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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/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 __iomem *buffer_virt;      /* combined buffer virtual address */
 44         unsigned long buffer_phys;      /* combined buffer physical address */
 45 
 46         char __iomem *write_buffer1;    /* write buffer 1 virtual address */
 47         char __iomem *write_buffer2;    /* write buffer 2 virtual address */
 48         char __iomem *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 __iomem *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 == NULL)
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);
356 

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