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 #include <linux/acpi.h>
32
33 MODULE_AUTHOR("Google, Inc.");
34 MODULE_DESCRIPTION("Android QEMU Audio Driver");
35 MODULE_LICENSE("GPL");
36 MODULE_VERSION("1.0");
37
38 struct goldfish_audio {
39 char __iomem *reg_base;
40 int irq;
41 /* lock protects access to buffer_status and to device registers */
42 spinlock_t lock;
43 wait_queue_head_t wait;
44
45 char *buffer_virt; /* combined buffer virtual address */
46 unsigned long buffer_phys; /* combined buffer physical address */
47
48 char *write_buffer1; /* write buffer 1 virtual address */
49 char *write_buffer2; /* write buffer 2 virtual address */
50 char *read_buffer; /* read buffer virtual address */
51 int buffer_status;
52 int read_supported; /* true if we have audio input support */
53 };
54
55 /*
56 * We will allocate two read buffers and two write buffers.
57 * Having two read buffers facilitate stereo -> mono conversion.
58 * Having two write buffers facilitate interleaved IO.
59 */
60 #define READ_BUFFER_SIZE 16384
61 #define WRITE_BUFFER_SIZE 16384
62 #define COMBINED_BUFFER_SIZE ((2 * READ_BUFFER_SIZE) + \
63 (2 * WRITE_BUFFER_SIZE))
64
65 #define AUDIO_READ(data, addr) (readl(data->reg_base + addr))
66 #define AUDIO_WRITE(data, addr, x) (writel(x, data->reg_base + addr))
67 #define AUDIO_WRITE64(data, addr, addr2, x) \
68 (gf_write_dma_addr((x), data->reg_base + addr, data->reg_base + addr2))
69
70 /*
71 * temporary variable used between goldfish_audio_probe() and
72 * goldfish_audio_open()
73 */
74 static struct goldfish_audio *audio_data;
75
76 enum {
77 /* audio status register */
78 AUDIO_INT_STATUS = 0x00,
79 /* set this to enable IRQ */
80 AUDIO_INT_ENABLE = 0x04,
81 /* set these to specify buffer addresses */
82 AUDIO_SET_WRITE_BUFFER_1 = 0x08,
83 AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
84 /* set number of bytes in buffer to write */
85 AUDIO_WRITE_BUFFER_1 = 0x10,
86 AUDIO_WRITE_BUFFER_2 = 0x14,
87 AUDIO_SET_WRITE_BUFFER_1_HIGH = 0x28,
88 AUDIO_SET_WRITE_BUFFER_2_HIGH = 0x30,
89
90 /* true if audio input is supported */
91 AUDIO_READ_SUPPORTED = 0x18,
92 /* buffer to use for audio input */
93 AUDIO_SET_READ_BUFFER = 0x1C,
94 AUDIO_SET_READ_BUFFER_HIGH = 0x34,
95
96 /* driver writes number of bytes to read */
97 AUDIO_START_READ = 0x20,
98
99 /* number of bytes available in read buffer */
100 AUDIO_READ_BUFFER_AVAILABLE = 0x24,
101
102 /* AUDIO_INT_STATUS bits */
103
104 /* this bit set when it is safe to write more bytes to the buffer */
105 AUDIO_INT_WRITE_BUFFER_1_EMPTY = 1U << 0,
106 AUDIO_INT_WRITE_BUFFER_2_EMPTY = 1U << 1,
107 AUDIO_INT_READ_BUFFER_FULL = 1U << 2,
108
109 AUDIO_INT_MASK = AUDIO_INT_WRITE_BUFFER_1_EMPTY |
110 AUDIO_INT_WRITE_BUFFER_2_EMPTY |
111 AUDIO_INT_READ_BUFFER_FULL,
112 };
113
114 static atomic_t open_count = ATOMIC_INIT(0);
115
goldfish_audio_read(struct file * fp,char __user * buf,size_t count,loff_t * pos)116 static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
117 size_t count, loff_t *pos)
118 {
119 struct goldfish_audio *data = fp->private_data;
120 unsigned long irq_flags;
121 int length;
122 int result = 0;
123
124 if (!data->read_supported)
125 return -ENODEV;
126
127 while (count > 0) {
128 length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
129 AUDIO_WRITE(data, AUDIO_START_READ, length);
130
131 wait_event_interruptible(data->wait, data->buffer_status &
132 AUDIO_INT_READ_BUFFER_FULL);
133
134 spin_lock_irqsave(&data->lock, irq_flags);
135 data->buffer_status &= ~AUDIO_INT_READ_BUFFER_FULL;
136 spin_unlock_irqrestore(&data->lock, irq_flags);
137
138 length = AUDIO_READ(data, AUDIO_READ_BUFFER_AVAILABLE);
139
140 /* copy data to user space */
141 if (copy_to_user(buf, data->read_buffer, length))
142 return -EFAULT;
143
144 result += length;
145 buf += length;
146 count -= length;
147 }
148 return result;
149 }
150
goldfish_audio_write(struct file * fp,const char __user * buf,size_t count,loff_t * pos)151 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
152 size_t count, loff_t *pos)
153 {
154 struct goldfish_audio *data = fp->private_data;
155 unsigned long irq_flags;
156 ssize_t result = 0;
157 char *kbuf;
158
159 while (count > 0) {
160 ssize_t copy = count;
161
162 if (copy > WRITE_BUFFER_SIZE)
163 copy = WRITE_BUFFER_SIZE;
164 wait_event_interruptible(data->wait, data->buffer_status &
165 (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
166 AUDIO_INT_WRITE_BUFFER_2_EMPTY));
167
168 if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
169 kbuf = data->write_buffer1;
170 else
171 kbuf = data->write_buffer2;
172
173 /* copy from user space to the appropriate buffer */
174 if (copy_from_user(kbuf, buf, copy)) {
175 result = -EFAULT;
176 break;
177 }
178
179 spin_lock_irqsave(&data->lock, irq_flags);
180 /*
181 * clear the buffer empty flag, and signal the emulator
182 * to start writing the buffer
183 */
184 if (kbuf == data->write_buffer1) {
185 data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
186 AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_1, copy);
187 } else {
188 data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
189 AUDIO_WRITE(data, AUDIO_WRITE_BUFFER_2, copy);
190 }
191 spin_unlock_irqrestore(&data->lock, irq_flags);
192
193 buf += copy;
194 result += copy;
195 count -= copy;
196 }
197 return result;
198 }
199
goldfish_audio_open(struct inode * ip,struct file * fp)200 static int goldfish_audio_open(struct inode *ip, struct file *fp)
201 {
202 if (!audio_data)
203 return -ENODEV;
204
205 if (atomic_inc_return(&open_count) == 1) {
206 fp->private_data = audio_data;
207 audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
208 AUDIO_INT_WRITE_BUFFER_2_EMPTY);
209 AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
210 return 0;
211 }
212
213 atomic_dec(&open_count);
214 return -EBUSY;
215 }
216
goldfish_audio_release(struct inode * ip,struct file * fp)217 static int goldfish_audio_release(struct inode *ip, struct file *fp)
218 {
219 atomic_dec(&open_count);
220 /* FIXME: surely this is wrong for the multi-opened case */
221 AUDIO_WRITE(audio_data, AUDIO_INT_ENABLE, 0);
222 return 0;
223 }
224
goldfish_audio_ioctl(struct file * fp,unsigned int cmd,unsigned long arg)225 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
226 unsigned long arg)
227 {
228 /* temporary workaround, until we switch to the ALSA API */
229 if (cmd == 315)
230 return -1;
231
232 return 0;
233 }
234
goldfish_audio_interrupt(int irq,void * dev_id)235 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
236 {
237 unsigned long irq_flags;
238 struct goldfish_audio *data = dev_id;
239 u32 status;
240
241 spin_lock_irqsave(&data->lock, irq_flags);
242
243 /* read buffer status flags */
244 status = AUDIO_READ(data, AUDIO_INT_STATUS);
245 status &= AUDIO_INT_MASK;
246 /*
247 * if buffers are newly empty, wake up blocked
248 * goldfish_audio_write() call
249 */
250 if (status) {
251 data->buffer_status = status;
252 wake_up(&data->wait);
253 }
254
255 spin_unlock_irqrestore(&data->lock, irq_flags);
256 return status ? IRQ_HANDLED : IRQ_NONE;
257 }
258
259 /* file operations for /dev/eac */
260 static const struct file_operations goldfish_audio_fops = {
261 .owner = THIS_MODULE,
262 .read = goldfish_audio_read,
263 .write = goldfish_audio_write,
264 .open = goldfish_audio_open,
265 .release = goldfish_audio_release,
266 .unlocked_ioctl = goldfish_audio_ioctl,
267 };
268
269 static struct miscdevice goldfish_audio_device = {
270 .minor = MISC_DYNAMIC_MINOR,
271 .name = "eac",
272 .fops = &goldfish_audio_fops,
273 };
274
goldfish_audio_probe(struct platform_device * pdev)275 static int goldfish_audio_probe(struct platform_device *pdev)
276 {
277 int ret;
278 struct resource *r;
279 struct goldfish_audio *data;
280 dma_addr_t buf_addr;
281
282 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
283 if (!data)
284 return -ENOMEM;
285 spin_lock_init(&data->lock);
286 init_waitqueue_head(&data->wait);
287 platform_set_drvdata(pdev, data);
288
289 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
290 if (!r) {
291 dev_err(&pdev->dev, "platform_get_resource failed\n");
292 return -ENODEV;
293 }
294 data->reg_base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
295 if (!data->reg_base)
296 return -ENOMEM;
297
298 data->irq = platform_get_irq(pdev, 0);
299 if (data->irq < 0) {
300 dev_err(&pdev->dev, "platform_get_irq failed\n");
301 return -ENODEV;
302 }
303 data->buffer_virt = dmam_alloc_coherent(&pdev->dev,
304 COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
305 if (!data->buffer_virt) {
306 dev_err(&pdev->dev, "allocate buffer failed\n");
307 return -ENOMEM;
308 }
309 data->buffer_phys = buf_addr;
310 data->write_buffer1 = data->buffer_virt;
311 data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
312 data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;
313
314 ret = devm_request_irq(&pdev->dev, data->irq, goldfish_audio_interrupt,
315 IRQF_SHARED, pdev->name, data);
316 if (ret) {
317 dev_err(&pdev->dev, "request_irq failed\n");
318 return ret;
319 }
320
321 ret = misc_register(&goldfish_audio_device);
322 if (ret) {
323 dev_err(&pdev->dev,
324 "misc_register returned %d in goldfish_audio_init\n",
325 ret);
326 return ret;
327 }
328
329 AUDIO_WRITE64(data, AUDIO_SET_WRITE_BUFFER_1,
330 AUDIO_SET_WRITE_BUFFER_1_HIGH, buf_addr);
331 buf_addr += WRITE_BUFFER_SIZE;
332
333 AUDIO_WRITE64(data, AUDIO_SET_WRITE_BUFFER_2,
334 AUDIO_SET_WRITE_BUFFER_2_HIGH, buf_addr);
335
336 buf_addr += WRITE_BUFFER_SIZE;
337
338 data->read_supported = AUDIO_READ(data, AUDIO_READ_SUPPORTED);
339 if (data->read_supported)
340 AUDIO_WRITE64(data, AUDIO_SET_READ_BUFFER,
341 AUDIO_SET_READ_BUFFER_HIGH, buf_addr);
342
343 audio_data = data;
344 return 0;
345 }
346
goldfish_audio_remove(struct platform_device * pdev)347 static int goldfish_audio_remove(struct platform_device *pdev)
348 {
349 misc_deregister(&goldfish_audio_device);
350 audio_data = NULL;
351 return 0;
352 }
353
354 static const struct of_device_id goldfish_audio_of_match[] = {
355 { .compatible = "google,goldfish-audio", },
356 {},
357 };
358 MODULE_DEVICE_TABLE(of, goldfish_audio_of_match);
359
360 static const struct acpi_device_id goldfish_audio_acpi_match[] = {
361 { "GFSH0005", 0 },
362 { },
363 };
364 MODULE_DEVICE_TABLE(acpi, goldfish_audio_acpi_match);
365
366 static struct platform_driver goldfish_audio_driver = {
367 .probe = goldfish_audio_probe,
368 .remove = goldfish_audio_remove,
369 .driver = {
370 .name = "goldfish_audio",
371 .of_match_table = goldfish_audio_of_match,
372 .acpi_match_table = ACPI_PTR(goldfish_audio_acpi_match),
373 }
374 };
375
376 module_platform_driver(goldfish_audio_driver);
377