drivers/staging/goldfish/goldfish_audio.c

   1 /*
   2  * drivers/misc/goldfish_audio.c
   3  *
   4  * Copyright (C) 2007 Google, Inc.
   5  * Copyright (C) 2012 Intel, Inc.
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/fs.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/types.h>
  23 #include <linux/pci.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/io.h>
  26 #include <linux/sched.h>
  27 #include <linux/dma-mapping.h>
  28 #include <linux/uaccess.h>
  29
  30 MODULE_AUTHOR("Google, Inc.");
  31 MODULE_DESCRIPTION("Android QEMU Audio Driver");
  32 MODULE_LICENSE("GPL");
  33 MODULE_VERSION("1.0");
  34
  35 struct goldfish_audio {
  36         char __iomem *reg_base;
  37         int irq;
  38         spinlock_t lock;
  39         wait_queue_head_t wait;
  40
  41         char __iomem *buffer_virt;      /* combined buffer virtual address */
  42         unsigned long buffer_phys;      /* combined buffer physical address */
  43
  44         char __iomem *write_buffer1;    /* write buffer 1 virtual address */
  45         char __iomem *write_buffer2;    /* write buffer 2 virtual address */
  46         char __iomem *read_buffer;      /* read buffer virtual address */
  47         int buffer_status;
  48         int read_supported;         /* true if we have audio input support */
  49 };
  50
  51 /*
  52  *  We will allocate two read buffers and two write buffers.
  53  *  Having two read buffers facilitate stereo -> mono conversion.
  54  *  Having two write buffers facilitate interleaved IO.
  55  */
  56 #define READ_BUFFER_SIZE        16384
  57 #define WRITE_BUFFER_SIZE       16384
  58 #define COMBINED_BUFFER_SIZE    ((2 * READ_BUFFER_SIZE) + \
  59                                         (2 * WRITE_BUFFER_SIZE))
  60
  61 #define AUDIO_READ(data, addr)          (readl(data->reg_base + addr))
  62 #define AUDIO_WRITE(data, addr, x)      (writel(x, data->reg_base + addr))
  63
  64 /*
  65  *  temporary variable used between goldfish_audio_probe() and
  66  *  goldfish_audio_open()
  67  */
  68 static struct goldfish_audio *audio_data;
  69
  70 enum {
  71         /* audio status register */
  72         AUDIO_INT_STATUS        = 0x00,
  73         /* set this to enable IRQ */
  74         AUDIO_INT_ENABLE        = 0x04,
  75         /* set these to specify buffer addresses */
  76         AUDIO_SET_WRITE_BUFFER_1 = 0x08,
  77         AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
  78         /* set number of bytes in buffer to write */
  79         AUDIO_WRITE_BUFFER_1  = 0x10,
  80         AUDIO_WRITE_BUFFER_2  = 0x14,
  81
  82         /* true if audio input is supported */
  83         AUDIO_READ_SUPPORTED = 0x18,
  84         /* buffer to use for audio input */
  85         AUDIO_SET_READ_BUFFER = 0x1C,
  86
  87         /* driver writes number of bytes to read */
  88         AUDIO_START_READ  = 0x20,
  89
  90         /* number of bytes available in read buffer */
  91         AUDIO_READ_BUFFER_AVAILABLE  = 0x24,
  92
  93         /* AUDIO_INT_STATUS bits */
  94
  95         /* this bit set when it is safe to write more bytes to the buffer */
  96         AUDIO_INT_WRITE_BUFFER_1_EMPTY  = 1U << 0,
  97         AUDIO_INT_WRITE_BUFFER_2_EMPTY  = 1U << 1,
  98         AUDIO_INT_READ_BUFFER_FULL      = 1U << 2,
  99
 100         AUDIO_INT_MASK                  = AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 101                                           AUDIO_INT_WRITE_BUFFER_2_EMPTY |
 102                                           AUDIO_INT_READ_BUFFER_FULL,
 103 };
 104
 105
 106 static atomic_t open_count = ATOMIC_INIT(0);
 107
 108
 109 static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 110                                                 size_t count, loff_t *pos)
 111 {
 112         struct goldfish_audio *data = fp->private_data;
 113         int length;
 114         int result = 0;
 115
 116         if (!data->read_supported)
 117                 return -ENODEV;
 118
 119         while (count > 0) {
 120                 length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
 121                 AUDIO_WRITE(data, AUDIO_START_READ, length);
 122
 123                 wait_event_interruptible(data->wait,
 124                         (data->buffer_status & AUDIO_INT_READ_BUFFER_FULL));
 125
 126                 length = AUDIO_READ(data,
 127                                                 AUDIO_READ_BUFFER_AVAILABLE);
 128
 129                 /* copy data to user space */
 130                 if (copy_to_user(buf, data->read_buffer, length))
 131                         return -EFAULT;
 132
 133                 result += length;
 134                 buf += length;
 135                 count -= length;
 136         }
 137         return result;
 138 }
 139
 140 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
 141                                                  size_t count, loff_t *pos)
 142 {
 143         struct goldfish_audio *data = fp->private_data;
 144         unsigned long irq_flags;
 145         ssize_t result = 0;
 146         char __iomem *kbuf;
 147
 148         while (count > 0) {
 149                 ssize_t copy = count;
 150
 151                 if (copy > WRITE_BUFFER_SIZE)
 152                         copy = WRITE_BUFFER_SIZE;
 153                 wait_event_interruptible(data->wait, (data->buffer_status &
 154                                         (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 155                                         AUDIO_INT_WRITE_BUFFER_2_EMPTY)));
 156
 157                 if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
 158                         kbuf = data->write_buffer1;
 159                 else
 160                         kbuf = data->write_buffer2;
 161
 162                 /* copy from user space to the appropriate buffer */
 163                 if (copy_from_user(kbuf, buf, copy)) {
 164                         result = -EFAULT;
 165                         break;
 166                 }
 167
 168                 spin_lock_irqsave(&data->lock, irq_flags);
 169                 /*
 170                  *  clear the buffer empty flag, and signal the emulator
 171                  *  to start writing the buffer
 172                  */
 173                 if (kbuf == data->write_buffer1) {
 174                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
 175                         AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_1, copy);
 176                 } else {
 177                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
 178                         AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_2, copy);
 179                 }
 180                 spin_unlock_irqrestore(&data->lock, irq_flags);
 181
 182                 buf += copy;
 183                 result += copy;
 184                 count -= copy;
 185         }
 186         return result;
 187 }
 188
 189 static int goldfish_audio_open(struct inode *ip, struct file *fp)
 190 {
 191         if (!audio_data)
 192                 return -ENODEV;
 193
 194         if (atomic_inc_return(&open_count) == 1) {
 195                 fp->private_data = audio_data;
 196                 audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 197                                              AUDIO_INT_WRITE_BUFFER_2_EMPTY);
 198                 AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
 199                 return 0;
 200         } else {
 201                 atomic_dec(&open_count);
 202                 return -EBUSY;
 203         }
 204 }
 205
 206 static int goldfish_audio_release(struct inode *ip, struct file *fp)
 207 {
 208         atomic_dec(&open_count);
 209         /* FIXME: surely this is wrong for the multi-opened case */
 210         AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, 0);
 211         return 0;
 212 }
 213
 214 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
 215                                                         unsigned long arg)
 216 {
 217         /* temporary workaround, until we switch to the ALSA API */
 218         if (cmd == 315)
 219                 return -1;
 220         else
 221                 return 0;
 222 }
 223
 224 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
 225 {
 226         unsigned long irq_flags;
 227         struct goldfish_audio   *data = dev_id;
 228         u32 status;
 229
 230         spin_lock_irqsave(&data->lock, irq_flags);
 231
 232         /* read buffer status flags */
 233         status = AUDIO_READ(data, AUDIO_INT_STATUS);
 234         status &= AUDIO_INT_MASK;
 235         /*
 236          *  if buffers are newly empty, wake up blocked
 237          *  goldfish_audio_write() call
 238          */
 239         if (status) {
 240                 data->buffer_status = status;
 241                 wake_up(&data->wait);
 242         }
 243
 244         spin_unlock_irqrestore(&data->lock, irq_flags);
 245         return status ? IRQ_HANDLED : IRQ_NONE;
 246 }
 247
 248 /* file operations for /dev/eac */
 249 static const struct file_operations goldfish_audio_fops = {
 250         .owner = THIS_MODULE,
 251         .read = goldfish_audio_read,
 252         .write = goldfish_audio_write,
 253         .open = goldfish_audio_open,
 254         .release = goldfish_audio_release,
 255         .unlocked_ioctl = goldfish_audio_ioctl,
 256 };
 257
 258 static struct miscdevice goldfish_audio_device = {
 259         .minor = MISC_DYNAMIC_MINOR,
 260         .name = "eac",
 261         .fops = &goldfish_audio_fops,
 262 };
 263
 264 static int goldfish_audio_probe(struct platform_device *pdev)
 265 {
 266         int ret;
 267         struct resource *r;
 268         struct goldfish_audio *data;
 269         dma_addr_t buf_addr;
 270
 271         data = kzalloc(sizeof(*data), GFP_KERNEL);
 272         if (data == NULL) {
 273                 ret = -ENOMEM;
 274                 goto err_data_alloc_failed;
 275         }
 276         spin_lock_init(&data->lock);
 277         init_waitqueue_head(&data->wait);
 278         platform_set_drvdata(pdev, data);
 279
 280         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 281         if (r == NULL) {
 282                 dev_err(&pdev->dev, "platform_get_resource failed\n");
 283                 ret = -ENODEV;
 284                 goto err_no_io_base;
 285         }
 286         data->reg_base = ioremap(r->start, PAGE_SIZE);
 287         if (data->reg_base == NULL) {
 288                 ret = -ENOMEM;
 289                 goto err_no_io_base;
 290         }
 291
 292         data->irq = platform_get_irq(pdev, 0);
 293         if (data->irq < 0) {
 294                 dev_err(&pdev->dev, "platform_get_irq failed\n");
 295                 ret = -ENODEV;
 296                 goto err_no_irq;
 297         }
 298         data->buffer_virt = dma_alloc_coherent(&pdev->dev,
 299                                 COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
 300         if (data->buffer_virt == 0) {
 301                 ret = -ENOMEM;
 302                 dev_err(&pdev->dev, "allocate buffer failed\n");
 303                 goto err_alloc_write_buffer_failed;
 304         }
 305         data->buffer_phys = buf_addr;
 306         data->write_buffer1 = data->buffer_virt;
 307         data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
 308         data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;
 309
 310         ret = request_irq(data->irq, goldfish_audio_interrupt,
 311                                         IRQF_SHARED, pdev->name, data);
 312         if (ret) {
 313                 dev_err(&pdev->dev, "request_irq failed\n");
 314                 goto err_request_irq_failed;
 315         }
 316
 317         ret = misc_register(&goldfish_audio_device);
 318         if (ret) {
 319                 dev_err(&pdev->dev,
 320                         "misc_register returned %d in goldfish_audio_init\n",
 321                                                                 ret);
 322                 goto err_misc_register_failed;
 323         }
 324
 325         AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_1, buf_addr);
 326         AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_2,
 327                                                 buf_addr + WRITE_BUFFER_SIZE);
 328
 329         data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
 330         if (data->read_supported)
 331                 AUDIO_WRITE(data, AUDIO_SET_READ_BUFFER,
 332                                         buf_addr + 2 * WRITE_BUFFER_SIZE);
 333
 334         audio_data = data;
 335         return 0;
 336
 337 err_misc_register_failed:
 338         free_irq(data->irq, data);
 339 err_request_irq_failed:
 340         dma_free_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
 341                                         data->buffer_virt, data->buffer_phys);
 342 err_alloc_write_buffer_failed:
 343 err_no_irq:
 344         iounmap(data->reg_base);
 345 err_no_io_base:
 346         kfree(data);
 347 err_data_alloc_failed:
 348         return ret;
 349 }
 350
 351 static int goldfish_audio_remove(struct platform_device *pdev)
 352 {
 353         struct goldfish_audio *data = platform_get_drvdata(pdev);
 354
 355         misc_deregister(&goldfish_audio_device);
 356         free_irq(data->irq, data);
 357         dma_free_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
 358                                         data->buffer_virt, data->buffer_phys);
 359         iounmap(data->reg_base);
 360         kfree(data);
 361         audio_data = NULL;
 362         return 0;
 363 }
 364
 365 static struct platform_driver goldfish_audio_driver = {
 366         .probe          = goldfish_audio_probe,
 367         .remove         = goldfish_audio_remove,
 368         .driver = {
 369                 .name = "goldfish_audio"
 370         }
 371 };
 372
 373 module_platform_driver(goldfish_audio_driver);