From 7067b04bc0f05e25621868e47e3de42befa8ac61 Mon Sep 17 00:00:00 2001 From: wm4 Date: Wed, 13 Jan 2016 19:43:35 +0100 Subject: [PATCH] bcm2835: access controls under the audio mutex I don't think the ALSA framework provides any kind of automatic synchronization within the control callbacks. We most likely need to ensure this manually, so add locking around all access to shared mutable data. In particular, bcm2835_audio_set_ctls() should probably always be called under our own audio lock. --- sound/arm/bcm2835-ctl.c | 74 +++++++++++++++++++++++++++++++++++++++++-------- sound/arm/bcm2835-pcm.c | 4 +++ 2 files changed, 66 insertions(+), 12 deletions(-) --- a/sound/arm/bcm2835-ctl.c +++ b/sound/arm/bcm2835-ctl.c @@ -94,6 +94,9 @@ static int snd_bcm2835_ctl_get(struct sn { struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol); + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + BUG_ON(!chip && !(chip->avail_substreams & AVAIL_SUBSTREAMS_MASK)); if (kcontrol->private_value == PCM_PLAYBACK_VOLUME) @@ -103,6 +106,7 @@ static int snd_bcm2835_ctl_get(struct sn else if (kcontrol->private_value == PCM_PLAYBACK_DEVICE) ucontrol->value.integer.value[0] = chip->dest; + mutex_unlock(&chip->audio_mutex); return 0; } @@ -112,11 +116,15 @@ static int snd_bcm2835_ctl_put(struct sn struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol); int changed = 0; + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + if (kcontrol->private_value == PCM_PLAYBACK_VOLUME) { audio_info("Volume change attempted.. volume = %d new_volume = %d\n", chip->volume, (int)ucontrol->value.integer.value[0]); if (chip->mute == CTRL_VOL_MUTE) { /* changed = toggle_mute(chip, CTRL_VOL_UNMUTE); */ - return 1; /* should return 0 to signify no change but the mixer takes this as the opposite sign (no idea why) */ + changed = 1; /* should return 0 to signify no change but the mixer takes this as the opposite sign (no idea why) */ + goto unlock; } if (changed || (ucontrol->value.integer.value[0] != chip2alsa(chip->volume))) { @@ -142,6 +150,8 @@ static int snd_bcm2835_ctl_put(struct sn printk(KERN_ERR "Failed to set ALSA controls..\n"); } +unlock: + mutex_unlock(&chip->audio_mutex); return changed; } @@ -198,10 +208,14 @@ static int snd_bcm2835_spdif_default_get struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol); int i; + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + for (i = 0; i < 4; i++) ucontrol->value.iec958.status[i] = (chip->spdif_status >> (i * 8)) && 0xff; + mutex_unlock(&chip->audio_mutex); return 0; } @@ -212,12 +226,16 @@ static int snd_bcm2835_spdif_default_put unsigned int val = 0; int i, change; + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + for (i = 0; i < 4; i++) val |= (unsigned int)ucontrol->value.iec958.status[i] << (i * 8); change = val != chip->spdif_status; chip->spdif_status = val; + mutex_unlock(&chip->audio_mutex); return change; } @@ -253,9 +271,14 @@ static int snd_bcm2835_spdif_stream_get( struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol); int i; + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + for (i = 0; i < 4; i++) ucontrol->value.iec958.status[i] = (chip->spdif_status >> (i * 8)) & 0xff; + + mutex_unlock(&chip->audio_mutex); return 0; } @@ -266,11 +289,15 @@ static int snd_bcm2835_spdif_stream_put( unsigned int val = 0; int i, change; + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + for (i = 0; i < 4; i++) val |= (unsigned int)ucontrol->value.iec958.status[i] << (i * 8); change = val != chip->spdif_status; chip->spdif_status = val; + mutex_unlock(&chip->audio_mutex); return change; } @@ -454,11 +481,17 @@ static int snd_bcm2835_chmap_ctl_get(str unsigned int idx = snd_ctl_get_ioffidx(kcontrol, &ucontrol->id); struct snd_pcm_substream *substream = snd_pcm_chmap_substream(info, idx); struct cea_channel_speaker_allocation *ch = NULL; + int res = 0; int cur = 0; int i; - if (!substream || !substream->runtime) - return -ENODEV; + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + + if (!substream || !substream->runtime) { + res = -ENODEV; + goto unlock; + } for (i = 0; i < ARRAY_SIZE(channel_allocations); i++) { if (channel_allocations[i].ca_index == chip->cea_chmap) @@ -476,7 +509,10 @@ static int snd_bcm2835_chmap_ctl_get(str } while (cur < 8) ucontrol->value.integer.value[cur++] = SNDRV_CHMAP_NA; - return 0; + +unlock: + mutex_unlock(&chip->audio_mutex); + return res; } static int snd_bcm2835_chmap_ctl_put(struct snd_kcontrol *kcontrol, @@ -487,10 +523,16 @@ static int snd_bcm2835_chmap_ctl_put(str unsigned int idx = snd_ctl_get_ioffidx(kcontrol, &ucontrol->id); struct snd_pcm_substream *substream = snd_pcm_chmap_substream(info, idx); int i, prepared = 0, cea_chmap = -1; + int res = 0; int remap[8]; - if (!substream || !substream->runtime) - return -ENODEV; + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + + if (!substream || !substream->runtime) { + res = -ENODEV; + goto unlock; + } switch (substream->runtime->status->state) { case SNDRV_PCM_STATE_OPEN: @@ -500,7 +542,8 @@ static int snd_bcm2835_chmap_ctl_put(str prepared = 1; break; default: - return -EBUSY; + res = -EBUSY; + goto unlock; } for (i = 0; i < ARRAY_SIZE(channel_allocations); i++) { @@ -538,19 +581,26 @@ static int snd_bcm2835_chmap_ctl_put(str } } - if (cea_chmap < 0) - return -EINVAL; + if (cea_chmap < 0) { + res = -EINVAL; + goto unlock; + } /* don't change the layout if another substream is active */ - if (chip->opened != (1 << substream->number) && chip->cea_chmap != cea_chmap) - return -EBUSY; /* unsure whether this is a good error code */ + if (chip->opened != (1 << substream->number) && chip->cea_chmap != cea_chmap) { + res = -EBUSY; /* unsure whether this is a good error code */ + goto unlock; + } chip->cea_chmap = cea_chmap; for (i = 0; i < 8; i++) chip->map_channels[i] = remap[i]; if (prepared) snd_bcm2835_pcm_prepare_again(substream); - return 0; + +unlock: + mutex_unlock(&chip->audio_mutex); + return res; } static int snd_bcm2835_add_chmap_ctl(bcm2835_chip_t * chip) --- a/sound/arm/bcm2835-pcm.c +++ b/sound/arm/bcm2835-pcm.c @@ -379,6 +379,9 @@ static int snd_bcm2835_pcm_prepare(struc audio_info(" .. IN\n"); + if (mutex_lock_interruptible(&chip->audio_mutex)) + return -EINTR; + snd_bcm2835_pcm_prepare_again(substream); bcm2835_audio_setup(alsa_stream); @@ -401,6 +404,7 @@ static int snd_bcm2835_pcm_prepare(struc alsa_stream->buffer_size, alsa_stream->period_size, alsa_stream->pos, runtime->frame_bits); + mutex_unlock(&chip->audio_mutex); audio_info(" .. OUT\n"); return 0; }