Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 733 insertions, 0 deletions

diff --git a/sound/firewire/isight.c b/sound/firewire/isight.c
new file mode 100644
index 000000000..f16e2e223
--- /dev/null
+++ b/sound/firewire/isight.c
@@ -0,0 +1,733 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Apple iSight audio driver
+ *
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ */
+
+#include <asm/byteorder.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/firewire.h>
+#include <linux/firewire-constants.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/tlv.h>
+#include "lib.h"
+#include "iso-resources.h"
+#include "packets-buffer.h"
+
+#define OUI_APPLE		0x000a27
+#define MODEL_APPLE_ISIGHT	0x000008
+#define SW_ISIGHT_AUDIO		0x000010
+
+#define REG_AUDIO_ENABLE	0x000
+#define  AUDIO_ENABLE		0x80000000
+#define REG_DEF_AUDIO_GAIN	0x204
+#define REG_GAIN_RAW_START	0x210
+#define REG_GAIN_RAW_END	0x214
+#define REG_GAIN_DB_START	0x218
+#define REG_GAIN_DB_END		0x21c
+#define REG_SAMPLE_RATE_INQUIRY	0x280
+#define REG_ISO_TX_CONFIG	0x300
+#define  SPEED_SHIFT		16
+#define REG_SAMPLE_RATE		0x400
+#define  RATE_48000		0x80000000
+#define REG_GAIN		0x500
+#define REG_MUTE		0x504
+
+#define MAX_FRAMES_PER_PACKET	475
+
+#define QUEUE_LENGTH		20
+
+struct isight {
+	struct snd_card *card;
+	struct fw_unit *unit;
+	struct fw_device *device;
+	u64 audio_base;
+	struct snd_pcm_substream *pcm;
+	struct mutex mutex;
+	struct iso_packets_buffer buffer;
+	struct fw_iso_resources resources;
+	struct fw_iso_context *context;
+	bool pcm_active;
+	bool pcm_running;
+	bool first_packet;
+	int packet_index;
+	u32 total_samples;
+	unsigned int buffer_pointer;
+	unsigned int period_counter;
+	s32 gain_min, gain_max;
+	unsigned int gain_tlv[4];
+};
+
+struct audio_payload {
+	__be32 sample_count;
+	__be32 signature;
+	__be32 sample_total;
+	__be32 reserved;
+	__be16 samples[2 * MAX_FRAMES_PER_PACKET];
+};
+
+MODULE_DESCRIPTION("iSight audio driver");
+MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
+MODULE_LICENSE("GPL");
+
+static struct fw_iso_packet audio_packet = {
+	.payload_length = sizeof(struct audio_payload),
+	.interrupt = 1,
+	.header_length = 4,
+};
+
+static void isight_update_pointers(struct isight *isight, unsigned int count)
+{
+	struct snd_pcm_runtime *runtime = isight->pcm->runtime;
+	unsigned int ptr;
+
+	smp_wmb(); /* update buffer data before buffer pointer */
+
+	ptr = isight->buffer_pointer;
+	ptr += count;
+	if (ptr >= runtime->buffer_size)
+		ptr -= runtime->buffer_size;
+	WRITE_ONCE(isight->buffer_pointer, ptr);
+
+	isight->period_counter += count;
+	if (isight->period_counter >= runtime->period_size) {
+		isight->period_counter -= runtime->period_size;
+		snd_pcm_period_elapsed(isight->pcm);
+	}
+}
+
+static void isight_samples(struct isight *isight,
+			   const __be16 *samples, unsigned int count)
+{
+	struct snd_pcm_runtime *runtime;
+	unsigned int count1;
+
+	if (!READ_ONCE(isight->pcm_running))
+		return;
+
+	runtime = isight->pcm->runtime;
+	if (isight->buffer_pointer + count <= runtime->buffer_size) {
+		memcpy(runtime->dma_area + isight->buffer_pointer * 4,
+		       samples, count * 4);
+	} else {
+		count1 = runtime->buffer_size - isight->buffer_pointer;
+		memcpy(runtime->dma_area + isight->buffer_pointer * 4,
+		       samples, count1 * 4);
+		samples += count1 * 2;
+		memcpy(runtime->dma_area, samples, (count - count1) * 4);
+	}
+
+	isight_update_pointers(isight, count);
+}
+
+static void isight_pcm_abort(struct isight *isight)
+{
+	if (READ_ONCE(isight->pcm_active))
+		snd_pcm_stop_xrun(isight->pcm);
+}
+
+static void isight_dropped_samples(struct isight *isight, unsigned int total)
+{
+	struct snd_pcm_runtime *runtime;
+	u32 dropped;
+	unsigned int count1;
+
+	if (!READ_ONCE(isight->pcm_running))
+		return;
+
+	runtime = isight->pcm->runtime;
+	dropped = total - isight->total_samples;
+	if (dropped < runtime->buffer_size) {
+		if (isight->buffer_pointer + dropped <= runtime->buffer_size) {
+			memset(runtime->dma_area + isight->buffer_pointer * 4,
+			       0, dropped * 4);
+		} else {
+			count1 = runtime->buffer_size - isight->buffer_pointer;
+			memset(runtime->dma_area + isight->buffer_pointer * 4,
+			       0, count1 * 4);
+			memset(runtime->dma_area, 0, (dropped - count1) * 4);
+		}
+		isight_update_pointers(isight, dropped);
+	} else {
+		isight_pcm_abort(isight);
+	}
+}
+
+static void isight_packet(struct fw_iso_context *context, u32 cycle,
+			  size_t header_length, void *header, void *data)
+{
+	struct isight *isight = data;
+	const struct audio_payload *payload;
+	unsigned int index, length, count, total;
+	int err;
+
+	if (isight->packet_index < 0)
+		return;
+	index = isight->packet_index;
+	payload = isight->buffer.packets[index].buffer;
+	length = be32_to_cpup(header) >> 16;
+
+	if (likely(length >= 16 &&
+		   payload->signature == cpu_to_be32(0x73676874/*"sght"*/))) {
+		count = be32_to_cpu(payload->sample_count);
+		if (likely(count <= (length - 16) / 4 &&
+			   count <= MAX_FRAMES_PER_PACKET)) {
+			total = be32_to_cpu(payload->sample_total);
+			if (unlikely(total != isight->total_samples)) {
+				if (!isight->first_packet)
+					isight_dropped_samples(isight, total);
+				isight->first_packet = false;
+				isight->total_samples = total;
+			}
+
+			isight_samples(isight, payload->samples, count);
+			isight->total_samples += count;
+		}
+	}
+
+	err = fw_iso_context_queue(isight->context, &audio_packet,
+				   &isight->buffer.iso_buffer,
+				   isight->buffer.packets[index].offset);
+	if (err < 0) {
+		dev_err(&isight->unit->device, "queueing error: %d\n", err);
+		isight_pcm_abort(isight);
+		isight->packet_index = -1;
+		return;
+	}
+	fw_iso_context_queue_flush(isight->context);
+
+	if (++index >= QUEUE_LENGTH)
+		index = 0;
+	isight->packet_index = index;
+}
+
+static int isight_connect(struct isight *isight)
+{
+	int ch, err;
+	__be32 value;
+
+retry_after_bus_reset:
+	ch = fw_iso_resources_allocate(&isight->resources,
+				       sizeof(struct audio_payload),
+				       isight->device->max_speed);
+	if (ch < 0) {
+		err = ch;
+		goto error;
+	}
+
+	value = cpu_to_be32(ch | (isight->device->max_speed << SPEED_SHIFT));
+	err = snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 isight->audio_base + REG_ISO_TX_CONFIG,
+				 &value, 4, FW_FIXED_GENERATION |
+				 isight->resources.generation);
+	if (err == -EAGAIN) {
+		fw_iso_resources_free(&isight->resources);
+		goto retry_after_bus_reset;
+	} else if (err < 0) {
+		goto err_resources;
+	}
+
+	return 0;
+
+err_resources:
+	fw_iso_resources_free(&isight->resources);
+error:
+	return err;
+}
+
+static int isight_open(struct snd_pcm_substream *substream)
+{
+	static const struct snd_pcm_hardware hardware = {
+		.info = SNDRV_PCM_INFO_MMAP |
+			SNDRV_PCM_INFO_MMAP_VALID |
+			SNDRV_PCM_INFO_BATCH |
+			SNDRV_PCM_INFO_INTERLEAVED |
+			SNDRV_PCM_INFO_BLOCK_TRANSFER,
+		.formats = SNDRV_PCM_FMTBIT_S16_BE,
+		.rates = SNDRV_PCM_RATE_48000,
+		.rate_min = 48000,
+		.rate_max = 48000,
+		.channels_min = 2,
+		.channels_max = 2,
+		.buffer_bytes_max = 4 * 1024 * 1024,
+		.period_bytes_min = MAX_FRAMES_PER_PACKET * 4,
+		.period_bytes_max = 1024 * 1024,
+		.periods_min = 2,
+		.periods_max = UINT_MAX,
+	};
+	struct isight *isight = substream->private_data;
+
+	substream->runtime->hw = hardware;
+
+	return iso_packets_buffer_init(&isight->buffer, isight->unit,
+				       QUEUE_LENGTH,
+				       sizeof(struct audio_payload),
+				       DMA_FROM_DEVICE);
+}
+
+static int isight_close(struct snd_pcm_substream *substream)
+{
+	struct isight *isight = substream->private_data;
+
+	iso_packets_buffer_destroy(&isight->buffer, isight->unit);
+
+	return 0;
+}
+
+static int isight_hw_params(struct snd_pcm_substream *substream,
+			    struct snd_pcm_hw_params *hw_params)
+{
+	struct isight *isight = substream->private_data;
+
+	WRITE_ONCE(isight->pcm_active, true);
+
+	return 0;
+}
+
+static int reg_read(struct isight *isight, int offset, __be32 *value)
+{
+	return snd_fw_transaction(isight->unit, TCODE_READ_QUADLET_REQUEST,
+				  isight->audio_base + offset, value, 4, 0);
+}
+
+static int reg_write(struct isight *isight, int offset, __be32 value)
+{
+	return snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
+				  isight->audio_base + offset, &value, 4, 0);
+}
+
+static void isight_stop_streaming(struct isight *isight)
+{
+	__be32 value;
+
+	if (!isight->context)
+		return;
+
+	fw_iso_context_stop(isight->context);
+	fw_iso_context_destroy(isight->context);
+	isight->context = NULL;
+	fw_iso_resources_free(&isight->resources);
+	value = 0;
+	snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
+			   isight->audio_base + REG_AUDIO_ENABLE,
+			   &value, 4, FW_QUIET);
+}
+
+static int isight_hw_free(struct snd_pcm_substream *substream)
+{
+	struct isight *isight = substream->private_data;
+
+	WRITE_ONCE(isight->pcm_active, false);
+
+	guard(mutex)(&isight->mutex);
+	isight_stop_streaming(isight);
+
+	return 0;
+}
+
+static int isight_start_streaming(struct isight *isight)
+{
+	unsigned int i;
+	int err;
+
+	if (isight->context) {
+		if (isight->packet_index < 0)
+			isight_stop_streaming(isight);
+		else
+			return 0;
+	}
+
+	err = reg_write(isight, REG_SAMPLE_RATE, cpu_to_be32(RATE_48000));
+	if (err < 0)
+		goto error;
+
+	err = isight_connect(isight);
+	if (err < 0)
+		goto error;
+
+	err = reg_write(isight, REG_AUDIO_ENABLE, cpu_to_be32(AUDIO_ENABLE));
+	if (err < 0)
+		goto err_resources;
+
+	isight->context = fw_iso_context_create(isight->device->card,
+						FW_ISO_CONTEXT_RECEIVE,
+						isight->resources.channel,
+						isight->device->max_speed,
+						4, isight_packet, isight);
+	if (IS_ERR(isight->context)) {
+		err = PTR_ERR(isight->context);
+		isight->context = NULL;
+		goto err_resources;
+	}
+
+	for (i = 0; i < QUEUE_LENGTH; ++i) {
+		err = fw_iso_context_queue(isight->context, &audio_packet,
+					   &isight->buffer.iso_buffer,
+					   isight->buffer.packets[i].offset);
+		if (err < 0)
+			goto err_context;
+	}
+
+	isight->first_packet = true;
+	isight->packet_index = 0;
+
+	err = fw_iso_context_start(isight->context, -1, 0,
+				   FW_ISO_CONTEXT_MATCH_ALL_TAGS/*?*/);
+	if (err < 0)
+		goto err_context;
+
+	return 0;
+
+err_context:
+	fw_iso_context_destroy(isight->context);
+	isight->context = NULL;
+err_resources:
+	fw_iso_resources_free(&isight->resources);
+	reg_write(isight, REG_AUDIO_ENABLE, 0);
+error:
+	return err;
+}
+
+static int isight_prepare(struct snd_pcm_substream *substream)
+{
+	struct isight *isight = substream->private_data;
+
+	isight->buffer_pointer = 0;
+	isight->period_counter = 0;
+
+	guard(mutex)(&isight->mutex);
+	return isight_start_streaming(isight);
+}
+
+static int isight_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct isight *isight = substream->private_data;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		WRITE_ONCE(isight->pcm_running, true);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+		WRITE_ONCE(isight->pcm_running, false);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static snd_pcm_uframes_t isight_pointer(struct snd_pcm_substream *substream)
+{
+	struct isight *isight = substream->private_data;
+
+	return READ_ONCE(isight->buffer_pointer);
+}
+
+static int isight_create_pcm(struct isight *isight)
+{
+	static const struct snd_pcm_ops ops = {
+		.open      = isight_open,
+		.close     = isight_close,
+		.hw_params = isight_hw_params,
+		.hw_free   = isight_hw_free,
+		.prepare   = isight_prepare,
+		.trigger   = isight_trigger,
+		.pointer   = isight_pointer,
+	};
+	struct snd_pcm *pcm;
+	int err;
+
+	err = snd_pcm_new(isight->card, "iSight", 0, 0, 1, &pcm);
+	if (err < 0)
+		return err;
+	pcm->private_data = isight;
+	pcm->nonatomic = true;
+	strscpy(pcm->name, "iSight");
+	isight->pcm = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
+	isight->pcm->ops = &ops;
+	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
+
+	return 0;
+}
+
+static int isight_gain_info(struct snd_kcontrol *ctl,
+			    struct snd_ctl_elem_info *info)
+{
+	struct isight *isight = ctl->private_data;
+
+	info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	info->count = 1;
+	info->value.integer.min = isight->gain_min;
+	info->value.integer.max = isight->gain_max;
+
+	return 0;
+}
+
+static int isight_gain_get(struct snd_kcontrol *ctl,
+			   struct snd_ctl_elem_value *value)
+{
+	struct isight *isight = ctl->private_data;
+	__be32 gain;
+	int err;
+
+	err = reg_read(isight, REG_GAIN, &gain);
+	if (err < 0)
+		return err;
+
+	value->value.integer.value[0] = (s32)be32_to_cpu(gain);
+
+	return 0;
+}
+
+static int isight_gain_put(struct snd_kcontrol *ctl,
+			   struct snd_ctl_elem_value *value)
+{
+	struct isight *isight = ctl->private_data;
+
+	if (value->value.integer.value[0] < isight->gain_min ||
+	    value->value.integer.value[0] > isight->gain_max)
+		return -EINVAL;
+
+	return reg_write(isight, REG_GAIN,
+			 cpu_to_be32(value->value.integer.value[0]));
+}
+
+static int isight_mute_get(struct snd_kcontrol *ctl,
+			   struct snd_ctl_elem_value *value)
+{
+	struct isight *isight = ctl->private_data;
+	__be32 mute;
+	int err;
+
+	err = reg_read(isight, REG_MUTE, &mute);
+	if (err < 0)
+		return err;
+
+	value->value.integer.value[0] = !mute;
+
+	return 0;
+}
+
+static int isight_mute_put(struct snd_kcontrol *ctl,
+			   struct snd_ctl_elem_value *value)
+{
+	struct isight *isight = ctl->private_data;
+
+	return reg_write(isight, REG_MUTE,
+			 (__force __be32)!value->value.integer.value[0]);
+}
+
+static int isight_create_mixer(struct isight *isight)
+{
+	static const struct snd_kcontrol_new gain_control = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Mic Capture Volume",
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+			  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+		.info = isight_gain_info,
+		.get = isight_gain_get,
+		.put = isight_gain_put,
+	};
+	static const struct snd_kcontrol_new mute_control = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Mic Capture Switch",
+		.info = snd_ctl_boolean_mono_info,
+		.get = isight_mute_get,
+		.put = isight_mute_put,
+	};
+	__be32 value;
+	struct snd_kcontrol *ctl;
+	int err;
+
+	err = reg_read(isight, REG_GAIN_RAW_START, &value);
+	if (err < 0)
+		return err;
+	isight->gain_min = be32_to_cpu(value);
+
+	err = reg_read(isight, REG_GAIN_RAW_END, &value);
+	if (err < 0)
+		return err;
+	isight->gain_max = be32_to_cpu(value);
+
+	isight->gain_tlv[SNDRV_CTL_TLVO_TYPE] = SNDRV_CTL_TLVT_DB_MINMAX;
+	isight->gain_tlv[SNDRV_CTL_TLVO_LEN] = 2 * sizeof(unsigned int);
+
+	err = reg_read(isight, REG_GAIN_DB_START, &value);
+	if (err < 0)
+		return err;
+	isight->gain_tlv[SNDRV_CTL_TLVO_DB_MINMAX_MIN] =
+						(s32)be32_to_cpu(value) * 100;
+
+	err = reg_read(isight, REG_GAIN_DB_END, &value);
+	if (err < 0)
+		return err;
+	isight->gain_tlv[SNDRV_CTL_TLVO_DB_MINMAX_MAX] =
+						(s32)be32_to_cpu(value) * 100;
+
+	ctl = snd_ctl_new1(&gain_control, isight);
+	if (ctl)
+		ctl->tlv.p = isight->gain_tlv;
+	err = snd_ctl_add(isight->card, ctl);
+	if (err < 0)
+		return err;
+
+	err = snd_ctl_add(isight->card, snd_ctl_new1(&mute_control, isight));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static void isight_card_free(struct snd_card *card)
+{
+	struct isight *isight = card->private_data;
+
+	fw_iso_resources_destroy(&isight->resources);
+}
+
+static u64 get_unit_base(struct fw_unit *unit)
+{
+	struct fw_csr_iterator i;
+	int key, value;
+
+	fw_csr_iterator_init(&i, unit->directory);
+	while (fw_csr_iterator_next(&i, &key, &value))
+		if (key == CSR_OFFSET)
+			return CSR_REGISTER_BASE + value * 4;
+	return 0;
+}
+
+static int isight_probe(struct fw_unit *unit,
+			const struct ieee1394_device_id *id)
+{
+	struct fw_device *fw_dev = fw_parent_device(unit);
+	struct snd_card *card;
+	struct isight *isight;
+	int err;
+
+	err = snd_card_new(&unit->device, -1, NULL, THIS_MODULE,
+			   sizeof(*isight), &card);
+	if (err < 0)
+		return err;
+
+	isight = card->private_data;
+	isight->card = card;
+	mutex_init(&isight->mutex);
+	isight->unit = fw_unit_get(unit);
+	isight->device = fw_dev;
+	isight->audio_base = get_unit_base(unit);
+	if (!isight->audio_base) {
+		dev_err(&unit->device, "audio unit base not found\n");
+		err = -ENXIO;
+		goto error;
+	}
+	fw_iso_resources_init(&isight->resources, unit);
+
+	card->private_free = isight_card_free;
+
+	strscpy(card->driver, "iSight");
+	strscpy(card->shortname, "Apple iSight");
+	snprintf(card->longname, sizeof(card->longname),
+		 "Apple iSight (GUID %08x%08x) at %s, S%d",
+		 fw_dev->config_rom[3], fw_dev->config_rom[4],
+		 dev_name(&unit->device), 100 << fw_dev->max_speed);
+	strscpy(card->mixername, "iSight");
+
+	err = isight_create_pcm(isight);
+	if (err < 0)
+		goto error;
+
+	err = isight_create_mixer(isight);
+	if (err < 0)
+		goto error;
+
+	err = snd_card_register(card);
+	if (err < 0)
+		goto error;
+
+	dev_set_drvdata(&unit->device, isight);
+
+	return 0;
+error:
+	snd_card_free(card);
+
+	mutex_destroy(&isight->mutex);
+	fw_unit_put(isight->unit);
+
+	return err;
+}
+
+static void isight_bus_reset(struct fw_unit *unit)
+{
+	struct isight *isight = dev_get_drvdata(&unit->device);
+
+	if (fw_iso_resources_update(&isight->resources) < 0) {
+		isight_pcm_abort(isight);
+
+		guard(mutex)(&isight->mutex);
+		isight_stop_streaming(isight);
+	}
+}
+
+static void isight_remove(struct fw_unit *unit)
+{
+	struct isight *isight = dev_get_drvdata(&unit->device);
+
+	isight_pcm_abort(isight);
+
+	snd_card_disconnect(isight->card);
+
+	scoped_guard(mutex, &isight->mutex) {
+		isight_stop_streaming(isight);
+	}
+
+	// Block till all of ALSA character devices are released.
+	snd_card_free(isight->card);
+
+	mutex_destroy(&isight->mutex);
+	fw_unit_put(isight->unit);
+}
+
+static const struct ieee1394_device_id isight_id_table[] = {
+	{
+		.match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
+				IEEE1394_MATCH_VERSION,
+		.specifier_id = OUI_APPLE,
+		.version      = SW_ISIGHT_AUDIO,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(ieee1394, isight_id_table);
+
+static struct fw_driver isight_driver = {
+	.driver   = {
+		.owner	= THIS_MODULE,
+		.name	= KBUILD_MODNAME,
+		.bus	= &fw_bus_type,
+	},
+	.probe    = isight_probe,
+	.update   = isight_bus_reset,
+	.remove   = isight_remove,
+	.id_table = isight_id_table,
+};
+
+static int __init alsa_isight_init(void)
+{
+	return driver_register(&isight_driver.driver);
+}
+
+static void __exit alsa_isight_exit(void)
+{
+	driver_unregister(&isight_driver.driver);
+}
+
+module_init(alsa_isight_init);
+module_exit(alsa_isight_exit);