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