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