root/sound/core/pcm_dmaengine.c

DEFINITIONS

1. substream_to_prtd
2. snd_dmaengine_pcm_get_chan
3. snd_hwparams_to_dma_slave_config
4. snd_dmaengine_pcm_set_config_from_dai_data
5. dmaengine_pcm_dma_complete
6. dmaengine_pcm_prepare_and_submit
7. snd_dmaengine_pcm_trigger
8. snd_dmaengine_pcm_pointer_no_residue
9. snd_dmaengine_pcm_pointer
10. snd_dmaengine_pcm_request_channel
11. snd_dmaengine_pcm_open
12. snd_dmaengine_pcm_open_request_chan
13. snd_dmaengine_pcm_close
14. snd_dmaengine_pcm_close_release_chan

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2012, Analog Devices Inc.
   4  *      Author: Lars-Peter Clausen <lars@metafoo.de>
   5  *
   6  *  Based on:
   7  *      imx-pcm-dma-mx2.c, Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
   8  *      mxs-pcm.c, Copyright (C) 2011 Freescale Semiconductor, Inc.
   9  *      ep93xx-pcm.c, Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
  10  *                    Copyright (C) 2006 Applied Data Systems
  11  */
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/dmaengine.h>
  15 #include <linux/slab.h>
  16 #include <sound/pcm.h>
  17 #include <sound/pcm_params.h>
  18 #include <sound/soc.h>
  19 
  20 #include <sound/dmaengine_pcm.h>
  21 
  22 struct dmaengine_pcm_runtime_data {
  23         struct dma_chan *dma_chan;
  24         dma_cookie_t cookie;
  25 
  26         unsigned int pos;
  27 };
  28 
  29 static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
  30         const struct snd_pcm_substream *substream)
  31 {
  32         return substream->runtime->private_data;
  33 }
  34 
  35 struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
  36 {
  37         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
  38 
  39         return prtd->dma_chan;
  40 }
  41 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_chan);
  42 
  43 /**
  44  * snd_hwparams_to_dma_slave_config - Convert hw_params to dma_slave_config
  45  * @substream: PCM substream
  46  * @params: hw_params
  47  * @slave_config: DMA slave config
  48  *
  49  * This function can be used to initialize a dma_slave_config from a substream
  50  * and hw_params in a dmaengine based PCM driver implementation.
  51  */
  52 int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
  53         const struct snd_pcm_hw_params *params,
  54         struct dma_slave_config *slave_config)
  55 {
  56         enum dma_slave_buswidth buswidth;
  57         int bits;
  58 
  59         bits = params_physical_width(params);
  60         if (bits < 8 || bits > 64)
  61                 return -EINVAL;
  62         else if (bits == 8)
  63                 buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
  64         else if (bits == 16)
  65                 buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
  66         else if (bits == 24)
  67                 buswidth = DMA_SLAVE_BUSWIDTH_3_BYTES;
  68         else if (bits <= 32)
  69                 buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
  70         else
  71                 buswidth = DMA_SLAVE_BUSWIDTH_8_BYTES;
  72 
  73         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
  74                 slave_config->direction = DMA_MEM_TO_DEV;
  75                 slave_config->dst_addr_width = buswidth;
  76         } else {
  77                 slave_config->direction = DMA_DEV_TO_MEM;
  78                 slave_config->src_addr_width = buswidth;
  79         }
  80 
  81         slave_config->device_fc = false;
  82 
  83         return 0;
  84 }
  85 EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);
  86 
  87 /**
  88  * snd_dmaengine_pcm_set_config_from_dai_data() - Initializes a dma slave config
  89  *  using DAI DMA data.
  90  * @substream: PCM substream
  91  * @dma_data: DAI DMA data
  92  * @slave_config: DMA slave configuration
  93  *
  94  * Initializes the {dst,src}_addr, {dst,src}_maxburst, {dst,src}_addr_width and
  95  * slave_id fields of the DMA slave config from the same fields of the DAI DMA
  96  * data struct. The src and dst fields will be initialized depending on the
  97  * direction of the substream. If the substream is a playback stream the dst
  98  * fields will be initialized, if it is a capture stream the src fields will be
  99  * initialized. The {dst,src}_addr_width field will only be initialized if the
 100  * SND_DMAENGINE_PCM_DAI_FLAG_PACK flag is set or if the addr_width field of
 101  * the DAI DMA data struct is not equal to DMA_SLAVE_BUSWIDTH_UNDEFINED. If
 102  * both conditions are met the latter takes priority.
 103  */
 104 void snd_dmaengine_pcm_set_config_from_dai_data(
 105         const struct snd_pcm_substream *substream,
 106         const struct snd_dmaengine_dai_dma_data *dma_data,
 107         struct dma_slave_config *slave_config)
 108 {
 109         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 110                 slave_config->dst_addr = dma_data->addr;
 111                 slave_config->dst_maxburst = dma_data->maxburst;
 112                 if (dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK)
 113                         slave_config->dst_addr_width =
 114                                 DMA_SLAVE_BUSWIDTH_UNDEFINED;
 115                 if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
 116                         slave_config->dst_addr_width = dma_data->addr_width;
 117         } else {
 118                 slave_config->src_addr = dma_data->addr;
 119                 slave_config->src_maxburst = dma_data->maxburst;
 120                 if (dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK)
 121                         slave_config->src_addr_width =
 122                                 DMA_SLAVE_BUSWIDTH_UNDEFINED;
 123                 if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
 124                         slave_config->src_addr_width = dma_data->addr_width;
 125         }
 126 
 127         slave_config->slave_id = dma_data->slave_id;
 128 }
 129 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data);
 130 
 131 static void dmaengine_pcm_dma_complete(void *arg)
 132 {
 133         struct snd_pcm_substream *substream = arg;
 134         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 135 
 136         prtd->pos += snd_pcm_lib_period_bytes(substream);
 137         if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream))
 138                 prtd->pos = 0;
 139 
 140         snd_pcm_period_elapsed(substream);
 141 }
 142 
 143 static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
 144 {
 145         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 146         struct dma_chan *chan = prtd->dma_chan;
 147         struct dma_async_tx_descriptor *desc;
 148         enum dma_transfer_direction direction;
 149         unsigned long flags = DMA_CTRL_ACK;
 150 
 151         direction = snd_pcm_substream_to_dma_direction(substream);
 152 
 153         if (!substream->runtime->no_period_wakeup)
 154                 flags |= DMA_PREP_INTERRUPT;
 155 
 156         prtd->pos = 0;
 157         desc = dmaengine_prep_dma_cyclic(chan,
 158                 substream->runtime->dma_addr,
 159                 snd_pcm_lib_buffer_bytes(substream),
 160                 snd_pcm_lib_period_bytes(substream), direction, flags);
 161 
 162         if (!desc)
 163                 return -ENOMEM;
 164 
 165         desc->callback = dmaengine_pcm_dma_complete;
 166         desc->callback_param = substream;
 167         prtd->cookie = dmaengine_submit(desc);
 168 
 169         return 0;
 170 }
 171 
 172 /**
 173  * snd_dmaengine_pcm_trigger - dmaengine based PCM trigger implementation
 174  * @substream: PCM substream
 175  * @cmd: Trigger command
 176  *
 177  * Returns 0 on success, a negative error code otherwise.
 178  *
 179  * This function can be used as the PCM trigger callback for dmaengine based PCM
 180  * driver implementations.
 181  */
 182 int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 183 {
 184         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 185         struct snd_pcm_runtime *runtime = substream->runtime;
 186         int ret;
 187 
 188         switch (cmd) {
 189         case SNDRV_PCM_TRIGGER_START:
 190                 ret = dmaengine_pcm_prepare_and_submit(substream);
 191                 if (ret)
 192                         return ret;
 193                 dma_async_issue_pending(prtd->dma_chan);
 194                 break;
 195         case SNDRV_PCM_TRIGGER_RESUME:
 196         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 197                 dmaengine_resume(prtd->dma_chan);
 198                 break;
 199         case SNDRV_PCM_TRIGGER_SUSPEND:
 200                 if (runtime->info & SNDRV_PCM_INFO_PAUSE)
 201                         dmaengine_pause(prtd->dma_chan);
 202                 else
 203                         dmaengine_terminate_async(prtd->dma_chan);
 204                 break;
 205         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 206                 dmaengine_pause(prtd->dma_chan);
 207                 break;
 208         case SNDRV_PCM_TRIGGER_STOP:
 209                 dmaengine_terminate_async(prtd->dma_chan);
 210                 break;
 211         default:
 212                 return -EINVAL;
 213         }
 214 
 215         return 0;
 216 }
 217 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);
 218 
 219 /**
 220  * snd_dmaengine_pcm_pointer_no_residue - dmaengine based PCM pointer implementation
 221  * @substream: PCM substream
 222  *
 223  * This function is deprecated and should not be used by new drivers, as its
 224  * results may be unreliable.
 225  */
 226 snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream *substream)
 227 {
 228         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 229         return bytes_to_frames(substream->runtime, prtd->pos);
 230 }
 231 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer_no_residue);
 232 
 233 /**
 234  * snd_dmaengine_pcm_pointer - dmaengine based PCM pointer implementation
 235  * @substream: PCM substream
 236  *
 237  * This function can be used as the PCM pointer callback for dmaengine based PCM
 238  * driver implementations.
 239  */
 240 snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
 241 {
 242         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 243         struct dma_tx_state state;
 244         enum dma_status status;
 245         unsigned int buf_size;
 246         unsigned int pos = 0;
 247 
 248         status = dmaengine_tx_status(prtd->dma_chan, prtd->cookie, &state);
 249         if (status == DMA_IN_PROGRESS || status == DMA_PAUSED) {
 250                 buf_size = snd_pcm_lib_buffer_bytes(substream);
 251                 if (state.residue > 0 && state.residue <= buf_size)
 252                         pos = buf_size - state.residue;
 253         }
 254 
 255         return bytes_to_frames(substream->runtime, pos);
 256 }
 257 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);
 258 
 259 /**
 260  * snd_dmaengine_pcm_request_channel - Request channel for the dmaengine PCM
 261  * @filter_fn: Filter function used to request the DMA channel
 262  * @filter_data: Data passed to the DMA filter function
 263  *
 264  * Returns NULL or the requested DMA channel.
 265  *
 266  * This function request a DMA channel for usage with dmaengine PCM.
 267  */
 268 struct dma_chan *snd_dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
 269         void *filter_data)
 270 {
 271         dma_cap_mask_t mask;
 272 
 273         dma_cap_zero(mask);
 274         dma_cap_set(DMA_SLAVE, mask);
 275         dma_cap_set(DMA_CYCLIC, mask);
 276 
 277         return dma_request_channel(mask, filter_fn, filter_data);
 278 }
 279 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_request_channel);
 280 
 281 /**
 282  * snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
 283  * @substream: PCM substream
 284  * @chan: DMA channel to use for data transfers
 285  *
 286  * Returns 0 on success, a negative error code otherwise.
 287  *
 288  * The function should usually be called from the pcm open callback. Note that
 289  * this function will use private_data field of the substream's runtime. So it
 290  * is not available to your pcm driver implementation.
 291  */
 292 int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
 293         struct dma_chan *chan)
 294 {
 295         struct dmaengine_pcm_runtime_data *prtd;
 296         int ret;
 297 
 298         if (!chan)
 299                 return -ENXIO;
 300 
 301         ret = snd_pcm_hw_constraint_integer(substream->runtime,
 302                                             SNDRV_PCM_HW_PARAM_PERIODS);
 303         if (ret < 0)
 304                 return ret;
 305 
 306         prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
 307         if (!prtd)
 308                 return -ENOMEM;
 309 
 310         prtd->dma_chan = chan;
 311 
 312         substream->runtime->private_data = prtd;
 313 
 314         return 0;
 315 }
 316 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
 317 
 318 /**
 319  * snd_dmaengine_pcm_open_request_chan - Open a dmaengine based PCM substream and request channel
 320  * @substream: PCM substream
 321  * @filter_fn: Filter function used to request the DMA channel
 322  * @filter_data: Data passed to the DMA filter function
 323  *
 324  * Returns 0 on success, a negative error code otherwise.
 325  *
 326  * This function will request a DMA channel using the passed filter function and
 327  * data. The function should usually be called from the pcm open callback. Note
 328  * that this function will use private_data field of the substream's runtime. So
 329  * it is not available to your pcm driver implementation.
 330  */
 331 int snd_dmaengine_pcm_open_request_chan(struct snd_pcm_substream *substream,
 332         dma_filter_fn filter_fn, void *filter_data)
 333 {
 334         return snd_dmaengine_pcm_open(substream,
 335                     snd_dmaengine_pcm_request_channel(filter_fn, filter_data));
 336 }
 337 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open_request_chan);
 338 
 339 /**
 340  * snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
 341  * @substream: PCM substream
 342  */
 343 int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
 344 {
 345         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 346 
 347         dmaengine_synchronize(prtd->dma_chan);
 348         kfree(prtd);
 349 
 350         return 0;
 351 }
 352 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);
 353 
 354 /**
 355  * snd_dmaengine_pcm_release_chan_close - Close a dmaengine based PCM substream and release channel
 356  * @substream: PCM substream
 357  *
 358  * Releases the DMA channel associated with the PCM substream.
 359  */
 360 int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream)
 361 {
 362         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 363 
 364         dmaengine_synchronize(prtd->dma_chan);
 365         dma_release_channel(prtd->dma_chan);
 366         kfree(prtd);
 367 
 368         return 0;
 369 }
 370 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close_release_chan);
 371 
 372 MODULE_LICENSE("GPL");