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 #include <linux/acpi.h>
  32
  33 MODULE_AUTHOR("Google, Inc.");
  34 MODULE_DESCRIPTION("Android QEMU Audio Driver");
  35 MODULE_LICENSE("GPL");
  36 MODULE_VERSION("1.0");
  37
  38 struct goldfish_audio {
  39         char __iomem *reg_base;
  40         int irq;
  41
  42         /* lock protects access to buffer_status and to device registers */
  43         spinlock_t lock;
  44         wait_queue_head_t wait;
  45
  46         char *buffer_virt;              /* combined buffer virtual address */
  47         unsigned long buffer_phys;      /* combined buffer physical address */
  48
  49         char *write_buffer1;            /* write buffer 1 virtual address */
  50         char *write_buffer2;            /* write buffer 2 virtual address */
  51         char *read_buffer;              /* read buffer virtual address */
  52         int buffer_status;
  53         int read_supported;     /* true if we have audio input support */
  54 };
  55
  56 /*
  57  *  We will allocate two read buffers and two write buffers.
  58  *  Having two read buffers facilitate stereo -> mono conversion.
  59  *  Having two write buffers facilitate interleaved IO.
  60  */
  61 #define READ_BUFFER_SIZE        16384
  62 #define WRITE_BUFFER_SIZE       16384
  63 #define COMBINED_BUFFER_SIZE    ((2 * READ_BUFFER_SIZE) + \
  64                                         (2 * WRITE_BUFFER_SIZE))
  65
  66 /*
  67  *  temporary variable used between goldfish_audio_probe() and
  68  *  goldfish_audio_open()
  69  */
  70 static struct goldfish_audio *audio_data;
  71
  72 enum {
  73         /* audio status register */
  74         AUDIO_INT_STATUS        = 0x00,
  75         /* set this to enable IRQ */
  76         AUDIO_INT_ENABLE        = 0x04,
  77         /* set these to specify buffer addresses */
  78         AUDIO_SET_WRITE_BUFFER_1 = 0x08,
  79         AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
  80         /* set number of bytes in buffer to write */
  81         AUDIO_WRITE_BUFFER_1  = 0x10,
  82         AUDIO_WRITE_BUFFER_2  = 0x14,
  83         AUDIO_SET_WRITE_BUFFER_1_HIGH = 0x28,
  84         AUDIO_SET_WRITE_BUFFER_2_HIGH = 0x30,
  85
  86         /* true if audio input is supported */
  87         AUDIO_READ_SUPPORTED = 0x18,
  88         /* buffer to use for audio input */
  89         AUDIO_SET_READ_BUFFER = 0x1C,
  90         AUDIO_SET_READ_BUFFER_HIGH = 0x34,
  91
  92         /* driver writes number of bytes to read */
  93         AUDIO_START_READ  = 0x20,
  94
  95         /* number of bytes available in read buffer */
  96         AUDIO_READ_BUFFER_AVAILABLE  = 0x24,
  97
  98         /* AUDIO_INT_STATUS bits */
  99
 100         /* this bit set when it is safe to write more bytes to the buffer */
 101         AUDIO_INT_WRITE_BUFFER_1_EMPTY  = 1U << 0,
 102         AUDIO_INT_WRITE_BUFFER_2_EMPTY  = 1U << 1,
 103         AUDIO_INT_READ_BUFFER_FULL      = 1U << 2,
 104
 105         AUDIO_INT_MASK                  = AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 106                                           AUDIO_INT_WRITE_BUFFER_2_EMPTY |
 107                                           AUDIO_INT_READ_BUFFER_FULL,
 108 };
 109
 110 static atomic_t open_count = ATOMIC_INIT(0);
 111
 112 static unsigned int audio_read(const struct goldfish_audio *data, int addr)
 113 {
 114         return readl(data->reg_base + addr);
 115 }
 116
 117 static void audio_write(const struct goldfish_audio *data,
 118                         int addr, unsigned int x)
 119 {
 120         writel(x, data->reg_base + addr);
 121 }
 122
 123 static void audio_write64(const struct goldfish_audio *data,
 124                           int addr_lo, int addr_hi, unsigned int x)
 125 {
 126         char __iomem *reg_base = data->reg_base;
 127
 128         gf_write_dma_addr(x, reg_base + addr_lo, reg_base + addr_hi);
 129 }
 130
 131 static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 132                                    size_t count, loff_t *pos)
 133 {
 134         struct goldfish_audio *data = fp->private_data;
 135         unsigned long irq_flags;
 136         int length;
 137         int result = 0;
 138
 139         if (!data->read_supported)
 140                 return -ENODEV;
 141
 142         while (count > 0) {
 143                 length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
 144                 audio_write(data, AUDIO_START_READ, length);
 145
 146                 wait_event_interruptible(data->wait, data->buffer_status &
 147                                          AUDIO_INT_READ_BUFFER_FULL);
 148
 149                 spin_lock_irqsave(&data->lock, irq_flags);
 150                 data->buffer_status &= ~AUDIO_INT_READ_BUFFER_FULL;
 151                 spin_unlock_irqrestore(&data->lock, irq_flags);
 152
 153                 length = audio_read(data, AUDIO_READ_BUFFER_AVAILABLE);
 154
 155                 /* copy data to user space */
 156                 if (copy_to_user(buf, data->read_buffer, length))
 157                         return -EFAULT;
 158
 159                 result += length;
 160                 buf += length;
 161                 count -= length;
 162         }
 163         return result;
 164 }
 165
 166 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
 167                                     size_t count, loff_t *pos)
 168 {
 169         struct goldfish_audio *data = fp->private_data;
 170         unsigned long irq_flags;
 171         ssize_t result = 0;
 172         char *kbuf;
 173
 174         while (count > 0) {
 175                 ssize_t copy = count;
 176
 177                 if (copy > WRITE_BUFFER_SIZE)
 178                         copy = WRITE_BUFFER_SIZE;
 179                 wait_event_interruptible(data->wait, data->buffer_status &
 180                                         (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 181                                         AUDIO_INT_WRITE_BUFFER_2_EMPTY));
 182
 183                 if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
 184                         kbuf = data->write_buffer1;
 185                 else
 186                         kbuf = data->write_buffer2;
 187
 188                 /* copy from user space to the appropriate buffer */
 189                 if (copy_from_user(kbuf, buf, copy)) {
 190                         result = -EFAULT;
 191                         break;
 192                 }
 193
 194                 spin_lock_irqsave(&data->lock, irq_flags);
 195                 /*
 196                  *  clear the buffer empty flag, and signal the emulator
 197                  *  to start writing the buffer
 198                  */
 199                 if (kbuf == data->write_buffer1) {
 200                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
 201                         audio_write(data, AUDIO_WRITE_BUFFER_1, copy);
 202                 } else {
 203                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
 204                         audio_write(data, AUDIO_WRITE_BUFFER_2, copy);
 205                 }
 206                 spin_unlock_irqrestore(&data->lock, irq_flags);
 207
 208                 buf += copy;
 209                 result += copy;
 210                 count -= copy;
 211         }
 212         return result;
 213 }
 214
 215 static int goldfish_audio_open(struct inode *ip, struct file *fp)
 216 {
 217         if (!audio_data)
 218                 return -ENODEV;
 219
 220         if (atomic_inc_return(&open_count) == 1) {
 221                 fp->private_data = audio_data;
 222                 audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 223                                              AUDIO_INT_WRITE_BUFFER_2_EMPTY);
 224                 audio_write(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
 225                 return 0;
 226         }
 227
 228         atomic_dec(&open_count);
 229         return -EBUSY;
 230 }
 231
 232 static int goldfish_audio_release(struct inode *ip, struct file *fp)
 233 {
 234         atomic_dec(&open_count);
 235         /* FIXME: surely this is wrong for the multi-opened case */
 236         audio_write(audio_data, AUDIO_INT_ENABLE, 0);
 237         return 0;
 238 }
 239
 240 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
 241                                  unsigned long arg)
 242 {
 243         /* temporary workaround, until we switch to the ALSA API */
 244         if (cmd == 315)
 245                 return -1;
 246
 247         return 0;
 248 }
 249
 250 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
 251 {
 252         unsigned long irq_flags;
 253         struct goldfish_audio   *data = dev_id;
 254         u32 status;
 255
 256         spin_lock_irqsave(&data->lock, irq_flags);
 257
 258         /* read buffer status flags */
 259         status = audio_read(data, AUDIO_INT_STATUS);
 260         status &= AUDIO_INT_MASK;
 261         /*
 262          *  if buffers are newly empty, wake up blocked
 263          *  goldfish_audio_write() call
 264          */
 265         if (status) {
 266                 data->buffer_status = status;
 267                 wake_up(&data->wait);
 268         }
 269
 270         spin_unlock_irqrestore(&data->lock, irq_flags);
 271         return status ? IRQ_HANDLED : IRQ_NONE;
 272 }
 273
 274 /* file operations for /dev/eac */
 275 static const struct file_operations goldfish_audio_fops = {
 276         .owner = THIS_MODULE,
 277         .read = goldfish_audio_read,
 278         .write = goldfish_audio_write,
 279         .open = goldfish_audio_open,
 280         .release = goldfish_audio_release,
 281         .unlocked_ioctl = goldfish_audio_ioctl,
 282 };
 283
 284 static struct miscdevice goldfish_audio_device = {
 285         .minor = MISC_DYNAMIC_MINOR,
 286         .name = "eac",
 287         .fops = &goldfish_audio_fops,
 288 };
 289
 290 static int goldfish_audio_probe(struct platform_device *pdev)
 291 {
 292         int ret;
 293         struct resource *r;
 294         struct goldfish_audio *data;
 295         dma_addr_t buf_addr;
 296
 297         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 298         if (!data)
 299                 return -ENOMEM;
 300         spin_lock_init(&data->lock);
 301         init_waitqueue_head(&data->wait);
 302         platform_set_drvdata(pdev, data);
 303
 304         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 305         if (!r) {
 306                 dev_err(&pdev->dev, "platform_get_resource failed\n");
 307                 return -ENODEV;
 308         }
 309         data->reg_base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
 310         if (!data->reg_base)
 311                 return -ENOMEM;
 312
 313         data->irq = platform_get_irq(pdev, 0);
 314         if (data->irq < 0) {
 315                 dev_err(&pdev->dev, "platform_get_irq failed\n");
 316                 return -ENODEV;
 317         }
 318         data->buffer_virt = dmam_alloc_coherent(&pdev->dev,
 319                                                 COMBINED_BUFFER_SIZE,
 320                                                 &buf_addr, GFP_KERNEL);
 321         if (!data->buffer_virt) {
 322                 dev_err(&pdev->dev, "allocate buffer failed\n");
 323                 return -ENOMEM;
 324         }
 325         data->buffer_phys = buf_addr;
 326         data->write_buffer1 = data->buffer_virt;
 327         data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
 328         data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;
 329
 330         ret = devm_request_irq(&pdev->dev, data->irq, goldfish_audio_interrupt,
 331                                IRQF_SHARED, pdev->name, data);
 332         if (ret) {
 333                 dev_err(&pdev->dev, "request_irq failed\n");
 334                 return ret;
 335         }
 336
 337         ret = misc_register(&goldfish_audio_device);
 338         if (ret) {
 339                 dev_err(&pdev->dev,
 340                         "misc_register returned %d in goldfish_audio_init\n",
 341                                                                 ret);
 342                 return ret;
 343         }
 344
 345         audio_write64(data, AUDIO_SET_WRITE_BUFFER_1,
 346                       AUDIO_SET_WRITE_BUFFER_1_HIGH, buf_addr);
 347         buf_addr += WRITE_BUFFER_SIZE;
 348
 349         audio_write64(data, AUDIO_SET_WRITE_BUFFER_2,
 350                       AUDIO_SET_WRITE_BUFFER_2_HIGH, buf_addr);
 351
 352         buf_addr += WRITE_BUFFER_SIZE;
 353
 354         data->read_supported = audio_read(data, AUDIO_READ_SUPPORTED);
 355         if (data->read_supported)
 356                 audio_write64(data, AUDIO_SET_READ_BUFFER,
 357                               AUDIO_SET_READ_BUFFER_HIGH, buf_addr);
 358
 359         audio_data = data;
 360         return 0;
 361 }
 362
 363 static int goldfish_audio_remove(struct platform_device *pdev)
 364 {
 365         misc_deregister(&goldfish_audio_device);
 366         audio_data = NULL;
 367         return 0;
 368 }
 369
 370 static const struct of_device_id goldfish_audio_of_match[] = {
 371         { .compatible = "google,goldfish-audio", },
 372         {},
 373 };
 374 MODULE_DEVICE_TABLE(of, goldfish_audio_of_match);
 375
 376 #ifdef CONFIG_ACPI
 377 static const struct acpi_device_id goldfish_audio_acpi_match[] = {
 378         { "GFSH0005", 0 },
 379         { },
 380 };
 381 MODULE_DEVICE_TABLE(acpi, goldfish_audio_acpi_match);
 382 #endif
 383
 384 static struct platform_driver goldfish_audio_driver = {
 385         .probe          = goldfish_audio_probe,
 386         .remove         = goldfish_audio_remove,
 387         .driver = {
 388                 .name = "goldfish_audio",
 389                 .of_match_table = goldfish_audio_of_match,
 390                 .acpi_match_table = ACPI_PTR(goldfish_audio_acpi_match),
 391         }
 392 };
 393
 394 module_platform_driver(goldfish_audio_driver);