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incubator-nuttx/drivers/i2s/i2schar.c

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/****************************************************************************
* drivers/i2s/i2schar.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.
*
****************************************************************************/
/****************************************************************************
*
* This is a simple character driver for testing I2C. It is not an audio
* driver but does conform to some of the buffer management heuristics of an
* audio driver. It is not suitable for use in any real driver application
* in its current form.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <assert.h>
#include <debug.h>
#include <errno.h>
#include <nuttx/mutex.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/audio/audio.h>
#include <nuttx/audio/i2s.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifndef CONFIG_AUDIO_I2SCHAR_RXTIMEOUT
# define CONFIG_AUDIO_I2SCHAR_RXTIMEOUT 0
#endif
#ifndef CONFIG_AUDIO_I2SCHAR_TXTIMEOUT
# define CONFIG_AUDIO_I2SCHAR_TXTIMEOUT 0
#endif
/* Device naming ************************************************************/
#define DEVNAME_FMT "/dev/i2schar%d"
#define DEVNAME_FMTLEN (12 + 3 + 1)
/****************************************************************************
* Private Types
****************************************************************************/
struct i2schar_dev_s
{
FAR struct i2s_dev_s *i2s; /* The lower half i2s driver */
mutex_t lock; /* Assures mutually exclusive access */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* I2S callback function */
static void i2schar_rxcallback(FAR struct i2s_dev_s *dev,
FAR struct ap_buffer_s *apb,
FAR void *arg,
int result);
static void i2schar_txcallback(FAR struct i2s_dev_s *dev,
FAR struct ap_buffer_s *apb,
FAR void *arg,
int result);
/* Character driver methods */
static ssize_t i2schar_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t i2schar_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int i2schar_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_i2schar_fops =
{
NULL, /* open */
NULL, /* close */
i2schar_read, /* read */
i2schar_write, /* write */
NULL, /* seek */
i2schar_ioctl, /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: i2schar_rxcallback
*
* Description:
* I2S RX transfer complete callback.
*
* NOTE: In this test driver, the RX is simply dumped in the bit bucket.
* You would not do this in a real application. You would return the
* received data to the caller via some IPC.
*
* Also, the test buffer is simply freed. This will work if this driver
* has the sole reference to buffer; in that case the buffer will be freed.
* Otherwise -- memory leak! A more efficient design would recycle the
* audio buffers.
*
****************************************************************************/
static void i2schar_rxcallback(FAR struct i2s_dev_s *dev,
FAR struct ap_buffer_s *apb,
FAR void *arg, int result)
{
FAR struct i2schar_dev_s *priv = (FAR struct i2schar_dev_s *)arg;
DEBUGASSERT(priv != NULL && apb != NULL);
UNUSED(priv);
i2sinfo("apb=%p nbytes=%d result=%d\n", apb, apb->nbytes, result);
/* REVISIT: If you want this to actually do something other than
* test I2S data transfer, then this is the point where you would
* want to pass the received I2S to some application.
*/
/* Release our reference to the audio buffer. Hopefully it will be freed
* now.
*/
i2sinfo("Freeing apb=%p crefs=%d\n", apb, apb->crefs);
apb_free(apb);
}
/****************************************************************************
* Name: i2schar_txcallback
*
* Description:
* I2S TX transfer complete callback
*
* NOTE: The test buffer is simply freed. This will work if this driver
* has the sole reference to buffer; in that case the buffer will be freed.
* Otherwise -- memory leak! A more efficient design would recycle the
* audio buffers.
*
****************************************************************************/
static void i2schar_txcallback(FAR struct i2s_dev_s *dev,
FAR struct ap_buffer_s *apb,
FAR void *arg, int result)
{
FAR struct i2schar_dev_s *priv = (FAR struct i2schar_dev_s *)arg;
DEBUGASSERT(priv != NULL && apb != NULL);
UNUSED(priv);
i2sinfo("apb=%p nbytes=%d result=%d\n", apb, apb->nbytes, result);
/* REVISIT: If you want this to actually do something other than
* test I2S data transfer, then this is the point where you would
* want to let some application know that the transfer has complete.
*/
/* Release our reference to the audio buffer. Hopefully it will be freed
* now.
*/
i2sinfo("Freeing apb=%p crefs=%d\n", apb, apb->crefs);
apb_free(apb);
}
/****************************************************************************
* Name: i2schar_read
*
* Description:
* Standard character driver read method
*
****************************************************************************/
static ssize_t i2schar_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode;
FAR struct i2schar_dev_s *priv;
FAR struct ap_buffer_s *apb;
size_t nbytes;
int ret;
i2sinfo("buffer=%p buflen=%d\n", buffer, (int)buflen);
/* Get our private data structure */
DEBUGASSERT(buffer != NULL);
inode = filep->f_inode;
priv = inode->i_private;
DEBUGASSERT(priv != NULL);
/* Verify that the buffer refers to one, correctly sized audio buffer */
DEBUGASSERT(buflen >= sizeof(struct ap_buffer_s));
apb = (FAR struct ap_buffer_s *)buffer;
nbytes = apb->nmaxbytes;
DEBUGASSERT(buflen >= (sizeof(struct ap_buffer_s) + nbytes));
/* Add a reference to the audio buffer */
apb_reference(apb);
/* Get exclusive access to i2c character driver */
ret = nxmutex_lock(&priv->lock);
if (ret < 0)
{
i2serr("ERROR: nxsem_wait returned: %d\n", ret);
goto errout_with_reference;
}
/* Give the buffer to the I2S driver */
ret = I2S_RECEIVE(priv->i2s, apb, i2schar_rxcallback, priv,
CONFIG_AUDIO_I2SCHAR_RXTIMEOUT);
if (ret < 0)
{
i2serr("ERROR: I2S_RECEIVE returned: %d\n", ret);
goto errout_with_reference;
}
/* Lie to the caller and tell them that all of the bytes have been
* received
*/
nxmutex_unlock(&priv->lock);
return sizeof(struct ap_buffer_s) + nbytes;
errout_with_reference:
apb_free(apb);
nxmutex_unlock(&priv->lock);
return ret;
}
/****************************************************************************
* Name: i2schar_write
*
* Description:
* Standard character driver write method
*
****************************************************************************/
static ssize_t i2schar_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
FAR struct inode *inode;
FAR struct i2schar_dev_s *priv;
FAR struct ap_buffer_s *apb;
size_t nbytes;
int ret;
i2sinfo("buffer=%p buflen=%d\n", buffer, (int)buflen);
/* Get our private data structure */
DEBUGASSERT(buffer);
inode = filep->f_inode;
priv = inode->i_private;
DEBUGASSERT(priv);
/* Verify that the buffer refers to one, correctly sized audio buffer */
DEBUGASSERT(buflen >= sizeof(struct ap_buffer_s));
apb = (FAR struct ap_buffer_s *)buffer;
nbytes = apb->nmaxbytes;
DEBUGASSERT(buflen >= (sizeof(struct ap_buffer_s) + nbytes));
/* Add a reference to the audio buffer */
apb_reference(apb);
/* Get exclusive access to i2c character driver */
ret = nxmutex_lock(&priv->lock);
if (ret < 0)
{
i2serr("ERROR: nxsem_wait returned: %d\n", ret);
goto errout_with_reference;
}
/* Give the audio buffer to the I2S driver */
ret = I2S_SEND(priv->i2s, apb, i2schar_txcallback, priv,
CONFIG_AUDIO_I2SCHAR_TXTIMEOUT);
if (ret < 0)
{
i2serr("ERROR: I2S_SEND returned: %d\n", ret);
goto errout_with_reference;
}
/* Lie to the caller and tell them that all of the bytes have been
* sent.
*/
nxmutex_unlock(&priv->lock);
return sizeof(struct ap_buffer_s) + nbytes;
errout_with_reference:
apb_free(apb);
nxmutex_unlock(&priv->lock);
return ret;
}
/****************************************************************************
* Name: i2char_ioctl
*
* Description:
* Perform I2S device ioctl if exists
*
****************************************************************************/
static int i2schar_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode;
FAR struct i2schar_dev_s *priv;
int ret = -ENOTTY;
/* Get our private data structure */
inode = filep->f_inode;
priv = inode->i_private;
DEBUGASSERT(priv != NULL && priv->i2s && priv->i2s->ops);
if (priv->i2s->ops->i2s_ioctl)
{
ret = priv->i2s->ops->i2s_ioctl(priv->i2s, cmd, arg);
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: i2schar_register
*
* Description:
* Create and register the I2S character driver.
*
* The I2S character driver is a simple character driver that supports I2S
* transfers via a read() and write(). The intent of this driver is to
* support I2S testing. It is not an audio driver but does conform to some
* of the buffer management heuristics of an audio driver. It is not
* suitable for use in any real driver application in its current form.
*
* Input Parameters:
* i2s - An instance of the lower half I2S driver
* minor - The device minor number. The I2S character device will be
* registers as /dev/i2scharN where N is the minor number
*
* Returned Value:
* OK if the driver was successfully register; A negated errno value is
* returned on any failure.
*
****************************************************************************/
int i2schar_register(FAR struct i2s_dev_s *i2s, int minor)
{
FAR struct i2schar_dev_s *priv;
char devname[DEVNAME_FMTLEN];
int ret;
/* Sanity check */
DEBUGASSERT(i2s != NULL && (unsigned)minor < 1000);
/* Allocate a I2S character device structure */
size_t dev_size = sizeof(struct i2schar_dev_s);
priv = kmm_zalloc(dev_size);
if (priv)
{
/* Initialize the I2S character device structure */
priv->i2s = i2s;
nxmutex_init(&priv->lock);
/* Create the character device name */
snprintf(devname, sizeof(devname), DEVNAME_FMT, minor);
ret = register_driver(devname, &g_i2schar_fops, 0666, priv);
if (ret < 0)
{
/* Free the device structure if we failed to create the character
* device.
*/
nxmutex_destroy(&priv->lock);
kmm_free(priv);
return ret;
}
/* Return the result of the registration */
return OK;
}
return -ENOMEM;
}
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