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 *buffer_virt; /* combined buffer virtual address */
44 unsigned long buffer_phys; /* combined buffer physical address */
45
46 char *write_buffer1; /* write buffer 1 virtual address */
47 char *write_buffer2; /* write buffer 2 virtual address */
48 char *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
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 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
goldfish_audio_write(struct file * fp,const char __user * buf,size_t count,loff_t * pos)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 *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
goldfish_audio_open(struct inode * ip,struct file * fp)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
goldfish_audio_release(struct inode * ip,struct file * fp)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
goldfish_audio_ioctl(struct file * fp,unsigned int cmd,unsigned long arg)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
goldfish_audio_interrupt(int irq,void * dev_id)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
goldfish_audio_probe(struct platform_device * pdev)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)
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
goldfish_audio_remove(struct platform_device * pdev)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