drivers/staging/goldfish/goldfish_audio.c - kernel/bruno - Git at Google

 /*
  * drivers/misc/goldfish_audio.c
  *
  * Copyright (C) 2007 Google, Inc.
  * Copyright (C) 2012 Intel, 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/module.h>
 #include <linux/miscdevice.h>
 #include <linux/fs.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
 #include <linux/pci.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/sched.h>
 #include <linux/dma-mapping.h>
 #include <linux/uaccess.h>
 #include <linux/goldfish.h>

 MODULE_AUTHOR("Google, Inc.");
 MODULE_DESCRIPTION("Android QEMU Audio Driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION("1.0");

 struct goldfish_audio {
 	char __iomem *reg_base;
 	int irq;
 	/* lock protects access to buffer_status and to device registers */
 	spinlock_t lock;
 	wait_queue_head_t wait;

 	char *buffer_virt;		/* combined buffer virtual address */
 	unsigned long buffer_phys;      /* combined buffer physical address */

 	char *write_buffer1;		/* write buffer 1 virtual address */
 	char *write_buffer2;		/* write buffer 2 virtual address */
 	char *read_buffer;		/* read buffer virtual address */
 	int buffer_status;
 	int read_supported;         /* true if we have audio input support */
 };

 /*
  *  We will allocate two read buffers and two write buffers.
  *  Having two read buffers facilitate stereo -> mono conversion.
  *  Having two write buffers facilitate interleaved IO.
  */
 #define READ_BUFFER_SIZE        16384
 #define WRITE_BUFFER_SIZE       16384
 #define COMBINED_BUFFER_SIZE    ((2 * READ_BUFFER_SIZE) + \
 					(2 * WRITE_BUFFER_SIZE))

 #define AUDIO_READ(data, addr)		(readl(data->reg_base + addr))
 #define AUDIO_WRITE(data, addr, x)	(writel(x, data->reg_base + addr))
 #define AUDIO_WRITE64(data, addr, addr2, x)	\
 	(gf_write_dma_addr((x), data->reg_base + addr, data->reg_base+addr2))

 /*
  *  temporary variable used between goldfish_audio_probe() and
  *  goldfish_audio_open()
  */
 static struct goldfish_audio *audio_data;

 enum {
 	/* audio status register */
 	AUDIO_INT_STATUS	= 0x00,
 	/* set this to enable IRQ */
 	AUDIO_INT_ENABLE	= 0x04,
 	/* set these to specify buffer addresses */
 	AUDIO_SET_WRITE_BUFFER_1 = 0x08,
 	AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
 	/* set number of bytes in buffer to write */
 	AUDIO_WRITE_BUFFER_1  = 0x10,
 	AUDIO_WRITE_BUFFER_2  = 0x14,
 	AUDIO_SET_WRITE_BUFFER_1_HIGH = 0x28,
 	AUDIO_SET_WRITE_BUFFER_2_HIGH = 0x30,

 	/* true if audio input is supported */
 	AUDIO_READ_SUPPORTED = 0x18,
 	/* buffer to use for audio input */
 	AUDIO_SET_READ_BUFFER = 0x1C,
 	AUDIO_SET_READ_BUFFER_HIGH = 0x34,

 	/* driver writes number of bytes to read */
 	AUDIO_START_READ  = 0x20,

 	/* number of bytes available in read buffer */
 	AUDIO_READ_BUFFER_AVAILABLE  = 0x24,

 	/* AUDIO_INT_STATUS bits */

 	/* this bit set when it is safe to write more bytes to the buffer */
 	AUDIO_INT_WRITE_BUFFER_1_EMPTY	= 1U << 0,
 	AUDIO_INT_WRITE_BUFFER_2_EMPTY	= 1U << 1,
 	AUDIO_INT_READ_BUFFER_FULL      = 1U << 2,

 	AUDIO_INT_MASK                  = AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 					  AUDIO_INT_WRITE_BUFFER_2_EMPTY |
 					  AUDIO_INT_READ_BUFFER_FULL,
 };

 static atomic_t open_count = ATOMIC_INIT(0);

 static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 				   size_t count, loff_t *pos)
 {
 	struct goldfish_audio *data = fp->private_data;
 	int length;
 	int result = 0;

 	if (!data->read_supported)
 		return -ENODEV;

 	while (count > 0) {
 		length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
 		AUDIO_WRITE(data, AUDIO_START_READ, length);

 		wait_event_interruptible(data->wait, data->buffer_status &
 					 AUDIO_INT_READ_BUFFER_FULL);

 		length = AUDIO_READ(data, AUDIO_READ_BUFFER_AVAILABLE);

 		/* copy data to user space */
 		if (copy_to_user(buf, data->read_buffer, length))
 			return -EFAULT;

 		result += length;
 		buf += length;
 		count -= length;
 	}
 	return result;
 }

 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
 				    size_t count, loff_t *pos)
 {
 	struct goldfish_audio *data = fp->private_data;
 	unsigned long irq_flags;
 	ssize_t result = 0;
 	char *kbuf;

 	while (count > 0) {
 		ssize_t copy = count;

 		if (copy > WRITE_BUFFER_SIZE)
 			copy = WRITE_BUFFER_SIZE;
 		wait_event_interruptible(data->wait, data->buffer_status &
 					(AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 					AUDIO_INT_WRITE_BUFFER_2_EMPTY));

 		if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
 			kbuf = data->write_buffer1;
 		else
 			kbuf = data->write_buffer2;

 		/* copy from user space to the appropriate buffer */
 		if (copy_from_user(kbuf, buf, copy)) {
 			result = -EFAULT;
 			break;
 		}

 		spin_lock_irqsave(&data->lock, irq_flags);
 		/*
 		 *  clear the buffer empty flag, and signal the emulator
 		 *  to start writing the buffer
 		 */
 		if (kbuf == data->write_buffer1) {
 			data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
 			AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_1, copy);
 		} else {
 			data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
 			AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_2, copy);
 		}
 		spin_unlock_irqrestore(&data->lock, irq_flags);

 		buf += copy;
 		result += copy;
 		count -= copy;
 	}
 	return result;
 }

 static int goldfish_audio_open(struct inode *ip, struct file *fp)
 {
 	if (!audio_data)
 		return -ENODEV;

 	if (atomic_inc_return(&open_count) == 1) {
 		fp->private_data = audio_data;
 		audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 					     AUDIO_INT_WRITE_BUFFER_2_EMPTY);
 		AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
 		return 0;
 	}

 	atomic_dec(&open_count);
 	return -EBUSY;
 }

 static int goldfish_audio_release(struct inode *ip, struct file *fp)
 {
 	atomic_dec(&open_count);
 	/* FIXME: surely this is wrong for the multi-opened case */
 	AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, 0);
 	return 0;
 }

 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
 				 unsigned long arg)
 {
 	/* temporary workaround, until we switch to the ALSA API */
 	if (cmd == 315)
 		return -1;

 	return 0;
 }

 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
 {
 	unsigned long irq_flags;
 	struct goldfish_audio	*data = dev_id;
 	u32 status;

 	spin_lock_irqsave(&data->lock, irq_flags);

 	/* read buffer status flags */
 	status = AUDIO_READ(data, AUDIO_INT_STATUS);
 	status &= AUDIO_INT_MASK;
 	/*
 	 *  if buffers are newly empty, wake up blocked
 	 *  goldfish_audio_write() call
 	 */
 	if (status) {
 		data->buffer_status = status;
 		wake_up(&data->wait);
 	}

 	spin_unlock_irqrestore(&data->lock, irq_flags);
 	return status ? IRQ_HANDLED : IRQ_NONE;
 }

 /* file operations for /dev/eac */
 static const struct file_operations goldfish_audio_fops = {
 	.owner = THIS_MODULE,
 	.read = goldfish_audio_read,
 	.write = goldfish_audio_write,
 	.open = goldfish_audio_open,
 	.release = goldfish_audio_release,
 	.unlocked_ioctl = goldfish_audio_ioctl,
 };

 static struct miscdevice goldfish_audio_device = {
 	.minor = MISC_DYNAMIC_MINOR,
 	.name = "eac",
 	.fops = &goldfish_audio_fops,
 };

 static int goldfish_audio_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct resource *r;
 	struct goldfish_audio *data;
 	dma_addr_t buf_addr;

 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 	spin_lock_init(&data->lock);
 	init_waitqueue_head(&data->wait);
 	platform_set_drvdata(pdev, data);

 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (r == NULL) {
 		dev_err(&pdev->dev, "platform_get_resource failed\n");
 		return -ENODEV;
 	}
 	data->reg_base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
 	if (data->reg_base == NULL)
 		return -ENOMEM;

 	data->irq = platform_get_irq(pdev, 0);
 	if (data->irq < 0) {
 		dev_err(&pdev->dev, "platform_get_irq failed\n");
 		return -ENODEV;
 	}
 	data->buffer_virt = dmam_alloc_coherent(&pdev->dev,
 				COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
 	if (data->buffer_virt == NULL) {
 		dev_err(&pdev->dev, "allocate buffer failed\n");
 		return -ENOMEM;
 	}
 	data->buffer_phys = buf_addr;
 	data->write_buffer1 = data->buffer_virt;
 	data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
 	data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;

 	ret = devm_request_irq(&pdev->dev, data->irq, goldfish_audio_interrupt,
 			       IRQF_SHARED, pdev->name, data);
 	if (ret) {
 		dev_err(&pdev->dev, "request_irq failed\n");
 		return ret;
 	}

 	ret = misc_register(&goldfish_audio_device);
 	if (ret) {
 		dev_err(&pdev->dev,
 			"misc_register returned %d in goldfish_audio_init\n",
 								ret);
 		return ret;
 	}

 	AUDIO_WRITE64(data, AUDIO_SET_WRITE_BUFFER_1,
 		      AUDIO_SET_WRITE_BUFFER_1_HIGH, buf_addr);
 	buf_addr += WRITE_BUFFER_SIZE;

 	AUDIO_WRITE64(data, AUDIO_SET_WRITE_BUFFER_2,
 		      AUDIO_SET_WRITE_BUFFER_2_HIGH, buf_addr);

 	buf_addr += WRITE_BUFFER_SIZE;

 	data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
 	if (data->read_supported)
 		AUDIO_WRITE64(data, AUDIO_SET_READ_BUFFER,
 			      AUDIO_SET_READ_BUFFER_HIGH, buf_addr);

 	audio_data = data;
 	return 0;
 }

 static int goldfish_audio_remove(struct platform_device *pdev)
 {
 	misc_deregister(&goldfish_audio_device);
 	audio_data = NULL;
 	return 0;
 }

 static struct platform_driver goldfish_audio_driver = {
 	.probe		= goldfish_audio_probe,
 	.remove		= goldfish_audio_remove,
 	.driver = {
 		.name = "goldfish_audio"
 	}
 };

 module_platform_driver(goldfish_audio_driver);
	/*
	* drivers/misc/goldfish_audio.c
	*
	* Copyright (C) 2007 Google, Inc.
	* Copyright (C) 2012 Intel, 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/module.h>
	#include <linux/miscdevice.h>
	#include <linux/fs.h>
	#include <linux/platform_device.h>
	#include <linux/types.h>
	#include <linux/pci.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/sched.h>
	#include <linux/dma-mapping.h>
	#include <linux/uaccess.h>
	#include <linux/goldfish.h>

	MODULE_AUTHOR("Google, Inc.");
	MODULE_DESCRIPTION("Android QEMU Audio Driver");
	MODULE_LICENSE("GPL");
	MODULE_VERSION("1.0");

	struct goldfish_audio {
	char __iomem *reg_base;
	int irq;
	/* lock protects access to buffer_status and to device registers */
	spinlock_t lock;
	wait_queue_head_t wait;

	char buffer_virt; / combined buffer virtual address */
	unsigned long buffer_phys; /* combined buffer physical address */

	char write_buffer1; / write buffer 1 virtual address */
	char write_buffer2; / write buffer 2 virtual address */
	char read_buffer; / read buffer virtual address */
	int buffer_status;
	int read_supported; /* true if we have audio input support */
	};

	/*
	* We will allocate two read buffers and two write buffers.
	* Having two read buffers facilitate stereo -> mono conversion.
	* Having two write buffers facilitate interleaved IO.
	*/
	#define READ_BUFFER_SIZE 16384
	#define WRITE_BUFFER_SIZE 16384
	#define COMBINED_BUFFER_SIZE ((2 * READ_BUFFER_SIZE) + \
	(2 * WRITE_BUFFER_SIZE))

	#define AUDIO_READ(data, addr) (readl(data->reg_base + addr))
	#define AUDIO_WRITE(data, addr, x) (writel(x, data->reg_base + addr))
	#define AUDIO_WRITE64(data, addr, addr2, x) \
	(gf_write_dma_addr((x), data->reg_base + addr, data->reg_base+addr2))

	/*
	* temporary variable used between goldfish_audio_probe() and
	* goldfish_audio_open()
	*/
	static struct goldfish_audio *audio_data;

	enum {
	/* audio status register */
	AUDIO_INT_STATUS = 0x00,
	/* set this to enable IRQ */
	AUDIO_INT_ENABLE = 0x04,
	/* set these to specify buffer addresses */
	AUDIO_SET_WRITE_BUFFER_1 = 0x08,
	AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
	/* set number of bytes in buffer to write */
	AUDIO_WRITE_BUFFER_1 = 0x10,
	AUDIO_WRITE_BUFFER_2 = 0x14,
	AUDIO_SET_WRITE_BUFFER_1_HIGH = 0x28,
	AUDIO_SET_WRITE_BUFFER_2_HIGH = 0x30,

	/* true if audio input is supported */
	AUDIO_READ_SUPPORTED = 0x18,
	/* buffer to use for audio input */
	AUDIO_SET_READ_BUFFER = 0x1C,
	AUDIO_SET_READ_BUFFER_HIGH = 0x34,

	/* driver writes number of bytes to read */
	AUDIO_START_READ = 0x20,

	/* number of bytes available in read buffer */
	AUDIO_READ_BUFFER_AVAILABLE = 0x24,

	/* AUDIO_INT_STATUS bits */

	/* this bit set when it is safe to write more bytes to the buffer */
	AUDIO_INT_WRITE_BUFFER_1_EMPTY = 1U << 0,
	AUDIO_INT_WRITE_BUFFER_2_EMPTY = 1U << 1,
	AUDIO_INT_READ_BUFFER_FULL = 1U << 2,

	AUDIO_INT_MASK = AUDIO_INT_WRITE_BUFFER_1_EMPTY \|
	AUDIO_INT_WRITE_BUFFER_2_EMPTY \|
	AUDIO_INT_READ_BUFFER_FULL,
	};

	static atomic_t open_count = ATOMIC_INIT(0);

	static ssize_t goldfish_audio_read(struct file fp, char __user buf,
	size_t count, loff_t *pos)
	{
	struct goldfish_audio *data = fp->private_data;
	int length;
	int result = 0;

	if (!data->read_supported)
	return -ENODEV;

	while (count > 0) {
	length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
	AUDIO_WRITE(data, AUDIO_START_READ, length);

	wait_event_interruptible(data->wait, data->buffer_status &
	AUDIO_INT_READ_BUFFER_FULL);

	length = AUDIO_READ(data, AUDIO_READ_BUFFER_AVAILABLE);

	/* copy data to user space */
	if (copy_to_user(buf, data->read_buffer, length))
	return -EFAULT;

	result += length;
	buf += length;
	count -= length;
	}
	return result;
	}

	static ssize_t goldfish_audio_write(struct file fp, const char __user buf,
	size_t count, loff_t *pos)
	{
	struct goldfish_audio *data = fp->private_data;
	unsigned long irq_flags;
	ssize_t result = 0;
	char *kbuf;

	while (count > 0) {
	ssize_t copy = count;

	if (copy > WRITE_BUFFER_SIZE)
	copy = WRITE_BUFFER_SIZE;
	wait_event_interruptible(data->wait, data->buffer_status &
	(AUDIO_INT_WRITE_BUFFER_1_EMPTY \|
	AUDIO_INT_WRITE_BUFFER_2_EMPTY));

	if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
	kbuf = data->write_buffer1;
	else
	kbuf = data->write_buffer2;

	/* copy from user space to the appropriate buffer */
	if (copy_from_user(kbuf, buf, copy)) {
	result = -EFAULT;
	break;
	}

	spin_lock_irqsave(&data->lock, irq_flags);
	/*
	* clear the buffer empty flag, and signal the emulator
	* to start writing the buffer
	*/
	if (kbuf == data->write_buffer1) {
	data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
	AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_1, copy);
	} else {
	data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
	AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_2, copy);
	}
	spin_unlock_irqrestore(&data->lock, irq_flags);

	buf += copy;
	result += copy;
	count -= copy;
	}
	return result;
	}

	static int goldfish_audio_open(struct inode ip, struct file fp)
	{
	if (!audio_data)
	return -ENODEV;

	if (atomic_inc_return(&open_count) == 1) {
	fp->private_data = audio_data;
	audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY \|
	AUDIO_INT_WRITE_BUFFER_2_EMPTY);
	AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
	return 0;
	}

	atomic_dec(&open_count);
	return -EBUSY;
	}

	static int goldfish_audio_release(struct inode ip, struct file fp)
	{
	atomic_dec(&open_count);
	/* FIXME: surely this is wrong for the multi-opened case */
	AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, 0);
	return 0;
	}

	static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
	unsigned long arg)
	{
	/* temporary workaround, until we switch to the ALSA API */
	if (cmd == 315)
	return -1;

	return 0;
	}

	static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
	{
	unsigned long irq_flags;
	struct goldfish_audio *data = dev_id;
	u32 status;

	spin_lock_irqsave(&data->lock, irq_flags);

	/* read buffer status flags */
	status = AUDIO_READ(data, AUDIO_INT_STATUS);
	status &= AUDIO_INT_MASK;
	/*
	* if buffers are newly empty, wake up blocked
	* goldfish_audio_write() call
	*/
	if (status) {
	data->buffer_status = status;
	wake_up(&data->wait);
	}

	spin_unlock_irqrestore(&data->lock, irq_flags);
	return status ? IRQ_HANDLED : IRQ_NONE;
	}

	/* file operations for /dev/eac */
	static const struct file_operations goldfish_audio_fops = {
	.owner = THIS_MODULE,
	.read = goldfish_audio_read,
	.write = goldfish_audio_write,
	.open = goldfish_audio_open,
	.release = goldfish_audio_release,
	.unlocked_ioctl = goldfish_audio_ioctl,
	};

	static struct miscdevice goldfish_audio_device = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "eac",
	.fops = &goldfish_audio_fops,
	};

	static int goldfish_audio_probe(struct platform_device *pdev)
	{
	int ret;
	struct resource *r;
	struct goldfish_audio *data;
	dma_addr_t buf_addr;

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;
	spin_lock_init(&data->lock);
	init_waitqueue_head(&data->wait);
	platform_set_drvdata(pdev, data);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (r == NULL) {
	dev_err(&pdev->dev, "platform_get_resource failed\n");
	return -ENODEV;
	}
	data->reg_base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
	if (data->reg_base == NULL)
	return -ENOMEM;

	data->irq = platform_get_irq(pdev, 0);
	if (data->irq < 0) {
	dev_err(&pdev->dev, "platform_get_irq failed\n");
	return -ENODEV;
	}
	data->buffer_virt = dmam_alloc_coherent(&pdev->dev,
	COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
	if (data->buffer_virt == NULL) {
	dev_err(&pdev->dev, "allocate buffer failed\n");
	return -ENOMEM;
	}
	data->buffer_phys = buf_addr;
	data->write_buffer1 = data->buffer_virt;
	data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
	data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;

	ret = devm_request_irq(&pdev->dev, data->irq, goldfish_audio_interrupt,
	IRQF_SHARED, pdev->name, data);
	if (ret) {
	dev_err(&pdev->dev, "request_irq failed\n");
	return ret;
	}

	ret = misc_register(&goldfish_audio_device);
	if (ret) {
	dev_err(&pdev->dev,
	"misc_register returned %d in goldfish_audio_init\n",
	ret);
	return ret;
	}

	AUDIO_WRITE64(data, AUDIO_SET_WRITE_BUFFER_1,
	AUDIO_SET_WRITE_BUFFER_1_HIGH, buf_addr);
	buf_addr += WRITE_BUFFER_SIZE;

	AUDIO_WRITE64(data, AUDIO_SET_WRITE_BUFFER_2,
	AUDIO_SET_WRITE_BUFFER_2_HIGH, buf_addr);

	buf_addr += WRITE_BUFFER_SIZE;

	data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
	if (data->read_supported)
	AUDIO_WRITE64(data, AUDIO_SET_READ_BUFFER,
	AUDIO_SET_READ_BUFFER_HIGH, buf_addr);

	audio_data = data;
	return 0;
	}

	static int goldfish_audio_remove(struct platform_device *pdev)
	{
	misc_deregister(&goldfish_audio_device);
	audio_data = NULL;
	return 0;
	}

	static struct platform_driver goldfish_audio_driver = {
	.probe = goldfish_audio_probe,
	.remove = goldfish_audio_remove,
	.driver = {
	.name = "goldfish_audio"
	}
	};

	module_platform_driver(goldfish_audio_driver);