target/linux/brcm2708/patches-4.4/0132-bcm2835-access-controls-under-the-audio-mutex.patch

   1 From 2a64337156d0f84537e04338b2ebd89eb6ec1f09 Mon Sep 17 00:00:00 2001
   2 From: wm4 <wm4@nowhere>
   3 Date: Wed, 13 Jan 2016 19:43:35 +0100
   4 Subject: [PATCH 132/170] bcm2835: access controls under the audio mutex
   5
   6 I don't think the ALSA framework provides any kind of automatic
   7 synchronization within the control callbacks. We most likely need
   8 to ensure this manually, so add locking around all access to shared
   9 mutable data. In particular, bcm2835_audio_set_ctls() should
  10 probably always be called under our own audio lock.
  11 ---
  12  sound/arm/bcm2835-ctl.c | 74 +++++++++++++++++++++++++++++++++++++++++--------
  13  sound/arm/bcm2835-pcm.c |  4 +++
  14  2 files changed, 66 insertions(+), 12 deletions(-)
  15
  16 --- a/sound/arm/bcm2835-ctl.c
  17 +++ b/sound/arm/bcm2835-ctl.c
  18 @@ -94,6 +94,9 @@ static int snd_bcm2835_ctl_get(struct sn
  19  {
  20         struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol);
  21
  22 +       if (mutex_lock_interruptible(&chip->audio_mutex))
  23 +               return -EINTR;
  24 +
  25         BUG_ON(!chip && !(chip->avail_substreams & AVAIL_SUBSTREAMS_MASK));
  26
  27         if (kcontrol->private_value == PCM_PLAYBACK_VOLUME)
  28 @@ -103,6 +106,7 @@ static int snd_bcm2835_ctl_get(struct sn
  29         else if (kcontrol->private_value == PCM_PLAYBACK_DEVICE)
  30                 ucontrol->value.integer.value[0] = chip->dest;
  31
  32 +       mutex_unlock(&chip->audio_mutex);
  33         return 0;
  34  }
  35
  36 @@ -112,11 +116,15 @@ static int snd_bcm2835_ctl_put(struct sn
  37         struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol);
  38         int changed = 0;
  39
  40 +       if (mutex_lock_interruptible(&chip->audio_mutex))
  41 +               return -EINTR;
  42 +
  43         if (kcontrol->private_value == PCM_PLAYBACK_VOLUME) {
  44                 audio_info("Volume change attempted.. volume = %d new_volume = %d\n", chip->volume, (int)ucontrol->value.integer.value[0]);
  45                 if (chip->mute == CTRL_VOL_MUTE) {
  46                         /* changed = toggle_mute(chip, CTRL_VOL_UNMUTE); */
  47 -                       return 1; /* should return 0 to signify no change but the mixer takes this as the opposite sign (no idea why) */
  48 +                       changed = 1; /* should return 0 to signify no change but the mixer takes this as the opposite sign (no idea why) */
  49 +                       goto unlock;
  50                 }
  51                 if (changed
  52                     || (ucontrol->value.integer.value[0] != chip2alsa(chip->volume))) {
  53 @@ -142,6 +150,8 @@ static int snd_bcm2835_ctl_put(struct sn
  54                         printk(KERN_ERR "Failed to set ALSA controls..\n");
  55         }
  56
  57 +unlock:
  58 +       mutex_unlock(&chip->audio_mutex);
  59         return changed;
  60  }
  61
  62 @@ -198,10 +208,14 @@ static int snd_bcm2835_spdif_default_get
  63         struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol);
  64         int i;
  65
  66 +       if (mutex_lock_interruptible(&chip->audio_mutex))
  67 +               return -EINTR;
  68 +
  69         for (i = 0; i < 4; i++)
  70                 ucontrol->value.iec958.status[i] =
  71                         (chip->spdif_status >> (i * 8)) && 0xff;
  72
  73 +       mutex_unlock(&chip->audio_mutex);
  74         return 0;
  75  }
  76
  77 @@ -212,12 +226,16 @@ static int snd_bcm2835_spdif_default_put
  78         unsigned int val = 0;
  79         int i, change;
  80
  81 +       if (mutex_lock_interruptible(&chip->audio_mutex))
  82 +               return -EINTR;
  83 +
  84         for (i = 0; i < 4; i++)
  85                 val |= (unsigned int)ucontrol->value.iec958.status[i] << (i * 8);
  86
  87         change = val != chip->spdif_status;
  88         chip->spdif_status = val;
  89
  90 +       mutex_unlock(&chip->audio_mutex);
  91         return change;
  92  }
  93
  94 @@ -253,9 +271,14 @@ static int snd_bcm2835_spdif_stream_get(
  95         struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol);
  96         int i;
  97
  98 +       if (mutex_lock_interruptible(&chip->audio_mutex))
  99 +               return -EINTR;
 100 +
 101         for (i = 0; i < 4; i++)
 102                 ucontrol->value.iec958.status[i] =
 103                         (chip->spdif_status >> (i * 8)) & 0xff;
 104 +
 105 +       mutex_unlock(&chip->audio_mutex);
 106         return 0;
 107  }
 108
 109 @@ -266,11 +289,15 @@ static int snd_bcm2835_spdif_stream_put(
 110         unsigned int val = 0;
 111         int i, change;
 112
 113 +       if (mutex_lock_interruptible(&chip->audio_mutex))
 114 +               return -EINTR;
 115 +
 116         for (i = 0; i < 4; i++)
 117                 val |= (unsigned int)ucontrol->value.iec958.status[i] << (i * 8);
 118         change = val != chip->spdif_status;
 119         chip->spdif_status = val;
 120
 121 +       mutex_unlock(&chip->audio_mutex);
 122         return change;
 123  }
 124
 125 @@ -454,11 +481,17 @@ static int snd_bcm2835_chmap_ctl_get(str
 126         unsigned int idx = snd_ctl_get_ioffidx(kcontrol, &ucontrol->id);
 127         struct snd_pcm_substream *substream = snd_pcm_chmap_substream(info, idx);
 128         struct cea_channel_speaker_allocation *ch = NULL;
 129 +       int res = 0;
 130         int cur = 0;
 131         int i;
 132
 133 -       if (!substream || !substream->runtime)
 134 -               return -ENODEV;
 135 +       if (mutex_lock_interruptible(&chip->audio_mutex))
 136 +               return -EINTR;
 137 +
 138 +       if (!substream || !substream->runtime) {
 139 +               res = -ENODEV;
 140 +               goto unlock;
 141 +       }
 142
 143         for (i = 0; i < ARRAY_SIZE(channel_allocations); i++) {
 144                 if (channel_allocations[i].ca_index == chip->cea_chmap)
 145 @@ -476,7 +509,10 @@ static int snd_bcm2835_chmap_ctl_get(str
 146         }
 147         while (cur < 8)
 148                 ucontrol->value.integer.value[cur++] = SNDRV_CHMAP_NA;
 149 -       return 0;
 150 +
 151 +unlock:
 152 +       mutex_unlock(&chip->audio_mutex);
 153 +       return res;
 154  }
 155
 156  static int snd_bcm2835_chmap_ctl_put(struct snd_kcontrol *kcontrol,
 157 @@ -487,10 +523,16 @@ static int snd_bcm2835_chmap_ctl_put(str
 158         unsigned int idx = snd_ctl_get_ioffidx(kcontrol, &ucontrol->id);
 159         struct snd_pcm_substream *substream = snd_pcm_chmap_substream(info, idx);
 160         int i, prepared = 0, cea_chmap = -1;
 161 +       int res = 0;
 162         int remap[8];
 163
 164 -       if (!substream || !substream->runtime)
 165 -               return -ENODEV;
 166 +       if (mutex_lock_interruptible(&chip->audio_mutex))
 167 +               return -EINTR;
 168 +
 169 +       if (!substream || !substream->runtime) {
 170 +               res = -ENODEV;
 171 +               goto unlock;
 172 +       }
 173
 174         switch (substream->runtime->status->state) {
 175         case SNDRV_PCM_STATE_OPEN:
 176 @@ -500,7 +542,8 @@ static int snd_bcm2835_chmap_ctl_put(str
 177                 prepared = 1;
 178                 break;
 179         default:
 180 -               return -EBUSY;
 181 +               res = -EBUSY;
 182 +               goto unlock;
 183         }
 184
 185         for (i = 0; i < ARRAY_SIZE(channel_allocations); i++) {
 186 @@ -538,19 +581,26 @@ static int snd_bcm2835_chmap_ctl_put(str
 187                 }
 188         }
 189
 190 -       if (cea_chmap < 0)
 191 -               return -EINVAL;
 192 +       if (cea_chmap < 0) {
 193 +               res = -EINVAL;
 194 +               goto unlock;
 195 +       }
 196
 197         /* don't change the layout if another substream is active */
 198 -       if (chip->opened != (1 << substream->number) && chip->cea_chmap != cea_chmap)
 199 -               return -EBUSY; /* unsure whether this is a good error code */
 200 +       if (chip->opened != (1 << substream->number) && chip->cea_chmap != cea_chmap) {
 201 +               res = -EBUSY; /* unsure whether this is a good error code */
 202 +               goto unlock;
 203 +       }
 204
 205         chip->cea_chmap = cea_chmap;
 206         for (i = 0; i < 8; i++)
 207                 chip->map_channels[i] = remap[i];
 208         if (prepared)
 209                 snd_bcm2835_pcm_prepare_again(substream);
 210 -       return 0;
 211 +
 212 +unlock:
 213 +       mutex_unlock(&chip->audio_mutex);
 214 +       return res;
 215  }
 216
 217  static int snd_bcm2835_add_chmap_ctl(bcm2835_chip_t * chip)
 218 --- a/sound/arm/bcm2835-pcm.c
 219 +++ b/sound/arm/bcm2835-pcm.c
 220 @@ -379,6 +379,9 @@ static int snd_bcm2835_pcm_prepare(struc
 221
 222         audio_info(" .. IN\n");
 223
 224 +       if (mutex_lock_interruptible(&chip->audio_mutex))
 225 +               return -EINTR;
 226 +
 227         snd_bcm2835_pcm_prepare_again(substream);
 228
 229         bcm2835_audio_setup(alsa_stream);
 230 @@ -401,6 +404,7 @@ static int snd_bcm2835_pcm_prepare(struc
 231                       alsa_stream->buffer_size, alsa_stream->period_size,
 232                       alsa_stream->pos, runtime->frame_bits);
 233
 234 +       mutex_unlock(&chip->audio_mutex);
 235         audio_info(" .. OUT\n");
 236         return 0;
 237  }