drivers/staging/goldfish/goldfish_audio.c

   1 /* drivers/misc/goldfish_audio.c
   2  *
   3  * Copyright (C) 2007 Google, Inc.
   4  * Copyright (C) 2012 Intel, Inc.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/fs.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/types.h>
  22 #include <linux/pci.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/io.h>
  25 #include <linux/sched.h>
  26 #include <linux/dma-mapping.h>
  27 #include <linux/uaccess.h>
  28
  29 MODULE_AUTHOR("Google, Inc.");
  30 MODULE_DESCRIPTION("Android QEMU Audio Driver");
  31 MODULE_LICENSE("GPL");
  32 MODULE_VERSION("1.0");
  33
  34 struct goldfish_audio {
  35         char __iomem *reg_base;
  36         int irq;
  37         spinlock_t lock;
  38         wait_queue_head_t wait;
  39
  40         char __iomem *buffer_virt;      /* combined buffer virtual address */
  41         unsigned long buffer_phys;      /* combined buffer physical address */
  42
  43         char __iomem *write_buffer1;    /* write buffer 1 virtual address */
  44         char __iomem *write_buffer2;    /* write buffer 2 virtual address */
  45         char __iomem *read_buffer;      /* read buffer virtual address */
  46         int buffer_status;
  47         int read_supported;         /* true if we have audio input support */
  48 };
  49
  50 /* We will allocate two read buffers and two write buffers.
  51    Having two read buffers facilitate stereo -> mono conversion.
  52    Having two write buffers facilitate interleaved IO.
  53 */
  54 #define READ_BUFFER_SIZE        16384
  55 #define WRITE_BUFFER_SIZE       16384
  56 #define COMBINED_BUFFER_SIZE    ((2 * READ_BUFFER_SIZE) + \
  57                                         (2 * WRITE_BUFFER_SIZE))
  58
  59 #define AUDIO_READ(data, addr)          (readl(data->reg_base + addr))
  60 #define AUDIO_WRITE(data, addr, x)      (writel(x, data->reg_base + addr))
  61
  62 /* temporary variable used between goldfish_audio_probe() and
  63    goldfish_audio_open() */
  64 static struct goldfish_audio *audio_data;
  65
  66 enum {
  67         /* audio status register */
  68         AUDIO_INT_STATUS        = 0x00,
  69         /* set this to enable IRQ */
  70         AUDIO_INT_ENABLE        = 0x04,
  71         /* set these to specify buffer addresses */
  72         AUDIO_SET_WRITE_BUFFER_1 = 0x08,
  73         AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
  74         /* set number of bytes in buffer to write */
  75         AUDIO_WRITE_BUFFER_1  = 0x10,
  76         AUDIO_WRITE_BUFFER_2  = 0x14,
  77
  78         /* true if audio input is supported */
  79         AUDIO_READ_SUPPORTED = 0x18,
  80         /* buffer to use for audio input */
  81         AUDIO_SET_READ_BUFFER = 0x1C,
  82
  83         /* driver writes number of bytes to read */
  84         AUDIO_START_READ  = 0x20,
  85
  86         /* number of bytes available in read buffer */
  87         AUDIO_READ_BUFFER_AVAILABLE  = 0x24,
  88
  89         /* AUDIO_INT_STATUS bits */
  90
  91         /* this bit set when it is safe to write more bytes to the buffer */
  92         AUDIO_INT_WRITE_BUFFER_1_EMPTY  = 1U << 0,
  93         AUDIO_INT_WRITE_BUFFER_2_EMPTY  = 1U << 1,
  94         AUDIO_INT_READ_BUFFER_FULL      = 1U << 2,
  95
  96         AUDIO_INT_MASK                  = AUDIO_INT_WRITE_BUFFER_1_EMPTY |
  97                                           AUDIO_INT_WRITE_BUFFER_2_EMPTY |
  98                                           AUDIO_INT_READ_BUFFER_FULL,
  99 };
 100
 101
 102 static atomic_t open_count = ATOMIC_INIT(0);
 103
 104
 105 static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 106                                                 size_t count, loff_t *pos)
 107 {
 108         struct goldfish_audio *data = fp->private_data;
 109         int length;
 110         int result = 0;
 111
 112         if (!data->read_supported)
 113                 return -ENODEV;
 114
 115         while (count > 0) {
 116                 length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
 117                 AUDIO_WRITE(data, AUDIO_START_READ, length);
 118
 119                 wait_event_interruptible(data->wait,
 120                         (data->buffer_status & AUDIO_INT_READ_BUFFER_FULL));
 121
 122                 length = AUDIO_READ(data,
 123                                                 AUDIO_READ_BUFFER_AVAILABLE);
 124
 125                 /* copy data to user space */
 126                 if (copy_to_user(buf, data->read_buffer, length))
 127                         return -EFAULT;
 128
 129                 result += length;
 130                 buf += length;
 131                 count -= length;
 132         }
 133         return result;
 134 }
 135
 136 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
 137                                                  size_t count, loff_t *pos)
 138 {
 139         struct goldfish_audio *data = fp->private_data;
 140         unsigned long irq_flags;
 141         ssize_t result = 0;
 142         char __iomem *kbuf;
 143
 144         while (count > 0) {
 145                 ssize_t copy = count;
 146                 if (copy > WRITE_BUFFER_SIZE)
 147                         copy = WRITE_BUFFER_SIZE;
 148                 wait_event_interruptible(data->wait, (data->buffer_status &
 149                                         (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 150                                         AUDIO_INT_WRITE_BUFFER_2_EMPTY)));
 151
 152                 if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
 153                         kbuf = data->write_buffer1;
 154                 else
 155                         kbuf = data->write_buffer2;
 156
 157                 /* copy from user space to the appropriate buffer */
 158                 if (copy_from_user(kbuf, buf, copy)) {
 159                         result = -EFAULT;
 160                         break;
 161                 }
 162
 163                 spin_lock_irqsave(&data->lock, irq_flags);
 164                 /* clear the buffer empty flag, and signal the emulator
 165                  * to start writing the buffer */
 166                 if (kbuf == data->write_buffer1) {
 167                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
 168                         AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_1, copy);
 169                 } else {
 170                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
 171                         AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_2, copy);
 172                 }
 173                 spin_unlock_irqrestore(&data->lock, irq_flags);
 174
 175                 buf += copy;
 176                 result += copy;
 177                 count -= copy;
 178         }
 179         return result;
 180 }
 181
 182 static int goldfish_audio_open(struct inode *ip, struct file *fp)
 183 {
 184         if (!audio_data)
 185                 return -ENODEV;
 186
 187         if (atomic_inc_return(&open_count) == 1) {
 188                 fp->private_data = audio_data;
 189                 audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 190                                              AUDIO_INT_WRITE_BUFFER_2_EMPTY);
 191                 AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
 192                 return 0;
 193         } else {
 194                 atomic_dec(&open_count);
 195                 return -EBUSY;
 196         }
 197 }
 198
 199 static int goldfish_audio_release(struct inode *ip, struct file *fp)
 200 {
 201         atomic_dec(&open_count);
 202         /* FIXME: surely this is wrong for the multi-opened case */
 203         AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, 0);
 204         return 0;
 205 }
 206
 207 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
 208                                                         unsigned long arg)
 209 {
 210         /* temporary workaround, until we switch to the ALSA API */
 211         if (cmd == 315)
 212                 return -1;
 213         else
 214                 return 0;
 215 }
 216
 217 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
 218 {
 219         unsigned long irq_flags;
 220         struct goldfish_audio   *data = dev_id;
 221         u32 status;
 222
 223         spin_lock_irqsave(&data->lock, irq_flags);
 224
 225         /* read buffer status flags */
 226         status = AUDIO_READ(data, AUDIO_INT_STATUS);
 227         status &= AUDIO_INT_MASK;
 228         /* if buffers are newly empty, wake up blocked
 229            goldfish_audio_write() call */
 230         if (status) {
 231                 data->buffer_status = status;
 232                 wake_up(&data->wait);
 233         }
 234
 235         spin_unlock_irqrestore(&data->lock, irq_flags);
 236         return status ? IRQ_HANDLED : IRQ_NONE;
 237 }
 238
 239 /* file operations for /dev/eac */
 240 static const struct file_operations goldfish_audio_fops = {
 241         .owner = THIS_MODULE,
 242         .read = goldfish_audio_read,
 243         .write = goldfish_audio_write,
 244         .open = goldfish_audio_open,
 245         .release = goldfish_audio_release,
 246         .unlocked_ioctl = goldfish_audio_ioctl,
 247 };
 248
 249 static struct miscdevice goldfish_audio_device = {
 250         .minor = MISC_DYNAMIC_MINOR,
 251         .name = "eac",
 252         .fops = &goldfish_audio_fops,
 253 };
 254
 255 static int goldfish_audio_probe(struct platform_device *pdev)
 256 {
 257         int ret;
 258         struct resource *r;
 259         struct goldfish_audio *data;
 260         dma_addr_t buf_addr;
 261
 262         data = kzalloc(sizeof(*data), GFP_KERNEL);
 263         if (data == NULL) {
 264                 ret = -ENOMEM;
 265                 goto err_data_alloc_failed;
 266         }
 267         spin_lock_init(&data->lock);
 268         init_waitqueue_head(&data->wait);
 269         platform_set_drvdata(pdev, data);
 270
 271         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 272         if (r == NULL) {
 273                 dev_err(&pdev->dev, "platform_get_resource failed\n");
 274                 ret = -ENODEV;
 275                 goto err_no_io_base;
 276         }
 277         data->reg_base = ioremap(r->start, PAGE_SIZE);
 278         if (data->reg_base == NULL) {
 279                 ret = -ENOMEM;
 280                 goto err_no_io_base;
 281         }
 282
 283         data->irq = platform_get_irq(pdev, 0);
 284         if (data->irq < 0) {
 285                 dev_err(&pdev->dev, "platform_get_irq failed\n");
 286                 ret = -ENODEV;
 287                 goto err_no_irq;
 288         }
 289         data->buffer_virt = dma_alloc_coherent(&pdev->dev,
 290                                 COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
 291         if (data->buffer_virt == 0) {
 292                 ret = -ENOMEM;
 293                 dev_err(&pdev->dev, "allocate buffer failed\n");
 294                 goto err_alloc_write_buffer_failed;
 295         }
 296         data->buffer_phys = buf_addr;
 297         data->write_buffer1 = data->buffer_virt;
 298         data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
 299         data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;
 300
 301         ret = request_irq(data->irq, goldfish_audio_interrupt,
 302                                         IRQF_SHARED, pdev->name, data);
 303         if (ret) {
 304                 dev_err(&pdev->dev, "request_irq failed\n");
 305                 goto err_request_irq_failed;
 306         }
 307
 308         ret = misc_register(&goldfish_audio_device);
 309         if (ret) {
 310                 dev_err(&pdev->dev,
 311                         "misc_register returned %d in goldfish_audio_init\n",
 312                                                                 ret);
 313                 goto err_misc_register_failed;
 314         }
 315
 316         AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_1, buf_addr);
 317         AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_2,
 318                                                 buf_addr + WRITE_BUFFER_SIZE);
 319
 320         data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
 321         if (data->read_supported)
 322                 AUDIO_WRITE(data, AUDIO_SET_READ_BUFFER,
 323                                         buf_addr + 2 * WRITE_BUFFER_SIZE);
 324
 325         audio_data = data;
 326         return 0;
 327
 328 err_misc_register_failed:
 329 err_request_irq_failed:
 330         dma_free_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
 331                                         data->buffer_virt, data->buffer_phys);
 332 err_alloc_write_buffer_failed:
 333 err_no_irq:
 334         iounmap(data->reg_base);
 335 err_no_io_base:
 336         kfree(data);
 337 err_data_alloc_failed:
 338         return ret;
 339 }
 340
 341 static int goldfish_audio_remove(struct platform_device *pdev)
 342 {
 343         struct goldfish_audio *data = platform_get_drvdata(pdev);
 344
 345         misc_deregister(&goldfish_audio_device);
 346         free_irq(data->irq, data);
 347         dma_free_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
 348                                         data->buffer_virt, data->buffer_phys);
 349         iounmap(data->reg_base);
 350         kfree(data);
 351         audio_data = NULL;
 352         return 0;
 353 }
 354
 355 static struct platform_driver goldfish_audio_driver = {
 356         .probe          = goldfish_audio_probe,
 357         .remove         = goldfish_audio_remove,
 358         .driver = {
 359                 .name = "goldfish_audio"
 360         }
 361 };
 362
 363 module_platform_driver(goldfish_audio_driver);