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Linux/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) {
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)
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) {
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 const struct of_device_id goldfish_audio_of_match[] = {
349         { .compatible = "google,goldfish-audio", },
350         {},
351 };
352 MODULE_DEVICE_TABLE(of, goldfish_audio_of_match);
353 
354 static struct platform_driver goldfish_audio_driver = {
355         .probe          = goldfish_audio_probe,
356         .remove         = goldfish_audio_remove,
357         .driver = {
358                 .name = "goldfish_audio",
359                 .of_match_table = goldfish_audio_of_match,
360         }
361 };
362 
363 module_platform_driver(goldfish_audio_driver);
364 

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