc_vmalloc_buffer(substream,
335 params_buffer_bytes(hw_params));
339 * pcm_hw_free - implements hw_free callback function for PCM middle layer
340 * @substream: substream pointer
342 * This is called to release the resources allocated via hw_params.
343 * This function will be always called before the close callback is called.
345 * Returns 0 on success or error code otherwise.
347 static int pcm_hw_free(struct snd_pcm_substream *substream)
349 return snd_pcm_lib_free_vmalloc_buffer(substream);
353 * pcm_prepare - implements prepare callback function for PCM middle layer
354 * @substream: substream pointer
356 * This callback is called when the PCM is "prepared". Format rate, sample rate,
357 * etc., can be set here. This callback can be called many times at each setup.
359 * Returns 0 on success or error code otherwise.
361 static int pcm_prepare(struct snd_pcm_substream *substream)
363 struct channel *channel = substream->private_data;
364 struct snd_pcm_runtime *runtime = substream->runtime;
365 struct most_channel_config *cfg = channel->cfg;
366 int width = snd_pcm_format_physical_width(runtime->format);
368 channel->copy_fn = NULL;
370 if (cfg->direction == MOST_CH_TX) {
371 if (snd_pcm_format_big_endian(runtime->format) || width == 8)
372 channel->copy_fn = alsa_to_most_memcpy;
373 else if (width == 16)
374 channel->copy_fn = alsa_to_most_copy16;
375 else if (width == 24)
376 channel->copy_fn = alsa_to_most_copy24;
377 else if (width == 32)
378 channel->copy_fn = alsa_to_most_copy32;
380 if (snd_pcm_format_big_endian(runtime->format) || width == 8)
381 channel->copy_fn = most_to_alsa_memcpy;
382 else if (width == 16)
383 channel->copy_fn = most_to_alsa_copy16;
384 else if (width == 24)
385 channel->copy_fn = most_to_alsa_copy24;
386 else if (width == 32)
387 channel->copy_fn = most_to_alsa_copy32;
390 if (!channel->copy_fn) {
391 pr_err("unsupported format\n");
395 channel->period_pos = 0;
396 channel->buffer_pos = 0;
402 * pcm_trigger - implements trigger callback function for PCM middle layer
403 * @substream: substream pointer
404 * @cmd: action to perform
406 * This is called when the PCM is started, stopped or paused. The action will be
407 * specified in the second argument, SNDRV_PCM_TRIGGER_XXX
409 * Returns 0 on success or error code otherwise.
411 static int pcm_trigger(struct snd_pcm_substream *substream, int cmd)
413 struct channel *channel = substream->private_data;
416 case SNDRV_PCM_TRIGGER_START:
417 channel->is_stream_running = true;
418 wake_up_interruptible(&channel->playback_waitq);
421 case SNDRV_PCM_TRIGGER_STOP:
422 channel->is_stream_running = false;
426 pr_info("%s(), invalid\n", __func__);
433 * pcm_pointer - implements pointer callback function for PCM middle layer
434 * @substream: substream pointer
436 * This callback is called when the PCM middle layer inquires the current
437 * hardware position on the buffer. The position must be returned in frames,
438 * ranging from 0 to buffer_size-1.
440 static snd_pcm_uframes_t pcm_pointer(struct snd_pcm_substream *substream)
442 struct channel *channel = substream->private_data;
444 return channel->buffer_pos;
448 * Initialization of struct snd_pcm_ops
450 static const struct snd_pcm_ops pcm_ops = {
453 .ioctl = snd_pcm_lib_ioctl,
454 .hw_params = pcm_hw_params,
455 .hw_free = pcm_hw_free,
456 .prepare = pcm_prepare,
457 .trigger = pcm_trigger,
458 .pointer = pcm_pointer,
459 .page = snd_pcm_lib_get_vmalloc_page,
462 static int split_arg_list(char *buf, char **card_name, u16 *ch_num,
468 *card_name = strsep(&buf, ".");
470 pr_err("Missing sound card name\n");
473 num = strsep(&buf, "x");
476 ret = kstrtou16(num, 0, ch_num);
479 *sample_res = strsep(&buf, ".\n");
485 pr_err("Bad PCM format\n");
489 static const struct sample_resolution_info {
490 const char *sample_res;
494 { "8", 1, SNDRV_PCM_FMTBIT_S8 },
495 { "16", 2, SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE },
496 { "24", 3, SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE },
497 { "32", 4, SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE },
500 static int audio_set_hw_params(struct snd_pcm_hardware *pcm_hw,
501 u16 ch_num, char *sample_res,
502 struct most_channel_config *cfg)
506 for (i = 0; i < ARRAY_SIZE(sinfo); i++) {
507 if (!strcmp(sample_res, sinfo[i].sample_res))
510 pr_err("Unsupported PCM format\n");
515 pr_err("Bad number of channels\n");
519 if (cfg->subbuffer_size != ch_num * sinfo[i].bytes) {
520 pr_err("Audio resolution doesn't fit subbuffer size\n");
524 pcm_hw->info = MOST_PCM_INFO;
525 pcm_hw->rates = SNDRV_PCM_RATE_48000;
526 pcm_hw->rate_min = 48000;
527 pcm_hw->rate_max = 48000;
528 pcm_hw->buffer_bytes_max = cfg->num_buffers * cfg->buffer_size;
529 pcm_hw->period_bytes_min = cfg->buffer_size;
530 pcm_hw->period_bytes_max = cfg->buffer_size;
531 pcm_hw->periods_min = 1;
532 pcm_hw->periods_max = cfg->num_buffers;
533 pcm_hw->channels_min = ch_num;
534 pcm_hw->channels_max = ch_num;
535 pcm_hw->formats = sinfo[i].formats;
540 * audio_probe_channel - probe function of the driver module
541 * @iface: pointer to interface instance
542 * @channel_id: channel index/ID
543 * @cfg: pointer to actual channel configuration
544 * @arg_list: string that provides the name of the device to be created in /dev
545 * plus the desired audio resolution
547 * Creates sound card, pcm device, sets pcm ops and registers sound card.
549 * Returns 0 on success or error code otherwise.
551 static int audio_probe_channel(struct most_interface *iface, int channel_id,
552 struct most_channel_config *cfg,
555 struct channel *channel;
556 struct snd_card *card;
558 int playback_count = 0;
559 int capture_count = 0;
569 if (cfg->data_type != MOST_CH_SYNC) {
570 pr_err("Incompatible channel type\n");
574 if (get_channel(iface, channel_id)) {
575 pr_err("channel (%s:%d) is already linked\n",
576 iface->description, channel_id);
580 if (cfg->direction == MOST_CH_TX) {
582 direction = SNDRV_PCM_STREAM_PLAYBACK;
585 direction = SNDRV_PCM_STREAM_CAPTURE;
588 ret = split_arg_list(arg_list, &card_name, &ch_num, &sample_res);
592 ret = snd_card_new(&iface->dev, -1, card_name, THIS_MODULE,
593 sizeof(*channel), &card);
597 channel = card->private_data;
598 channel->card = card;
600 channel->iface = iface;
601 channel->id = channel_id;
602 init_waitqueue_head(&channel->playback_waitq);
604 ret = audio_set_hw_params(&channel->pcm_hardware, ch_num, sample_res,
609 snprintf(card->driver, sizeof(card->driver), "%s", DRIVER_NAME);
610 snprintf(card->shortname, sizeof(card->shortname), "Microchip MOST:%d",
612 snprintf(card->longname, sizeof(card->longname), "%s at %s, ch %d",
613 card->shortname, iface->description, channel_id);
615 ret = snd_pcm_new(card, card_name, 0, playback_count,
616 capture_count, &pcm);
620 pcm->private_data = channel;
622 snd_pcm_set_ops(pcm, direction, &pcm_ops);
624 ret = snd_card_register(card);
628 list_add_tail(&channel->list, &dev_list);
638 * audio_disconnect_channel - function to disconnect a channel
639 * @iface: pointer to interface instance
640 * @channel_id: channel index
642 * This frees allocated memory and removes the sound card from ALSA
644 * Returns 0 on success or error code otherwise.
646 static int audio_disconnect_channel(struct most_interface *iface,
649 struct channel *channel;
651 channel = get_channel(iface, channel_id);
653 pr_err("sound_disconnect_channel(), invalid channel %d\n",
658 list_del(&channel->list);
659 snd_card_free(channel->card);
665 * audio_rx_completion - completion handler for rx channels
666 * @mbo: pointer to buffer object that has completed
668 * This searches for the channel this MBO belongs to and copy the data from MBO
671 * Returns 0 on success or error code otherwise.
673 static int audio_rx_completion(struct mbo *mbo)
675 struct channel *channel = get_channel(mbo->ifp, mbo->hdm_channel_id);
676 bool period_elapsed = false;
679 pr_err("sound_rx_completion(), invalid channel %d\n",
680 mbo->hdm_channel_id);
684 if (channel->is_stream_running)
685 period_elapsed = copy_data(channel, mbo);
690 snd_pcm_period_elapsed(channel->substream);
696 * audio_tx_completion - completion handler for tx channels
697 * @iface: pointer to interface instance
698 * @channel_id: channel index/ID
700 * This searches the channel that belongs to this combination of interface
701 * pointer and channel ID and wakes a process sitting in the wait queue of
704 * Returns 0 on success or error code otherwise.
706 static int audio_tx_completion(struct most_interface *iface, int channel_id)
708 struct channel *channel = get_channel(iface, channel_id);
711 pr_err("sound_tx_completion(), invalid channel %d\n",
716 wake_up_interruptible(&channel->playback_waitq);
722 * Initialization of the struct core_component
724 static struct core_component comp = {
726 .probe_channel = audio_probe_channel,
727 .disconnect_channel = audio_disconnect_channel,
728 .rx_completion = audio_rx_completion,
729 .tx_completion = audio_tx_completion,
732 static int __init audio_init(void)
736 INIT_LIST_HEAD(&dev_list);
738 return most_register_component(&comp);
741 static void __exit audio_exit(void)
743 struct channel *channel, *tmp;
747 list_for_each_entry_safe(channel, tmp, &dev_list, list) {
748 list_del(&channel->list);
749 snd_card_free(channel->card);
752 most_deregister_component(&comp);
755 module_init(audio_init);
756 module_exit(audio_exit);
758 MODULE_LICENSE("GPL");
759 MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
760 MODULE_DESCRIPTION("Sound Component Module for Mostcore");