--- /dev/null
+/* 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>
+
+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;
+ 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 AUDIO_READ(data, addr) (readl(data->reg_base + addr))
+#define 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);
+ 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 __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)) {
+ 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;
+ } else {
+ 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;
+ else
+ 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 = 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) {
+ dev_err(&pdev->dev, "platform_get_resource failed\n");
+ ret = -ENODEV;
+ goto err_no_io_base;
+ }
+ data->reg_base = ioremap(r->start, PAGE_SIZE);
+ if (data->reg_base == NULL) {
+ ret = -ENOMEM;
+ goto err_no_io_base;
+ }
+
+ data->irq = platform_get_irq(pdev, 0);
+ if (data->irq < 0) {
+ dev_err(&pdev->dev, "platform_get_irq failed\n");
+ ret = -ENODEV;
+ goto err_no_irq;
+ }
+ data->buffer_virt = dma_alloc_coherent(&pdev->dev,
+ COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
+ if (data->buffer_virt == 0) {
+ ret = -ENOMEM;
+ dev_err(&pdev->dev, "allocate buffer failed\n");
+ 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) {
+ dev_err(&pdev->dev, "request_irq failed\n");
+ goto err_request_irq_failed;
+ }
+
+ ret = misc_register(&goldfish_audio_device);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "misc_register returned %d in goldfish_audio_init\n",
+ ret);
+ goto err_misc_register_failed;
+ }
+
+ AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_1, buf_addr);
+ AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_2,
+ buf_addr + WRITE_BUFFER_SIZE);
+
+ data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
+ if (data->read_supported)
+ 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_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
+ data->buffer_virt, data->buffer_phys);
+err_alloc_write_buffer_failed:
+err_no_irq:
+ iounmap(data->reg_base);
+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_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
+ data->buffer_virt, data->buffer_phys);
+ iounmap(data->reg_base);
+ 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"
+ }
+};
+
+module_platform_driver(goldfish_audio_driver);
projects / platform / kernel / linux-rpi.git / commitdiff