From aefe5257bf3ed9bf950ad962a63e5315566c2f97 Mon Sep 17 00:00:00 2001
From: Mike Lockwood <lockwood@google.com>
Date: Mon, 23 Jul 2007 09:31:54 -0400
Subject: [PATCH 120/134] [ARM] goldfish: Add audio driver for goldfish.

Signed-off-by: Mike A. Chan <mikechan@google.com>
---
 arch/arm/mach-goldfish/Makefile |    2 +-
 arch/arm/mach-goldfish/audio.c  |  379 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 380 insertions(+), 1 deletions(-)
 create mode 100644 arch/arm/mach-goldfish/audio.c

--- a/arch/arm/mach-goldfish/Makefile
+++ b/arch/arm/mach-goldfish/Makefile
@@ -4,6 +4,6 @@
 
 # Object file lists.
 
-obj-y				:= pdev_bus.o timer.o
+obj-y				:= pdev_bus.o timer.o audio.o
 obj-$(CONFIG_MACH_GOLDFISH)	+= board-goldfish.o
 
--- /dev/null
+++ b/arch/arm/mach-goldfish/audio.c
@@ -0,0 +1,379 @@
+/* arch/arm/mach-goldfish/audio.c
+**
+** Copyright (C) 2007 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/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 <asm/types.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+
+MODULE_AUTHOR("Google, Inc.");
+MODULE_DESCRIPTION("Android QEMU Audio Driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0");
+
+struct goldfish_audio {
+	uint32_t reg_base;
+	int irq;
+	spinlock_t lock;
+	wait_queue_head_t wait;
+	
+	char __iomem *buffer_virt;      /* combined buffer virtual address */
+	unsigned long buffer_phys;      /* combined buffer physical address */
+
+	char __iomem *write_buffer1;    /* write buffer 1 virtual address */
+	char __iomem *write_buffer2;    /* write buffer 2 virtual address */
+	char __iomem *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 GOLDFISH_AUDIO_READ(data, addr)   (readl(data->reg_base + addr))
+#define GOLDFISH_AUDIO_WRITE(data, addr, x)   (writel(x, data->reg_base + addr))
+
+/* 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,
+
+	/* true if audio input is supported */
+	AUDIO_READ_SUPPORTED = 0x18,
+	/* buffer to use for audio input */
+	AUDIO_SET_READ_BUFFER = 0x1C,
+	
+	/* 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);
+		GOLDFISH_AUDIO_WRITE(data, AUDIO_START_READ, length);
+
+		wait_event_interruptible(data->wait, (data->buffer_status & AUDIO_INT_READ_BUFFER_FULL));
+
+		length = GOLDFISH_AUDIO_READ(data, AUDIO_READ_BUFFER_AVAILABLE);
+   
+		/* copy data to user space */
+		if (copy_to_user(buf, data->read_buffer, length))
+		{
+			printk("copy_from_user failed!\n");
+			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 __iomem *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))
+		{
+			printk("copy_from_user failed!\n");
+			result = -EFAULT;
+			break;
+		}
+		else
+		{
+			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;
+				GOLDFISH_AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_1, copy);
+			} else {
+				data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
+				GOLDFISH_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);
+		GOLDFISH_AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
+		return 0;
+	} 
+	else 
+	{
+		atomic_dec(&open_count);
+		return -EBUSY;
+	}
+}
+
+static int goldfish_audio_release(struct inode *ip, struct file* fp)
+{
+	atomic_dec(&open_count);
+	GOLDFISH_AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, 0);
+	return 0;
+}
+	   
+static int goldfish_audio_ioctl(struct inode* ip, struct file* fp, unsigned int cmd, unsigned long arg)
+{
+	/* temporary workaround, until we switch to the ALSA API */
+	if (cmd == 315)
+		return -1;
+	else
+		return 0;
+}
+
+static irqreturn_t
+goldfish_audio_interrupt(int irq, void *dev_id)
+{
+	unsigned long irq_flags;
+	struct goldfish_audio	*data = dev_id;
+	uint32_t status;
+
+	spin_lock_irqsave(&data->lock, irq_flags);
+	
+	/* read buffer status flags */
+	status = GOLDFISH_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 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,
+   .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;
+
+printk("goldfish_audio_probe\n");
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if(data == NULL) {
+		ret = -ENOMEM;
+		goto err_data_alloc_failed;
+	}
+	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) {
+		printk("platform_get_resource failed\n");
+		ret = -ENODEV;
+		goto err_no_io_base;
+	}
+	data->reg_base = IO_ADDRESS(r->start - IO_START);
+
+	data->irq = platform_get_irq(pdev, 0);
+	if(data->irq < 0) {
+		printk("platform_get_irq failed\n");
+		ret = -ENODEV;
+		goto err_no_irq;
+	}
+
+	data->buffer_virt = dma_alloc_writecombine(&pdev->dev, COMBINED_BUFFER_SIZE,
+												&buf_addr, GFP_KERNEL);
+	if(data->buffer_virt == 0) {
+		ret = -ENOMEM;
+		goto err_alloc_write_buffer_failed;
+	}
+	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 = request_irq(data->irq, goldfish_audio_interrupt, IRQF_SHARED, pdev->name, data);
+	if(ret)
+		goto err_request_irq_failed;
+
+	if((ret = misc_register(&goldfish_audio_device))) 
+	{
+		printk("misc_register returned %d in goldfish_audio_init\n", ret);
+		goto err_misc_register_failed;
+	}
+
+	
+	GOLDFISH_AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_1, buf_addr);
+	GOLDFISH_AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_2, buf_addr + WRITE_BUFFER_SIZE);
+
+	data->read_supported = GOLDFISH_AUDIO_READ(data, AUDIO_READ_SUPPORTED);
+	if (data->read_supported)
+		GOLDFISH_AUDIO_WRITE(data, AUDIO_SET_READ_BUFFER, buf_addr + 2 * WRITE_BUFFER_SIZE);
+
+	audio_data = data;
+	return 0;
+
+err_misc_register_failed:
+err_request_irq_failed:
+	dma_free_writecombine(&pdev->dev, COMBINED_BUFFER_SIZE, data->buffer_virt, data->buffer_phys);
+err_alloc_write_buffer_failed:
+err_no_irq:
+err_no_io_base:
+	kfree(data);
+err_data_alloc_failed:
+	return ret;
+}
+
+static int goldfish_audio_remove(struct platform_device *pdev)
+{
+	struct goldfish_audio *data = platform_get_drvdata(pdev);
+
+	misc_deregister(&goldfish_audio_device);
+	free_irq(data->irq, data);
+	dma_free_writecombine(&pdev->dev, COMBINED_BUFFER_SIZE, data->buffer_virt, data->buffer_phys);
+	kfree(data);
+	audio_data = NULL;
+	return 0;
+}
+
+static struct platform_driver goldfish_audio_driver = {
+	.probe		= goldfish_audio_probe,
+	.remove		= goldfish_audio_remove,
+	.driver = {
+		.name = "goldfish_audio"
+	}
+};
+
+static int __init goldfish_audio_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&goldfish_audio_driver);
+	if (ret < 0)
+	{
+		printk("platform_driver_register returned %d\n", ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static void __exit goldfish_audio_exit(void)
+{
+	platform_driver_unregister(&goldfish_audio_driver);
+}
+
+module_init(goldfish_audio_init);
+module_exit(goldfish_audio_exit);
