drivers/staging/greybus/audio-pcm.c

   1 #include <linux/kernel.h>
   2 #include <linux/device.h>
   3 #include <linux/interrupt.h>
   4 #include <linux/module.h>
   5 #include <linux/platform_device.h>
   6 #include <linux/workqueue.h>
   7 #include <linux/i2c.h>
   8 #include <sound/core.h>
   9 #include <sound/pcm.h>
  10 #include <sound/pcm_params.h>
  11 #include <sound/soc.h>
  12 #include <sound/dmaengine_pcm.h>
  13 #include <sound/simple_card.h>
  14 #include "greybus.h"
  15 #include "gpbridge.h"
  16 #include "audio.h"
  17
  18 /*
  19  * timer/workqueue logic for pushing pcm data.
  20  *
  21  * Since when we are playing audio, we don't get any
  22  * status or feedback from the codec, we have to use a
  23  * hrtimer to trigger sending data to the remote codec.
  24  * However since the hrtimer runs in irq context, so we
  25  * have to schedule a workqueue to actually send the
  26  * greybus data.
  27  */
  28
  29 static void gb_pcm_work(struct work_struct *work)
  30 {
  31         struct gb_snd *snd_dev = container_of(work, struct gb_snd, work);
  32         struct snd_pcm_substream *substream = snd_dev->substream;
  33         struct snd_pcm_runtime *runtime = substream->runtime;
  34         unsigned int stride, frames, oldptr;
  35         int period_elapsed;
  36         char *address;
  37         long len;
  38
  39         if (!snd_dev)
  40                 return;
  41
  42         if (!atomic_read(&snd_dev->running))
  43                 return;
  44
  45         address = runtime->dma_area + snd_dev->hwptr_done;
  46
  47         len = frames_to_bytes(runtime,
  48                               runtime->buffer_size) - snd_dev->hwptr_done;
  49         len = min(len, MAX_SEND_DATA_LEN);
  50         gb_i2s_send_data(snd_dev->i2s_tx_connection, snd_dev->send_data_req_buf,
  51                                 address, len, snd_dev->send_data_sample_count);
  52
  53         snd_dev->send_data_sample_count += CONFIG_SAMPLES_PER_MSG;
  54
  55         stride = runtime->frame_bits >> 3;
  56         frames = len/stride;
  57
  58         snd_pcm_stream_lock(substream);
  59         oldptr = snd_dev->hwptr_done;
  60         snd_dev->hwptr_done += len;
  61         if (snd_dev->hwptr_done >= runtime->buffer_size * stride)
  62                 snd_dev->hwptr_done -= runtime->buffer_size * stride;
  63
  64         frames = (len + (oldptr % stride)) / stride;
  65
  66         snd_dev->transfer_done += frames;
  67         if (snd_dev->transfer_done >= runtime->period_size) {
  68                 snd_dev->transfer_done -= runtime->period_size;
  69                 period_elapsed = 1;
  70         }
  71
  72         snd_pcm_stream_unlock(substream);
  73         if (period_elapsed)
  74                 snd_pcm_period_elapsed(snd_dev->substream);
  75 }
  76
  77 static enum hrtimer_restart gb_pcm_timer_function(struct hrtimer *hrtimer)
  78 {
  79         struct gb_snd *snd_dev = container_of(hrtimer, struct gb_snd, timer);
  80
  81         if (!atomic_read(&snd_dev->running))
  82                 return HRTIMER_NORESTART;
  83         queue_work(snd_dev->workqueue, &snd_dev->work);
  84         hrtimer_forward_now(hrtimer, ns_to_ktime(CONFIG_PERIOD_NS));
  85         return HRTIMER_RESTART;
  86 }
  87
  88 void gb_pcm_hrtimer_start(struct gb_snd *snd_dev)
  89 {
  90         atomic_set(&snd_dev->running, 1);
  91         hrtimer_start(&snd_dev->timer, ns_to_ktime(CONFIG_PERIOD_NS),
  92                                                 HRTIMER_MODE_REL);
  93 }
  94
  95 void gb_pcm_hrtimer_stop(struct gb_snd *snd_dev)
  96 {
  97         atomic_set(&snd_dev->running, 0);
  98         hrtimer_cancel(&snd_dev->timer);
  99 }
 100
 101 static int gb_pcm_hrtimer_init(struct gb_snd *snd_dev)
 102 {
 103         hrtimer_init(&snd_dev->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 104         snd_dev->timer.function = gb_pcm_timer_function;
 105         atomic_set(&snd_dev->running, 0);
 106         snd_dev->workqueue = alloc_workqueue("gb-audio", WQ_HIGHPRI, 0);
 107         if (!snd_dev->workqueue)
 108                 return -ENOMEM;
 109         INIT_WORK(&snd_dev->work, gb_pcm_work);
 110         return 0;
 111 }
 112
 113
 114 /*
 115  * Core gb pcm structure
 116  */
 117 static struct snd_pcm_hardware gb_plat_pcm_hardware = {
 118         .info                   = SNDRV_PCM_INFO_INTERLEAVED |
 119                                   SNDRV_PCM_INFO_MMAP        |
 120                                   SNDRV_PCM_INFO_MMAP_VALID,
 121         .formats                = GB_FMTS,
 122         .rates                  = GB_RATES,
 123         .rate_min               = 8000,
 124         .rate_max               = GB_SAMPLE_RATE,
 125         .channels_min           = 1,
 126         .channels_max           = 2,
 127         /* XXX - All the values below are junk */
 128         .buffer_bytes_max       = 64 * 1024,
 129         .period_bytes_min       = 32,
 130         .period_bytes_max       = 8192,
 131         .periods_min            = 2,
 132         .periods_max            = 32,
 133 };
 134
 135 static snd_pcm_uframes_t gb_pcm_pointer(struct snd_pcm_substream *substream)
 136 {
 137         struct snd_soc_pcm_runtime *rtd = substream->private_data;
 138         struct gb_snd *snd_dev;
 139
 140         snd_dev = snd_soc_dai_get_drvdata(rtd->cpu_dai);
 141
 142         return snd_dev->hwptr_done  / (substream->runtime->frame_bits >> 3);
 143 }
 144
 145 static int gb_pcm_prepare(struct snd_pcm_substream *substream)
 146 {
 147         struct snd_soc_pcm_runtime *rtd = substream->private_data;
 148         struct gb_snd *snd_dev;
 149
 150         snd_dev = snd_soc_dai_get_drvdata(rtd->cpu_dai);
 151         snd_dev->hwptr_done = 0;
 152         snd_dev->transfer_done = 0;
 153         return 0;
 154 }
 155
 156 static unsigned int rates[] = {GB_SAMPLE_RATE};
 157 static struct snd_pcm_hw_constraint_list constraints_rates = {
 158         .count = ARRAY_SIZE(rates),
 159         .list = rates,
 160         .mask = 0,
 161 };
 162
 163 static int gb_pcm_open(struct snd_pcm_substream *substream)
 164 {
 165         struct snd_pcm_runtime *runtime = substream->runtime;
 166         struct snd_soc_pcm_runtime *rtd = substream->private_data;
 167         struct gb_snd *snd_dev;
 168         unsigned long flags;
 169         int ret;
 170
 171         snd_dev = snd_soc_dai_get_drvdata(rtd->cpu_dai);
 172
 173         spin_lock_irqsave(&snd_dev->lock, flags);
 174         runtime->private_data = snd_dev;
 175         snd_dev->substream = substream;
 176         ret = gb_pcm_hrtimer_init(snd_dev);
 177         spin_unlock_irqrestore(&snd_dev->lock, flags);
 178
 179         if (ret)
 180                 return ret;
 181
 182         snd_soc_set_runtime_hwparams(substream, &gb_plat_pcm_hardware);
 183
 184         ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
 185                                         SNDRV_PCM_HW_PARAM_RATE,
 186                                         &constraints_rates);
 187         if (ret < 0)
 188                 return ret;
 189
 190         return snd_pcm_hw_constraint_integer(runtime,
 191                                              SNDRV_PCM_HW_PARAM_PERIODS);
 192 }
 193
 194 static int gb_pcm_close(struct snd_pcm_substream *substream)
 195 {
 196         substream->runtime->private_data = NULL;
 197         return 0;
 198 }
 199
 200 static int gb_pcm_hw_params(struct snd_pcm_substream *substream,
 201                                 struct snd_pcm_hw_params *hw_params)
 202 {
 203         return snd_pcm_lib_malloc_pages(substream,
 204                                         params_buffer_bytes(hw_params));
 205 }
 206
 207 static int gb_pcm_hw_free(struct snd_pcm_substream *substream)
 208 {
 209         return snd_pcm_lib_free_pages(substream);
 210 }
 211
 212 static struct snd_pcm_ops gb_pcm_ops = {
 213         .open           = gb_pcm_open,
 214         .close          = gb_pcm_close,
 215         .ioctl          = snd_pcm_lib_ioctl,
 216         .hw_params      = gb_pcm_hw_params,
 217         .hw_free        = gb_pcm_hw_free,
 218         .prepare        = gb_pcm_prepare,
 219         .pointer        = gb_pcm_pointer,
 220 };
 221
 222 static void gb_pcm_free(struct snd_pcm *pcm)
 223 {
 224         snd_pcm_lib_preallocate_free_for_all(pcm);
 225 }
 226
 227 static int gb_pcm_new(struct snd_soc_pcm_runtime *rtd)
 228 {
 229         struct snd_pcm *pcm = rtd->pcm;
 230
 231         return snd_pcm_lib_preallocate_pages_for_all(
 232                         pcm,
 233                         SNDRV_DMA_TYPE_CONTINUOUS,
 234                         snd_dma_continuous_data(GFP_KERNEL),
 235                         PREALLOC_BUFFER, PREALLOC_BUFFER_MAX);
 236 }
 237
 238 struct snd_soc_platform_driver gb_soc_platform = {
 239         .ops            = &gb_pcm_ops,
 240         .pcm_new        = gb_pcm_new,
 241         .pcm_free       = gb_pcm_free,
 242 };
 243
 244 static int gb_soc_platform_probe(struct platform_device *pdev)
 245 {
 246         return snd_soc_register_platform(&pdev->dev, &gb_soc_platform);
 247 }
 248
 249 static int gb_soc_platform_remove(struct platform_device *pdev)
 250 {
 251         snd_soc_unregister_platform(&pdev->dev);
 252         return 0;
 253 }
 254
 255 struct platform_driver gb_audio_pcm_driver = {
 256         .driver = {
 257                         .name = "gb-pcm-audio",
 258                         .owner = THIS_MODULE,
 259         },
 260         .probe = gb_soc_platform_probe,
 261         .remove = gb_soc_platform_remove,
 262 };