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 #include <linux/goldfish.h>
  30
  31 MODULE_AUTHOR("Google, Inc.");
  32 MODULE_DESCRIPTION("Android QEMU Audio Driver");
  33 MODULE_LICENSE("GPL");
  34 MODULE_VERSION("1.0");
  35
  36 struct goldfish_audio {
  37         char __iomem *reg_base;
  38         int irq;
  39         spinlock_t lock;
  40         wait_queue_head_t wait;
  41
  42         char __iomem *buffer_virt;      /* combined buffer virtual address */
  43         unsigned long buffer_phys;      /* combined buffer physical address */
  44
  45         char __iomem *write_buffer1;    /* write buffer 1 virtual address */
  46         char __iomem *write_buffer2;    /* write buffer 2 virtual address */
  47         char __iomem *read_buffer;      /* read buffer virtual address */
  48         int buffer_status;
  49         int read_supported;         /* true if we have audio input support */
  50 };
  51
  52 /*
  53  *  We will allocate two read buffers and two write buffers.
  54  *  Having two read buffers facilitate stereo -> mono conversion.
  55  *  Having two write buffers facilitate interleaved IO.
  56  */
  57 #define READ_BUFFER_SIZE        16384
  58 #define WRITE_BUFFER_SIZE       16384
  59 #define COMBINED_BUFFER_SIZE    ((2 * READ_BUFFER_SIZE) + \
  60                                         (2 * WRITE_BUFFER_SIZE))
  61
  62 #define AUDIO_READ(data, addr)          (readl(data->reg_base + addr))
  63 #define AUDIO_WRITE(data, addr, x)      (writel(x, data->reg_base + addr))
  64 #define AUDIO_WRITE64(data, addr, addr2, x)     \
  65         (gf_write64((u64)(x), data->reg_base + addr, data->reg_base+addr2))
  66
  67 /*
  68  *  temporary variable used between goldfish_audio_probe() and
  69  *  goldfish_audio_open()
  70  */
  71 static struct goldfish_audio *audio_data;
  72
  73 enum {
  74         /* audio status register */
  75         AUDIO_INT_STATUS        = 0x00,
  76         /* set this to enable IRQ */
  77         AUDIO_INT_ENABLE        = 0x04,
  78         /* set these to specify buffer addresses */
  79         AUDIO_SET_WRITE_BUFFER_1 = 0x08,
  80         AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
  81         /* set number of bytes in buffer to write */
  82         AUDIO_WRITE_BUFFER_1  = 0x10,
  83         AUDIO_WRITE_BUFFER_2  = 0x14,
  84         AUDIO_SET_WRITE_BUFFER_1_HIGH = 0x28,
  85         AUDIO_SET_WRITE_BUFFER_2_HIGH = 0x30,
  86
  87         /* true if audio input is supported */
  88         AUDIO_READ_SUPPORTED = 0x18,
  89         /* buffer to use for audio input */
  90         AUDIO_SET_READ_BUFFER = 0x1C,
  91         AUDIO_SET_READ_BUFFER_HIGH = 0x34,
  92
  93         /* driver writes number of bytes to read */
  94         AUDIO_START_READ  = 0x20,
  95
  96         /* number of bytes available in read buffer */
  97         AUDIO_READ_BUFFER_AVAILABLE  = 0x24,
  98
  99         /* AUDIO_INT_STATUS bits */
 100
 101         /* this bit set when it is safe to write more bytes to the buffer */
 102         AUDIO_INT_WRITE_BUFFER_1_EMPTY  = 1U << 0,
 103         AUDIO_INT_WRITE_BUFFER_2_EMPTY  = 1U << 1,
 104         AUDIO_INT_READ_BUFFER_FULL      = 1U << 2,
 105
 106         AUDIO_INT_MASK                  = AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 107                                           AUDIO_INT_WRITE_BUFFER_2_EMPTY |
 108                                           AUDIO_INT_READ_BUFFER_FULL,
 109 };
 110
 111
 112 static atomic_t open_count = ATOMIC_INIT(0);
 113
 114
 115 static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 116                                                 size_t count, loff_t *pos)
 117 {
 118         struct goldfish_audio *data = fp->private_data;
 119         int length;
 120         int result = 0;
 121
 122         if (!data->read_supported)
 123                 return -ENODEV;
 124
 125         while (count > 0) {
 126                 length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
 127                 AUDIO_WRITE(data, AUDIO_START_READ, length);
 128
 129                 wait_event_interruptible(data->wait,
 130                         (data->buffer_status & AUDIO_INT_READ_BUFFER_FULL));
 131
 132                 length = AUDIO_READ(data,
 133                                                 AUDIO_READ_BUFFER_AVAILABLE);
 134
 135                 /* copy data to user space */
 136                 if (copy_to_user(buf, data->read_buffer, length))
 137                         return -EFAULT;
 138
 139                 result += length;
 140                 buf += length;
 141                 count -= length;
 142         }
 143         return result;
 144 }
 145
 146 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
 147                                                  size_t count, loff_t *pos)
 148 {
 149         struct goldfish_audio *data = fp->private_data;
 150         unsigned long irq_flags;
 151         ssize_t result = 0;
 152         char __iomem *kbuf;
 153
 154         while (count > 0) {
 155                 ssize_t copy = count;
 156
 157                 if (copy > WRITE_BUFFER_SIZE)
 158                         copy = WRITE_BUFFER_SIZE;
 159                 wait_event_interruptible(data->wait, (data->buffer_status &
 160                                         (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 161                                         AUDIO_INT_WRITE_BUFFER_2_EMPTY)));
 162
 163                 if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
 164                         kbuf = data->write_buffer1;
 165                 else
 166                         kbuf = data->write_buffer2;
 167
 168                 /* copy from user space to the appropriate buffer */
 169                 if (copy_from_user(kbuf, buf, copy)) {
 170                         result = -EFAULT;
 171                         break;
 172                 }
 173
 174                 spin_lock_irqsave(&data->lock, irq_flags);
 175                 /*
 176                  *  clear the buffer empty flag, and signal the emulator
 177                  *  to start writing the buffer
 178                  */
 179                 if (kbuf == data->write_buffer1) {
 180                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
 181                         AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_1, copy);
 182                 } else {
 183                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
 184                         AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_2, copy);
 185                 }
 186                 spin_unlock_irqrestore(&data->lock, irq_flags);
 187
 188                 buf += copy;
 189                 result += copy;
 190                 count -= copy;
 191         }
 192         return result;
 193 }
 194
 195 static int goldfish_audio_open(struct inode *ip, struct file *fp)
 196 {
 197         if (!audio_data)
 198                 return -ENODEV;
 199
 200         if (atomic_inc_return(&open_count) == 1) {
 201                 fp->private_data = audio_data;
 202                 audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 203                                              AUDIO_INT_WRITE_BUFFER_2_EMPTY);
 204                 AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
 205                 return 0;
 206         } else {
 207                 atomic_dec(&open_count);
 208                 return -EBUSY;
 209         }
 210 }
 211
 212 static int goldfish_audio_release(struct inode *ip, struct file *fp)
 213 {
 214         atomic_dec(&open_count);
 215         /* FIXME: surely this is wrong for the multi-opened case */
 216         AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, 0);
 217         return 0;
 218 }
 219
 220 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
 221                                                         unsigned long arg)
 222 {
 223         /* temporary workaround, until we switch to the ALSA API */
 224         if (cmd == 315)
 225                 return -1;
 226         else
 227                 return 0;
 228 }
 229
 230 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
 231 {
 232         unsigned long irq_flags;
 233         struct goldfish_audio   *data = dev_id;
 234         u32 status;
 235
 236         spin_lock_irqsave(&data->lock, irq_flags);
 237
 238         /* read buffer status flags */
 239         status = AUDIO_READ(data, AUDIO_INT_STATUS);
 240         status &= AUDIO_INT_MASK;
 241         /*
 242          *  if buffers are newly empty, wake up blocked
 243          *  goldfish_audio_write() call
 244          */
 245         if (status) {
 246                 data->buffer_status = status;
 247                 wake_up(&data->wait);
 248         }
 249
 250         spin_unlock_irqrestore(&data->lock, irq_flags);
 251         return status ? IRQ_HANDLED : IRQ_NONE;
 252 }
 253
 254 /* file operations for /dev/eac */
 255 static const struct file_operations goldfish_audio_fops = {
 256         .owner = THIS_MODULE,
 257         .read = goldfish_audio_read,
 258         .write = goldfish_audio_write,
 259         .open = goldfish_audio_open,
 260         .release = goldfish_audio_release,
 261         .unlocked_ioctl = goldfish_audio_ioctl,
 262 };
 263
 264 static struct miscdevice goldfish_audio_device = {
 265         .minor = MISC_DYNAMIC_MINOR,
 266         .name = "eac",
 267         .fops = &goldfish_audio_fops,
 268 };
 269
 270 static int goldfish_audio_probe(struct platform_device *pdev)
 271 {
 272         int ret;
 273         struct resource *r;
 274         struct goldfish_audio *data;
 275         dma_addr_t buf_addr;
 276
 277         data = kzalloc(sizeof(*data), GFP_KERNEL);
 278         if (data == NULL) {
 279                 ret = -ENOMEM;
 280                 goto err_data_alloc_failed;
 281         }
 282         spin_lock_init(&data->lock);
 283         init_waitqueue_head(&data->wait);
 284         platform_set_drvdata(pdev, data);
 285
 286         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 287         if (r == NULL) {
 288                 dev_err(&pdev->dev, "platform_get_resource failed\n");
 289                 ret = -ENODEV;
 290                 goto err_no_io_base;
 291         }
 292         data->reg_base = ioremap(r->start, PAGE_SIZE);
 293         if (data->reg_base == NULL) {
 294                 ret = -ENOMEM;
 295                 goto err_no_io_base;
 296         }
 297
 298         data->irq = platform_get_irq(pdev, 0);
 299         if (data->irq < 0) {
 300                 dev_err(&pdev->dev, "platform_get_irq failed\n");
 301                 ret = -ENODEV;
 302                 goto err_no_irq;
 303         }
 304         data->buffer_virt = dma_alloc_coherent(&pdev->dev,
 305                                 COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
 306         if (data->buffer_virt == 0) {
 307                 ret = -ENOMEM;
 308                 dev_err(&pdev->dev, "allocate buffer failed\n");
 309                 goto err_alloc_write_buffer_failed;
 310         }
 311         data->buffer_phys = buf_addr;
 312         data->write_buffer1 = data->buffer_virt;
 313         data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
 314         data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;
 315
 316         ret = request_irq(data->irq, goldfish_audio_interrupt,
 317                                         IRQF_SHARED, pdev->name, data);
 318         if (ret) {
 319                 dev_err(&pdev->dev, "request_irq failed\n");
 320                 goto err_request_irq_failed;
 321         }
 322
 323         ret = misc_register(&goldfish_audio_device);
 324         if (ret) {
 325                 dev_err(&pdev->dev,
 326                         "misc_register returned %d in goldfish_audio_init\n",
 327                                                                 ret);
 328                 goto err_misc_register_failed;
 329         }
 330
 331         AUDIO_WRITE64(data, AUDIO_SET_WRITE_BUFFER_1,
 332                                 AUDIO_SET_WRITE_BUFFER_1_HIGH, buf_addr);
 333         buf_addr += WRITE_BUFFER_SIZE;
 334
 335         AUDIO_WRITE64(data, AUDIO_SET_WRITE_BUFFER_2,
 336                                 AUDIO_SET_WRITE_BUFFER_2_HIGH, buf_addr);
 337
 338         buf_addr += WRITE_BUFFER_SIZE;
 339
 340         data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
 341         if (data->read_supported)
 342                 AUDIO_WRITE64(data, AUDIO_SET_READ_BUFFER,
 343                                 AUDIO_SET_READ_BUFFER_HIGH, buf_addr);
 344
 345         audio_data = data;
 346         return 0;
 347
 348 err_misc_register_failed:
 349         free_irq(data->irq, data);
 350 err_request_irq_failed:
 351         dma_free_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
 352                                         data->buffer_virt, data->buffer_phys);
 353 err_alloc_write_buffer_failed:
 354 err_no_irq:
 355         iounmap(data->reg_base);
 356 err_no_io_base:
 357         kfree(data);
 358 err_data_alloc_failed:
 359         return ret;
 360 }
 361
 362 static int goldfish_audio_remove(struct platform_device *pdev)
 363 {
 364         struct goldfish_audio *data = platform_get_drvdata(pdev);
 365
 366         misc_deregister(&goldfish_audio_device);
 367         free_irq(data->irq, data);
 368         dma_free_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
 369                                         data->buffer_virt, data->buffer_phys);
 370         iounmap(data->reg_base);
 371         kfree(data);
 372         audio_data = NULL;
 373         return 0;
 374 }
 375
 376 static struct platform_driver goldfish_audio_driver = {
 377         .probe          = goldfish_audio_probe,
 378         .remove         = goldfish_audio_remove,
 379         .driver = {
 380                 .name = "goldfish_audio"
 381         }
 382 };
 383
 384 module_platform_driver(goldfish_audio_driver);