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)
91 while (i < bytes - 2) {
92 dest[i] = source[i + 2];
93 dest[i + 1] = source[i + 1];
94 dest[i + 2] = source[i];
99 static void swap_copy32(u32 *dest, const u32 *source, unsigned int bytes)
103 while (i < bytes / 4) {
104 dest[i] = swap32(source[i]);
109 static void alsa_to_most_memcpy(void *alsa, void *most, unsigned int bytes)
111 memcpy(most, alsa, bytes);
114 static void alsa_to_most_copy16(void *alsa, void *most, unsigned int bytes)
116 swap_copy16(most, alsa, bytes);
119 static void alsa_to_most_copy24(void *alsa, void *most, unsigned int bytes)
121 swap_copy24(most, alsa, bytes);
124 static void alsa_to_most_copy32(void *alsa, void *most, unsigned int bytes)
126 swap_copy32(most, alsa, bytes);
129 static void most_to_alsa_memcpy(void *alsa, void *most, unsigned int bytes)
131 memcpy(alsa, most, bytes);
134 static void most_to_alsa_copy16(void *alsa, void *most, unsigned int bytes)
136 swap_copy16(alsa, most, bytes);
139 static void most_to_alsa_copy24(void *alsa, void *most, unsigned int bytes)
141 swap_copy24(alsa, most, bytes);
144 static void most_to_alsa_copy32(void *alsa, void *most, unsigned int bytes)
146 swap_copy32(alsa, most, bytes);
150 * get_channel - get pointer to channel
151 * @iface: interface structure
152 * @channel_id: channel ID
154 * This traverses the channel list and returns the channel matching the
157 * Returns pointer to channel on success or NULL otherwise.
159 static struct channel *get_channel(struct most_interface *iface,
162 struct channel *channel, *tmp;
164 list_for_each_entry_safe(channel, tmp, &dev_list, list) {
165 if ((channel->iface == iface) && (channel->id == channel_id))
173 * copy_data - implements data copying function
175 * @mbo: MBO from core
177 * Copy data from/to ring buffer to/from MBO and update the buffer position
179 static bool copy_data(struct channel *channel, struct mbo *mbo)
181 struct snd_pcm_runtime *const runtime = channel->substream->runtime;
182 unsigned int const frame_bytes = channel->cfg->subbuffer_size;
183 unsigned int const buffer_size = runtime->buffer_size;
187 if (channel->cfg->direction & MOST_CH_RX)
188 frames = mbo->processed_length / frame_bytes;
190 frames = mbo->buffer_length / frame_bytes;
191 fr0 = min(buffer_size - channel->buffer_pos, frames);
193 channel->copy_fn(runtime->dma_area + channel->buffer_pos * frame_bytes,
198 /* wrap around at end of ring buffer */
199 channel->copy_fn(runtime->dma_area,
200 mbo->virt_address + fr0 * frame_bytes,
201 (frames - fr0) * frame_bytes);
204 channel->buffer_pos += frames;
205 if (channel->buffer_pos >= buffer_size)
206 channel->buffer_pos -= buffer_size;
207 channel->period_pos += frames;
208 if (channel->period_pos >= runtime->period_size) {
209 channel->period_pos -= runtime->period_size;
217 * playback_thread - function implements the playback thread
218 * @data: private data
220 * Thread which does the playback functionality in a loop. It waits for a free
221 * MBO from mostcore for a particular channel and copy the data from ring buffer
222 * to MBO. Submit the MBO back to mostcore, after copying the data.
224 * Returns 0 on success or error code otherwise.
226 static int playback_thread(void *data)
228 struct channel *const channel = data;
230 while (!kthread_should_stop()) {
231 struct mbo *mbo = NULL;
232 bool period_elapsed = false;
234 wait_event_interruptible(
235 channel->playback_waitq,
236 kthread_should_stop() ||
237 (channel->is_stream_running &&
238 (mbo = most_get_mbo(channel->iface, channel->id,
243 if (channel->is_stream_running)
244 period_elapsed = copy_data(channel, mbo);
246 memset(mbo->virt_address, 0, mbo->buffer_length);
248 most_submit_mbo(mbo);
250 snd_pcm_period_elapsed(channel->substream);
257 * pcm_open - implements open callback function for PCM middle layer
258 * @substream: pointer to ALSA PCM substream
260 * This is called when a PCM substream is opened. At least, the function should
261 * initialize the runtime->hw record.
263 * Returns 0 on success or error code otherwise.
265 static int pcm_open(struct snd_pcm_substream *substream)
267 struct channel *channel = substream->private_data;
268 struct snd_pcm_runtime *runtime = substream->runtime;
269 struct most_channel_config *cfg = channel->cfg;
271 channel->substream = substream;
273 if (cfg->direction == MOST_CH_TX) {
274 channel->playback_task = kthread_run(playback_thread, channel,
275 "most_audio_playback");
276 if (IS_ERR(channel->playback_task)) {
277 pr_err("Couldn't start thread\n");
278 return PTR_ERR(channel->playback_task);
282 if (most_start_channel(channel->iface, channel->id, &comp)) {
283 pr_err("most_start_channel() failed!\n");
284 if (cfg->direction == MOST_CH_TX)
285 kthread_stop(channel->playback_task);
289 runtime->hw = channel->pcm_hardware;
294 * pcm_close - implements close callback function for PCM middle layer
295 * @substream: sub-stream pointer
297 * Obviously, this is called when a PCM substream is closed. Any private
298 * instance for a PCM substream allocated in the open callback will be
301 * Returns 0 on success or error code otherwise.
303 static int pcm_close(struct snd_pcm_substream *substream)
305 struct channel *channel = substream->private_data;
307 if (channel->cfg->direction == MOST_CH_TX)
308 kthread_stop(channel->playback_task);
309 most_stop_channel(channel->iface, channel->id, &comp);
315 * pcm_hw_params - implements hw_params callback function for PCM middle layer
316 * @substream: sub-stream pointer
317 * @hw_params: contains the hardware parameters set by the application
319 * This is called when the hardware parameters is set by the application, that
320 * is, once when the buffer size, the period size, the format, etc. are defined
321 * for the PCM substream. Many hardware setups should be done is this callback,
322 * including the allocation of buffers.
324 * Returns 0 on success or error code otherwise.
326 static int pcm_hw_params(struct snd_pcm_substream *substream,
327 struct snd_pcm_hw_params *hw_params)
329 struct channel *channel = substream->private_data;
331 if ((params_channels(hw_params) > channel->pcm_hardware.channels_max) ||
332 (params_channels(hw_params) < channel->pcm_hardware.channels_min)) {
333 pr_err("Requested number of channels not supported.\n");
336 return snd_pcm_lib_alloc_vmalloc_buffer(substream,
337 params_buffer_bytes(hw_params));
341 * pcm_hw_free - implements hw_free callback function for PCM middle layer
342 * @substream: substream pointer
344 * This is called to release the resources allocated via hw_params.
345 * This function will be always called before the close callback is called.
347 * Returns 0 on success or error code otherwise.
349 static int pcm_hw_free(struct snd_pcm_substream *substream)
351 return snd_pcm_lib_free_vmalloc_buffer(substream);
355 * pcm_prepare - implements prepare callback function for PCM middle layer
356 * @substream: substream pointer
358 * This callback is called when the PCM is "prepared". Format rate, sample rate,
359 * etc., can be set here. This callback can be called many times at each setup.
361 * Returns 0 on success or error code otherwise.
363 static int pcm_prepare(struct snd_pcm_substream *substream)
365 struct channel *channel = substream->private_data;
366 struct snd_pcm_runtime *runtime = substream->runtime;
367 struct most_channel_config *cfg = channel->cfg;
368 int width = snd_pcm_format_physical_width(runtime->format);
370 channel->copy_fn = NULL;
372 if (cfg->direction == MOST_CH_TX) {
373 if (snd_pcm_format_big_endian(runtime->format) || width == 8)
374 channel->copy_fn = alsa_to_most_memcpy;
375 else if (width == 16)
376 channel->copy_fn = alsa_to_most_copy16;
377 else if (width == 24)
378 channel->copy_fn = alsa_to_most_copy24;
379 else if (width == 32)
380 channel->copy_fn = alsa_to_most_copy32;
382 if (snd_pcm_format_big_endian(runtime->format) || width == 8)
383 channel->copy_fn = most_to_alsa_memcpy;
384 else if (width == 16)
385 channel->copy_fn = most_to_alsa_copy16;
386 else if (width == 24)
387 channel->copy_fn = most_to_alsa_copy24;
388 else if (width == 32)
389 channel->copy_fn = most_to_alsa_copy32;
392 if (!channel->copy_fn) {
393 pr_err("unsupported format\n");
397 channel->period_pos = 0;
398 channel->buffer_pos = 0;
404 * pcm_trigger - implements trigger callback function for PCM middle layer
405 * @substream: substream pointer
406 * @cmd: action to perform
408 * This is called when the PCM is started, stopped or paused. The action will be
409 * specified in the second argument, SNDRV_PCM_TRIGGER_XXX
411 * Returns 0 on success or error code otherwise.
413 static int pcm_trigger(struct snd_pcm_substream *substream, int cmd)
415 struct channel *channel = substream->private_data;
418 case SNDRV_PCM_TRIGGER_START:
419 channel->is_stream_running = true;
420 wake_up_interruptible(&channel->playback_waitq);
423 case SNDRV_PCM_TRIGGER_STOP:
424 channel->is_stream_running = false;
428 pr_info("%s(), invalid\n", __func__);
435 * pcm_pointer - implements pointer callback function for PCM middle layer
436 * @substream: substream pointer
438 * This callback is called when the PCM middle layer inquires the current
439 * hardware position on the buffer. The position must be returned in frames,
440 * ranging from 0 to buffer_size-1.
442 static snd_pcm_uframes_t pcm_pointer(struct snd_pcm_substream *substream)
444 struct channel *channel = substream->private_data;
446 return channel->buffer_pos;
450 * Initialization of struct snd_pcm_ops
452 static const struct snd_pcm_ops pcm_ops = {
455 .ioctl = snd_pcm_lib_ioctl,
456 .hw_params = pcm_hw_params,
457 .hw_free = pcm_hw_free,
458 .prepare = pcm_prepare,
459 .trigger = pcm_trigger,
460 .pointer = pcm_pointer,
461 .page = snd_pcm_lib_get_vmalloc_page,
464 static int split_arg_list(char *buf, char **card_name, u16 *ch_num,
470 *card_name = strsep(&buf, ".");
472 pr_err("Missing sound card name\n");
475 num = strsep(&buf, "x");
478 ret = kstrtou16(num, 0, ch_num);
481 *sample_res = strsep(&buf, ".\n");
487 pr_err("Bad PCM format\n");
491 static const struct sample_resolution_info {
492 const char *sample_res;
496 { "8", 1, SNDRV_PCM_FMTBIT_S8 },
497 { "16", 2, SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE },
498 { "24", 3, SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE },
499 { "32", 4, SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE },
502 static int audio_set_hw_params(struct snd_pcm_hardware *pcm_hw,
503 u16 ch_num, char *sample_res,
504 struct most_channel_config *cfg)
508 for (i = 0; i < ARRAY_SIZE(sinfo); i++) {
509 if (!strcmp(sample_res, sinfo[i].sample_res))
512 pr_err("Unsupported PCM format\n");
517 pr_err("Bad number of channels\n");
521 if (cfg->subbuffer_size != ch_num * sinfo[i].bytes) {
522 pr_err("Audio resolution doesn't fit subbuffer size\n");
526 pcm_hw->info = MOST_PCM_INFO;
527 pcm_hw->rates = SNDRV_PCM_RATE_48000;
528 pcm_hw->rate_min = 48000;
529 pcm_hw->rate_max = 48000;
530 pcm_hw->buffer_bytes_max = cfg->num_buffers * cfg->buffer_size;
531 pcm_hw->period_bytes_min = cfg->buffer_size;
532 pcm_hw->period_bytes_max = cfg->buffer_size;
533 pcm_hw->periods_min = 1;
534 pcm_hw->periods_max = cfg->num_buffers;
535 pcm_hw->channels_min = ch_num;
536 pcm_hw->channels_max = ch_num;
537 pcm_hw->formats = sinfo[i].formats;
542 * audio_probe_channel - probe function of the driver module
543 * @iface: pointer to interface instance
544 * @channel_id: channel index/ID
545 * @cfg: pointer to actual channel configuration
546 * @arg_list: string that provides the name of the device to be created in /dev
547 * plus the desired audio resolution
549 * Creates sound card, pcm device, sets pcm ops and registers sound card.
551 * Returns 0 on success or error code otherwise.
553 static int audio_probe_channel(struct most_interface *iface, int channel_id,
554 struct most_channel_config *cfg,
557 struct channel *channel;
558 struct snd_card *card;
560 int playback_count = 0;
561 int capture_count = 0;
571 if (cfg->data_type != MOST_CH_SYNC) {
572 pr_err("Incompatible channel type\n");
576 if (get_channel(iface, channel_id)) {
577 pr_err("channel (%s:%d) is already linked\n",
578 iface->description, channel_id);
582 if (cfg->direction == MOST_CH_TX) {
584 direction = SNDRV_PCM_STREAM_PLAYBACK;
587 direction = SNDRV_PCM_STREAM_CAPTURE;
590 ret = split_arg_list(arg_list, &card_name, &ch_num, &sample_res);
594 ret = snd_card_new(&iface->dev, -1, card_name, THIS_MODULE,
595 sizeof(*channel), &card);
599 channel = card->private_data;
600 channel->card = card;
602 channel->iface = iface;
603 channel->id = channel_id;
604 init_waitqueue_head(&channel->playback_waitq);
606 ret = audio_set_hw_params(&channel->pcm_hardware, ch_num, sample_res,
611 snprintf(card->driver, sizeof(card->driver), "%s", DRIVER_NAME);
612 snprintf(card->shortname, sizeof(card->shortname), "Microchip MOST:%d",
614 snprintf(card->longname, sizeof(card->longname), "%s at %s, ch %d",
615 card->shortname, iface->description, channel_id);
617 ret = snd_pcm_new(card, card_name, 0, playback_count,
618 capture_count, &pcm);
622 pcm->private_data = channel;
624 snd_pcm_set_ops(pcm, direction, &pcm_ops);
626 ret = snd_card_register(card);
630 list_add_tail(&channel->list, &dev_list);
640 * audio_disconnect_channel - function to disconnect a channel
641 * @iface: pointer to interface instance
642 * @channel_id: channel index
644 * This frees allocated memory and removes the sound card from ALSA
646 * Returns 0 on success or error code otherwise.
648 static int audio_disconnect_channel(struct most_interface *iface,
651 struct channel *channel;
653 channel = get_channel(iface, channel_id);
655 pr_err("sound_disconnect_channel(), invalid channel %d\n",
660 list_del(&channel->list);
661 snd_card_free(channel->card);
667 * audio_rx_completion - completion handler for rx channels
668 * @mbo: pointer to buffer object that has completed
670 * This searches for the channel this MBO belongs to and copy the data from MBO
673 * Returns 0 on success or error code otherwise.
675 static int audio_rx_completion(struct mbo *mbo)
677 struct channel *channel = get_channel(mbo->ifp, mbo->hdm_channel_id);
678 bool period_elapsed = false;
681 pr_err("sound_rx_completion(), invalid channel %d\n",
682 mbo->hdm_channel_id);
686 if (channel->is_stream_running)
687 period_elapsed = copy_data(channel, mbo);
692 snd_pcm_period_elapsed(channel->substream);
698 * audio_tx_completion - completion handler for tx channels
699 * @iface: pointer to interface instance
700 * @channel_id: channel index/ID
702 * This searches the channel that belongs to this combination of interface
703 * pointer and channel ID and wakes a process sitting in the wait queue of
706 * Returns 0 on success or error code otherwise.
708 static int audio_tx_completion(struct most_interface *iface, int channel_id)
710 struct channel *channel = get_channel(iface, channel_id);
713 pr_err("sound_tx_completion(), invalid channel %d\n",
718 wake_up_interruptible(&channel->playback_waitq);
724 * Initialization of the struct core_component
726 static struct core_component comp = {
728 .probe_channel = audio_probe_channel,
729 .disconnect_channel = audio_disconnect_channel,
730 .rx_completion = audio_rx_completion,
731 .tx_completion = audio_tx_completion,
734 static int __init audio_init(void)
738 INIT_LIST_HEAD(&dev_list);
740 return most_register_component(&comp);
743 static void __exit audio_exit(void)
745 struct channel *channel, *tmp;
749 list_for_each_entry_safe(channel, tmp, &dev_list, list) {
750 list_del(&channel->list);
751 snd_card_free(channel->card);
754 most_deregister_component(&comp);
757 module_init(audio_init);
758 module_exit(audio_exit);
760 MODULE_LICENSE("GPL");
761 MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
762 MODULE_DESCRIPTION("Sound Component Module for Mostcore");