Skip to content
Fetching contributors…
Cannot retrieve contributors at this time
825 lines (684 sloc) 21.6 KB
/*
* Gadget Function Driver for USB audio source device
*
* Copyright (C) 2012 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/device.h>
#include <linux/usb/audio.h>
#include <linux/wait.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#define SAMPLE_RATE 44100
/* Each frame is two 16 bit integers (one per channel) */
#define BYTES_PER_FRAME 4
#define FRAMES_PER_MSEC (SAMPLE_RATE / 1000)
/* Add one to FRAMES_PER_MSEC to adjust for round-off above */
#define IN_EP_MAX_PACKET_SIZE ((FRAMES_PER_MSEC + 1) * BYTES_PER_FRAME)
/* Number of requests to allocate */
#define IN_EP_REQ_COUNT 16
#define AUDIO_AC_INTERFACE 0
#define AUDIO_AS_INTERFACE 1
#define AUDIO_NUM_INTERFACES 2
/* B.3.1 Standard AC Interface Descriptor */
static struct usb_interface_descriptor ac_interface_desc = {
.bLength = USB_DT_INTERFACE_SIZE,
.bDescriptorType = USB_DT_INTERFACE,
.bNumEndpoints = 0,
.bInterfaceClass = USB_CLASS_AUDIO,
.bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL,
};
DECLARE_UAC_AC_HEADER_DESCRIPTOR(2);
#define UAC_DT_AC_HEADER_LENGTH UAC_DT_AC_HEADER_SIZE(AUDIO_NUM_INTERFACES)
/* 1 input terminal, 1 output terminal and 1 feature unit */
#define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH \
+ UAC_DT_INPUT_TERMINAL_SIZE + UAC_DT_OUTPUT_TERMINAL_SIZE \
+ UAC_DT_FEATURE_UNIT_SIZE(0))
/* B.3.2 Class-Specific AC Interface Descriptor */
static struct uac1_ac_header_descriptor_2 ac_header_desc = {
.bLength = UAC_DT_AC_HEADER_LENGTH,
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubtype = UAC_HEADER,
.bcdADC = __constant_cpu_to_le16(0x0100),
.wTotalLength = __constant_cpu_to_le16(UAC_DT_TOTAL_LENGTH),
.bInCollection = AUDIO_NUM_INTERFACES,
.baInterfaceNr = {
[0] = AUDIO_AC_INTERFACE,
[1] = AUDIO_AS_INTERFACE,
}
};
#define INPUT_TERMINAL_ID 1
static struct uac_input_terminal_descriptor input_terminal_desc = {
.bLength = UAC_DT_INPUT_TERMINAL_SIZE,
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubtype = UAC_INPUT_TERMINAL,
.bTerminalID = INPUT_TERMINAL_ID,
.wTerminalType = UAC_INPUT_TERMINAL_MICROPHONE,
.bAssocTerminal = 0,
.wChannelConfig = 0x3,
};
DECLARE_UAC_FEATURE_UNIT_DESCRIPTOR(0);
#define FEATURE_UNIT_ID 2
static struct uac_feature_unit_descriptor_0 feature_unit_desc = {
.bLength = UAC_DT_FEATURE_UNIT_SIZE(0),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubtype = UAC_FEATURE_UNIT,
.bUnitID = FEATURE_UNIT_ID,
.bSourceID = INPUT_TERMINAL_ID,
.bControlSize = 2,
};
#define OUTPUT_TERMINAL_ID 3
static struct uac1_output_terminal_descriptor output_terminal_desc = {
.bLength = UAC_DT_OUTPUT_TERMINAL_SIZE,
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
.bTerminalID = OUTPUT_TERMINAL_ID,
.wTerminalType = UAC_TERMINAL_STREAMING,
.bAssocTerminal = FEATURE_UNIT_ID,
.bSourceID = FEATURE_UNIT_ID,
};
/* B.4.1 Standard AS Interface Descriptor */
static struct usb_interface_descriptor as_interface_alt_0_desc = {
.bLength = USB_DT_INTERFACE_SIZE,
.bDescriptorType = USB_DT_INTERFACE,
.bAlternateSetting = 0,
.bNumEndpoints = 0,
.bInterfaceClass = USB_CLASS_AUDIO,
.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
};
static struct usb_interface_descriptor as_interface_alt_1_desc = {
.bLength = USB_DT_INTERFACE_SIZE,
.bDescriptorType = USB_DT_INTERFACE,
.bAlternateSetting = 1,
.bNumEndpoints = 1,
.bInterfaceClass = USB_CLASS_AUDIO,
.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
};
/* B.4.2 Class-Specific AS Interface Descriptor */
static struct uac1_as_header_descriptor as_header_desc = {
.bLength = UAC_DT_AS_HEADER_SIZE,
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubtype = UAC_AS_GENERAL,
.bTerminalLink = INPUT_TERMINAL_ID,
.bDelay = 1,
.wFormatTag = UAC_FORMAT_TYPE_I_PCM,
};
DECLARE_UAC_FORMAT_TYPE_I_DISCRETE_DESC(1);
static struct uac_format_type_i_discrete_descriptor_1 as_type_i_desc = {
.bLength = UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
.bDescriptorType = USB_DT_CS_INTERFACE,
.bDescriptorSubtype = UAC_FORMAT_TYPE,
.bFormatType = UAC_FORMAT_TYPE_I,
.bSubframeSize = 2,
.bBitResolution = 16,
.bSamFreqType = 1,
};
/* Standard ISO IN Endpoint Descriptor for highspeed */
static struct usb_endpoint_descriptor hs_as_in_ep_desc = {
.bLength = USB_DT_ENDPOINT_AUDIO_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_SYNC_SYNC
| USB_ENDPOINT_XFER_ISOC,
.wMaxPacketSize = __constant_cpu_to_le16(IN_EP_MAX_PACKET_SIZE),
.bInterval = 4, /* poll 1 per millisecond */
};
/* Standard ISO IN Endpoint Descriptor for highspeed */
static struct usb_endpoint_descriptor fs_as_in_ep_desc = {
.bLength = USB_DT_ENDPOINT_AUDIO_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_SYNC_SYNC
| USB_ENDPOINT_XFER_ISOC,
.wMaxPacketSize = __constant_cpu_to_le16(IN_EP_MAX_PACKET_SIZE),
.bInterval = 1, /* poll 1 per millisecond */
};
/* Class-specific AS ISO OUT Endpoint Descriptor */
static struct uac_iso_endpoint_descriptor as_iso_in_desc = {
.bLength = UAC_ISO_ENDPOINT_DESC_SIZE,
.bDescriptorType = USB_DT_CS_ENDPOINT,
.bDescriptorSubtype = UAC_EP_GENERAL,
.bmAttributes = 1,
.bLockDelayUnits = 1,
.wLockDelay = __constant_cpu_to_le16(1),
};
static struct usb_descriptor_header *hs_audio_desc[] = {
(struct usb_descriptor_header *)&ac_interface_desc,
(struct usb_descriptor_header *)&ac_header_desc,
(struct usb_descriptor_header *)&input_terminal_desc,
(struct usb_descriptor_header *)&output_terminal_desc,
(struct usb_descriptor_header *)&feature_unit_desc,
(struct usb_descriptor_header *)&as_interface_alt_0_desc,
(struct usb_descriptor_header *)&as_interface_alt_1_desc,
(struct usb_descriptor_header *)&as_header_desc,
(struct usb_descriptor_header *)&as_type_i_desc,
(struct usb_descriptor_header *)&hs_as_in_ep_desc,
(struct usb_descriptor_header *)&as_iso_in_desc,
NULL,
};
static struct usb_descriptor_header *fs_audio_desc[] = {
(struct usb_descriptor_header *)&ac_interface_desc,
(struct usb_descriptor_header *)&ac_header_desc,
(struct usb_descriptor_header *)&input_terminal_desc,
(struct usb_descriptor_header *)&output_terminal_desc,
(struct usb_descriptor_header *)&feature_unit_desc,
(struct usb_descriptor_header *)&as_interface_alt_0_desc,
(struct usb_descriptor_header *)&as_interface_alt_1_desc,
(struct usb_descriptor_header *)&as_header_desc,
(struct usb_descriptor_header *)&as_type_i_desc,
(struct usb_descriptor_header *)&fs_as_in_ep_desc,
(struct usb_descriptor_header *)&as_iso_in_desc,
NULL,
};
static struct snd_pcm_hardware audio_hw_info = {
.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_LE,
.channels_min = 2,
.channels_max = 2,
.rate_min = SAMPLE_RATE,
.rate_max = SAMPLE_RATE,
.buffer_bytes_max = 1024 * 1024,
.period_bytes_min = 64,
.period_bytes_max = 512 * 1024,
.periods_min = 2,
.periods_max = 1024,
};
/*-------------------------------------------------------------------------*/
struct audio_source_config {
int card;
int device;
};
struct audio_dev {
struct usb_function func;
struct snd_card *card;
struct snd_pcm *pcm;
struct snd_pcm_substream *substream;
struct list_head idle_reqs;
struct usb_ep *in_ep;
struct usb_endpoint_descriptor *in_desc;
spinlock_t lock;
/* beginning, end and current position in our buffer */
void *buffer_start;
void *buffer_end;
void *buffer_pos;
/* byte size of a "period" */
unsigned int period;
/* bytes sent since last call to snd_pcm_period_elapsed */
unsigned int period_offset;
/* time we started playing */
ktime_t start_time;
/* number of frames sent since start_time */
s64 frames_sent;
};
static inline struct audio_dev *func_to_audio(struct usb_function *f)
{
return container_of(f, struct audio_dev, func);
}
/*-------------------------------------------------------------------------*/
static struct usb_request *audio_request_new(struct usb_ep *ep, int buffer_size)
{
struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
if (!req)
return NULL;
req->buf = kmalloc(buffer_size, GFP_KERNEL);
if (!req->buf) {
usb_ep_free_request(ep, req);
return NULL;
}
req->length = buffer_size;
return req;
}
static void audio_request_free(struct usb_request *req, struct usb_ep *ep)
{
if (req) {
kfree(req->buf);
usb_ep_free_request(ep, req);
}
}
static void audio_req_put(struct audio_dev *audio, struct usb_request *req)
{
unsigned long flags;
spin_lock_irqsave(&audio->lock, flags);
list_add_tail(&req->list, &audio->idle_reqs);
spin_unlock_irqrestore(&audio->lock, flags);
}
static struct usb_request *audio_req_get(struct audio_dev *audio)
{
unsigned long flags;
struct usb_request *req;
spin_lock_irqsave(&audio->lock, flags);
if (list_empty(&audio->idle_reqs)) {
req = 0;
} else {
req = list_first_entry(&audio->idle_reqs, struct usb_request,
list);
list_del(&req->list);
}
spin_unlock_irqrestore(&audio->lock, flags);
return req;
}
/* send the appropriate number of packets to match our bitrate */
static void audio_send(struct audio_dev *audio)
{
struct snd_pcm_runtime *runtime;
struct usb_request *req;
int length, length1, length2, ret;
s64 msecs;
s64 frames;
ktime_t now;
/* audio->substream will be null if we have been closed */
if (!audio->substream)
return;
/* audio->buffer_pos will be null if we have been stopped */
if (!audio->buffer_pos)
return;
runtime = audio->substream->runtime;
now = ktime_get();
msecs = ktime_to_ns(now) - ktime_to_ns(audio->start_time);
do_div(msecs, 1000000);
/* Add a bit to msecs so we queue some extra requests in case
* we miss a few SOFs due to interrupts being disabled or CPU load.
*/
msecs += IN_EP_REQ_COUNT/2;
frames = msecs * SAMPLE_RATE;
do_div(frames, 1000);
/* Readjust our frames_sent if we fall too far behind.
* If we get too far behind it is better to drop some frames than
* to keep sending data too fast in an attempt to catch up.
*/
if (frames - audio->frames_sent > 2 * FRAMES_PER_MSEC * IN_EP_REQ_COUNT)
audio->frames_sent = frames - FRAMES_PER_MSEC;
frames -= audio->frames_sent;
while (frames > 0) {
req = audio_req_get(audio);
if (!req)
break;
length = frames_to_bytes(runtime, frames);
if (length > IN_EP_MAX_PACKET_SIZE)
length = IN_EP_MAX_PACKET_SIZE;
if (audio->buffer_pos + length > audio->buffer_end)
length1 = audio->buffer_end - audio->buffer_pos;
else
length1 = length;
memcpy(req->buf, audio->buffer_pos, length1);
if (length1 < length) {
/* Wrap around and copy remaining length
* at beginning of buffer.
*/
length2 = length - length1;
memcpy(req->buf + length1, audio->buffer_start,
length2);
audio->buffer_pos = audio->buffer_start + length2;
} else {
audio->buffer_pos += length1;
if (audio->buffer_pos >= audio->buffer_end)
audio->buffer_pos = audio->buffer_start;
}
req->length = length;
ret = usb_ep_queue(audio->in_ep, req, GFP_ATOMIC);
if (ret < 0) {
pr_err("usb_ep_queue failed ret: %d\n", ret);
audio_req_put(audio, req);
break;
}
frames -= bytes_to_frames(runtime, length);
audio->frames_sent += bytes_to_frames(runtime, length);
}
}
static void audio_control_complete(struct usb_ep *ep, struct usb_request *req)
{
/* nothing to do here */
}
static void audio_data_complete(struct usb_ep *ep, struct usb_request *req)
{
struct audio_dev *audio = req->context;
pr_debug("audio_data_complete req->status %d req->actual %d\n",
req->status, req->actual);
audio_req_put(audio, req);
if (!audio->buffer_start)
return;
audio->period_offset += req->actual;
if (audio->period_offset >= audio->period) {
snd_pcm_period_elapsed(audio->substream);
audio->period_offset = 0;
}
audio_send(audio);
}
static int audio_set_endpoint_req(struct usb_function *f,
const struct usb_ctrlrequest *ctrl)
{
int value = -EOPNOTSUPP;
u16 ep = le16_to_cpu(ctrl->wIndex);
u16 len = le16_to_cpu(ctrl->wLength);
u16 w_value = le16_to_cpu(ctrl->wValue);
pr_debug("bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
ctrl->bRequest, w_value, len, ep);
switch (ctrl->bRequest) {
case UAC_SET_CUR:
case UAC_SET_MIN:
case UAC_SET_MAX:
case UAC_SET_RES:
value = len;
break;
default:
break;
}
return value;
}
static int audio_get_endpoint_req(struct usb_function *f,
const struct usb_ctrlrequest *ctrl)
{
struct usb_composite_dev *cdev = f->config->cdev;
int value = -EOPNOTSUPP;
u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
u16 len = le16_to_cpu(ctrl->wLength);
u16 w_value = le16_to_cpu(ctrl->wValue);
u8 *buf = cdev->req->buf;
pr_debug("bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
ctrl->bRequest, w_value, len, ep);
if (w_value == UAC_EP_CS_ATTR_SAMPLE_RATE << 8) {
switch (ctrl->bRequest) {
case UAC_GET_CUR:
case UAC_GET_MIN:
case UAC_GET_MAX:
case UAC_GET_RES:
/* return our sample rate */
buf[0] = (u8)SAMPLE_RATE;
buf[1] = (u8)(SAMPLE_RATE >> 8);
buf[2] = (u8)(SAMPLE_RATE >> 16);
value = 3;
break;
default:
break;
}
}
return value;
}
static int
audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
{
struct usb_composite_dev *cdev = f->config->cdev;
struct usb_request *req = cdev->req;
int value = -EOPNOTSUPP;
u16 w_index = le16_to_cpu(ctrl->wIndex);
u16 w_value = le16_to_cpu(ctrl->wValue);
u16 w_length = le16_to_cpu(ctrl->wLength);
/* composite driver infrastructure handles everything; interface
* activation uses set_alt().
*/
switch (ctrl->bRequestType) {
case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
value = audio_set_endpoint_req(f, ctrl);
break;
case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
value = audio_get_endpoint_req(f, ctrl);
break;
}
/* respond with data transfer or status phase? */
if (value >= 0) {
pr_debug("audio req%02x.%02x v%04x i%04x l%d\n",
ctrl->bRequestType, ctrl->bRequest,
w_value, w_index, w_length);
req->zero = 0;
req->length = value;
req->complete = audio_control_complete;
value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
if (value < 0)
pr_err("audio response on err %d\n", value);
}
/* device either stalls (value < 0) or reports success */
return value;
}
static int audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
struct audio_dev *audio = func_to_audio(f);
pr_debug("audio_set_alt intf %d, alt %d\n", intf, alt);
usb_ep_enable(audio->in_ep, audio->in_desc);
return 0;
}
static void audio_disable(struct usb_function *f)
{
struct audio_dev *audio = func_to_audio(f);
pr_debug("audio_disable\n");
usb_ep_disable(audio->in_ep);
}
/*-------------------------------------------------------------------------*/
static void audio_build_desc(struct audio_dev *audio)
{
u8 *sam_freq;
int rate;
/* Set channel numbers */
input_terminal_desc.bNrChannels = 2;
as_type_i_desc.bNrChannels = 2;
/* Set sample rates */
rate = SAMPLE_RATE;
sam_freq = as_type_i_desc.tSamFreq[0];
memcpy(sam_freq, &rate, 3);
}
/* audio function driver setup/binding */
static int
audio_bind(struct usb_configuration *c, struct usb_function *f)
{
struct usb_composite_dev *cdev = c->cdev;
struct audio_dev *audio = func_to_audio(f);
int status;
struct usb_ep *ep;
struct usb_request *req;
int i;
audio_build_desc(audio);
/* allocate instance-specific interface IDs, and patch descriptors */
status = usb_interface_id(c, f);
if (status < 0)
goto fail;
ac_interface_desc.bInterfaceNumber = status;
status = usb_interface_id(c, f);
if (status < 0)
goto fail;
as_interface_alt_0_desc.bInterfaceNumber = status;
as_interface_alt_1_desc.bInterfaceNumber = status;
status = -ENODEV;
/* allocate our endpoint */
ep = usb_ep_autoconfig(cdev->gadget, &fs_as_in_ep_desc);
if (!ep)
goto fail;
audio->in_ep = ep;
ep->driver_data = audio; /* claim */
if (gadget_is_dualspeed(c->cdev->gadget))
hs_as_in_ep_desc.bEndpointAddress =
fs_as_in_ep_desc.bEndpointAddress;
f->descriptors = fs_audio_desc;
f->hs_descriptors = hs_audio_desc;
for (i = 0, status = 0; i < IN_EP_REQ_COUNT && status == 0; i++) {
req = audio_request_new(ep, IN_EP_MAX_PACKET_SIZE);
if (req) {
req->context = audio;
req->complete = audio_data_complete;
audio_req_put(audio, req);
} else
status = -ENOMEM;
}
fail:
return status;
}
static void
audio_unbind(struct usb_configuration *c, struct usb_function *f)
{
struct audio_dev *audio = func_to_audio(f);
struct usb_request *req;
while ((req = audio_req_get(audio)))
audio_request_free(req, audio->in_ep);
snd_card_free_when_closed(audio->card);
kfree(audio);
}
static void audio_pcm_playback_start(struct audio_dev *audio)
{
audio->start_time = ktime_get();
audio->frames_sent = 0;
audio_send(audio);
}
static void audio_pcm_playback_stop(struct audio_dev *audio)
{
unsigned long flags;
spin_lock_irqsave(&audio->lock, flags);
audio->buffer_start = 0;
audio->buffer_end = 0;
audio->buffer_pos = 0;
spin_unlock_irqrestore(&audio->lock, flags);
}
static int audio_pcm_open(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct audio_dev *audio = substream->private_data;
runtime->private_data = audio;
runtime->hw = audio_hw_info;
snd_pcm_limit_hw_rates(runtime);
runtime->hw.channels_max = 2;
audio->substream = substream;
return 0;
}
static int audio_pcm_close(struct snd_pcm_substream *substream)
{
struct audio_dev *audio = substream->private_data;
unsigned long flags;
spin_lock_irqsave(&audio->lock, flags);
audio->substream = NULL;
spin_unlock_irqrestore(&audio->lock, flags);
return 0;
}
static int audio_pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
unsigned int channels = params_channels(params);
unsigned int rate = params_rate(params);
if (rate != SAMPLE_RATE)
return -EINVAL;
if (channels != 2)
return -EINVAL;
return snd_pcm_lib_alloc_vmalloc_buffer(substream,
params_buffer_bytes(params));
}
static int audio_pcm_hw_free(struct snd_pcm_substream *substream)
{
return snd_pcm_lib_free_vmalloc_buffer(substream);
}
static int audio_pcm_prepare(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct audio_dev *audio = runtime->private_data;
audio->period = snd_pcm_lib_period_bytes(substream);
audio->period_offset = 0;
audio->buffer_start = runtime->dma_area;
audio->buffer_end = audio->buffer_start
+ snd_pcm_lib_buffer_bytes(substream);
audio->buffer_pos = audio->buffer_start;
return 0;
}
static snd_pcm_uframes_t audio_pcm_pointer(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct audio_dev *audio = runtime->private_data;
ssize_t bytes = audio->buffer_pos - audio->buffer_start;
/* return offset of next frame to fill in our buffer */
return bytes_to_frames(runtime, bytes);
}
static int audio_pcm_playback_trigger(struct snd_pcm_substream *substream,
int cmd)
{
struct audio_dev *audio = substream->runtime->private_data;
int ret = 0;
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
case SNDRV_PCM_TRIGGER_RESUME:
audio_pcm_playback_start(audio);
break;
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_SUSPEND:
audio_pcm_playback_stop(audio);
break;
default:
ret = -EINVAL;
}
return ret;
}
static struct snd_pcm_ops audio_playback_ops = {
.open = audio_pcm_open,
.close = audio_pcm_close,
.ioctl = snd_pcm_lib_ioctl,
.hw_params = audio_pcm_hw_params,
.hw_free = audio_pcm_hw_free,
.prepare = audio_pcm_prepare,
.trigger = audio_pcm_playback_trigger,
.pointer = audio_pcm_pointer,
};
int audio_source_bind_config(struct usb_configuration *c,
struct audio_source_config *config)
{
struct audio_dev *audio;
struct snd_card *card;
struct snd_pcm *pcm;
int err;
config->card = -1;
config->device = -1;
audio = kzalloc(sizeof *audio, GFP_KERNEL);
if (!audio)
return -ENOMEM;
audio->func.name = "audio_source";
spin_lock_init(&audio->lock);
audio->func.bind = audio_bind;
audio->func.unbind = audio_unbind;
audio->func.set_alt = audio_set_alt;
audio->func.setup = audio_setup;
audio->func.disable = audio_disable;
audio->in_desc = &fs_as_in_ep_desc;
INIT_LIST_HEAD(&audio->idle_reqs);
err = snd_card_create(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
THIS_MODULE, 0, &card);
if (err)
goto snd_card_fail;
snd_card_set_dev(card, &c->cdev->gadget->dev);
err = snd_pcm_new(card, "USB audio source", 0, 1, 0, &pcm);
if (err)
goto pcm_fail;
pcm->private_data = audio;
pcm->info_flags = 0;
audio->pcm = pcm;
strlcpy(pcm->name, "USB gadget audio", sizeof(pcm->name));
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &audio_playback_ops);
snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
NULL, 0, 64 * 1024);
strlcpy(card->driver, "audio_source", sizeof(card->driver));
strlcpy(card->shortname, card->driver, sizeof(card->shortname));
strlcpy(card->longname, "USB accessory audio source",
sizeof(card->longname));
err = snd_card_register(card);
if (err)
goto register_fail;
err = usb_add_function(c, &audio->func);
if (err)
goto add_fail;
config->card = pcm->card->number;
config->device = pcm->device;
audio->card = card;
return 0;
add_fail:
register_fail:
pcm_fail:
snd_card_free(audio->card);
snd_card_fail:
kfree(audio);
return err;
}
Something went wrong with that request. Please try again.