cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cx231xx-audio.c (16985B)


      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *  Conexant Cx231xx audio extension
      4 *
      5 *  Copyright (C) 2008 <srinivasa.deevi at conexant dot com>
      6 *       Based on em28xx driver
      7 */
      8
      9#include "cx231xx.h"
     10#include <linux/kernel.h>
     11#include <linux/init.h>
     12#include <linux/sound.h>
     13#include <linux/spinlock.h>
     14#include <linux/soundcard.h>
     15#include <linux/slab.h>
     16#include <linux/module.h>
     17#include <sound/core.h>
     18#include <sound/pcm.h>
     19#include <sound/pcm_params.h>
     20#include <sound/info.h>
     21#include <sound/initval.h>
     22#include <sound/control.h>
     23#include <media/v4l2-common.h>
     24
     25static int debug;
     26module_param(debug, int, 0644);
     27MODULE_PARM_DESC(debug, "activates debug info");
     28
     29static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
     30
     31static int cx231xx_isoc_audio_deinit(struct cx231xx *dev)
     32{
     33	int i;
     34
     35	dev_dbg(dev->dev, "Stopping isoc\n");
     36
     37	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
     38		if (dev->adev.urb[i]) {
     39			if (!irqs_disabled())
     40				usb_kill_urb(dev->adev.urb[i]);
     41			else
     42				usb_unlink_urb(dev->adev.urb[i]);
     43
     44			usb_free_urb(dev->adev.urb[i]);
     45			dev->adev.urb[i] = NULL;
     46
     47			kfree(dev->adev.transfer_buffer[i]);
     48			dev->adev.transfer_buffer[i] = NULL;
     49		}
     50	}
     51
     52	return 0;
     53}
     54
     55static int cx231xx_bulk_audio_deinit(struct cx231xx *dev)
     56{
     57	int i;
     58
     59	dev_dbg(dev->dev, "Stopping bulk\n");
     60
     61	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
     62		if (dev->adev.urb[i]) {
     63			if (!irqs_disabled())
     64				usb_kill_urb(dev->adev.urb[i]);
     65			else
     66				usb_unlink_urb(dev->adev.urb[i]);
     67
     68			usb_free_urb(dev->adev.urb[i]);
     69			dev->adev.urb[i] = NULL;
     70
     71			kfree(dev->adev.transfer_buffer[i]);
     72			dev->adev.transfer_buffer[i] = NULL;
     73		}
     74	}
     75
     76	return 0;
     77}
     78
     79static void cx231xx_audio_isocirq(struct urb *urb)
     80{
     81	struct cx231xx *dev = urb->context;
     82	int i;
     83	unsigned int oldptr;
     84	int period_elapsed = 0;
     85	int status;
     86	unsigned char *cp;
     87	unsigned int stride;
     88	struct snd_pcm_substream *substream;
     89	struct snd_pcm_runtime *runtime;
     90
     91	if (dev->state & DEV_DISCONNECTED)
     92		return;
     93
     94	switch (urb->status) {
     95	case 0:		/* success */
     96	case -ETIMEDOUT:	/* NAK */
     97		break;
     98	case -ECONNRESET:	/* kill */
     99	case -ENOENT:
    100	case -ESHUTDOWN:
    101		return;
    102	default:		/* error */
    103		dev_dbg(dev->dev, "urb completion error %d.\n",
    104			urb->status);
    105		break;
    106	}
    107
    108	if (atomic_read(&dev->stream_started) == 0)
    109		return;
    110
    111	if (dev->adev.capture_pcm_substream) {
    112		substream = dev->adev.capture_pcm_substream;
    113		runtime = substream->runtime;
    114		stride = runtime->frame_bits >> 3;
    115
    116		for (i = 0; i < urb->number_of_packets; i++) {
    117			unsigned long flags;
    118			int length = urb->iso_frame_desc[i].actual_length /
    119				     stride;
    120			cp = (unsigned char *)urb->transfer_buffer +
    121					      urb->iso_frame_desc[i].offset;
    122
    123			if (!length)
    124				continue;
    125
    126			oldptr = dev->adev.hwptr_done_capture;
    127			if (oldptr + length >= runtime->buffer_size) {
    128				unsigned int cnt;
    129
    130				cnt = runtime->buffer_size - oldptr;
    131				memcpy(runtime->dma_area + oldptr * stride, cp,
    132				       cnt * stride);
    133				memcpy(runtime->dma_area, cp + cnt * stride,
    134				       length * stride - cnt * stride);
    135			} else {
    136				memcpy(runtime->dma_area + oldptr * stride, cp,
    137				       length * stride);
    138			}
    139
    140			snd_pcm_stream_lock_irqsave(substream, flags);
    141
    142			dev->adev.hwptr_done_capture += length;
    143			if (dev->adev.hwptr_done_capture >=
    144						runtime->buffer_size)
    145				dev->adev.hwptr_done_capture -=
    146						runtime->buffer_size;
    147
    148			dev->adev.capture_transfer_done += length;
    149			if (dev->adev.capture_transfer_done >=
    150				runtime->period_size) {
    151				dev->adev.capture_transfer_done -=
    152						runtime->period_size;
    153				period_elapsed = 1;
    154			}
    155			snd_pcm_stream_unlock_irqrestore(substream, flags);
    156		}
    157		if (period_elapsed)
    158			snd_pcm_period_elapsed(substream);
    159	}
    160	urb->status = 0;
    161
    162	status = usb_submit_urb(urb, GFP_ATOMIC);
    163	if (status < 0) {
    164		dev_err(dev->dev,
    165			"resubmit of audio urb failed (error=%i)\n",
    166			status);
    167	}
    168	return;
    169}
    170
    171static void cx231xx_audio_bulkirq(struct urb *urb)
    172{
    173	struct cx231xx *dev = urb->context;
    174	unsigned int oldptr;
    175	int period_elapsed = 0;
    176	int status;
    177	unsigned char *cp;
    178	unsigned int stride;
    179	struct snd_pcm_substream *substream;
    180	struct snd_pcm_runtime *runtime;
    181
    182	if (dev->state & DEV_DISCONNECTED)
    183		return;
    184
    185	switch (urb->status) {
    186	case 0:		/* success */
    187	case -ETIMEDOUT:	/* NAK */
    188		break;
    189	case -ECONNRESET:	/* kill */
    190	case -ENOENT:
    191	case -ESHUTDOWN:
    192		return;
    193	default:		/* error */
    194		dev_dbg(dev->dev, "urb completion error %d.\n",
    195			urb->status);
    196		break;
    197	}
    198
    199	if (atomic_read(&dev->stream_started) == 0)
    200		return;
    201
    202	if (dev->adev.capture_pcm_substream) {
    203		substream = dev->adev.capture_pcm_substream;
    204		runtime = substream->runtime;
    205		stride = runtime->frame_bits >> 3;
    206
    207		if (1) {
    208			unsigned long flags;
    209			int length = urb->actual_length /
    210				     stride;
    211			cp = (unsigned char *)urb->transfer_buffer;
    212
    213			oldptr = dev->adev.hwptr_done_capture;
    214			if (oldptr + length >= runtime->buffer_size) {
    215				unsigned int cnt;
    216
    217				cnt = runtime->buffer_size - oldptr;
    218				memcpy(runtime->dma_area + oldptr * stride, cp,
    219				       cnt * stride);
    220				memcpy(runtime->dma_area, cp + cnt * stride,
    221				       length * stride - cnt * stride);
    222			} else {
    223				memcpy(runtime->dma_area + oldptr * stride, cp,
    224				       length * stride);
    225			}
    226
    227			snd_pcm_stream_lock_irqsave(substream, flags);
    228
    229			dev->adev.hwptr_done_capture += length;
    230			if (dev->adev.hwptr_done_capture >=
    231						runtime->buffer_size)
    232				dev->adev.hwptr_done_capture -=
    233						runtime->buffer_size;
    234
    235			dev->adev.capture_transfer_done += length;
    236			if (dev->adev.capture_transfer_done >=
    237				runtime->period_size) {
    238				dev->adev.capture_transfer_done -=
    239						runtime->period_size;
    240				period_elapsed = 1;
    241			}
    242			snd_pcm_stream_unlock_irqrestore(substream, flags);
    243		}
    244		if (period_elapsed)
    245			snd_pcm_period_elapsed(substream);
    246	}
    247	urb->status = 0;
    248
    249	status = usb_submit_urb(urb, GFP_ATOMIC);
    250	if (status < 0) {
    251		dev_err(dev->dev,
    252			"resubmit of audio urb failed (error=%i)\n",
    253			status);
    254	}
    255	return;
    256}
    257
    258static int cx231xx_init_audio_isoc(struct cx231xx *dev)
    259{
    260	int i, errCode;
    261	int sb_size;
    262
    263	dev_dbg(dev->dev,
    264		"%s: Starting ISO AUDIO transfers\n", __func__);
    265
    266	if (dev->state & DEV_DISCONNECTED)
    267		return -ENODEV;
    268
    269	sb_size = CX231XX_ISO_NUM_AUDIO_PACKETS * dev->adev.max_pkt_size;
    270
    271	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
    272		struct urb *urb;
    273		int j, k;
    274
    275		dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_ATOMIC);
    276		if (!dev->adev.transfer_buffer[i])
    277			return -ENOMEM;
    278
    279		memset(dev->adev.transfer_buffer[i], 0x80, sb_size);
    280		urb = usb_alloc_urb(CX231XX_ISO_NUM_AUDIO_PACKETS, GFP_ATOMIC);
    281		if (!urb) {
    282			for (j = 0; j < i; j++) {
    283				usb_free_urb(dev->adev.urb[j]);
    284				kfree(dev->adev.transfer_buffer[j]);
    285			}
    286			return -ENOMEM;
    287		}
    288
    289		urb->dev = dev->udev;
    290		urb->context = dev;
    291		urb->pipe = usb_rcvisocpipe(dev->udev,
    292						dev->adev.end_point_addr);
    293		urb->transfer_flags = URB_ISO_ASAP;
    294		urb->transfer_buffer = dev->adev.transfer_buffer[i];
    295		urb->interval = 1;
    296		urb->complete = cx231xx_audio_isocirq;
    297		urb->number_of_packets = CX231XX_ISO_NUM_AUDIO_PACKETS;
    298		urb->transfer_buffer_length = sb_size;
    299
    300		for (j = k = 0; j < CX231XX_ISO_NUM_AUDIO_PACKETS;
    301			j++, k += dev->adev.max_pkt_size) {
    302			urb->iso_frame_desc[j].offset = k;
    303			urb->iso_frame_desc[j].length = dev->adev.max_pkt_size;
    304		}
    305		dev->adev.urb[i] = urb;
    306	}
    307
    308	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
    309		errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
    310		if (errCode < 0) {
    311			cx231xx_isoc_audio_deinit(dev);
    312			return errCode;
    313		}
    314	}
    315
    316	return errCode;
    317}
    318
    319static int cx231xx_init_audio_bulk(struct cx231xx *dev)
    320{
    321	int i, errCode;
    322	int sb_size;
    323
    324	dev_dbg(dev->dev,
    325		"%s: Starting BULK AUDIO transfers\n", __func__);
    326
    327	if (dev->state & DEV_DISCONNECTED)
    328		return -ENODEV;
    329
    330	sb_size = CX231XX_NUM_AUDIO_PACKETS * dev->adev.max_pkt_size;
    331
    332	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
    333		struct urb *urb;
    334		int j;
    335
    336		dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_ATOMIC);
    337		if (!dev->adev.transfer_buffer[i])
    338			return -ENOMEM;
    339
    340		memset(dev->adev.transfer_buffer[i], 0x80, sb_size);
    341		urb = usb_alloc_urb(CX231XX_NUM_AUDIO_PACKETS, GFP_ATOMIC);
    342		if (!urb) {
    343			for (j = 0; j < i; j++) {
    344				usb_free_urb(dev->adev.urb[j]);
    345				kfree(dev->adev.transfer_buffer[j]);
    346			}
    347			return -ENOMEM;
    348		}
    349
    350		urb->dev = dev->udev;
    351		urb->context = dev;
    352		urb->pipe = usb_rcvbulkpipe(dev->udev,
    353						dev->adev.end_point_addr);
    354		urb->transfer_flags = 0;
    355		urb->transfer_buffer = dev->adev.transfer_buffer[i];
    356		urb->complete = cx231xx_audio_bulkirq;
    357		urb->transfer_buffer_length = sb_size;
    358
    359		dev->adev.urb[i] = urb;
    360
    361	}
    362
    363	for (i = 0; i < CX231XX_AUDIO_BUFS; i++) {
    364		errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
    365		if (errCode < 0) {
    366			cx231xx_bulk_audio_deinit(dev);
    367			return errCode;
    368		}
    369	}
    370
    371	return errCode;
    372}
    373
    374static const struct snd_pcm_hardware snd_cx231xx_hw_capture = {
    375	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER	|
    376	    SNDRV_PCM_INFO_MMAP			|
    377	    SNDRV_PCM_INFO_INTERLEAVED		|
    378	    SNDRV_PCM_INFO_MMAP_VALID,
    379
    380	.formats = SNDRV_PCM_FMTBIT_S16_LE,
    381
    382	.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_KNOT,
    383
    384	.rate_min = 48000,
    385	.rate_max = 48000,
    386	.channels_min = 2,
    387	.channels_max = 2,
    388	.buffer_bytes_max = 62720 * 8,	/* just about the value in usbaudio.c */
    389	.period_bytes_min = 64,		/* 12544/2, */
    390	.period_bytes_max = 12544,
    391	.periods_min = 2,
    392	.periods_max = 98,		/* 12544, */
    393};
    394
    395static int snd_cx231xx_capture_open(struct snd_pcm_substream *substream)
    396{
    397	struct cx231xx *dev = snd_pcm_substream_chip(substream);
    398	struct snd_pcm_runtime *runtime = substream->runtime;
    399	int ret = 0;
    400
    401	dev_dbg(dev->dev,
    402		"opening device and trying to acquire exclusive lock\n");
    403
    404	if (dev->state & DEV_DISCONNECTED) {
    405		dev_err(dev->dev,
    406			"Can't open. the device was removed.\n");
    407		return -ENODEV;
    408	}
    409
    410	/* set alternate setting for audio interface */
    411	/* 1 - 48000 samples per sec */
    412	mutex_lock(&dev->lock);
    413	if (dev->USE_ISO)
    414		ret = cx231xx_set_alt_setting(dev, INDEX_AUDIO, 1);
    415	else
    416		ret = cx231xx_set_alt_setting(dev, INDEX_AUDIO, 0);
    417	mutex_unlock(&dev->lock);
    418	if (ret < 0) {
    419		dev_err(dev->dev,
    420			"failed to set alternate setting !\n");
    421
    422		return ret;
    423	}
    424
    425	runtime->hw = snd_cx231xx_hw_capture;
    426
    427	mutex_lock(&dev->lock);
    428	/* inform hardware to start streaming */
    429	ret = cx231xx_capture_start(dev, 1, Audio);
    430
    431	dev->adev.users++;
    432	mutex_unlock(&dev->lock);
    433
    434	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
    435	dev->adev.capture_pcm_substream = substream;
    436	runtime->private_data = dev;
    437
    438	return 0;
    439}
    440
    441static int snd_cx231xx_pcm_close(struct snd_pcm_substream *substream)
    442{
    443	int ret;
    444	struct cx231xx *dev = snd_pcm_substream_chip(substream);
    445
    446	dev_dbg(dev->dev, "closing device\n");
    447
    448	/* inform hardware to stop streaming */
    449	mutex_lock(&dev->lock);
    450	ret = cx231xx_capture_start(dev, 0, Audio);
    451
    452	/* set alternate setting for audio interface */
    453	/* 1 - 48000 samples per sec */
    454	ret = cx231xx_set_alt_setting(dev, INDEX_AUDIO, 0);
    455	if (ret < 0) {
    456		dev_err(dev->dev,
    457			"failed to set alternate setting !\n");
    458
    459		mutex_unlock(&dev->lock);
    460		return ret;
    461	}
    462
    463	dev->adev.users--;
    464	mutex_unlock(&dev->lock);
    465
    466	if (dev->adev.users == 0 && dev->adev.shutdown == 1) {
    467		dev_dbg(dev->dev, "audio users: %d\n", dev->adev.users);
    468		dev_dbg(dev->dev, "disabling audio stream!\n");
    469		dev->adev.shutdown = 0;
    470		dev_dbg(dev->dev, "released lock\n");
    471		if (atomic_read(&dev->stream_started) > 0) {
    472			atomic_set(&dev->stream_started, 0);
    473			schedule_work(&dev->wq_trigger);
    474		}
    475	}
    476	return 0;
    477}
    478
    479static int snd_cx231xx_prepare(struct snd_pcm_substream *substream)
    480{
    481	struct cx231xx *dev = snd_pcm_substream_chip(substream);
    482
    483	dev->adev.hwptr_done_capture = 0;
    484	dev->adev.capture_transfer_done = 0;
    485
    486	return 0;
    487}
    488
    489static void audio_trigger(struct work_struct *work)
    490{
    491	struct cx231xx *dev = container_of(work, struct cx231xx, wq_trigger);
    492
    493	if (atomic_read(&dev->stream_started)) {
    494		dev_dbg(dev->dev, "starting capture");
    495		if (is_fw_load(dev) == 0)
    496			cx25840_call(dev, core, load_fw);
    497		if (dev->USE_ISO)
    498			cx231xx_init_audio_isoc(dev);
    499		else
    500			cx231xx_init_audio_bulk(dev);
    501	} else {
    502		dev_dbg(dev->dev, "stopping capture");
    503		cx231xx_isoc_audio_deinit(dev);
    504	}
    505}
    506
    507static int snd_cx231xx_capture_trigger(struct snd_pcm_substream *substream,
    508				       int cmd)
    509{
    510	struct cx231xx *dev = snd_pcm_substream_chip(substream);
    511	int retval = 0;
    512
    513	if (dev->state & DEV_DISCONNECTED)
    514		return -ENODEV;
    515
    516	spin_lock(&dev->adev.slock);
    517	switch (cmd) {
    518	case SNDRV_PCM_TRIGGER_START:
    519		atomic_set(&dev->stream_started, 1);
    520		break;
    521	case SNDRV_PCM_TRIGGER_STOP:
    522		atomic_set(&dev->stream_started, 0);
    523		break;
    524	default:
    525		retval = -EINVAL;
    526		break;
    527	}
    528	spin_unlock(&dev->adev.slock);
    529
    530	schedule_work(&dev->wq_trigger);
    531
    532	return retval;
    533}
    534
    535static snd_pcm_uframes_t snd_cx231xx_capture_pointer(struct snd_pcm_substream
    536						     *substream)
    537{
    538	struct cx231xx *dev;
    539	unsigned long flags;
    540	snd_pcm_uframes_t hwptr_done;
    541
    542	dev = snd_pcm_substream_chip(substream);
    543
    544	spin_lock_irqsave(&dev->adev.slock, flags);
    545	hwptr_done = dev->adev.hwptr_done_capture;
    546	spin_unlock_irqrestore(&dev->adev.slock, flags);
    547
    548	return hwptr_done;
    549}
    550
    551static const struct snd_pcm_ops snd_cx231xx_pcm_capture = {
    552	.open = snd_cx231xx_capture_open,
    553	.close = snd_cx231xx_pcm_close,
    554	.prepare = snd_cx231xx_prepare,
    555	.trigger = snd_cx231xx_capture_trigger,
    556	.pointer = snd_cx231xx_capture_pointer,
    557};
    558
    559static int cx231xx_audio_init(struct cx231xx *dev)
    560{
    561	struct cx231xx_audio *adev = &dev->adev;
    562	struct snd_pcm *pcm;
    563	struct snd_card *card;
    564	static int devnr;
    565	int err;
    566	struct usb_interface *uif;
    567	int i, isoc_pipe = 0;
    568
    569	if (dev->has_alsa_audio != 1) {
    570		/* This device does not support the extension (in this case
    571		   the device is expecting the snd-usb-audio module or
    572		   doesn't have analog audio support at all) */
    573		return 0;
    574	}
    575
    576	dev_dbg(dev->dev,
    577		"probing for cx231xx non standard usbaudio\n");
    578
    579	err = snd_card_new(dev->dev, index[devnr], "Cx231xx Audio",
    580			   THIS_MODULE, 0, &card);
    581	if (err < 0)
    582		return err;
    583
    584	spin_lock_init(&adev->slock);
    585	err = snd_pcm_new(card, "Cx231xx Audio", 0, 0, 1, &pcm);
    586	if (err < 0)
    587		goto err_free_card;
    588
    589	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
    590			&snd_cx231xx_pcm_capture);
    591	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
    592	pcm->info_flags = 0;
    593	pcm->private_data = dev;
    594	strscpy(pcm->name, "Conexant cx231xx Capture", sizeof(pcm->name));
    595	strscpy(card->driver, "Cx231xx-Audio", sizeof(card->driver));
    596	strscpy(card->shortname, "Cx231xx Audio", sizeof(card->shortname));
    597	strscpy(card->longname, "Conexant cx231xx Audio", sizeof(card->longname));
    598
    599	INIT_WORK(&dev->wq_trigger, audio_trigger);
    600
    601	err = snd_card_register(card);
    602	if (err < 0)
    603		goto err_free_card;
    604
    605	adev->sndcard = card;
    606	adev->udev = dev->udev;
    607
    608	/* compute alternate max packet sizes for Audio */
    609	uif =
    610	    dev->udev->actconfig->interface[dev->current_pcb_config.
    611					    hs_config_info[0].interface_info.
    612					    audio_index + 1];
    613
    614	if (uif->altsetting[0].desc.bNumEndpoints < isoc_pipe + 1) {
    615		err = -ENODEV;
    616		goto err_free_card;
    617	}
    618
    619	adev->end_point_addr =
    620	    uif->altsetting[0].endpoint[isoc_pipe].desc.
    621			bEndpointAddress;
    622
    623	adev->num_alt = uif->num_altsetting;
    624	dev_info(dev->dev,
    625		"audio EndPoint Addr 0x%x, Alternate settings: %i\n",
    626		adev->end_point_addr, adev->num_alt);
    627	adev->alt_max_pkt_size = kmalloc_array(32, adev->num_alt, GFP_KERNEL);
    628	if (!adev->alt_max_pkt_size) {
    629		err = -ENOMEM;
    630		goto err_free_card;
    631	}
    632
    633	for (i = 0; i < adev->num_alt; i++) {
    634		u16 tmp;
    635
    636		if (uif->altsetting[i].desc.bNumEndpoints < isoc_pipe + 1) {
    637			err = -ENODEV;
    638			goto err_free_pkt_size;
    639		}
    640
    641		tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].desc.
    642				wMaxPacketSize);
    643		adev->alt_max_pkt_size[i] =
    644		    (tmp & 0x07ff) * (((tmp & 0x1800) >> 11) + 1);
    645		dev_dbg(dev->dev,
    646			"audio alternate setting %i, max size= %i\n", i,
    647			adev->alt_max_pkt_size[i]);
    648	}
    649
    650	return 0;
    651
    652err_free_pkt_size:
    653	kfree(adev->alt_max_pkt_size);
    654err_free_card:
    655	snd_card_free(card);
    656
    657	return err;
    658}
    659
    660static int cx231xx_audio_fini(struct cx231xx *dev)
    661{
    662	if (dev == NULL)
    663		return 0;
    664
    665	if (dev->has_alsa_audio != 1) {
    666		/* This device does not support the extension (in this case
    667		   the device is expecting the snd-usb-audio module or
    668		   doesn't have analog audio support at all) */
    669		return 0;
    670	}
    671
    672	if (dev->adev.sndcard) {
    673		snd_card_free_when_closed(dev->adev.sndcard);
    674		kfree(dev->adev.alt_max_pkt_size);
    675		dev->adev.sndcard = NULL;
    676	}
    677
    678	return 0;
    679}
    680
    681static struct cx231xx_ops audio_ops = {
    682	.id = CX231XX_AUDIO,
    683	.name = "Cx231xx Audio Extension",
    684	.init = cx231xx_audio_init,
    685	.fini = cx231xx_audio_fini,
    686};
    687
    688static int __init cx231xx_alsa_register(void)
    689{
    690	return cx231xx_register_extension(&audio_ops);
    691}
    692
    693static void __exit cx231xx_alsa_unregister(void)
    694{
    695	cx231xx_unregister_extension(&audio_ops);
    696}
    697
    698MODULE_LICENSE("GPL");
    699MODULE_AUTHOR("Srinivasa Deevi <srinivasa.deevi@conexant.com>");
    700MODULE_DESCRIPTION("Cx231xx Audio driver");
    701
    702module_init(cx231xx_alsa_register);
    703module_exit(cx231xx_alsa_unregister);