root/drivers/staging/goldfish/goldfish_audio.c

DEFINITIONS

1. audio_read
2. audio_write
3. audio_write64
4. goldfish_audio_read
5. goldfish_audio_write
6. goldfish_audio_open
7. goldfish_audio_release
8. goldfish_audio_ioctl
9. goldfish_audio_interrupt
10. goldfish_audio_probe
11. goldfish_audio_remove

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * drivers/misc/goldfish_audio.c
   4  *
   5  * Copyright (C) 2007 Google, Inc.
   6  * Copyright (C) 2012 Intel, Inc.
   7  */
   8 
   9 #include <linux/module.h>
  10 #include <linux/miscdevice.h>
  11 #include <linux/fs.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/types.h>
  14 #include <linux/pci.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/io.h>
  17 #include <linux/sched.h>
  18 #include <linux/dma-mapping.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/slab.h>
  21 #include <linux/goldfish.h>
  22 #include <linux/acpi.h>
  23 
  24 MODULE_AUTHOR("Google, Inc.");
  25 MODULE_DESCRIPTION("Android QEMU Audio Driver");
  26 MODULE_LICENSE("GPL");
  27 MODULE_VERSION("1.0");
  28 
  29 struct goldfish_audio {
  30         char __iomem *reg_base;
  31         int irq;
  32 
  33         /* lock protects access to buffer_status and to device registers */
  34         spinlock_t lock;
  35         wait_queue_head_t wait;
  36 
  37         char *buffer_virt;              /* combined buffer virtual address */
  38         unsigned long buffer_phys;      /* combined buffer physical address */
  39 
  40         char *write_buffer1;            /* write buffer 1 virtual address */
  41         char *write_buffer2;            /* write buffer 2 virtual address */
  42         char *read_buffer;              /* read buffer virtual address */
  43         int buffer_status;
  44         int read_supported;     /* true if we have audio input support */
  45 };
  46 
  47 /*
  48  *  We will allocate two read buffers and two write buffers.
  49  *  Having two read buffers facilitate stereo -> mono conversion.
  50  *  Having two write buffers facilitate interleaved IO.
  51  */
  52 #define READ_BUFFER_SIZE        16384
  53 #define WRITE_BUFFER_SIZE       16384
  54 #define COMBINED_BUFFER_SIZE    ((2 * READ_BUFFER_SIZE) + \
  55                                         (2 * WRITE_BUFFER_SIZE))
  56 
  57 /*
  58  *  temporary variable used between goldfish_audio_probe() and
  59  *  goldfish_audio_open()
  60  */
  61 static struct goldfish_audio *audio_data;
  62 
  63 enum {
  64         /* audio status register */
  65         AUDIO_INT_STATUS        = 0x00,
  66         /* set this to enable IRQ */
  67         AUDIO_INT_ENABLE        = 0x04,
  68         /* set these to specify buffer addresses */
  69         AUDIO_SET_WRITE_BUFFER_1 = 0x08,
  70         AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
  71         /* set number of bytes in buffer to write */
  72         AUDIO_WRITE_BUFFER_1  = 0x10,
  73         AUDIO_WRITE_BUFFER_2  = 0x14,
  74         AUDIO_SET_WRITE_BUFFER_1_HIGH = 0x28,
  75         AUDIO_SET_WRITE_BUFFER_2_HIGH = 0x30,
  76 
  77         /* true if audio input is supported */
  78         AUDIO_READ_SUPPORTED = 0x18,
  79         /* buffer to use for audio input */
  80         AUDIO_SET_READ_BUFFER = 0x1C,
  81         AUDIO_SET_READ_BUFFER_HIGH = 0x34,
  82 
  83         /* driver writes number of bytes to read */
  84         AUDIO_START_READ  = 0x20,
  85 
  86         /* number of bytes available in read buffer */
  87         AUDIO_READ_BUFFER_AVAILABLE  = 0x24,
  88 
  89         /* AUDIO_INT_STATUS bits */
  90 
  91         /* this bit set when it is safe to write more bytes to the buffer */
  92         AUDIO_INT_WRITE_BUFFER_1_EMPTY  = 1U << 0,
  93         AUDIO_INT_WRITE_BUFFER_2_EMPTY  = 1U << 1,
  94         AUDIO_INT_READ_BUFFER_FULL      = 1U << 2,
  95 
  96         AUDIO_INT_MASK                  = AUDIO_INT_WRITE_BUFFER_1_EMPTY |
  97                                           AUDIO_INT_WRITE_BUFFER_2_EMPTY |
  98                                           AUDIO_INT_READ_BUFFER_FULL,
  99 };
 100 
 101 static atomic_t open_count = ATOMIC_INIT(0);
 102 
 103 static unsigned int audio_read(const struct goldfish_audio *data, int addr)
 104 {
 105         return readl(data->reg_base + addr);
 106 }
 107 
 108 static void audio_write(const struct goldfish_audio *data,
 109                         int addr, unsigned int x)
 110 {
 111         writel(x, data->reg_base + addr);
 112 }
 113 
 114 static void audio_write64(const struct goldfish_audio *data,
 115                           int addr_lo, int addr_hi, unsigned int x)
 116 {
 117         char __iomem *reg_base = data->reg_base;
 118 
 119         gf_write_dma_addr(x, reg_base + addr_lo, reg_base + addr_hi);
 120 }
 121 
 122 static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 123                                    size_t count, loff_t *pos)
 124 {
 125         struct goldfish_audio *data = fp->private_data;
 126         unsigned long irq_flags;
 127         int length;
 128         int result = 0;
 129 
 130         if (!data->read_supported)
 131                 return -ENODEV;
 132 
 133         while (count > 0) {
 134                 length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
 135                 audio_write(data, AUDIO_START_READ, length);
 136 
 137                 wait_event_interruptible(data->wait, data->buffer_status &
 138                                          AUDIO_INT_READ_BUFFER_FULL);
 139 
 140                 spin_lock_irqsave(&data->lock, irq_flags);
 141                 data->buffer_status &= ~AUDIO_INT_READ_BUFFER_FULL;
 142                 spin_unlock_irqrestore(&data->lock, irq_flags);
 143 
 144                 length = audio_read(data, AUDIO_READ_BUFFER_AVAILABLE);
 145 
 146                 /* copy data to user space */
 147                 if (copy_to_user(buf, data->read_buffer, length))
 148                         return -EFAULT;
 149 
 150                 result += length;
 151                 buf += length;
 152                 count -= length;
 153         }
 154         return result;
 155 }
 156 
 157 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
 158                                     size_t count, loff_t *pos)
 159 {
 160         struct goldfish_audio *data = fp->private_data;
 161         unsigned long irq_flags;
 162         ssize_t result = 0;
 163         char *kbuf;
 164 
 165         while (count > 0) {
 166                 ssize_t copy = count;
 167 
 168                 if (copy > WRITE_BUFFER_SIZE)
 169                         copy = WRITE_BUFFER_SIZE;
 170                 wait_event_interruptible(data->wait, data->buffer_status &
 171                                         (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 172                                         AUDIO_INT_WRITE_BUFFER_2_EMPTY));
 173 
 174                 if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
 175                         kbuf = data->write_buffer1;
 176                 else
 177                         kbuf = data->write_buffer2;
 178 
 179                 /* copy from user space to the appropriate buffer */
 180                 if (copy_from_user(kbuf, buf, copy)) {
 181                         result = -EFAULT;
 182                         break;
 183                 }
 184 
 185                 spin_lock_irqsave(&data->lock, irq_flags);
 186                 /*
 187                  *  clear the buffer empty flag, and signal the emulator
 188                  *  to start writing the buffer
 189                  */
 190                 if (kbuf == data->write_buffer1) {
 191                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
 192                         audio_write(data, AUDIO_WRITE_BUFFER_1, copy);
 193                 } else {
 194                         data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
 195                         audio_write(data, AUDIO_WRITE_BUFFER_2, copy);
 196                 }
 197                 spin_unlock_irqrestore(&data->lock, irq_flags);
 198 
 199                 buf += copy;
 200                 result += copy;
 201                 count -= copy;
 202         }
 203         return result;
 204 }
 205 
 206 static int goldfish_audio_open(struct inode *ip, struct file *fp)
 207 {
 208         if (!audio_data)
 209                 return -ENODEV;
 210 
 211         if (atomic_inc_return(&open_count) == 1) {
 212                 fp->private_data = audio_data;
 213                 audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
 214                                              AUDIO_INT_WRITE_BUFFER_2_EMPTY);
 215                 audio_write(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
 216                 return 0;
 217         }
 218 
 219         atomic_dec(&open_count);
 220         return -EBUSY;
 221 }
 222 
 223 static int goldfish_audio_release(struct inode *ip, struct file *fp)
 224 {
 225         atomic_dec(&open_count);
 226         /* FIXME: surely this is wrong for the multi-opened case */
 227         audio_write(audio_data, AUDIO_INT_ENABLE, 0);
 228         return 0;
 229 }
 230 
 231 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
 232                                  unsigned long arg)
 233 {
 234         /* temporary workaround, until we switch to the ALSA API */
 235         if (cmd == 315)
 236                 return -1;
 237 
 238         return 0;
 239 }
 240 
 241 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
 242 {
 243         unsigned long irq_flags;
 244         struct goldfish_audio   *data = dev_id;
 245         u32 status;
 246 
 247         spin_lock_irqsave(&data->lock, irq_flags);
 248 
 249         /* read buffer status flags */
 250         status = audio_read(data, AUDIO_INT_STATUS);
 251         status &= AUDIO_INT_MASK;
 252         /*
 253          *  if buffers are newly empty, wake up blocked
 254          *  goldfish_audio_write() call
 255          */
 256         if (status) {
 257                 data->buffer_status = status;
 258                 wake_up(&data->wait);
 259         }
 260 
 261         spin_unlock_irqrestore(&data->lock, irq_flags);
 262         return status ? IRQ_HANDLED : IRQ_NONE;
 263 }
 264 
 265 /* file operations for /dev/eac */
 266 static const struct file_operations goldfish_audio_fops = {
 267         .owner = THIS_MODULE,
 268         .read = goldfish_audio_read,
 269         .write = goldfish_audio_write,
 270         .open = goldfish_audio_open,
 271         .release = goldfish_audio_release,
 272         .unlocked_ioctl = goldfish_audio_ioctl,
 273 };
 274 
 275 static struct miscdevice goldfish_audio_device = {
 276         .minor = MISC_DYNAMIC_MINOR,
 277         .name = "eac",
 278         .fops = &goldfish_audio_fops,
 279 };
 280 
 281 static int goldfish_audio_probe(struct platform_device *pdev)
 282 {
 283         int ret;
 284         struct resource *r;
 285         struct goldfish_audio *data;
 286         dma_addr_t buf_addr;
 287 
 288         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 289         if (!data)
 290                 return -ENOMEM;
 291         spin_lock_init(&data->lock);
 292         init_waitqueue_head(&data->wait);
 293         platform_set_drvdata(pdev, data);
 294 
 295         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 296         if (!r) {
 297                 dev_err(&pdev->dev, "platform_get_resource failed\n");
 298                 return -ENODEV;
 299         }
 300         data->reg_base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
 301         if (!data->reg_base)
 302                 return -ENOMEM;
 303 
 304         data->irq = platform_get_irq(pdev, 0);
 305         if (data->irq < 0)
 306                 return -ENODEV;
 307         data->buffer_virt = dmam_alloc_coherent(&pdev->dev,
 308                                                 COMBINED_BUFFER_SIZE,
 309                                                 &buf_addr, GFP_KERNEL);
 310         if (!data->buffer_virt) {
 311                 dev_err(&pdev->dev, "allocate buffer failed\n");
 312                 return -ENOMEM;
 313         }
 314         data->buffer_phys = buf_addr;
 315         data->write_buffer1 = data->buffer_virt;
 316         data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
 317         data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;
 318 
 319         ret = devm_request_irq(&pdev->dev, data->irq, goldfish_audio_interrupt,
 320                                IRQF_SHARED, pdev->name, data);
 321         if (ret) {
 322                 dev_err(&pdev->dev, "request_irq failed\n");
 323                 return ret;
 324         }
 325 
 326         ret = misc_register(&goldfish_audio_device);
 327         if (ret) {
 328                 dev_err(&pdev->dev,
 329                         "misc_register returned %d in goldfish_audio_init\n",
 330                                                                 ret);
 331                 return ret;
 332         }
 333 
 334         audio_write64(data, AUDIO_SET_WRITE_BUFFER_1,
 335                       AUDIO_SET_WRITE_BUFFER_1_HIGH, buf_addr);
 336         buf_addr += WRITE_BUFFER_SIZE;
 337 
 338         audio_write64(data, AUDIO_SET_WRITE_BUFFER_2,
 339                       AUDIO_SET_WRITE_BUFFER_2_HIGH, buf_addr);
 340 
 341         buf_addr += WRITE_BUFFER_SIZE;
 342 
 343         data->read_supported = audio_read(data, AUDIO_READ_SUPPORTED);
 344         if (data->read_supported)
 345                 audio_write64(data, AUDIO_SET_READ_BUFFER,
 346                               AUDIO_SET_READ_BUFFER_HIGH, buf_addr);
 347 
 348         audio_data = data;
 349         return 0;
 350 }
 351 
 352 static int goldfish_audio_remove(struct platform_device *pdev)
 353 {
 354         misc_deregister(&goldfish_audio_device);
 355         audio_data = NULL;
 356         return 0;
 357 }
 358 
 359 static const struct of_device_id goldfish_audio_of_match[] = {
 360         { .compatible = "google,goldfish-audio", },
 361         {},
 362 };
 363 MODULE_DEVICE_TABLE(of, goldfish_audio_of_match);
 364 
 365 #ifdef CONFIG_ACPI
 366 static const struct acpi_device_id goldfish_audio_acpi_match[] = {
 367         { "GFSH0005", 0 },
 368         { },
 369 };
 370 MODULE_DEVICE_TABLE(acpi, goldfish_audio_acpi_match);
 371 #endif
 372 
 373 static struct platform_driver goldfish_audio_driver = {
 374         .probe          = goldfish_audio_probe,
 375         .remove         = goldfish_audio_remove,
 376         .driver = {
 377                 .name = "goldfish_audio",
 378                 .of_match_table = goldfish_audio_of_match,
 379                 .acpi_match_table = ACPI_PTR(goldfish_audio_acpi_match),
 380         }
 381 };
 382 
 383 module_platform_driver(goldfish_audio_driver);