--- /dev/null
+/*
+ * 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
+#define FRAMES_PER_MSEC (SAMPLE_RATE / 1000)
+
+#define IN_EP_MAX_PACKET_SIZE 384
+
+/* Number of requests to allocate */
+#define IN_EP_REQ_COUNT 4
+
+#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;
+
+ 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;
+
+ /* compute number of frames to send */
+ now = ktime_get();
+ msecs = ktime_to_ns(now) - ktime_to_ns(audio->start_time);
+ do_div(msecs, 1000000);
+ 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 > 10 * FRAMES_PER_MSEC)
+ audio->frames_sent = frames - FRAMES_PER_MSEC;
+
+ frames -= audio->frames_sent;
+
+ /* We need to send something to keep the pipeline going */
+ if (frames <= 0)
+ frames = FRAMES_PER_MSEC;
+
+ 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 || req->status)
+ 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);
+ struct usb_composite_dev *cdev = f->config->cdev;
+ int ret;
+
+ pr_debug("audio_set_alt intf %d, alt %d\n", intf, alt);
+
+ ret = config_ep_by_speed(cdev->gadget, f, audio->in_ep);
+ if (ret)
+ return ret;
+
+ usb_ep_enable(audio->in_ep);
+ 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);
+ audio->card = NULL;
+ audio->pcm = NULL;
+ audio->substream = NULL;
+ audio->in_ep = NULL;
+}
+
+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 audio_dev _audio_dev = {
+ .func = {
+ .name = "audio_source",
+ .bind = audio_bind,
+ .unbind = audio_unbind,
+ .set_alt = audio_set_alt,
+ .setup = audio_setup,
+ .disable = audio_disable,
+ },
+ .lock = __SPIN_LOCK_UNLOCKED(_audio_dev.lock),
+ .idle_reqs = LIST_HEAD_INIT(_audio_dev.idle_reqs),
+};
+
+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 = &_audio_dev;
+
+ err = snd_card_create(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
+ THIS_MODULE, 0, &card);
+ if (err)
+ return err;
+
+ 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);
+ return err;
+}
projects / firefly-linux-kernel-4.4.55.git / commitdiff