1 /* drivers/misc/goldfish_audio.c
2 *
3 * Copyright (C) 2007 Google, Inc.
4 * Copyright (C) 2012 Intel, Inc.
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 */
16
17 #include <linux/module.h>
18 #include <linux/miscdevice.h>
19 #include <linux/fs.h>
20 #include <linux/platform_device.h>
21 #include <linux/types.h>
22 #include <linux/pci.h>
23 #include <linux/interrupt.h>
24 #include <linux/io.h>
25 #include <linux/sched.h>
26 #include <linux/dma-mapping.h>
27 #include <linux/uaccess.h>
28 #include <linux/slab.h>
29 #include <linux/acpi.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 spinlock_t lock;
40 wait_queue_head_t wait;
41
42 char __iomem *buffer_virt; /* combined buffer virtual address */
43 unsigned long buffer_phys; /* combined buffer physical address */
44
45 char __iomem *write_buffer1; /* write buffer 1 virtual address */
46 char __iomem *write_buffer2; /* write buffer 2 virtual address */
47 char __iomem *read_buffer; /* read buffer virtual address */
48 int buffer_status;
49 int read_supported; /* true if we have audio input support */
50 };
51
52 /* We will allocate two read buffers and two write buffers.
53 Having two read buffers facilitate stereo -> mono conversion.
54 Having two write buffers facilitate interleaved IO.
55 */
56 #define READ_BUFFER_SIZE 16384
57 #define WRITE_BUFFER_SIZE 16384
58 #define COMBINED_BUFFER_SIZE ((2 * READ_BUFFER_SIZE) + \
59 (2 * WRITE_BUFFER_SIZE))
60
61 #define AUDIO_READ(data, addr) (readl(data->reg_base + addr))
62 #define AUDIO_WRITE(data, addr, x) (writel(x, data->reg_base + addr))
63
64 /* temporary variable used between goldfish_audio_probe() and
65 goldfish_audio_open() */
66 static struct goldfish_audio *audio_data;
67
68 enum {
69 /* audio status register */
70 AUDIO_INT_STATUS = 0x00,
71 /* set this to enable IRQ */
72 AUDIO_INT_ENABLE = 0x04,
73 /* set these to specify buffer addresses */
74 AUDIO_SET_WRITE_BUFFER_1 = 0x08,
75 AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
76 /* set number of bytes in buffer to write */
77 AUDIO_WRITE_BUFFER_1 = 0x10,
78 AUDIO_WRITE_BUFFER_2 = 0x14,
79 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
80 AUDIO_SET_WRITE_BUFFER_1_HIGH = 0x28,
81 AUDIO_SET_WRITE_BUFFER_2_HIGH = 0x30,
82 #endif
83
84 /* true if audio input is supported */
85 AUDIO_READ_SUPPORTED = 0x18,
86 /* buffer to use for audio input */
87 AUDIO_SET_READ_BUFFER = 0x1C,
88 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
89 AUDIO_SET_READ_BUFFER_HIGH = 0x34,
90 #endif
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
111 static atomic_t open_count = ATOMIC_INIT(0);
112
113
goldfish_audio_read(struct file * fp,char __user * buf,size_t count,loff_t * pos)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 unsigned long irq_flags;
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,
130 (data->buffer_status & AUDIO_INT_READ_BUFFER_FULL));
131
132 spin_lock_irqsave(&data->lock, irq_flags);
133 data->buffer_status &= ~AUDIO_INT_READ_BUFFER_FULL;
134 spin_unlock_irqrestore(&data->lock, irq_flags);
135
136 length = AUDIO_READ(data,
137 AUDIO_READ_BUFFER_AVAILABLE);
138
139 /* copy data to user space */
140 if (copy_to_user(buf, data->read_buffer, length))
141 return -EFAULT;
142
143 result += length;
144 buf += length;
145 count -= length;
146 }
147 return result;
148 }
149
goldfish_audio_write(struct file * fp,const char __user * buf,size_t count,loff_t * pos)150 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
151 size_t count, loff_t *pos)
152 {
153 struct goldfish_audio *data = fp->private_data;
154 unsigned long irq_flags;
155 ssize_t result = 0;
156 char __iomem *kbuf;
157
158 while (count > 0) {
159 ssize_t copy = count;
160 if (copy > WRITE_BUFFER_SIZE)
161 copy = WRITE_BUFFER_SIZE;
162 wait_event_interruptible(data->wait, (data->buffer_status &
163 (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
164 AUDIO_INT_WRITE_BUFFER_2_EMPTY)));
165
166 if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
167 kbuf = data->write_buffer1;
168 else
169 kbuf = data->write_buffer2;
170
171 /* copy from user space to the appropriate buffer */
172 if (copy_from_user(kbuf, buf, copy)) {
173 result = -EFAULT;
174 break;
175 }
176
177 spin_lock_irqsave(&data->lock, irq_flags);
178 /* clear the buffer empty flag, and signal the emulator
179 * to start writing the buffer */
180 if (kbuf == data->write_buffer1) {
181 data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
182 AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_1, copy);
183 } else {
184 data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
185 AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_2, copy);
186 }
187 spin_unlock_irqrestore(&data->lock, irq_flags);
188
189 buf += copy;
190 result += copy;
191 count -= copy;
192 }
193 return result;
194 }
195
goldfish_audio_open(struct inode * ip,struct file * fp)196 static int goldfish_audio_open(struct inode *ip, struct file *fp)
197 {
198 if (!audio_data)
199 return -ENODEV;
200
201 if (atomic_inc_return(&open_count) == 1) {
202 fp->private_data = audio_data;
203 audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
204 AUDIO_INT_WRITE_BUFFER_2_EMPTY);
205 AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
206 return 0;
207 } else {
208 atomic_dec(&open_count);
209 return -EBUSY;
210 }
211 }
212
goldfish_audio_release(struct inode * ip,struct file * fp)213 static int goldfish_audio_release(struct inode *ip, struct file *fp)
214 {
215 atomic_dec(&open_count);
216 /* FIXME: surely this is wrong for the multi-opened case */
217 AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, 0);
218 return 0;
219 }
220
goldfish_audio_ioctl(struct file * fp,unsigned int cmd,unsigned long arg)221 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
222 unsigned long arg)
223 {
224 /* temporary workaround, until we switch to the ALSA API */
225 if (cmd == 315)
226 return -1;
227 else
228 return 0;
229 }
230
goldfish_audio_interrupt(int irq,void * dev_id)231 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
232 {
233 unsigned long irq_flags;
234 struct goldfish_audio *data = dev_id;
235 u32 status;
236
237 spin_lock_irqsave(&data->lock, irq_flags);
238
239 /* read buffer status flags */
240 status = AUDIO_READ(data, AUDIO_INT_STATUS);
241 status &= AUDIO_INT_MASK;
242 /* if buffers are newly empty, wake up blocked
243 goldfish_audio_write() call */
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
goldfish_audio_probe(struct platform_device * pdev)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 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
276 u32 buf_addr_high, buf_addr_low;
277 #endif
278
279 data = kzalloc(sizeof(*data), GFP_KERNEL);
280 if (data == NULL) {
281 ret = -ENOMEM;
282 goto err_data_alloc_failed;
283 }
284 spin_lock_init(&data->lock);
285 init_waitqueue_head(&data->wait);
286 platform_set_drvdata(pdev, data);
287
288 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
289 if (r == NULL) {
290 dev_err(&pdev->dev, "platform_get_resource failed\n");
291 ret = -ENODEV;
292 goto err_no_io_base;
293 }
294 data->reg_base = ioremap(r->start, PAGE_SIZE);
295 if (data->reg_base == NULL) {
296 ret = -ENOMEM;
297 goto err_no_io_base;
298 }
299
300 data->irq = platform_get_irq(pdev, 0);
301 if (data->irq < 0) {
302 dev_err(&pdev->dev, "platform_get_irq failed\n");
303 ret = -ENODEV;
304 goto err_no_irq;
305 }
306 data->buffer_virt = dma_alloc_coherent(&pdev->dev,
307 COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
308 if (data->buffer_virt == 0) {
309 ret = -ENOMEM;
310 dev_err(&pdev->dev, "allocate buffer failed\n");
311 goto err_alloc_write_buffer_failed;
312 }
313 data->buffer_phys = buf_addr;
314 data->write_buffer1 = data->buffer_virt;
315 data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
316 data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;
317
318 ret = request_irq(data->irq, goldfish_audio_interrupt,
319 IRQF_SHARED, pdev->name, data);
320 if (ret) {
321 dev_err(&pdev->dev, "request_irq failed\n");
322 goto err_request_irq_failed;
323 }
324
325 ret = misc_register(&goldfish_audio_device);
326 if (ret) {
327 dev_err(&pdev->dev,
328 "misc_register returned %d in goldfish_audio_init\n",
329 ret);
330 goto err_misc_register_failed;
331 }
332
333 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
334 buf_addr_low = (u32)(buf_addr);
335 buf_addr_high = (u32)((buf_addr) >> 32);
336
337 AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_1, buf_addr_low);
338 AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_1_HIGH, buf_addr_high);
339
340 buf_addr_low = (u32)(buf_addr + WRITE_BUFFER_SIZE);
341 buf_addr_high = (u32)((buf_addr + WRITE_BUFFER_SIZE) >> 32);
342
343 AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_2, buf_addr_low);
344 AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_2_HIGH, buf_addr_high);
345
346 buf_addr_low = (u32)(buf_addr + 2 * WRITE_BUFFER_SIZE);
347 buf_addr_high = (u32)((buf_addr + 2 * WRITE_BUFFER_SIZE) >> 32);
348
349 data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
350 if (data->read_supported){
351 AUDIO_WRITE(data, AUDIO_SET_READ_BUFFER, buf_addr_low);
352 AUDIO_WRITE(data, AUDIO_SET_READ_BUFFER_HIGH, buf_addr_high);
353 }
354 #else
355 AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_1, buf_addr);
356 AUDIO_WRITE(data, AUDIO_SET_WRITE_BUFFER_2,
357 buf_addr + WRITE_BUFFER_SIZE);
358
359 data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
360 if (data->read_supported)
361 AUDIO_WRITE(data, AUDIO_SET_READ_BUFFER,
362 buf_addr + 2 * WRITE_BUFFER_SIZE);
363 #endif
364
365 audio_data = data;
366 return 0;
367
368 err_misc_register_failed:
369 err_request_irq_failed:
370 dma_free_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
371 data->buffer_virt, data->buffer_phys);
372 err_alloc_write_buffer_failed:
373 err_no_irq:
374 iounmap(data->reg_base);
375 err_no_io_base:
376 kfree(data);
377 err_data_alloc_failed:
378 return ret;
379 }
380
goldfish_audio_remove(struct platform_device * pdev)381 static int goldfish_audio_remove(struct platform_device *pdev)
382 {
383 struct goldfish_audio *data = platform_get_drvdata(pdev);
384
385 misc_deregister(&goldfish_audio_device);
386 free_irq(data->irq, data);
387 dma_free_coherent(&pdev->dev, COMBINED_BUFFER_SIZE,
388 data->buffer_virt, data->buffer_phys);
389 iounmap(data->reg_base);
390 kfree(data);
391 audio_data = NULL;
392 return 0;
393 }
394
395 static const struct of_device_id goldfish_audio_of_match[] = {
396 { .compatible = "generic,goldfish-audio", },
397 {},
398 };
399 MODULE_DEVICE_TABLE(of, goldfish_audio_of_match);
400
401 static const struct acpi_device_id goldfish_audio_acpi_match[] = {
402 { "GFSH0005", 0 },
403 { },
404 };
405 MODULE_DEVICE_TABLE(acpi, goldfish_audio_acpi_match);
406
407 static struct platform_driver goldfish_audio_driver = {
408 .probe = goldfish_audio_probe,
409 .remove = goldfish_audio_remove,
410 .driver = {
411 .name = "goldfish_audio",
412 .of_match_table = goldfish_audio_of_match,
413 .acpi_match_table = ACPI_PTR(goldfish_audio_acpi_match),
414 }
415 };
416
417 module_platform_driver(goldfish_audio_driver);
418