staging: bcm2835-audio: initial staging submission

Initial cleanup of bcm2835-audio driver for the
bcm2535(Raspberry PI)

Driver provides HDMI audio through ALSA and is built
on top of the vc04_services driver.

Original version of the driver is available at:
http://www.github.com/raspberry/linux

Driver compiles without any build errors or warnings.

Tested on a RPI 3 running in ARM64 mode with the
vlc player and alsautils.
Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/Kconfig

@@ -102,4 +102,6 @@ source "drivers/staging/greybus/Kconfig"
 
 source "drivers/staging/vc04_services/Kconfig"
 
+source "drivers/staging/bcm2835-audio/Kconfig"
+
 endif # STAGING

drivers/staging/Makefile

@@ -40,3 +40,5 @@ obj-$(CONFIG_MOST)		+= most/
 obj-$(CONFIG_KS7010)		+= ks7010/
 obj-$(CONFIG_GREYBUS)		+= greybus/
 obj-$(CONFIG_BCM2835_VCHIQ)	+= vc04_services/
+obj-$(CONFIG_SND_BCM2835)	+= bcm2835-audio/
+

drivers/staging/bcm2835-audio/Kconfig

+config SND_BCM2835
+        tristate "BCM2835 ALSA driver"
+        depends on ARCH_BCM2835 && BCM2835_VCHIQ && SND
+        select SND_PCM
+        help
+          Say Y or M if you want to support BCM2835 Alsa pcm card driver
+

drivers/staging/bcm2835-audio/Makefile

+obj-$(CONFIG_SND_BCM2835)	+= snd-bcm2835.o
+snd-bcm2835-objs		:= bcm2835.o bcm2835-ctl.o bcm2835-pcm.o bcm2835-vchiq.o
+
+ccflags-y += -Idrivers/staging/vc04_services -Idrivers/staging/vc04_services/interface/vcos/linuxkernel -D__VCCOREVER__=0x04000000
+

drivers/staging/bcm2835-audio/bcm2835-ctl.c

+/*****************************************************************************
+ * Copyright 2011 Broadcom Corporation.  All rights reserved.
+ *
+ * Unless you and Broadcom execute a separate written software license
+ * agreement governing use of this software, this software is licensed to you
+ * under the terms of the GNU General Public License version 2, available at
+ * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+ *
+ * Notwithstanding the above, under no circumstances may you combine this
+ * software in any way with any other Broadcom software provided under a
+ * license other than the GPL, without Broadcom's express prior written
+ * consent.
+ *****************************************************************************/
+
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/wait.h>
+#include <linux/delay.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/rawmidi.h>
+#include <sound/initval.h>
+#include <sound/tlv.h>
+#include <sound/asoundef.h>
+
+#include "bcm2835.h"
+
+/* volume maximum and minimum in terms of 0.01dB */
+#define CTRL_VOL_MAX 400
+#define CTRL_VOL_MIN -10239 /* originally -10240 */
+
+static int snd_bcm2835_ctl_info(struct snd_kcontrol *kcontrol,
+				struct snd_ctl_elem_info *uinfo)
+{
+	audio_info(" ... IN\n");
+	if (kcontrol->private_value == PCM_PLAYBACK_VOLUME) {
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+		uinfo->count = 1;
+		uinfo->value.integer.min = CTRL_VOL_MIN;
+		uinfo->value.integer.max = CTRL_VOL_MAX; /* 2303 */
+	} else if (kcontrol->private_value == PCM_PLAYBACK_MUTE) {
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+		uinfo->count = 1;
+		uinfo->value.integer.min = 0;
+		uinfo->value.integer.max = 1;
+	} else if (kcontrol->private_value == PCM_PLAYBACK_DEVICE) {
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+		uinfo->count = 1;
+		uinfo->value.integer.min = 0;
+		uinfo->value.integer.max = AUDIO_DEST_MAX - 1;
+	}
+	audio_info(" ... OUT\n");
+	return 0;
+}
+
+/* toggles mute on or off depending on the value of nmute, and returns
+ * 1 if the mute value was changed, otherwise 0
+ */
+static int toggle_mute(struct bcm2835_chip *chip, int nmute)
+{
+	/* if settings are ok, just return 0 */
+	if (chip->mute == nmute)
+		return 0;
+
+	/* if the sound is muted then we need to unmute */
+	if (chip->mute == CTRL_VOL_MUTE) {
+		chip->volume = chip->old_volume; /* copy the old volume back */
+		audio_info("Unmuting, old_volume = %d, volume = %d ...\n", chip->old_volume, chip->volume);
+	} else /* otherwise we mute */ {
+		chip->old_volume = chip->volume;
+		chip->volume = 26214; /* set volume to minimum level AKA mute */
+		audio_info("Muting, old_volume = %d, volume = %d ...\n", chip->old_volume, chip->volume);
+	}
+
+	chip->mute = nmute;
+	return 1;
+}
+
+static int snd_bcm2835_ctl_get(struct snd_kcontrol *kcontrol,
+			       struct snd_ctl_elem_value *ucontrol)
+{
+	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)
+		ucontrol->value.integer.value[0] = chip2alsa(chip->volume);
+	else if (kcontrol->private_value == PCM_PLAYBACK_MUTE)
+		ucontrol->value.integer.value[0] = chip->mute;
+	else if (kcontrol->private_value == PCM_PLAYBACK_DEVICE)
+		ucontrol->value.integer.value[0] = chip->dest;
+
+	mutex_unlock(&chip->audio_mutex);
+	return 0;
+}
+
+static int snd_bcm2835_ctl_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	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); */
+			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))) {
+
+			chip->volume = alsa2chip(ucontrol->value.integer.value[0]);
+			changed = 1;
+		}
+
+	} else if (kcontrol->private_value == PCM_PLAYBACK_MUTE) {
+		/* Now implemented */
+		audio_info(" Mute attempted\n");
+		changed = toggle_mute(chip, ucontrol->value.integer.value[0]);
+
+	} else if (kcontrol->private_value == PCM_PLAYBACK_DEVICE) {
+		if (ucontrol->value.integer.value[0] != chip->dest) {
+			chip->dest = ucontrol->value.integer.value[0];
+			changed = 1;
+		}
+	}
+
+	if (changed) {
+		if (bcm2835_audio_set_ctls(chip))
+			printk(KERN_ERR "Failed to set ALSA controls..\n");
+	}
+
+unlock:
+	mutex_unlock(&chip->audio_mutex);
+	return changed;
+}
+
+static DECLARE_TLV_DB_SCALE(snd_bcm2835_db_scale, CTRL_VOL_MIN, 1, 1);
+
+static struct snd_kcontrol_new snd_bcm2835_ctl[] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "PCM Playback Volume",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+		.private_value = PCM_PLAYBACK_VOLUME,
+		.info = snd_bcm2835_ctl_info,
+		.get = snd_bcm2835_ctl_get,
+		.put = snd_bcm2835_ctl_put,
+		.count = 1,
+		.tlv =
+		{.p = snd_bcm2835_db_scale}
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "PCM Playback Switch",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.private_value = PCM_PLAYBACK_MUTE,
+		.info = snd_bcm2835_ctl_info,
+		.get = snd_bcm2835_ctl_get,
+		.put = snd_bcm2835_ctl_put,
+		.count = 1,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "PCM Playback Route",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.private_value = PCM_PLAYBACK_DEVICE,
+		.info = snd_bcm2835_ctl_info,
+		.get = snd_bcm2835_ctl_get,
+		.put = snd_bcm2835_ctl_put,
+		.count = 1,
+	},
+};
+
+static int snd_bcm2835_spdif_default_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
+	uinfo->count = 1;
+	return 0;
+}
+
+static int snd_bcm2835_spdif_default_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	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;
+}
+
+static int snd_bcm2835_spdif_default_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol);
+	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;
+}
+
+static int snd_bcm2835_spdif_mask_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
+	uinfo->count = 1;
+	return 0;
+}
+
+static int snd_bcm2835_spdif_mask_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	/* bcm2835 supports only consumer mode and sets all other format flags
+	 * automatically. So the only thing left is signalling non-audio
+	 * content */
+	ucontrol->value.iec958.status[0] = IEC958_AES0_NONAUDIO;
+	return 0;
+}
+
+static int snd_bcm2835_spdif_stream_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
+	uinfo->count = 1;
+	return 0;
+}
+
+static int snd_bcm2835_spdif_stream_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	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;
+}
+
+static int snd_bcm2835_spdif_stream_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct bcm2835_chip *chip = snd_kcontrol_chip(kcontrol);
+	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;
+}
+
+static struct snd_kcontrol_new snd_bcm2835_spdif[] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
+		.name = SNDRV_CTL_NAME_IEC958("", PLAYBACK, DEFAULT),
+		.info = snd_bcm2835_spdif_default_info,
+		.get = snd_bcm2835_spdif_default_get,
+		.put = snd_bcm2835_spdif_default_put
+	},
+	{
+		.access = SNDRV_CTL_ELEM_ACCESS_READ,
+		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
+		.name = SNDRV_CTL_NAME_IEC958("", PLAYBACK, CON_MASK),
+		.info = snd_bcm2835_spdif_mask_info,
+		.get = snd_bcm2835_spdif_mask_get,
+	},
+	{
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		SNDRV_CTL_ELEM_ACCESS_INACTIVE,
+		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
+		.name = SNDRV_CTL_NAME_IEC958("", PLAYBACK, PCM_STREAM),
+		.info = snd_bcm2835_spdif_stream_info,
+		.get = snd_bcm2835_spdif_stream_get,
+		.put = snd_bcm2835_spdif_stream_put,
+	},
+};
+
+int snd_bcm2835_new_ctl(struct bcm2835_chip *chip)
+{
+	int err;
+	unsigned int idx;
+
+	strcpy(chip->card->mixername, "Broadcom Mixer");
+	for (idx = 0; idx < ARRAY_SIZE(snd_bcm2835_ctl); idx++) {
+		err = snd_ctl_add(chip->card,
+				  snd_ctl_new1(&snd_bcm2835_ctl[idx], chip));
+		if (err < 0)
+			return err;
+	}
+	for (idx = 0; idx < ARRAY_SIZE(snd_bcm2835_spdif); idx++) {
+		err = snd_ctl_add(chip->card,
+				  snd_ctl_new1(&snd_bcm2835_spdif[idx], chip));
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}

drivers/staging/bcm2835-audio/bcm2835-pcm.c

+/*****************************************************************************
+ * Copyright 2011 Broadcom Corporation.  All rights reserved.
+ *
+ * Unless you and Broadcom execute a separate written software license
+ * agreement governing use of this software, this software is licensed to you
+ * under the terms of the GNU General Public License version 2, available at
+ * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+ *
+ * Notwithstanding the above, under no circumstances may you combine this
+ * software in any way with any other Broadcom software provided under a
+ * license other than the GPL, without Broadcom's express prior written
+ * consent.
+ *****************************************************************************/
+
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+
+#include <sound/asoundef.h>
+
+#include "bcm2835.h"
+
+/* hardware definition */
+static struct snd_pcm_hardware snd_bcm2835_playback_hw = {
+	.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
+	SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),
+	.formats = SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE,
+	.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
+	.rate_min = 8000,
+	.rate_max = 48000,
+	.channels_min = 1,
+	.channels_max = 2,
+	.buffer_bytes_max = 128 * 1024,
+	.period_bytes_min = 1 * 1024,
+	.period_bytes_max = 128 * 1024,
+	.periods_min = 1,
+	.periods_max = 128,
+};
+
+static struct snd_pcm_hardware snd_bcm2835_playback_spdif_hw = {
+	.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
+	SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),
+	.formats = SNDRV_PCM_FMTBIT_S16_LE,
+	.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_44100 |
+	SNDRV_PCM_RATE_48000,
+	.rate_min = 44100,
+	.rate_max = 48000,
+	.channels_min = 2,
+	.channels_max = 2,
+	.buffer_bytes_max = 128 * 1024,
+	.period_bytes_min = 1 * 1024,
+	.period_bytes_max = 128 * 1024,
+	.periods_min = 1,
+	.periods_max = 128,
+};
+
+static void snd_bcm2835_playback_free(struct snd_pcm_runtime *runtime)
+{
+	audio_info("Freeing up alsa stream here ..\n");
+	if (runtime->private_data)
+		kfree(runtime->private_data);
+	runtime->private_data = NULL;
+}
+
+static irqreturn_t bcm2835_playback_fifo_irq(int irq, void *dev_id)
+{
+	struct bcm2835_alsa_stream *alsa_stream = dev_id;
+	unsigned int consumed = 0;
+	int new_period = 0;
+
+	audio_info(" .. IN\n");
+
+	audio_info("alsa_stream=%p substream=%p\n", alsa_stream,
+		alsa_stream ? alsa_stream->substream : 0);
+
+	if (alsa_stream->open)
+		consumed = bcm2835_audio_retrieve_buffers(alsa_stream);
+
+	/* We get called only if playback was triggered, So, the number of buffers we retrieve in
+	 * each iteration are the buffers that have been played out already
+	 */
+
+	if (alsa_stream->period_size) {
+		if ((alsa_stream->pos / alsa_stream->period_size) !=
+			((alsa_stream->pos + consumed) / alsa_stream->period_size))
+			new_period = 1;
+	}
+	audio_debug("updating pos cur: %d + %d max:%d period_bytes:%d, hw_ptr: %d new_period:%d\n",
+		alsa_stream->pos,
+		consumed,
+		alsa_stream->buffer_size,
+		(int) (alsa_stream->period_size * alsa_stream->substream->runtime->periods),
+		frames_to_bytes(alsa_stream->substream->runtime, alsa_stream->substream->runtime->status->hw_ptr),
+		new_period);
+	if (alsa_stream->buffer_size) {
+		alsa_stream->pos += consumed &~(1 << 30);
+		alsa_stream->pos %= alsa_stream->buffer_size;
+	}
+
+	if (alsa_stream->substream) {
+		if (new_period)
+			snd_pcm_period_elapsed(alsa_stream->substream);
+	} else {
+		audio_warning(" unexpected NULL substream\n");
+	}
+	audio_info(" .. OUT\n");
+
+	return IRQ_HANDLED;
+}
+
+/* open callback */
+static int snd_bcm2835_playback_open_generic(
+	struct snd_pcm_substream *substream, int spdif)
+{
+	struct bcm2835_chip *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct bcm2835_alsa_stream *alsa_stream;
+	int idx;
+	int err;
+
+	audio_info(" .. IN (%d)\n", substream->number);
+
+	if (mutex_lock_interruptible(&chip->audio_mutex)) {
+		audio_error("Interrupted whilst waiting for lock\n");
+		return -EINTR;
+	}
+	audio_info("Alsa open (%d)\n", substream->number);
+	idx = substream->number;
+
+	if (spdif && chip->opened) {
+		err = -EBUSY;
+		goto out;
+	} else if (!spdif && (chip->opened & (1 << idx))) {
+		err = -EBUSY;
+		goto out;
+	}
+	if (idx > MAX_SUBSTREAMS) {
+		audio_error
+			("substream(%d) device doesn't exist max(%d) substreams allowed\n",
+			idx, MAX_SUBSTREAMS);
+		err = -ENODEV;
+		goto out;
+	}
+
+	/* Check if we are ready */
+	if (!(chip->avail_substreams & (1 << idx))) {
+		/* We are not ready yet */
+		audio_error("substream(%d) device is not ready yet\n", idx);
+		err = -EAGAIN;
+		goto out;
+	}
+
+	alsa_stream = kzalloc(sizeof(*alsa_stream), GFP_KERNEL);
+	if (!alsa_stream) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/* Initialise alsa_stream */
+	alsa_stream->chip = chip;
+	alsa_stream->substream = substream;
+	alsa_stream->idx = idx;
+
+	sema_init(&alsa_stream->buffers_update_sem, 0);
+	sema_init(&alsa_stream->control_sem, 0);
+	spin_lock_init(&alsa_stream->lock);
+
+	/* Enabled in start trigger, called on each "fifo irq" after that */
+	alsa_stream->enable_fifo_irq = 0;
+	alsa_stream->fifo_irq_handler = bcm2835_playback_fifo_irq;
+
+	err = bcm2835_audio_open(alsa_stream);
+	if (err) {
+		kfree(alsa_stream);
+		goto out;
+	}
+	runtime->private_data = alsa_stream;
+	runtime->private_free = snd_bcm2835_playback_free;
+	if (spdif) {
+		runtime->hw = snd_bcm2835_playback_spdif_hw;
+	} else {
+		/* clear spdif status, as we are not in spdif mode */
+		chip->spdif_status = 0;
+		runtime->hw = snd_bcm2835_playback_hw;
+	}
+	/* minimum 16 bytes alignment (for vchiq bulk transfers) */
+	snd_pcm_hw_constraint_step(runtime,
+				   0,
+				   SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
+				   16);
+
+	chip->alsa_stream[idx] = alsa_stream;
+
+	chip->opened |= (1 << idx);
+	alsa_stream->open = 1;
+	alsa_stream->draining = 1;
+
+out:
+	mutex_unlock(&chip->audio_mutex);
+
+	audio_info(" .. OUT =%d\n", err);
+
+	return err;
+}
+
+static int snd_bcm2835_playback_open(struct snd_pcm_substream *substream)
+{
+	return snd_bcm2835_playback_open_generic(substream, 0);
+}
+
+static int snd_bcm2835_playback_spdif_open(struct snd_pcm_substream *substream)
+{
+	return snd_bcm2835_playback_open_generic(substream, 1);
+}
+
+/* close callback */
+static int snd_bcm2835_playback_close(struct snd_pcm_substream *substream)
+{
+	/* the hardware-specific codes will be here */
+
+	struct bcm2835_chip *chip;
+	struct snd_pcm_runtime *runtime;
+	struct bcm2835_alsa_stream *alsa_stream;
+
+	audio_info(" .. IN\n");
+
+	chip = snd_pcm_substream_chip(substream);
+	if (mutex_lock_interruptible(&chip->audio_mutex)) {
+		audio_error("Interrupted whilst waiting for lock\n");
+		return -EINTR;
+	}
+	runtime = substream->runtime;
+	alsa_stream = runtime->private_data;
+
+	audio_info("Alsa close\n");
+
+	/*
+	 * Call stop if it's still running. This happens when app
+	 * is force killed and we don't get a stop trigger.
+	 */
+	if (alsa_stream->running) {
+		int err;
+		err = bcm2835_audio_stop(alsa_stream);
+		alsa_stream->running = 0;
+		if (err)
+			audio_error(" Failed to STOP alsa device\n");
+	}
+
+	alsa_stream->period_size = 0;
+	alsa_stream->buffer_size = 0;
+
+	if (alsa_stream->open) {
+		alsa_stream->open = 0;
+		bcm2835_audio_close(alsa_stream);
+	}
+	if (alsa_stream->chip)
+		alsa_stream->chip->alsa_stream[alsa_stream->idx] = NULL;
+	/*
+	 * Do not free up alsa_stream here, it will be freed up by
+	 * runtime->private_free callback we registered in *_open above
+	 */
+
+	chip->opened &= ~(1 << substream->number);
+
+	mutex_unlock(&chip->audio_mutex);
+	audio_info(" .. OUT\n");
+
+	return 0;
+}
+
+/* hw_params callback */
+static int snd_bcm2835_pcm_hw_params(struct snd_pcm_substream *substream,
+	struct snd_pcm_hw_params *params)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct bcm2835_alsa_stream *alsa_stream = runtime->private_data;
+	int err;
+
+	audio_info(" .. IN\n");
+
+	err = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
+	if (err < 0) {
+		audio_error
+			(" pcm_lib_malloc failed to allocated pages for buffers\n");
+		return err;
+	}
+
+	alsa_stream->channels = params_channels(params);
+	alsa_stream->params_rate = params_rate(params);
+	alsa_stream->pcm_format_width = snd_pcm_format_width(params_format(params));
+	audio_info(" .. OUT\n");
+
+	return err;
+}
+
+/* hw_free callback */
+static int snd_bcm2835_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	audio_info(" .. IN\n");
+	return snd_pcm_lib_free_pages(substream);
+}
+
+/* prepare callback */
+static int snd_bcm2835_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct bcm2835_chip *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct bcm2835_alsa_stream *alsa_stream = runtime->private_data;
+	int channels;
+	int err;
+
+	audio_info(" .. IN\n");
+
+	if (mutex_lock_interruptible(&chip->audio_mutex))
+		return -EINTR;
+
+	/* notify the vchiq that it should enter spdif passthrough mode by
+	 * setting channels=0 (see
+	 * https://github.com/raspberrypi/linux/issues/528) */
+	if (chip->spdif_status & IEC958_AES0_NONAUDIO)
+		channels = 0;
+	else
+		channels = alsa_stream->channels;
+
+	err = bcm2835_audio_set_params(alsa_stream, channels,
+		alsa_stream->params_rate,
+		alsa_stream->pcm_format_width);
+	if (err < 0) {
+		audio_error(" error setting hw params\n");
+	}
+
+	bcm2835_audio_setup(alsa_stream);
+
+	/* in preparation of the stream, set the controls (volume level) of the stream */
+	bcm2835_audio_set_ctls(alsa_stream->chip);
+
+
+	memset(&alsa_stream->pcm_indirect, 0, sizeof(alsa_stream->pcm_indirect));
+
+	alsa_stream->pcm_indirect.hw_buffer_size =
+		alsa_stream->pcm_indirect.sw_buffer_size =
+		snd_pcm_lib_buffer_bytes(substream);
+
+	alsa_stream->buffer_size = snd_pcm_lib_buffer_bytes(substream);
+	alsa_stream->period_size = snd_pcm_lib_period_bytes(substream);
+	alsa_stream->pos = 0;
+
+	audio_debug("buffer_size=%d, period_size=%d pos=%d frame_bits=%d\n",
+		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;
+}
+
+static void snd_bcm2835_pcm_transfer(struct snd_pcm_substream *substream,
+	struct snd_pcm_indirect *rec, size_t bytes)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct bcm2835_alsa_stream *alsa_stream = runtime->private_data;
+	void *src = (void *) (substream->runtime->dma_area + rec->sw_data);
+	int err;
+
+	err = bcm2835_audio_write(alsa_stream, bytes, src);
+	if (err)
+		audio_error(" Failed to transfer to alsa device (%d)\n", err);
+
+}
+
+static int snd_bcm2835_pcm_ack(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct bcm2835_alsa_stream *alsa_stream = runtime->private_data;
+	struct snd_pcm_indirect *pcm_indirect = &alsa_stream->pcm_indirect;
+
+	pcm_indirect->hw_queue_size = runtime->hw.buffer_bytes_max;
+	snd_pcm_indirect_playback_transfer(substream, pcm_indirect,
+					   snd_bcm2835_pcm_transfer);
+	return 0;
+}
+
+/* trigger callback */
+static int snd_bcm2835_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct bcm2835_alsa_stream *alsa_stream = runtime->private_data;
+	int err = 0;
+
+	audio_info(" .. IN\n");
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		audio_debug("bcm2835_AUDIO_TRIGGER_START running=%d\n",
+			alsa_stream->running);
+		if (!alsa_stream->running) {
+			err = bcm2835_audio_start(alsa_stream);
+			if (!err) {
+				alsa_stream->pcm_indirect.hw_io =
+					alsa_stream->pcm_indirect.hw_data =
+					bytes_to_frames(runtime,
+					alsa_stream->pos);
+				substream->ops->ack(substream);
+				alsa_stream->running = 1;
+				alsa_stream->draining = 1;
+			} else {
+				audio_error(" Failed to START alsa device (%d)\n", err);
+			}
+		}
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+		audio_debug
+			("bcm2835_AUDIO_TRIGGER_STOP running=%d draining=%d\n",
+			alsa_stream->running, runtime->status->state == SNDRV_PCM_STATE_DRAINING);
+		if (runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
+			audio_info("DRAINING\n");
+			alsa_stream->draining = 1;
+		} else {
+			audio_info("DROPPING\n");
+			alsa_stream->draining = 0;
+		}
+		if (alsa_stream->running) {
+			err = bcm2835_audio_stop(alsa_stream);
+			if (err != 0)
+				audio_error(" Failed to STOP alsa device (%d)\n", err);
+			alsa_stream->running = 0;
+		}
+		break;
+	default:
+		err = -EINVAL;
+	}
+
+	audio_info(" .. OUT\n");
+	return err;
+}
+
+/* pointer callback */
+static snd_pcm_uframes_t
+snd_bcm2835_pcm_pointer(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct bcm2835_alsa_stream *alsa_stream = runtime->private_data;
+
+	audio_info(" .. IN\n");
+
+	audio_debug("pcm_pointer... (%d) hwptr=%d appl=%d pos=%d\n", 0,
+		frames_to_bytes(runtime, runtime->status->hw_ptr),
+		frames_to_bytes(runtime, runtime->control->appl_ptr),
+		alsa_stream->pos);
+
+	audio_info(" .. OUT\n");
+	return snd_pcm_indirect_playback_pointer(substream,
+		&alsa_stream->pcm_indirect,
+		alsa_stream->pos);
+}
+
+static int snd_bcm2835_pcm_lib_ioctl(struct snd_pcm_substream *substream,
+	unsigned int cmd, void *arg)
+{
+	int ret = snd_pcm_lib_ioctl(substream, cmd, arg);
+	audio_info(" .. substream=%p, cmd=%d, arg=%p (%x) ret=%d\n", substream,
+		cmd, arg, arg ? *(unsigned *) arg : 0, ret);
+	return ret;
+}
+
+/* operators */
+static struct snd_pcm_ops snd_bcm2835_playback_ops = {
+	.open = snd_bcm2835_playback_open,
+	.close = snd_bcm2835_playback_close,
+	.ioctl = snd_bcm2835_pcm_lib_ioctl,
+	.hw_params = snd_bcm2835_pcm_hw_params,
+	.hw_free = snd_bcm2835_pcm_hw_free,
+	.prepare = snd_bcm2835_pcm_prepare,
+	.trigger = snd_bcm2835_pcm_trigger,
+	.pointer = snd_bcm2835_pcm_pointer,
+	.ack = snd_bcm2835_pcm_ack,
+};
+
+static struct snd_pcm_ops snd_bcm2835_playback_spdif_ops = {
+	.open = snd_bcm2835_playback_spdif_open,
+	.close = snd_bcm2835_playback_close,
+	.ioctl = snd_bcm2835_pcm_lib_ioctl,
+	.hw_params = snd_bcm2835_pcm_hw_params,
+	.hw_free = snd_bcm2835_pcm_hw_free,
+	.prepare = snd_bcm2835_pcm_prepare,
+	.trigger = snd_bcm2835_pcm_trigger,
+	.pointer = snd_bcm2835_pcm_pointer,
+	.ack = snd_bcm2835_pcm_ack,
+};
+
+/* create a pcm device */
+int snd_bcm2835_new_pcm(struct bcm2835_chip *chip)
+{
+	struct snd_pcm *pcm;
+	int err;
+
+	audio_info(" .. IN\n");
+	mutex_init(&chip->audio_mutex);
+	if (mutex_lock_interruptible(&chip->audio_mutex)) {
+		audio_error("Interrupted whilst waiting for lock\n");
+		return -EINTR;
+	}
+	err = snd_pcm_new(chip->card, "bcm2835 ALSA", 0, MAX_SUBSTREAMS, 0, &pcm);
+	if (err < 0)
+		goto out;
+	pcm->private_data = chip;
+	strcpy(pcm->name, "bcm2835 ALSA");
+	chip->pcm = pcm;
+	chip->dest = AUDIO_DEST_AUTO;
+	chip->volume = alsa2chip(0);
+	chip->mute = CTRL_VOL_UNMUTE; /*disable mute on startup */
+	/* set operators */
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
+			&snd_bcm2835_playback_ops);
+
+	/* pre-allocation of buffers */
+	/* NOTE: this may fail */
+	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
+					      snd_dma_continuous_data(GFP_KERNEL),
+					      snd_bcm2835_playback_hw.buffer_bytes_max,
+					      snd_bcm2835_playback_hw.buffer_bytes_max);
+
+
+out:
+	mutex_unlock(&chip->audio_mutex);
+	audio_info(" .. OUT\n");
+
+	return 0;
+}
+
+int snd_bcm2835_new_spdif_pcm(struct bcm2835_chip *chip)
+{
+	struct snd_pcm *pcm;
+	int err;
+
+	audio_info(" .. IN\n");
+	if (mutex_lock_interruptible(&chip->audio_mutex)) {
+		audio_error("Interrupted whilst waiting for lock\n");
+		return -EINTR;
+	}
+	err = snd_pcm_new(chip->card, "bcm2835 ALSA", 1, 1, 0, &pcm);
+	if (err < 0)
+		goto out;
+
+	pcm->private_data = chip;
+	strcpy(pcm->name, "bcm2835 IEC958/HDMI");
+	chip->pcm_spdif = pcm;
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
+			&snd_bcm2835_playback_spdif_ops);
+
+	/* pre-allocation of buffers */
+	/* NOTE: this may fail */
+	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
+		snd_dma_continuous_data(GFP_KERNEL),
+		snd_bcm2835_playback_spdif_hw.buffer_bytes_max, snd_bcm2835_playback_spdif_hw.buffer_bytes_max);
+out:
+	mutex_unlock(&chip->audio_mutex);
+	audio_info(" .. OUT\n");
+
+	return 0;
+}

drivers/staging/bcm2835-audio/bcm2835-vchiq.c

+/*****************************************************************************
+ * Copyright 2011 Broadcom Corporation.  All rights reserved.
+ *
+ * Unless you and Broadcom execute a separate written software license
+ * agreement governing use of this software, this software is licensed to you
+ * under the terms of the GNU General Public License version 2, available at
+ * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+ *
+ * Notwithstanding the above, under no circumstances may you combine this
+ * software in any way with any other Broadcom software provided under a
+ * license other than the GPL, without Broadcom's express prior written
+ * consent.
+ *****************************************************************************/
+
+#include <linux/device.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/syscalls.h>
+#include <asm/uaccess.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/atomic.h>
+#include <linux/module.h>
+#include <linux/completion.h>
+
+#include "bcm2835.h"
+
+/* ---- Include Files -------------------------------------------------------- */
+
+#include "interface/vchi/vchi.h"
+#include "vc_vchi_audioserv_defs.h"
+
+/* ---- Private Constants and Types ------------------------------------------ */
+
+#define BCM2835_AUDIO_STOP           0
+#define BCM2835_AUDIO_START          1
+#define BCM2835_AUDIO_WRITE          2
+
+/* Logging macros (for remapping to other logging mechanisms, i.e., printf) */
+#ifdef AUDIO_DEBUG_ENABLE
+#define LOG_ERR( fmt, arg... )   pr_err( "%s:%d " fmt, __func__, __LINE__, ##arg)
+#define LOG_WARN( fmt, arg... )  pr_info( "%s:%d " fmt, __func__, __LINE__, ##arg)
+#define LOG_INFO( fmt, arg... )  pr_info( "%s:%d " fmt, __func__, __LINE__, ##arg)
+#define LOG_DBG( fmt, arg... )   pr_info( "%s:%d " fmt, __func__, __LINE__, ##arg)
+#else
+#define LOG_ERR( fmt, arg... )   pr_err( "%s:%d " fmt, __func__, __LINE__, ##arg)
+#define LOG_WARN( fmt, arg... )
+#define LOG_INFO( fmt, arg... )
+#define LOG_DBG( fmt, arg... )
+#endif
+
+struct bcm2835_audio_instance {
+	unsigned int num_connections;
+	VCHI_SERVICE_HANDLE_T vchi_handle[VCHI_MAX_NUM_CONNECTIONS];
+	struct completion msg_avail_comp;
+	struct mutex vchi_mutex;
+	struct bcm2835_alsa_stream *alsa_stream;
+	int result;
+	short peer_version;
+};
+
+bool force_bulk = false;
+
+/* ---- Private Variables ---------------------------------------------------- */
+
+/* ---- Private Function Prototypes ------------------------------------------ */
+
+/* ---- Private Functions ---------------------------------------------------- */
+
+static int bcm2835_audio_stop_worker(struct bcm2835_alsa_stream *alsa_stream);
+static int bcm2835_audio_start_worker(struct bcm2835_alsa_stream *alsa_stream);
+static int bcm2835_audio_write_worker(struct bcm2835_alsa_stream *alsa_stream,
+				      unsigned int count, void *src);
+
+
+// Routine to send a message across a service
+
+static ssize_t
+bcm2835_vchi_msg_queue_callback(void *context, void *dest,
+				size_t offset, size_t maxsize)
+{
+	memcpy(dest, context + offset, maxsize);
+	return maxsize;
+}
+
+static int
+bcm2835_vchi_msg_queue(VCHI_SERVICE_HANDLE_T handle,
+		       void *data,
+		       unsigned int size)
+{
+	return vchi_msg_queue(handle,
+			      bcm2835_vchi_msg_queue_callback,
+			      data,
+			      size);
+}
+
+struct bcm2835_audio_work {
+	struct work_struct my_work;
+	struct bcm2835_alsa_stream *alsa_stream;
+	int cmd;
+	void *src;
+	unsigned int count;
+};
+
+static void my_wq_function(struct work_struct *work)
+{
+	struct bcm2835_audio_work *w =
+		container_of(work, struct bcm2835_audio_work, my_work);
+	int ret = -9;
+	LOG_DBG(" .. IN %p:%d\n", w->alsa_stream, w->cmd);
+	switch (w->cmd) {
+	case BCM2835_AUDIO_START:
+		ret = bcm2835_audio_start_worker(w->alsa_stream);
+		break;
+	case BCM2835_AUDIO_STOP:
+		ret = bcm2835_audio_stop_worker(w->alsa_stream);
+		break;
+	case BCM2835_AUDIO_WRITE:
+		ret = bcm2835_audio_write_worker(w->alsa_stream, w->count,
+						 w->src);
+		break;
+	default:
+		LOG_ERR(" Unexpected work: %p:%d\n", w->alsa_stream, w->cmd);
+		break;
+	}
+	kfree((void *) work);
+	LOG_DBG(" .. OUT %d\n", ret);
+}
+
+int bcm2835_audio_start(struct bcm2835_alsa_stream *alsa_stream)
+{
+	int ret = -1;
+	LOG_DBG(" .. IN\n");
+	if (alsa_stream->my_wq) {
+		struct bcm2835_audio_work *work =
+			kmalloc(sizeof(struct bcm2835_audio_work *), GFP_ATOMIC);
+		/*--- Queue some work (item 1) ---*/
+		if (work) {
+			INIT_WORK(&work->my_work, my_wq_function);
+			work->alsa_stream = alsa_stream;
+			work->cmd = BCM2835_AUDIO_START;
+			if (queue_work(alsa_stream->my_wq, &work->my_work))
+				ret = 0;
+		} else
+			LOG_ERR(" .. Error: NULL work kmalloc\n");
+	}
+	LOG_DBG(" .. OUT %d\n", ret);
+	return ret;
+}
+
+int bcm2835_audio_stop(struct bcm2835_alsa_stream *alsa_stream)
+{
+	int ret = -1;
+	LOG_DBG(" .. IN\n");
+	if (alsa_stream->my_wq) {
+		struct bcm2835_audio_work *work =
+			kmalloc(sizeof(struct bcm2835_audio_work *), GFP_ATOMIC);
+		/*--- Queue some work (item 1) ---*/
+		if (work) {
+			INIT_WORK(&work->my_work, my_wq_function);
+			work->alsa_stream = alsa_stream;
+			work->cmd = BCM2835_AUDIO_STOP;
+			if (queue_work(alsa_stream->my_wq, &work->my_work))
+				ret = 0;
+		} else
+			LOG_ERR(" .. Error: NULL work kmalloc\n");
+	}
+	LOG_DBG(" .. OUT %d\n", ret);
+	return ret;
+}
+
+int bcm2835_audio_write(struct bcm2835_alsa_stream *alsa_stream,
+			unsigned int count, void *src)
+{
+	int ret = -1;
+	LOG_DBG(" .. IN\n");
+	if (alsa_stream->my_wq) {
+		struct bcm2835_audio_work *work =
+			kmalloc(sizeof(struct bcm2835_audio_work *), GFP_ATOMIC);
+		/*--- Queue some work (item 1) ---*/
+		if (work) {
+			INIT_WORK(&work->my_work, my_wq_function);
+			work->alsa_stream = alsa_stream;
+			work->cmd = BCM2835_AUDIO_WRITE;
+			work->src = src;
+			work->count = count;
+			if (queue_work(alsa_stream->my_wq, &work->my_work))
+				ret = 0;
+		} else
+			LOG_ERR(" .. Error: NULL work kmalloc\n");
+	}
+	LOG_DBG(" .. OUT %d\n", ret);
+	return ret;
+}
+
+void my_workqueue_init(struct bcm2835_alsa_stream *alsa_stream)
+{
+	alsa_stream->my_wq = alloc_workqueue("my_queue", WQ_HIGHPRI, 1);
+	return;
+}
+
+void my_workqueue_quit(struct bcm2835_alsa_stream *alsa_stream)
+{
+	if (alsa_stream->my_wq) {
+		flush_workqueue(alsa_stream->my_wq);
+		destroy_workqueue(alsa_stream->my_wq);
+		alsa_stream->my_wq = NULL;
+	}
+	return;
+}
+
+static void audio_vchi_callback(void *param,
+				const VCHI_CALLBACK_REASON_T reason,
+				void *msg_handle)
+{
+	struct bcm2835_audio_instance *instance = param;
+	int status;
+	int msg_len;
+	struct vc_audio_msg m;
+	LOG_DBG(" .. IN instance=%p, handle=%p, alsa=%p, reason=%d, handle=%p\n",
+		instance, instance ? instance->vchi_handle[0] : NULL, instance ? instance->alsa_stream : NULL, reason, msg_handle);
+
+	if (reason != VCHI_CALLBACK_MSG_AVAILABLE) {
+		return;
+	}
+	if (!instance) {
+		LOG_ERR(" .. instance is null\n");
+		BUG();
+		return;
+	}
+	if (!instance->vchi_handle[0]) {
+		LOG_ERR(" .. instance->vchi_handle[0] is null\n");
+		BUG();
+		return;
+	}
+	status = vchi_msg_dequeue(instance->vchi_handle[0],
+				  &m, sizeof(m), &msg_len, VCHI_FLAGS_NONE);
+	if (m.type == VC_AUDIO_MSG_TYPE_RESULT) {
+		LOG_DBG(" .. instance=%p, m.type=VC_AUDIO_MSG_TYPE_RESULT, success=%d\n",
+			instance, m.u.result.success);
+		instance->result = m.u.result.success;
+		complete(&instance->msg_avail_comp);
+	} else if (m.type == VC_AUDIO_MSG_TYPE_COMPLETE) {
+		struct bcm2835_alsa_stream *alsa_stream = instance->alsa_stream;
+#if defined(CONFIG_64BIT)
+		irq_handler_t callback =
+			(irq_handler_t) (((unsigned long) m.u.complete.callbackl) |
+			((unsigned long) m.u.complete.callbackh << 32));
+#else
+		irq_handler_t callback = (irq_handler_t) m.u.complete.callback;
+#endif
+		LOG_DBG(" .. instance=%p, m.type=VC_AUDIO_MSG_TYPE_COMPLETE, complete=%d\n",
+			instance, m.u.complete.count);
+		if (alsa_stream && callback) {
+			atomic_add(m.u.complete.count, &alsa_stream->retrieved);
+			callback(0, alsa_stream);
+		} else {
+			LOG_ERR(" .. unexpected alsa_stream=%p, callback=%p\n",
+				alsa_stream, callback);
+		}
+	} else {
+		LOG_ERR(" .. unexpected m.type=%d\n", m.type);
+	}
+	LOG_DBG(" .. OUT\n");
+}
+
+static struct bcm2835_audio_instance *
+vc_vchi_audio_init(VCHI_INSTANCE_T vchi_instance,
+		   VCHI_CONNECTION_T **vchi_connections,
+		   unsigned int num_connections)
+{
+	unsigned int i;
+	struct bcm2835_audio_instance *instance;
+	int status;
+
+	LOG_DBG("%s: start", __func__);
+
+	if (num_connections > VCHI_MAX_NUM_CONNECTIONS) {
+		LOG_ERR("%s: unsupported number of connections %u (max=%u)\n",
+			__func__, num_connections, VCHI_MAX_NUM_CONNECTIONS);
+
+		return NULL;
+	}
+	/* Allocate memory for this instance */
+	instance = kmalloc(sizeof(*instance), GFP_KERNEL);
+	if (!instance)
+		return NULL;
+
+	memset(instance, 0, sizeof(*instance));
+	instance->num_connections = num_connections;
+
+	/* Create a lock for exclusive, serialized VCHI connection access */
+	mutex_init(&instance->vchi_mutex);
+	/* Open the VCHI service connections */
+	for (i = 0; i < num_connections; i++) {
+		SERVICE_CREATION_T params = {
+			VCHI_VERSION_EX(VC_AUDIOSERV_VER, VC_AUDIOSERV_MIN_VER),
+			VC_AUDIO_SERVER_NAME, // 4cc service code
+			vchi_connections[i], // passed in fn pointers
+			0, // rx fifo size (unused)
+			0, // tx fifo size (unused)
+			audio_vchi_callback, // service callback
+			instance, // service callback parameter
+			1, //TODO: remove VCOS_FALSE,   // unaligned bulk recieves
+			1, //TODO: remove VCOS_FALSE,   // unaligned bulk transmits
+			0 // want crc check on bulk transfers
+		};
+
+		LOG_DBG("%s: about to open %i\n", __func__, i);
+		status = vchi_service_open(vchi_instance, &params,
+			&instance->vchi_handle[i]);
+		LOG_DBG("%s: opened %i: %p=%d\n", __func__, i, instance->vchi_handle[i], status);
+		if (status) {
+			LOG_ERR("%s: failed to open VCHI service connection (status=%d)\n",
+				__func__, status);
+
+			goto err_close_services;
+		}
+		/* Finished with the service for now */
+		vchi_service_release(instance->vchi_handle[i]);
+	}
+
+	LOG_DBG("%s: okay\n", __func__);
+	return instance;
+
+err_close_services:
+	for (i = 0; i < instance->num_connections; i++) {
+		LOG_ERR("%s: closing %i: %p\n", __func__, i, instance->vchi_handle[i]);
+		if (instance->vchi_handle[i])
+			vchi_service_close(instance->vchi_handle[i]);
+	}
+
+	kfree(instance);
+	LOG_ERR("%s: error\n", __func__);
+
+	return NULL;
+}
+
+static int vc_vchi_audio_deinit(struct bcm2835_audio_instance *instance)
+{
+	unsigned int i;
+
+	LOG_DBG(" .. IN\n");
+
+	if (!instance) {
+		LOG_ERR("%s: invalid handle %p\n", __func__, instance);
+
+		return -1;
+	}
+
+	LOG_DBG(" .. about to lock (%d)\n", instance->num_connections);
+	if (mutex_lock_interruptible(&instance->vchi_mutex)) {
+		LOG_DBG("Interrupted whilst waiting for lock on (%d)\n",
+			instance->num_connections);
+		return -EINTR;
+	}
+
+	/* Close all VCHI service connections */
+	for (i = 0; i < instance->num_connections; i++) {
+		int status;
+		LOG_DBG(" .. %i:closing %p\n", i, instance->vchi_handle[i]);
+		vchi_service_use(instance->vchi_handle[i]);
+
+		status = vchi_service_close(instance->vchi_handle[i]);
+		if (status) {
+			LOG_DBG("%s: failed to close VCHI service connection (status=%d)\n",
+				__func__, status);
+		}
+	}
+
+	mutex_unlock(&instance->vchi_mutex);
+
+	kfree(instance);
+
+	LOG_DBG(" .. OUT\n");
+
+	return 0;
+}
+
+static int bcm2835_audio_open_connection(struct bcm2835_alsa_stream *alsa_stream)
+{
+	static VCHI_INSTANCE_T vchi_instance;
+	static VCHI_CONNECTION_T *vchi_connection;
+	static int initted;
+	struct bcm2835_audio_instance *instance =
+		(struct bcm2835_audio_instance *)alsa_stream->instance;
+	int ret;
+	LOG_DBG(" .. IN\n");
+
+	LOG_INFO("%s: start\n", __func__);
+	BUG_ON(instance);
+	if (instance) {
+		LOG_ERR("%s: VCHI instance already open (%p)\n",
+			__func__, instance);
+		instance->alsa_stream = alsa_stream;
+		alsa_stream->instance = instance;
+		ret = 0; // xxx todo -1;
+		goto err_free_mem;
+	}
+
+	/* Initialize and create a VCHI connection */
+	if (!initted) {
+		ret = vchi_initialise(&vchi_instance);
+		if (ret) {
+			LOG_ERR("%s: failed to initialise VCHI instance (ret=%d)\n",
+				__func__, ret);
+
+			ret = -EIO;
+			goto err_free_mem;
+		}
+		ret = vchi_connect(NULL, 0, vchi_instance);
+		if (ret) {
+			LOG_ERR("%s: failed to connect VCHI instance (ret=%d)\n",
+				__func__, ret);
+
+			ret = -EIO;
+			goto err_free_mem;
+		}
+		initted = 1;
+	}
+
+	/* Initialize an instance of the audio service */
+	instance = vc_vchi_audio_init(vchi_instance, &vchi_connection, 1);
+
+	if (!instance) {
+		LOG_ERR("%s: failed to initialize audio service\n", __func__);
+
+		ret = -EPERM;
+		goto err_free_mem;
+	}
+
+	instance->alsa_stream = alsa_stream;
+	alsa_stream->instance = instance;
+
+	LOG_DBG(" success !\n");
+err_free_mem:
+	LOG_DBG(" .. OUT\n");
+
+	return ret;
+}
+
+int bcm2835_audio_open(struct bcm2835_alsa_stream *alsa_stream)
+{
+	struct bcm2835_audio_instance *instance;
+	struct vc_audio_msg m;
+	int status;
+	int ret;
+	LOG_DBG(" .. IN\n");
+
+	my_workqueue_init(alsa_stream);
+
+	ret = bcm2835_audio_open_connection(alsa_stream);
+	if (ret) {
+		ret = -1;
+		goto exit;
+	}
+	instance = alsa_stream->instance;
+	LOG_DBG(" instance (%p)\n", instance);
+
+	if (mutex_lock_interruptible(&instance->vchi_mutex)) {
+		LOG_DBG("Interrupted whilst waiting for lock on (%d)\n", instance->num_connections);
+		return -EINTR;
+	}
+	vchi_service_use(instance->vchi_handle[0]);
+
+	m.type = VC_AUDIO_MSG_TYPE_OPEN;
+
+	/* Send the message to the videocore */
+	status = bcm2835_vchi_msg_queue(instance->vchi_handle[0],
+					&m, sizeof(m));
+
+	if (status) {
+		LOG_ERR("%s: failed on vchi_msg_queue (status=%d)\n",
+			__func__, status);
+
+		ret = -1;
+		goto unlock;
+	}
+
+	ret = 0;
+
+unlock:
+	vchi_service_release(instance->vchi_handle[0]);
+	mutex_unlock(&instance->vchi_mutex);
+exit:
+	LOG_DBG(" .. OUT\n");
+	return ret;
+}
+
+static int bcm2835_audio_set_ctls_chan(struct bcm2835_alsa_stream *alsa_stream,
+				       struct bcm2835_chip *chip)
+{
+	struct vc_audio_msg m;
+	struct bcm2835_audio_instance *instance = alsa_stream->instance;
+	int status;
+	int ret;
+	LOG_DBG(" .. IN\n");
+
+	LOG_INFO(" Setting ALSA dest(%d), volume(%d)\n",
+		 chip->dest, chip->volume);
+
+	if (mutex_lock_interruptible(&instance->vchi_mutex)) {
+		LOG_DBG("Interrupted whilst waiting for lock on (%d)\n",
+			instance->num_connections);
+		return -EINTR;
+	}
+	vchi_service_use(instance->vchi_handle[0]);
+
+	instance->result = -1;
+
+	m.type = VC_AUDIO_MSG_TYPE_CONTROL;
+	m.u.control.dest = chip->dest;
+	m.u.control.volume = chip->volume;
+
+	/* Create the message available completion */
+	init_completion(&instance->msg_avail_comp);
+
+	/* Send the message to the videocore */
+	status = bcm2835_vchi_msg_queue(instance->vchi_handle[0],
+					&m, sizeof(m));
+
+	if (status) {
+		LOG_ERR("%s: failed on vchi_msg_queue (status=%d)\n",
+			__func__, status);
+
+		ret = -1;
+		goto unlock;
+	}
+
+	/* We are expecting a reply from the videocore */
+	wait_for_completion(&instance->msg_avail_comp);
+
+	if (instance->result) {
+		LOG_ERR("%s: result=%d\n", __func__, instance->result);
+
+		ret = -1;
+		goto unlock;
+	}
+
+	ret = 0;
+
+unlock:
+	vchi_service_release(instance->vchi_handle[0]);
+	mutex_unlock(&instance->vchi_mutex);
+
+	LOG_DBG(" .. OUT\n");
+	return ret;
+}
+
+int bcm2835_audio_set_ctls(struct bcm2835_chip *chip)
+{
+	int i;
+	int ret = 0;
+	LOG_DBG(" .. IN\n");
+	LOG_DBG(" Setting ALSA dest(%d), volume(%d)\n", chip->dest, chip->volume);
+
+	/* change ctls for all substreams */
+	for (i = 0; i < MAX_SUBSTREAMS; i++) {
+		if (chip->avail_substreams & (1 << i)) {
+			if (!chip->alsa_stream[i]) {
+				LOG_DBG(" No ALSA stream available?! %i:%p (%x)\n", i, chip->alsa_stream[i], chip->avail_substreams);
+				ret = 0;
+			} else if (bcm2835_audio_set_ctls_chan(chip->alsa_stream[i], chip) != 0) {
+				LOG_ERR("Couldn't set the controls for stream %d\n", i);
+				ret = -1;
+			} else LOG_DBG(" Controls set for stream %d\n", i);
+		}
+	}
+	LOG_DBG(" .. OUT ret=%d\n", ret);
+	return ret;
+}
+
+int bcm2835_audio_set_params(struct bcm2835_alsa_stream *alsa_stream,
+			     unsigned int channels, unsigned int samplerate,
+			     unsigned int bps)
+{
+	struct vc_audio_msg m;
+	struct bcm2835_audio_instance *instance = alsa_stream->instance;
+	int status;
+	int ret;
+	LOG_DBG(" .. IN\n");
+
+	LOG_INFO(" Setting ALSA channels(%d), samplerate(%d), bits-per-sample(%d)\n",
+		channels, samplerate, bps);
+
+	/* resend ctls - alsa_stream may not have been open when first send */
+	ret = bcm2835_audio_set_ctls_chan(alsa_stream, alsa_stream->chip);
+	if (ret) {
+		LOG_ERR(" Alsa controls not supported\n");
+		return -EINVAL;
+	}
+
+	if (mutex_lock_interruptible(&instance->vchi_mutex)) {
+		LOG_DBG("Interrupted whilst waiting for lock on (%d)\n", instance->num_connections);
+		return -EINTR;
+	}
+	vchi_service_use(instance->vchi_handle[0]);
+
+	instance->result = -1;
+
+	m.type = VC_AUDIO_MSG_TYPE_CONFIG;
+	m.u.config.channels = channels;
+	m.u.config.samplerate = samplerate;
+	m.u.config.bps = bps;
+
+	/* Create the message available completion */
+	init_completion(&instance->msg_avail_comp);
+
+	/* Send the message to the videocore */
+	status = bcm2835_vchi_msg_queue(instance->vchi_handle[0],
+					&m, sizeof(m));
+
+	if (status) {
+		LOG_ERR("%s: failed on vchi_msg_queue (status=%d)\n",
+			__func__, status);
+
+		ret = -1;
+		goto unlock;
+	}
+
+	/* We are expecting a reply from the videocore */
+	wait_for_completion(&instance->msg_avail_comp);
+
+	if (instance->result) {
+		LOG_ERR("%s: result=%d", __func__, instance->result);
+
+		ret = -1;
+		goto unlock;
+	}
+
+	ret = 0;
+
+unlock:
+	vchi_service_release(instance->vchi_handle[0]);
+	mutex_unlock(&instance->vchi_mutex);
+
+	LOG_DBG(" .. OUT\n");
+	return ret;
+}
+
+int bcm2835_audio_setup(struct bcm2835_alsa_stream *alsa_stream)
+{
+	LOG_DBG(" .. IN\n");
+
+	LOG_DBG(" .. OUT\n");
+
+	return 0;
+}
+
+static int bcm2835_audio_start_worker(struct bcm2835_alsa_stream *alsa_stream)
+{
+	struct vc_audio_msg m;
+	struct bcm2835_audio_instance *instance = alsa_stream->instance;
+	int status;
+	int ret;
+	LOG_DBG(" .. IN\n");
+
+	if (mutex_lock_interruptible(&instance->vchi_mutex)) {
+		LOG_DBG("Interrupted whilst waiting for lock on (%d)\n",
+			instance->num_connections);
+		return -EINTR;
+	}
+	vchi_service_use(instance->vchi_handle[0]);
+
+	m.type = VC_AUDIO_MSG_TYPE_START;
+
+	/* Send the message to the videocore */
+	status = bcm2835_vchi_msg_queue(instance->vchi_handle[0],
+					&m, sizeof(m));
+
+	if (status) {
+		LOG_ERR("%s: failed on vchi_msg_queue (status=%d)\n",
+			__func__, status);
+
+		ret = -1;
+		goto unlock;
+	}
+
+	ret = 0;
+
+unlock:
+	vchi_service_release(instance->vchi_handle[0]);
+	mutex_unlock(&instance->vchi_mutex);
+	LOG_DBG(" .. OUT\n");
+	return ret;
+}
+
+static int bcm2835_audio_stop_worker(struct bcm2835_alsa_stream *alsa_stream)
+{
+	struct vc_audio_msg m;
+	struct bcm2835_audio_instance *instance = alsa_stream->instance;
+	int status;
+	int ret;
+	LOG_DBG(" .. IN\n");
+
+	if (mutex_lock_interruptible(&instance->vchi_mutex)) {
+		LOG_DBG("Interrupted whilst waiting for lock on (%d)\n",
+			instance->num_connections);
+		return -EINTR;
+	}
+	vchi_service_use(instance->vchi_handle[0]);
+
+	m.type = VC_AUDIO_MSG_TYPE_STOP;
+	m.u.stop.draining = alsa_stream->draining;
+
+	/* Send the message to the videocore */
+	status = bcm2835_vchi_msg_queue(instance->vchi_handle[0],
+					&m, sizeof(m));
+
+	if (status) {
+		LOG_ERR("%s: failed on vchi_msg_queue (status=%d)\n",
+			__func__, status);
+
+		ret = -1;
+		goto unlock;
+	}
+
+	ret = 0;
+
+unlock:
+	vchi_service_release(instance->vchi_handle[0]);
+	mutex_unlock(&instance->vchi_mutex);
+	LOG_DBG(" .. OUT\n");
+	return ret;
+}
+
+int bcm2835_audio_close(struct bcm2835_alsa_stream *alsa_stream)
+{
+	struct vc_audio_msg m;
+	struct bcm2835_audio_instance *instance = alsa_stream->instance;
+	int status;
+	int ret;
+	LOG_DBG(" .. IN\n");
+
+	my_workqueue_quit(alsa_stream);
+
+	if (mutex_lock_interruptible(&instance->vchi_mutex)) {
+		LOG_DBG("Interrupted whilst waiting for lock on (%d)\n",
+			instance->num_connections);
+		return -EINTR;
+	}
+	vchi_service_use(instance->vchi_handle[0]);
+
+	m.type = VC_AUDIO_MSG_TYPE_CLOSE;
+
+	/* Create the message available completion */
+	init_completion(&instance->msg_avail_comp);
+
+	/* Send the message to the videocore */
+	status = bcm2835_vchi_msg_queue(instance->vchi_handle[0],
+					&m, sizeof(m));
+
+	if (status) {
+		LOG_ERR("%s: failed on vchi_msg_queue (status=%d)\n",
+			__func__, status);
+		ret = -1;
+		goto unlock;
+	}
+
+	/* We are expecting a reply from the videocore */
+	wait_for_completion(&instance->msg_avail_comp);
+
+	if (instance->result) {
+		LOG_ERR("%s: failed result (result=%d)\n",
+			__func__, instance->result);
+
+		ret = -1;
+		goto unlock;
+	}
+
+	ret = 0;
+
+unlock:
+	vchi_service_release(instance->vchi_handle[0]);
+	mutex_unlock(&instance->vchi_mutex);
+
+	/* Stop the audio service */
+	if (instance) {
+		vc_vchi_audio_deinit(instance);
+		alsa_stream->instance = NULL;
+	}
+	LOG_DBG(" .. OUT\n");
+	return ret;
+}
+
+int bcm2835_audio_write_worker(struct bcm2835_alsa_stream *alsa_stream,
+			       unsigned int count, void *src)
+{
+	struct vc_audio_msg m;
+	struct bcm2835_audio_instance *instance = alsa_stream->instance;
+	int status;
+	int ret;
+
+	LOG_DBG(" .. IN\n");
+
+	LOG_INFO(" Writing %d bytes from %p\n", count, src);
+
+	if (mutex_lock_interruptible(&instance->vchi_mutex)) {
+		LOG_DBG("Interrupted whilst waiting for lock on (%d)\n",
+			instance->num_connections);
+		return -EINTR;
+	}
+	vchi_service_use(instance->vchi_handle[0]);
+
+	if (instance->peer_version == 0 && vchi_get_peer_version(instance->vchi_handle[0], &instance->peer_version) == 0) {
+		LOG_DBG("%s: client version %d connected\n", __func__, instance->peer_version);
+	}
+	m.type = VC_AUDIO_MSG_TYPE_WRITE;
+	m.u.write.count = count;
+	// old version uses bulk, new version uses control
+	m.u.write.max_packet = instance->peer_version < 2 || force_bulk ? 0 : 4000;
+#if defined(CONFIG_64BIT)
+	m.u.write.callbackl = (u32) (((unsigned long) alsa_stream->fifo_irq_handler)&0xFFFFFFFF);
+	m.u.write.callbackh = (u32) ((((unsigned long) alsa_stream->fifo_irq_handler) >> 32)&0xFFFFFFFF);
+#else
+	m.u.write.callback = alsa_stream->fifo_irq_handler;
+	m.u.write.cookie = alsa_stream;
+#endif
+	m.u.write.silence = src == NULL;
+
+	/* Send the message to the videocore */
+	status = bcm2835_vchi_msg_queue(instance->vchi_handle[0],
+					&m, sizeof(m));
+
+	if (status) {
+		LOG_ERR("%s: failed on vchi_msg_queue (status=%d)\n",
+			__func__, status);
+
+		ret = -1;
+		goto unlock;
+	}
+	if (!m.u.write.silence) {
+		if (!m.u.write.max_packet) {
+			/* Send the message to the videocore */
+			status = vchi_bulk_queue_transmit(instance->vchi_handle[0],
+				src, count,
+				0 *
+				VCHI_FLAGS_BLOCK_UNTIL_QUEUED
+				+
+				1 *
+				VCHI_FLAGS_BLOCK_UNTIL_DATA_READ,
+				NULL);
+		} else {
+			while (count > 0) {
+				int bytes = min((int) m.u.write.max_packet, (int) count);
+				status = bcm2835_vchi_msg_queue(instance->vchi_handle[0],
+								src, bytes);
+				src = (char *)src + bytes;
+				count -= bytes;
+			}
+		}
+		if (status) {
+			LOG_ERR("%s: failed on vchi_bulk_queue_transmit (status=%d)\n",
+				__func__, status);
+
+			ret = -1;
+			goto unlock;
+		}
+	}
+	ret = 0;
+
+unlock:
+	vchi_service_release(instance->vchi_handle[0]);
+	mutex_unlock(&instance->vchi_mutex);
+	LOG_DBG(" .. OUT\n");
+	return ret;
+}
+
+/**
+ * Returns all buffers from arm->vc
+ */
+void bcm2835_audio_flush_buffers(struct bcm2835_alsa_stream *alsa_stream)
+{
+	LOG_DBG(" .. IN\n");
+	LOG_DBG(" .. OUT\n");
+	return;
+}
+
+/**
+ * Forces VC to flush(drop) its filled playback buffers and
+ * return them the us. (VC->ARM)
+ */
+void bcm2835_audio_flush_playback_buffers(struct bcm2835_alsa_stream *alsa_stream)
+{
+	LOG_DBG(" .. IN\n");
+	LOG_DBG(" .. OUT\n");
+}
+
+unsigned int bcm2835_audio_retrieve_buffers(struct bcm2835_alsa_stream *alsa_stream)
+{
+	unsigned int count = atomic_read(&alsa_stream->retrieved);
+	atomic_sub(count, &alsa_stream->retrieved);
+	return count;
+}
+
+module_param(force_bulk, bool, 0444);
+MODULE_PARM_DESC(force_bulk, "Force use of vchiq bulk for audio");

drivers/staging/bcm2835-audio/bcm2835.c

+/*****************************************************************************
+ * Copyright 2011 Broadcom Corporation.  All rights reserved.
+ *
+ * Unless you and Broadcom execute a separate written software license
+ * agreement governing use of this software, this software is licensed to you
+ * under the terms of the GNU General Public License version 2, available at
+ * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+ *
+ * Notwithstanding the above, under no circumstances may you combine this
+ * software in any way with any other Broadcom software provided under a
+ * license other than the GPL, without Broadcom's express prior written
+ * consent.
+ *****************************************************************************/
+
+#include <linux/platform_device.h>
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include "bcm2835.h"
+
+/* module parameters (see "Module Parameters") */
+/* SNDRV_CARDS: maximum number of cards supported by this module */
+static int index[MAX_SUBSTREAMS] = {[0 ... (MAX_SUBSTREAMS - 1)] = -1};
+static char *id[MAX_SUBSTREAMS] = {[0 ... (MAX_SUBSTREAMS - 1)] = NULL};
+static int enable[MAX_SUBSTREAMS] = {[0 ... (MAX_SUBSTREAMS - 1)] = 1};
+
+/* HACKY global pointers needed for successive probes to work : ssp
+ * But compared against the changes we will have to do in VC audio_ipc code
+ * to export 8 audio_ipc devices as a single IPC device and then monitor all
+ * four devices in a thread, this gets things done quickly and should be easier
+ * to debug if we run into issues
+ */
+
+static struct snd_card *g_card = NULL;
+static struct bcm2835_chip *g_chip = NULL;
+
+static int snd_bcm2835_free(struct bcm2835_chip *chip)
+{
+	kfree(chip);
+	return 0;
+}
+
+/* component-destructor
+ * (see "Management of Cards and Components")
+ */
+static int snd_bcm2835_dev_free(struct snd_device *device)
+{
+	return snd_bcm2835_free(device->device_data);
+}
+
+/* chip-specific constructor
+ * (see "Management of Cards and Components")
+ */
+static int snd_bcm2835_create(struct snd_card *card,
+	struct platform_device *pdev,
+	struct bcm2835_chip ** rchip)
+{
+	struct bcm2835_chip *chip;
+	int err;
+	static struct snd_device_ops ops = {
+		.dev_free = snd_bcm2835_dev_free,
+	};
+
+	*rchip = NULL;
+
+	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+	if (chip == NULL)
+		return -ENOMEM;
+
+	chip->card = card;
+
+	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
+	if (err < 0) {
+		snd_bcm2835_free(chip);
+		return err;
+	}
+
+	*rchip = chip;
+	return 0;
+}
+
+static int snd_bcm2835_alsa_probe_dt(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct bcm2835_chip *chip;
+	struct snd_card *card;
+	u32 numchans;
+	int err, i;
+
+	err = of_property_read_u32(dev->of_node, "brcm,pwm-channels",
+		&numchans);
+	if (err) {
+		dev_err(dev, "Failed to get DT property 'brcm,pwm-channels'");
+		return err;
+	}
+
+	if (numchans == 0 || numchans > MAX_SUBSTREAMS) {
+		numchans = MAX_SUBSTREAMS;
+		dev_warn(dev, "Illegal 'brcm,pwm-channels' value, will use %u\n",
+			numchans);
+	}
+
+	err = snd_card_new(&pdev->dev, -1, NULL, THIS_MODULE, 0, &card);
+	if (err) {
+		dev_err(dev, "Failed to create soundcard structure\n");
+		return err;
+	}
+
+	snd_card_set_dev(card, dev);
+	strcpy(card->driver, "bcm2835");
+	strcpy(card->shortname, "bcm2835 ALSA");
+	sprintf(card->longname, "%s", card->shortname);
+
+	err = snd_bcm2835_create(card, pdev, &chip);
+	if (err < 0) {
+		dev_err(dev, "Failed to create bcm2835 chip\n");
+		goto err_free;
+	}
+
+	err = snd_bcm2835_new_pcm(chip);
+	if (err < 0) {
+		dev_err(dev, "Failed to create new bcm2835 pcm device\n");
+		goto err_free;
+	}
+
+	err = snd_bcm2835_new_spdif_pcm(chip);
+	if (err < 0) {
+		dev_err(dev, "Failed to create new bcm2835 spdif pcm device\n");
+		goto err_free;
+	}
+
+	err = snd_bcm2835_new_ctl(chip);
+	if (err < 0) {
+		dev_err(dev, "Failed to create new bcm2835 ctl\n");
+		goto err_free;
+	}
+
+	for (i = 0; i < numchans; i++) {
+		chip->avail_substreams |= (1 << i);
+		chip->pdev[i] = pdev;
+	}
+
+	err = snd_card_register(card);
+	if (err) {
+		dev_err(dev, "Failed to register bcm2835 ALSA card \n");
+		goto err_free;
+	}
+
+	g_card = card;
+	g_chip = chip;
+	platform_set_drvdata(pdev, card);
+	audio_info("bcm2835 ALSA card created with %u channels\n", numchans);
+
+	return 0;
+
+err_free:
+	snd_card_free(card);
+
+	return err;
+}
+
+static int snd_bcm2835_alsa_probe(struct platform_device *pdev)
+{
+	static int dev;
+	struct bcm2835_chip *chip;
+	struct snd_card *card;
+	int err;
+
+	if (pdev->dev.of_node)
+		return snd_bcm2835_alsa_probe_dt(pdev);
+
+	if (dev >= MAX_SUBSTREAMS)
+		return -ENODEV;
+
+	if (!enable[dev]) {
+		dev++;
+		return -ENOENT;
+	}
+
+	if (dev > 0)
+		goto add_register_map;
+
+	err = snd_card_new(&pdev->dev, index[dev], id[dev], THIS_MODULE, 0, &g_card);
+	if (err < 0)
+		goto out;
+
+	snd_card_set_dev(g_card, &pdev->dev);
+	strcpy(g_card->driver, "bcm2835");
+	strcpy(g_card->shortname, "bcm2835 ALSA");
+	sprintf(g_card->longname, "%s", g_card->shortname);
+
+	err = snd_bcm2835_create(g_card, pdev, &chip);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Failed to create bcm2835 chip\n");
+		goto out_bcm2835_create;
+	}
+
+	g_chip = chip;
+	err = snd_bcm2835_new_pcm(chip);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Failed to create new BCM2835 pcm device\n");
+		goto out_bcm2835_new_pcm;
+	}
+
+	err = snd_bcm2835_new_spdif_pcm(chip);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Failed to create new BCM2835 spdif pcm device\n");
+		goto out_bcm2835_new_spdif;
+	}
+
+	err = snd_bcm2835_new_ctl(chip);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Failed to create new BCM2835 ctl\n");
+		goto out_bcm2835_new_ctl;
+	}
+
+add_register_map:
+	card = g_card;
+	chip = g_chip;
+
+	BUG_ON(!(card && chip));
+
+	chip->avail_substreams |= (1 << dev);
+	chip->pdev[dev] = pdev;
+
+	if (!dev) {
+		err = snd_card_register(card);
+		if (err < 0) {
+			dev_err(&pdev->dev,
+				"Failed to register bcm2835 ALSA card \n");
+			goto out_card_register;
+		}
+		platform_set_drvdata(pdev, card);
+		audio_info("bcm2835 ALSA card created!\n");
+	} else {
+		audio_info("bcm2835 ALSA chip created!\n");
+		platform_set_drvdata(pdev, (void*)(long)dev);
+	}
+
+	dev++;
+
+	return 0;
+
+out_card_register:
+	out_bcm2835_new_ctl :
+		out_bcm2835_new_spdif :
+		out_bcm2835_new_pcm :
+		out_bcm2835_create :
+		BUG_ON(!g_card);
+	if (snd_card_free(g_card))
+		dev_err(&pdev->dev, "Failed to free Registered alsa card\n");
+	g_card = NULL;
+out:
+	dev = SNDRV_CARDS; /* stop more avail_substreams from being probed */
+	dev_err(&pdev->dev, "BCM2835 ALSA Probe failed !!\n");
+	return err;
+}
+
+static int snd_bcm2835_alsa_remove(struct platform_device *pdev)
+{
+	int idx;
+	void *drv_data;
+
+	drv_data = platform_get_drvdata(pdev);
+
+	if (drv_data == (void *) g_card) {
+		/* This is the card device */
+		snd_card_free((struct snd_card *)drv_data);
+		g_card = NULL;
+		g_chip = NULL;
+	} else {
+		idx = (int)(long)drv_data;
+		if (g_card) {
+			BUG_ON(!g_chip);
+			/* We pass chip device numbers in audio ipc devices
+			 * other than the one we registered our card with
+			 */
+			idx = (int)(long)drv_data;
+			BUG_ON(!idx || idx > MAX_SUBSTREAMS);
+			g_chip->avail_substreams &= ~(1 << idx);
+			/* There should be atleast one substream registered
+			 * after we are done here, as it wil be removed when
+			 * the *remove* is called for the card device
+			 */
+			BUG_ON(!g_chip->avail_substreams);
+		}
+	}
+
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int snd_bcm2835_alsa_suspend(struct platform_device *pdev,
+	pm_message_t state)
+{
+	return 0;
+}
+
+static int snd_bcm2835_alsa_resume(struct platform_device *pdev)
+{
+	return 0;
+}
+
+#endif
+
+static const struct of_device_id snd_bcm2835_of_match_table[] = {
+	{ .compatible = "brcm,bcm2835-audio",},
+	{},
+};
+MODULE_DEVICE_TABLE(of, snd_bcm2835_of_match_table);
+
+static struct platform_driver bcm2835_alsa0_driver = {
+	.probe = snd_bcm2835_alsa_probe,
+	.remove = snd_bcm2835_alsa_remove,
+#ifdef CONFIG_PM
+	.suspend = snd_bcm2835_alsa_suspend,
+	.resume = snd_bcm2835_alsa_resume,
+#endif
+	.driver =
+	{
+		.name = "bcm2835_AUD0",
+		.owner = THIS_MODULE,
+		.of_match_table = snd_bcm2835_of_match_table,
+	},
+};
+
+static struct platform_driver bcm2835_alsa1_driver = {
+	.probe = snd_bcm2835_alsa_probe,
+	.remove = snd_bcm2835_alsa_remove,
+#ifdef CONFIG_PM
+	.suspend = snd_bcm2835_alsa_suspend,
+	.resume = snd_bcm2835_alsa_resume,
+#endif
+	.driver =
+	{
+		.name = "bcm2835_AUD1",
+		.owner = THIS_MODULE,
+	},
+};
+
+static struct platform_driver bcm2835_alsa2_driver = {
+	.probe = snd_bcm2835_alsa_probe,
+	.remove = snd_bcm2835_alsa_remove,
+#ifdef CONFIG_PM
+	.suspend = snd_bcm2835_alsa_suspend,
+	.resume = snd_bcm2835_alsa_resume,
+#endif
+	.driver =
+	{
+		.name = "bcm2835_AUD2",
+		.owner = THIS_MODULE,
+	},
+};
+
+static struct platform_driver bcm2835_alsa3_driver = {
+	.probe = snd_bcm2835_alsa_probe,
+	.remove = snd_bcm2835_alsa_remove,
+#ifdef CONFIG_PM
+	.suspend = snd_bcm2835_alsa_suspend,
+	.resume = snd_bcm2835_alsa_resume,
+#endif
+	.driver =
+	{
+		.name = "bcm2835_AUD3",
+		.owner = THIS_MODULE,
+	},
+};
+
+static struct platform_driver bcm2835_alsa4_driver = {
+	.probe = snd_bcm2835_alsa_probe,
+	.remove = snd_bcm2835_alsa_remove,
+#ifdef CONFIG_PM
+	.suspend = snd_bcm2835_alsa_suspend,
+	.resume = snd_bcm2835_alsa_resume,
+#endif
+	.driver =
+	{
+		.name = "bcm2835_AUD4",
+		.owner = THIS_MODULE,
+	},
+};
+
+static struct platform_driver bcm2835_alsa5_driver = {
+	.probe = snd_bcm2835_alsa_probe,
+	.remove = snd_bcm2835_alsa_remove,
+#ifdef CONFIG_PM
+	.suspend = snd_bcm2835_alsa_suspend,
+	.resume = snd_bcm2835_alsa_resume,
+#endif
+	.driver =
+	{
+		.name = "bcm2835_AUD5",
+		.owner = THIS_MODULE,
+	},
+};
+
+static struct platform_driver bcm2835_alsa6_driver = {
+	.probe = snd_bcm2835_alsa_probe,
+	.remove = snd_bcm2835_alsa_remove,
+#ifdef CONFIG_PM
+	.suspend = snd_bcm2835_alsa_suspend,
+	.resume = snd_bcm2835_alsa_resume,
+#endif
+	.driver =
+	{
+		.name = "bcm2835_AUD6",
+		.owner = THIS_MODULE,
+	},
+};
+
+static struct platform_driver bcm2835_alsa7_driver = {
+	.probe = snd_bcm2835_alsa_probe,
+	.remove = snd_bcm2835_alsa_remove,
+#ifdef CONFIG_PM
+	.suspend = snd_bcm2835_alsa_suspend,
+	.resume = snd_bcm2835_alsa_resume,
+#endif
+	.driver =
+	{
+		.name = "bcm2835_AUD7",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int bcm2835_alsa_device_init(void)
+{
+	int err;
+	err = platform_driver_register(&bcm2835_alsa0_driver);
+	if (err) {
+		pr_err("Error registering bcm2835_alsa0_driver %d .\n", err);
+		goto out;
+	}
+
+	err = platform_driver_register(&bcm2835_alsa1_driver);
+	if (err) {
+		pr_err("Error registering bcm2835_alsa0_driver %d .\n", err);
+		goto unregister_0;
+	}
+
+	err = platform_driver_register(&bcm2835_alsa2_driver);
+	if (err) {
+		pr_err("Error registering bcm2835_alsa0_driver %d .\n", err);
+		goto unregister_1;
+	}
+
+	err = platform_driver_register(&bcm2835_alsa3_driver);
+	if (err) {
+		pr_err("Error registering bcm2835_alsa0_driver %d .\n", err);
+		goto unregister_2;
+	}
+
+	err = platform_driver_register(&bcm2835_alsa4_driver);
+	if (err) {
+		pr_err("Error registering bcm2835_alsa0_driver %d .\n", err);
+		goto unregister_3;
+	}
+
+	err = platform_driver_register(&bcm2835_alsa5_driver);
+	if (err) {
+		pr_err("Error registering bcm2835_alsa0_driver %d .\n", err);
+		goto unregister_4;
+	}
+
+	err = platform_driver_register(&bcm2835_alsa6_driver);
+	if (err) {
+		pr_err("Error registering bcm2835_alsa0_driver %d .\n", err);
+		goto unregister_5;
+	}
+
+	err = platform_driver_register(&bcm2835_alsa7_driver);
+	if (err) {
+		pr_err("Error registering bcm2835_alsa0_driver %d .\n", err);
+		goto unregister_6;
+	}
+
+	return 0;
+
+unregister_6:
+	platform_driver_unregister(&bcm2835_alsa6_driver);
+unregister_5:
+	platform_driver_unregister(&bcm2835_alsa5_driver);
+unregister_4:
+	platform_driver_unregister(&bcm2835_alsa4_driver);
+unregister_3:
+	platform_driver_unregister(&bcm2835_alsa3_driver);
+unregister_2:
+	platform_driver_unregister(&bcm2835_alsa2_driver);
+unregister_1:
+	platform_driver_unregister(&bcm2835_alsa1_driver);
+unregister_0:
+	platform_driver_unregister(&bcm2835_alsa0_driver);
+out:
+	return err;
+}
+
+static void bcm2835_alsa_device_exit(void)
+{
+	platform_driver_unregister(&bcm2835_alsa0_driver);
+	platform_driver_unregister(&bcm2835_alsa1_driver);
+	platform_driver_unregister(&bcm2835_alsa2_driver);
+	platform_driver_unregister(&bcm2835_alsa3_driver);
+	platform_driver_unregister(&bcm2835_alsa4_driver);
+	platform_driver_unregister(&bcm2835_alsa5_driver);
+	platform_driver_unregister(&bcm2835_alsa6_driver);
+	platform_driver_unregister(&bcm2835_alsa7_driver);
+}
+
+late_initcall(bcm2835_alsa_device_init);
+module_exit(bcm2835_alsa_device_exit);
+
+MODULE_AUTHOR("Dom Cobley");
+MODULE_DESCRIPTION("Alsa driver for BCM2835 chip");
+MODULE_LICENSE("GPL");

drivers/staging/bcm2835-audio/bcm2835.h

+/*****************************************************************************
+ * Copyright 2011 Broadcom Corporation.  All rights reserved.
+ *
+ * Unless you and Broadcom execute a separate written software license
+ * agreement governing use of this software, this software is licensed to you
+ * under the terms of the GNU General Public License version 2, available at
+ * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+ *
+ * Notwithstanding the above, under no circumstances may you combine this
+ * software in any way with any other Broadcom software provided under a
+ * license other than the GPL, without Broadcom's express prior written
+ * consent.
+ *****************************************************************************/
+
+#ifndef __SOUND_ARM_BCM2835_H
+#define __SOUND_ARM_BCM2835_H
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/pcm-indirect.h>
+#include <linux/workqueue.h>
+
+/*
+#define AUDIO_DEBUG_ENABLE
+#define AUDIO_VERBOSE_DEBUG_ENABLE
+ */
+
+/* Debug macros */
+
+#ifdef AUDIO_DEBUG_ENABLE
+#ifdef AUDIO_VERBOSE_DEBUG_ENABLE
+
+#define audio_debug(fmt, arg...) \
+	printk(KERN_INFO"%s:%d " fmt, __func__, __LINE__, ##arg)
+
+#define audio_info(fmt, arg...) \
+	printk(KERN_INFO"%s:%d " fmt, __func__, __LINE__, ##arg)
+
+#else
+
+#define audio_debug(fmt, arg...)
+
+#define audio_info(fmt, arg...)
+
+#endif /* AUDIO_VERBOSE_DEBUG_ENABLE */
+
+#else
+
+#define audio_debug(fmt, arg...)
+
+#define audio_info(fmt, arg...)
+
+#endif /* AUDIO_DEBUG_ENABLE */
+
+#define audio_error(fmt, arg...) \
+	printk(KERN_ERR"%s:%d " fmt, __func__, __LINE__, ##arg)
+
+#define audio_warning(fmt, arg...) \
+	printk(KERN_WARNING"%s:%d " fmt, __func__, __LINE__, ##arg)
+
+#define audio_alert(fmt, arg...) \
+	printk(KERN_ALERT"%s:%d " fmt, __func__, __LINE__, ##arg)
+
+#define MAX_SUBSTREAMS   (8)
+#define AVAIL_SUBSTREAMS_MASK  (0xff)
+
+enum {
+	CTRL_VOL_MUTE,
+	CTRL_VOL_UNMUTE
+};
+
+/* macros for alsa2chip and chip2alsa, instead of functions */
+
+#define alsa2chip(vol) (uint)(-((vol << 8) / 100)) /* convert alsa to chip volume (defined as macro rather than function call) */
+#define chip2alsa(vol) -((vol * 100) >> 8)   /* convert chip to alsa volume */
+
+/* Some constants for values .. */
+enum snd_bcm2835_route {
+	AUDIO_DEST_AUTO = 0,
+	AUDIO_DEST_HEADPHONES = 1,
+	AUDIO_DEST_HDMI = 2,
+	AUDIO_DEST_MAX,
+};
+
+enum snd_bcm2835_ctrl {
+	PCM_PLAYBACK_VOLUME,
+	PCM_PLAYBACK_MUTE,
+	PCM_PLAYBACK_DEVICE,
+};
+
+/* definition of the chip-specific record */
+struct bcm2835_chip {
+	struct snd_card *card;
+	struct snd_pcm *pcm;
+	struct snd_pcm *pcm_spdif;
+	/* Bitmat for valid reg_base and irq numbers */
+	unsigned int avail_substreams;
+	struct platform_device *pdev[MAX_SUBSTREAMS];
+	struct bcm2835_alsa_stream *alsa_stream[MAX_SUBSTREAMS];
+
+	int volume;
+	int old_volume; /* stores the volume value whist muted */
+	int dest;
+	int mute;
+
+	unsigned int opened;
+	unsigned int spdif_status;
+	struct mutex audio_mutex;
+};
+
+struct bcm2835_alsa_stream {
+	struct bcm2835_chip *chip;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_indirect pcm_indirect;
+
+	struct semaphore buffers_update_sem;
+	struct semaphore control_sem;
+	spinlock_t lock;
+	volatile unsigned int control;
+	volatile unsigned int status;
+
+	int open;
+	int running;
+	int draining;
+
+	int channels;
+	int params_rate;
+	int pcm_format_width;
+
+	unsigned int pos;
+	unsigned int buffer_size;
+	unsigned int period_size;
+
+	unsigned int enable_fifo_irq;
+	irq_handler_t fifo_irq_handler;
+
+	atomic_t retrieved;
+	struct bcm2835_audio_instance *instance;
+	struct workqueue_struct *my_wq;
+	int idx;
+};
+
+int snd_bcm2835_new_ctl(struct bcm2835_chip *chip);
+int snd_bcm2835_new_pcm(struct bcm2835_chip *chip);
+int snd_bcm2835_new_spdif_pcm(struct bcm2835_chip *chip);
+
+int bcm2835_audio_open(struct bcm2835_alsa_stream *alsa_stream);
+int bcm2835_audio_close(struct bcm2835_alsa_stream *alsa_stream);
+int bcm2835_audio_set_params(struct bcm2835_alsa_stream *alsa_stream,
+			     unsigned int channels, unsigned int samplerate,
+			     unsigned int bps);
+int bcm2835_audio_setup(struct bcm2835_alsa_stream *alsa_stream);
+int bcm2835_audio_start(struct bcm2835_alsa_stream *alsa_stream);
+int bcm2835_audio_stop(struct bcm2835_alsa_stream *alsa_stream);
+int bcm2835_audio_set_ctls(struct bcm2835_chip *chip);
+int bcm2835_audio_write(struct bcm2835_alsa_stream *alsa_stream,
+			unsigned int count,
+			void *src);
+unsigned int bcm2835_audio_retrieve_buffers(struct bcm2835_alsa_stream *alsa_stream);
+void bcm2835_audio_flush_buffers(struct bcm2835_alsa_stream *alsa_stream);
+void bcm2835_audio_flush_playback_buffers(struct bcm2835_alsa_stream *alsa_stream);
+
+#endif /* __SOUND_ARM_BCM2835_H */

drivers/staging/bcm2835-audio/vc_vchi_audioserv_defs.h

+/*****************************************************************************
+ * Copyright 2011 Broadcom Corporation.  All rights reserved.
+ *
+ * Unless you and Broadcom execute a separate written software license
+ * agreement governing use of this software, this software is licensed to you
+ * under the terms of the GNU General Public License version 2, available at
+ * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+ *
+ * Notwithstanding the above, under no circumstances may you combine this
+ * software in any way with any other Broadcom software provided under a
+ * license other than the GPL, without Broadcom's express prior written
+ * consent.
+ *****************************************************************************/
+
+#ifndef _VC_AUDIO_DEFS_H_
+#define _VC_AUDIO_DEFS_H_
+
+#define VC_AUDIOSERV_MIN_VER 1
+#define VC_AUDIOSERV_VER 2
+
+/* FourCC code used for VCHI connection */
+#define VC_AUDIO_SERVER_NAME  MAKE_FOURCC("AUDS")
+
+/* Maximum message length */
+#define VC_AUDIO_MAX_MSG_LEN  (sizeof( VC_AUDIO_MSG_T ))
+
+/*
+ *  List of screens that are currently supported
+ *  All message types supported for HOST->VC direction
+ */
+
+enum vc_audio_msg_type {
+	VC_AUDIO_MSG_TYPE_RESULT, // Generic result
+	VC_AUDIO_MSG_TYPE_COMPLETE, // Generic result
+	VC_AUDIO_MSG_TYPE_CONFIG, // Configure audio
+	VC_AUDIO_MSG_TYPE_CONTROL, // Configure audio
+	VC_AUDIO_MSG_TYPE_OPEN, // Configure audio
+	VC_AUDIO_MSG_TYPE_CLOSE, // Configure audio
+	VC_AUDIO_MSG_TYPE_START, // Configure audio
+	VC_AUDIO_MSG_TYPE_STOP, // Configure audio
+	VC_AUDIO_MSG_TYPE_WRITE, // Configure audio
+	VC_AUDIO_MSG_TYPE_MAX
+};
+
+/* configure the audio */
+
+struct vc_audio_config {
+	u32 channels;
+	u32 samplerate;
+	u32 bps;
+};
+
+struct vc_audio_control {
+	u32 volume;
+	u32 dest;
+};
+
+struct vc_audio_open {
+	u32 dummy;
+};
+
+struct vc_audio_close {
+	u32 dummy;
+};
+
+struct vc_audio_start {
+	u32 dummy;
+};
+
+struct vc_audio_stop {
+	u32 draining;
+};
+
+/* configure the write audio samples */
+struct vc_audio_write {
+	u32 count; // in bytes
+#if defined(CONFIG_64BIT)
+	u32 callbackl;
+	u32 callbackh;
+#else
+	void *callback;
+	void *cookie;
+#endif
+	s16 silence;
+	s16 max_packet;
+};
+
+/* Generic result for a request (VC->HOST) */
+struct vc_audio_result {
+	s32 success; // Success value
+};
+
+/* Generic result for a request (VC->HOST) */
+struct vc_audio_complete {
+	s32 count; // Success value
+#if defined(CONFIG_64BIT)
+	u32 callbackl;
+	u32 callbackh;
+#else
+	void *callback;
+	void *cookie;
+#endif
+};
+
+/* Message header for all messages in HOST->VC direction */
+struct vc_audio_msg {
+	s32 type; /* Message type (VC_AUDIO_MSG_TYPE) */
+	union {
+		struct vc_audio_config config;
+		struct vc_audio_control control;
+		struct vc_audio_open open;
+		struct vc_audio_close close;
+		struct vc_audio_start start;
+		struct vc_audio_stop stop;
+		struct vc_audio_write write;
+		struct vc_audio_result result;
+		struct vc_audio_complete complete;
+	} u;
+};
+
+#endif /* _VC_AUDIO_DEFS_H_ */