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incubator-nuttx/audio/audio.c

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/****************************************************************************
* audio/audio.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/mqueue.h>
#include <nuttx/arch.h>
#include <nuttx/fs/fs.h>
#include <nuttx/audio/audio.h>
#include <nuttx/mutex.h>
#include <arch/irq.h>
#ifdef CONFIG_AUDIO
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Debug ********************************************************************/
/* Non-standard debug that may be enabled just for testing Audio */
#ifndef AUDIO_MAX_DEVICE_PATH
# define AUDIO_MAX_DEVICE_PATH 32
#endif
#ifndef CONFIG_AUDIO_BUFFER_DEQUEUE_PRIO
# define CONFIG_AUDIO_BUFFER_DEQUEUE_PRIO 1
#endif
/****************************************************************************
* Private Type Definitions
****************************************************************************/
/* This structure describes the state of the upper half driver */
struct audio_upperhalf_s
{
uint8_t crefs; /* The number of times the device has been opened */
volatile bool started; /* True: playback is active */
mutex_t lock; /* Supports mutual exclusion */
FAR struct audio_lowerhalf_s *dev; /* lower-half state */
struct file *usermq; /* User mode app's message queue */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int audio_open(FAR struct file *filep);
static int audio_close(FAR struct file *filep);
static ssize_t audio_read(FAR struct file *filep,
FAR char *buffer,
size_t buflen);
static ssize_t audio_write(FAR struct file *filep,
FAR const char *buffer,
size_t buflen);
static int audio_ioctl(FAR struct file *filep,
int cmd,
unsigned long arg);
#ifdef CONFIG_AUDIO_MULTI_SESSION
static int audio_start(FAR struct audio_upperhalf_s *upper,
FAR void *session);
static void audio_callback(FAR void *priv,
uint16_t reason,
FAR struct ap_buffer_s *apb,
uint16_t status,
FAR void *session);
#else
static int audio_start(FAR struct audio_upperhalf_s *upper);
static void audio_callback(FAR void *priv,
uint16_t reason,
FAR struct ap_buffer_s *apb,
uint16_t status);
#endif /* CONFIG_AUDIO_MULTI_SESSION */
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_audioops =
{
audio_open, /* open */
audio_close, /* close */
audio_read, /* read */
audio_write, /* write */
NULL, /* seek */
audio_ioctl, /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: audio_open
*
* Description:
* This function is called whenever the Audio device is opened.
*
****************************************************************************/
static int audio_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct audio_upperhalf_s *upper = inode->i_private;
uint8_t tmp;
int ret;
audinfo("crefs: %d\n", upper->crefs);
/* Get exclusive access to the device structures */
ret = nxmutex_lock(&upper->lock);
if (ret < 0)
{
goto errout;
}
/* Increment the count of references to the device. If this the first
* time that the driver has been opened for this device, then initialize
* the device.
*/
tmp = upper->crefs + 1;
if (tmp == 0)
{
/* More than 255 opens; uint8_t overflows to zero */
ret = -EMFILE;
goto errout_with_lock;
}
/* Save the new open count on success */
upper->crefs = tmp;
ret = OK;
errout_with_lock:
nxmutex_unlock(&upper->lock);
errout:
return ret;
}
/****************************************************************************
* Name: audio_close
*
* Description:
* This function is called when the Audio device is closed.
*
****************************************************************************/
static int audio_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct audio_upperhalf_s *upper = inode->i_private;
int ret;
audinfo("crefs: %d\n", upper->crefs);
/* Get exclusive access to the device structures */
ret = nxmutex_lock(&upper->lock);
if (ret < 0)
{
goto errout;
}
/* Decrement the references to the driver. If the reference count will
* decrement to 0, then uninitialize the driver.
*/
if (upper->crefs > 1)
{
upper->crefs--;
}
else
{
FAR struct audio_lowerhalf_s *lower = upper->dev;
/* There are no more references to the port */
upper->crefs = 0;
/* Disable the Audio device */
DEBUGASSERT(lower->ops->shutdown != NULL);
audinfo("calling shutdown\n");
lower->ops->shutdown(lower);
upper->usermq = NULL;
}
ret = OK;
nxmutex_unlock(&upper->lock);
errout:
return ret;
}
/****************************************************************************
* Name: audio_read
*
* Description:
* A dummy read method. This is provided only to satsify the VFS layer.
*
****************************************************************************/
static ssize_t audio_read(FAR struct file *filep,
FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct audio_upperhalf_s *upper = inode->i_private;
FAR struct audio_lowerhalf_s *lower = upper->dev;
/* TODO: Should we check permissions here? */
/* Audio read operations get passed directly to the lower-level */
if (lower->ops->read != NULL)
{
return lower->ops->read(lower, buffer, buflen);
}
return 0;
}
/****************************************************************************
* Name: audio_write
*
* Description:
* A dummy write method. This is provided only to satsify the VFS layer.
*
****************************************************************************/
static ssize_t audio_write(FAR struct file *filep,
FAR const char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct audio_upperhalf_s *upper = inode->i_private;
FAR struct audio_lowerhalf_s *lower = upper->dev;
/* TODO: Should we check permissions here? */
/* Audio write operations get passed directly to the lower-level */
if (lower->ops->write != NULL)
{
return lower->ops->write(lower, buffer, buflen);
}
return 0;
}
/****************************************************************************
* Name: audio_start
*
* Description:
* Handle the AUDIOIOC_START ioctl command
*
****************************************************************************/
#ifdef CONFIG_AUDIO_MULTI_SESSION
static int audio_start(FAR struct audio_upperhalf_s *upper,
FAR void *session)
#else
static int audio_start(FAR struct audio_upperhalf_s *upper)
#endif
{
FAR struct audio_lowerhalf_s *lower = upper->dev;
int ret = OK;
DEBUGASSERT(upper != NULL && lower->ops->start != NULL);
/* Verify that the Audio is not already running */
if (!upper->started)
{
/* Invoke the bottom half method to start the audio stream */
#ifdef CONFIG_AUDIO_MULTI_SESSION
ret = lower->ops->start(lower, session);
#else
ret = lower->ops->start(lower);
#endif
/* A return value of zero means that the audio stream was started
* successfully.
*/
if (ret == OK)
{
/* Indicate that the audio stream has started */
upper->started = true;
}
}
return ret;
}
/****************************************************************************
* Name: audio_ioctl
*
* Description:
* The standard ioctl method. This is where ALL of the Audio work is done.
*
****************************************************************************/
static int audio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct audio_upperhalf_s *upper = inode->i_private;
FAR struct audio_lowerhalf_s *lower = upper->dev;
FAR struct audio_buf_desc_s *bufdesc;
#ifdef CONFIG_AUDIO_MULTI_SESSION
FAR void *session;
#endif
int ret;
audinfo("cmd: %d arg: %ld\n", cmd, arg);
/* Get exclusive access to the device structures */
ret = nxmutex_lock(&upper->lock);
if (ret < 0)
{
return ret;
}
/* Handle built-in ioctl commands */
switch (cmd)
{
/* AUDIOIOC_GETCAPS - Get the audio device capabilities.
*
* ioctl argument: A pointer to the audio_caps_s structure.
*/
case AUDIOIOC_GETCAPS:
{
FAR struct audio_caps_s *caps =
(FAR struct audio_caps_s *)((uintptr_t)arg);
DEBUGASSERT(lower->ops->getcaps != NULL);
audinfo("AUDIOIOC_GETCAPS: Device=%d\n", caps->ac_type);
/* Call the lower-half driver capabilities handler */
ret = lower->ops->getcaps(lower, caps->ac_type, caps);
}
break;
case AUDIOIOC_CONFIGURE:
{
FAR const struct audio_caps_desc_s *caps =
(FAR const struct audio_caps_desc_s *)((uintptr_t)arg);
DEBUGASSERT(lower->ops->configure != NULL);
audinfo("AUDIOIOC_INITIALIZE: Device=%d\n", caps->caps.ac_type);
/* Call the lower-half driver configure handler */
#ifdef CONFIG_AUDIO_MULTI_SESSION
ret = lower->ops->configure(lower, caps->session, &caps->caps);
#else
ret = lower->ops->configure(lower, &caps->caps);
#endif
}
break;
case AUDIOIOC_SHUTDOWN:
{
DEBUGASSERT(lower->ops->shutdown != NULL);
audinfo("AUDIOIOC_SHUTDOWN\n");
/* Call the lower-half driver initialize handler */
ret = lower->ops->shutdown(lower);
}
break;
/* AUDIOIOC_START - Start the audio stream.
* The AUDIOIOC_SETCHARACTERISTICS
* command must have previously been sent.
*
* ioctl argument: Audio session
*/
case AUDIOIOC_START:
{
audinfo("AUDIOIOC_START\n");
DEBUGASSERT(lower->ops->start != NULL);
/* Start the audio stream */
#ifdef CONFIG_AUDIO_MULTI_SESSION
session = (FAR void *) arg;
ret = audio_start(upper, session);
#else
ret = audio_start(upper);
#endif
}
break;
/* AUDIOIOC_STOP - Stop the audio stream.
*
* ioctl argument: Audio session
*/
#ifndef CONFIG_AUDIO_EXCLUDE_STOP
case AUDIOIOC_STOP:
{
audinfo("AUDIOIOC_STOP\n");
DEBUGASSERT(lower->ops->stop != NULL);
if (upper->started)
{
#ifdef CONFIG_AUDIO_MULTI_SESSION
session = (FAR void *) arg;
ret = lower->ops->stop(lower, session);
#else
ret = lower->ops->stop(lower);
#endif
upper->started = false;
}
}
break;
#endif /* CONFIG_AUDIO_EXCLUDE_STOP */
/* AUDIOIOC_PAUSE - Pause the audio stream.
*
* ioctl argument: Audio session
*/
#ifndef CONFIG_AUDIO_EXCLUDE_PAUSE_RESUME
case AUDIOIOC_PAUSE:
{
audinfo("AUDIOIOC_PAUSE\n");
DEBUGASSERT(lower->ops->pause != NULL);
if (upper->started)
{
#ifdef CONFIG_AUDIO_MULTI_SESSION
session = (FAR void *) arg;
ret = lower->ops->pause(lower, session);
#else
ret = lower->ops->pause(lower);
#endif
}
}
break;
/* AUDIOIOC_RESUME - Resume the audio stream.
*
* ioctl argument: Audio session
*/
case AUDIOIOC_RESUME:
{
audinfo("AUDIOIOC_RESUME\n");
DEBUGASSERT(lower->ops->resume != NULL);
if (upper->started)
{
#ifdef CONFIG_AUDIO_MULTI_SESSION
session = (FAR void *) arg;
ret = lower->ops->resume(lower, session);
#else
ret = lower->ops->resume(lower);
#endif
}
}
break;
#endif /* CONFIG_AUDIO_EXCLUDE_PAUSE_RESUME */
/* AUDIOIOC_ALLOCBUFFER - Allocate an audio buffer
*
* ioctl argument: pointer to an audio_buf_desc_s structure
*/
case AUDIOIOC_ALLOCBUFFER:
{
audinfo("AUDIOIOC_ALLOCBUFFER\n");
bufdesc = (FAR struct audio_buf_desc_s *) arg;
if (lower->ops->allocbuffer)
{
ret = lower->ops->allocbuffer(lower, bufdesc);
}
else
{
/* Perform a simple kumm_malloc operation assuming 1 session */
ret = apb_alloc(bufdesc);
}
}
break;
/* AUDIOIOC_FREEBUFFER - Free an audio buffer
*
* ioctl argument: pointer to an audio_buf_desc_s structure
*/
case AUDIOIOC_FREEBUFFER:
{
audinfo("AUDIOIOC_FREEBUFFER\n");
bufdesc = (FAR struct audio_buf_desc_s *) arg;
if (lower->ops->freebuffer)
{
ret = lower->ops->freebuffer(lower, bufdesc);
}
else
{
/* Perform a simple apb_free operation */
DEBUGASSERT(bufdesc->u.buffer != NULL);
apb_free(bufdesc->u.buffer);
ret = sizeof(struct audio_buf_desc_s);
}
}
break;
/* AUDIOIOC_ENQUEUEBUFFER - Enqueue an audio buffer
*
* ioctl argument: pointer to an audio_buf_desc_s structure
*/
case AUDIOIOC_ENQUEUEBUFFER:
{
audinfo("AUDIOIOC_ENQUEUEBUFFER\n");
DEBUGASSERT(lower->ops->enqueuebuffer != NULL);
bufdesc = (FAR struct audio_buf_desc_s *) arg;
ret = lower->ops->enqueuebuffer(lower, bufdesc->u.buffer);
}
break;
/* AUDIOIOC_REGISTERMQ - Register a client Message Queue
*
* TODO: This needs to have multi session support.
*/
case AUDIOIOC_REGISTERMQ:
{
audinfo("AUDIOIOC_REGISTERMQ\n");
ret = fs_getfilep((mqd_t)arg, &upper->usermq);
}
break;
/* AUDIOIOC_UNREGISTERMQ - Register a client Message Queue
*
* TODO: This needs to have multi session support.
*/
case AUDIOIOC_UNREGISTERMQ:
{
audinfo("AUDIOIOC_UNREGISTERMQ\n");
upper->usermq = NULL;
ret = OK;
}
break;
/* AUDIOIOC_RESERVE - Reserve a session with the driver
*
* ioctl argument - pointer to receive the session context
*/
case AUDIOIOC_RESERVE:
{
audinfo("AUDIOIOC_RESERVE\n");
DEBUGASSERT(lower->ops->reserve != NULL);
/* Call lower-half to perform the reservation */
#ifdef CONFIG_AUDIO_MULTI_SESSION
ret = lower->ops->reserve(lower, (FAR void **) arg);
#else
ret = lower->ops->reserve(lower);
#endif
}
break;
/* AUDIOIOC_RESERVE - Reserve a session with the driver
*
* ioctl argument - pointer to receive the session context
*/
case AUDIOIOC_RELEASE:
{
audinfo("AUDIOIOC_RELEASE\n");
DEBUGASSERT(lower->ops->release != NULL);
/* Call lower-half to perform the release */
#ifdef CONFIG_AUDIO_MULTI_SESSION
ret = lower->ops->release(lower, (FAR void *) arg);
#else
ret = lower->ops->release(lower);
#endif
}
break;
/* Any unrecognized IOCTL commands might be
* platform-specific ioctl commands
*/
default:
{
audinfo("Forwarding unrecognized cmd: %d arg: %ld\n", cmd, arg);
DEBUGASSERT(lower->ops->ioctl != NULL);
ret = lower->ops->ioctl(lower, cmd, arg);
}
break;
}
nxmutex_unlock(&upper->lock);
return ret;
}
/****************************************************************************
* Name: audio_dequeuebuffer
*
* Description:
* Dequeues a previously enqueued Audio Pipeline Buffer.
*
* 1. The upper half driver calls the enqueuebuffer method, providing the
* lower half driver with the ab_buffer to process.
* 2. The lower half driver's enqueuebuffer will either processes the
* buffer directly, or more likely add it to a queue for processing
* by a background thread or worker task.
* 3. When the lower half driver has completed processing of the enqueued
* ab_buffer, it will call this routine to indicate processing of the
* buffer is complete.
* 4. When this routine is called, it will check if any threads are waiting
* to enqueue additional buffers and "wake them up" for further
* processing.
*
* Input Parameters:
* handle - This is the handle that was provided to the lower-half
* start() method.
* apb - A pointer to the previsously enqueued ap_buffer_s
* status - Status of the dequeue operation
*
* Returned Value:
* None
*
* Assumptions:
* This function may be called from an interrupt handler.
*
****************************************************************************/
#ifdef CONFIG_AUDIO_MULTI_SESSION
static inline void audio_dequeuebuffer(FAR struct audio_upperhalf_s *upper,
FAR struct ap_buffer_s *apb, uint16_t status,
FAR void *session)
#else
static inline void audio_dequeuebuffer(FAR struct audio_upperhalf_s *upper,
FAR struct ap_buffer_s *apb, uint16_t status)
#endif
{
struct audio_msg_s msg;
audinfo("Entry\n");
/* Send a dequeue message to the user if a message queue is registered */
if (upper->usermq != NULL)
{
msg.msg_id = AUDIO_MSG_DEQUEUE;
msg.u.ptr = apb;
#ifdef CONFIG_AUDIO_MULTI_SESSION
msg.session = session;
#endif
apb->flags |= AUDIO_APB_DEQUEUED;
file_mq_send(upper->usermq, (FAR const char *)&msg, sizeof(msg),
CONFIG_AUDIO_BUFFER_DEQUEUE_PRIO);
}
}
/****************************************************************************
* Name: audio_complete
*
* Description:
* Send an AUDIO_MSG_COMPLETE message to the client to indicate that the
* active playback has completed. The lower-half driver initiates this
* call via its callback pointer to our upper-half driver.
*
****************************************************************************/
#ifdef CONFIG_AUDIO_MULTI_SESSION
static inline void audio_complete(FAR struct audio_upperhalf_s *upper,
FAR struct ap_buffer_s *apb, uint16_t status,
FAR void *session)
#else
static inline void audio_complete(FAR struct audio_upperhalf_s *upper,
FAR struct ap_buffer_s *apb, uint16_t status)
#endif
{
struct audio_msg_s msg;
audinfo("Entry\n");
/* Send a dequeue message to the user if a message queue is registered */
upper->started = false;
if (upper->usermq != NULL)
{
msg.msg_id = AUDIO_MSG_COMPLETE;
msg.u.ptr = NULL;
#ifdef CONFIG_AUDIO_MULTI_SESSION
msg.session = session;
#endif
file_mq_send(upper->usermq, (FAR const char *)&msg, sizeof(msg),
CONFIG_AUDIO_BUFFER_DEQUEUE_PRIO);
}
}
/****************************************************************************
* Name: audio_message
*
* Description:
* Send an custom message to the client to indicate that the
* active message has delivered. The lower-half driver initiates this
* call via its callback pointer to our upper-half driver.
*
****************************************************************************/
#ifdef CONFIG_AUDIO_MULTI_SESSION
static inline void audio_message(FAR struct audio_upperhalf_s *upper,
FAR struct ap_buffer_s *apb, uint16_t status,
FAR void *session)
#else
static inline void audio_message(FAR struct audio_upperhalf_s *upper,
FAR struct ap_buffer_s *apb, uint16_t status)
#endif
{
struct audio_msg_s *msg = (FAR struct audio_msg_s *)apb;
/* Send a message to the user if a message queue is registered */
if (upper->usermq != NULL)
{
#ifdef CONFIG_AUDIO_MULTI_SESSION
msg->session = session;
#endif
file_mq_send(upper->usermq, (FAR const char *)msg, sizeof(*msg),
CONFIG_AUDIO_BUFFER_DEQUEUE_PRIO);
}
}
/****************************************************************************
* Name: audio_callback
*
* Description:
* Provides a callback interface for lower-half drivers to call to the
* upper-half for buffer dequeueing, error reporting, etc.
*
* Input Parameters:
* priv - Private context data owned by the upper-half
* reason - The reason code for the callback
* apb - A pointer to the previsously enqueued ap_buffer_s
* status - Status information associated with the callback
*
* Returned Value:
* None
*
* Assumptions:
* This function may be called from an interrupt handler.
*
****************************************************************************/
#ifdef CONFIG_AUDIO_MULTI_SESSION
static void audio_callback(FAR void *handle, uint16_t reason,
FAR struct ap_buffer_s *apb, uint16_t status,
FAR void *session)
#else
static void audio_callback(FAR void *handle, uint16_t reason,
FAR struct ap_buffer_s *apb, uint16_t status)
#endif
{
FAR struct audio_upperhalf_s *upper =
(FAR struct audio_upperhalf_s *)handle;
audinfo("Entry\n");
/* Perform operation based on reason code */
switch (reason)
{
case AUDIO_CALLBACK_DEQUEUE:
{
/* Call the dequeue routine */
#ifdef CONFIG_AUDIO_MULTI_SESSION
audio_dequeuebuffer(upper, apb, status, session);
#else
audio_dequeuebuffer(upper, apb, status);
#endif
break;
}
/* Lower-half I/O error occurred */
case AUDIO_CALLBACK_IOERR:
{
}
break;
/* Lower-half driver has completed a playback */
case AUDIO_CALLBACK_COMPLETE:
{
/* Send a complete message to the user if a message queue
* is registered
*/
#ifdef CONFIG_AUDIO_MULTI_SESSION
audio_complete(upper, apb, status, session);
#else
audio_complete(upper, apb, status);
#endif
}
break;
case AUDIO_CALLBACK_MESSAGE:
{
#ifdef CONFIG_AUDIO_MULTI_SESSION
audio_message(upper, apb, status, session);
#else
audio_message(upper, apb, status);
#endif
}
break;
default:
{
auderr("ERROR: Unknown callback reason code %d\n", reason);
break;
}
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: audio_register
*
* Description:
* This function binds an instance of a "lower half" audio driver with the
* "upper half" Audio device and registers that device so that can be used
* by application code.
*
* When this function is called, the "lower half" driver should be in the
* reset state (as if the shutdown() method had already been called).
*
* Input Parameters:
* path - The full path to the driver to be registers in the NuttX pseudo-
* filesystem. The recommended convention is to name Audio drivers
* based on the function they provide, such as "/dev/pcm0", "/dev/mp31",
* etc.
* dev - A pointer to an instance of lower half audio driver.
* This instance is bound to the Audio driver and must persists as long
* as the driver persists.
*
* Returned Value:
* Zero on success; a negated errno value on failure.
*
****************************************************************************/
int audio_register(FAR const char *name, FAR struct audio_lowerhalf_s *dev)
{
FAR struct audio_upperhalf_s *upper;
char path[AUDIO_MAX_DEVICE_PATH];
static bool dev_audio_created = false;
#ifndef CONFIG_AUDIO_CUSTOM_DEV_PATH
FAR const char *devname = "/dev/audio";
#elif !defined(CONFIG_AUDIO_DEV_ROOT)
FAR const char *devname = CONFIG_AUDIO_DEV_PATH;
FAR const char *ptr;
FAR char *pathptr;
#endif
/* Allocate the upper-half data structure */
upper = kmm_zalloc(sizeof(struct audio_upperhalf_s));
if (!upper)
{
auderr("ERROR: Allocation failed\n");
return -ENOMEM;
}
/* Initialize the Audio device structure
* (it was already zeroed by kmm_zalloc())
*/
nxmutex_init(&upper->lock);
upper->dev = dev;
#ifdef CONFIG_AUDIO_CUSTOM_DEV_PATH
#ifdef CONFIG_AUDIO_DEV_ROOT
/* This is the simple case ... No need to make a directory */
strlcpy(path, "/dev/", sizeof(path));
strlcat(path, name, sizeof(path));
#else
/* Ensure the path begins with "/dev" as we don't support placing device
* anywhere but in the /dev directory
*/
DEBUGASSERT(strncmp(devname, "/dev", 4) == 0);
/* Create a /dev/audio directory. */
if (!dev_audio_created)
{
/* Get path name after "/dev" */
ptr = &devname[4];
if (*ptr == '/')
{
ptr++;
}
strlcpy(path, "/dev/", sizeof(path));
pathptr = &path[5];
/* Do mkdir for each segment of the path */
while (*ptr != '\0')
{
/* Build next path segment into path variable */
while (*ptr != '/' && *ptr != '\0')
{
*pathptr++ = *ptr++;
}
*pathptr = '\0';
/* Make this level of directory */
mkdir(path, 0644);
/* Check for another level */
*pathptr++ = '/';
if (*ptr == '/')
{
ptr++;
}
}
/* Indicate we have created the audio dev path */
dev_audio_created = true;
}
/* Now build the path for registration */
strlcpy(path, devname, sizeof(path));
if (devname[sizeof(devname)-1] != '/')
{
strlcat(path, "/", sizeof(path));
}
strlcat(path, name, sizeof(path));
#endif /* CONFIG_AUDIO_DEV_PATH=="/dev" */
#else /* CONFIG_AUDIO_CUSTOM_DEV_PATH */
/* Create a /dev/audio directory. */
if (!dev_audio_created)
{
/* We don't check for error here because even if it fails, then
* the register_driver call below will return an error condition
* for us.
*/
mkdir(devname, 0644);
dev_audio_created = true;
}
/* Register the Audio device */
strlcpy(path, devname, sizeof(path));
strlcat(path, "/", sizeof(path));
strlcat(path, name, sizeof(path));
#endif
/* Give the lower-half a context to the upper half */
dev->upper = audio_callback;
dev->priv = upper;
audinfo("Registering %s\n", path);
return register_driver(path, &g_audioops, 0666, upper);
}
#endif /* CONFIG_AUDIO */
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