1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/misc/goldfish_audio.c
5 * Copyright (C) 2007 Google, Inc.
6 * Copyright (C) 2012 Intel, Inc.
9 #include <linux/module.h>
10 #include <linux/miscdevice.h>
12 #include <linux/platform_device.h>
13 #include <linux/types.h>
14 #include <linux/pci.h>
15 #include <linux/interrupt.h>
17 #include <linux/sched.h>
18 #include <linux/dma-mapping.h>
19 #include <linux/uaccess.h>
20 #include <linux/slab.h>
21 #include <linux/goldfish.h>
22 #include <linux/acpi.h>
24 MODULE_AUTHOR("Google, Inc.");
25 MODULE_DESCRIPTION("Android QEMU Audio Driver");
26 MODULE_LICENSE("GPL");
27 MODULE_VERSION("1.0");
29 struct goldfish_audio {
30 char __iomem *reg_base;
33 /* lock protects access to buffer_status and to device registers */
35 wait_queue_head_t wait;
37 char *buffer_virt; /* combined buffer virtual address */
38 unsigned long buffer_phys; /* combined buffer physical address */
40 char *write_buffer1; /* write buffer 1 virtual address */
41 char *write_buffer2; /* write buffer 2 virtual address */
42 char *read_buffer; /* read buffer virtual address */
44 int read_supported; /* true if we have audio input support */
48 * We will allocate two read buffers and two write buffers.
49 * Having two read buffers facilitate stereo -> mono conversion.
50 * Having two write buffers facilitate interleaved IO.
52 #define READ_BUFFER_SIZE 16384
53 #define WRITE_BUFFER_SIZE 16384
54 #define COMBINED_BUFFER_SIZE ((2 * READ_BUFFER_SIZE) + \
55 (2 * WRITE_BUFFER_SIZE))
58 * temporary variable used between goldfish_audio_probe() and
59 * goldfish_audio_open()
61 static struct goldfish_audio *audio_data;
64 /* audio status register */
65 AUDIO_INT_STATUS = 0x00,
66 /* set this to enable IRQ */
67 AUDIO_INT_ENABLE = 0x04,
68 /* set these to specify buffer addresses */
69 AUDIO_SET_WRITE_BUFFER_1 = 0x08,
70 AUDIO_SET_WRITE_BUFFER_2 = 0x0C,
71 /* set number of bytes in buffer to write */
72 AUDIO_WRITE_BUFFER_1 = 0x10,
73 AUDIO_WRITE_BUFFER_2 = 0x14,
74 AUDIO_SET_WRITE_BUFFER_1_HIGH = 0x28,
75 AUDIO_SET_WRITE_BUFFER_2_HIGH = 0x30,
77 /* true if audio input is supported */
78 AUDIO_READ_SUPPORTED = 0x18,
79 /* buffer to use for audio input */
80 AUDIO_SET_READ_BUFFER = 0x1C,
81 AUDIO_SET_READ_BUFFER_HIGH = 0x34,
83 /* driver writes number of bytes to read */
84 AUDIO_START_READ = 0x20,
86 /* number of bytes available in read buffer */
87 AUDIO_READ_BUFFER_AVAILABLE = 0x24,
89 /* AUDIO_INT_STATUS bits */
91 /* this bit set when it is safe to write more bytes to the buffer */
92 AUDIO_INT_WRITE_BUFFER_1_EMPTY = 1U << 0,
93 AUDIO_INT_WRITE_BUFFER_2_EMPTY = 1U << 1,
94 AUDIO_INT_READ_BUFFER_FULL = 1U << 2,
96 AUDIO_INT_MASK = AUDIO_INT_WRITE_BUFFER_1_EMPTY |
97 AUDIO_INT_WRITE_BUFFER_2_EMPTY |
98 AUDIO_INT_READ_BUFFER_FULL,
101 static atomic_t open_count = ATOMIC_INIT(0);
103 static unsigned int audio_read(const struct goldfish_audio *data, int addr)
105 return readl(data->reg_base + addr);
108 static void audio_write(const struct goldfish_audio *data,
109 int addr, unsigned int x)
111 writel(x, data->reg_base + addr);
114 static void audio_write64(const struct goldfish_audio *data,
115 int addr_lo, int addr_hi, unsigned int x)
117 char __iomem *reg_base = data->reg_base;
119 gf_write_dma_addr(x, reg_base + addr_lo, reg_base + addr_hi);
122 static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
123 size_t count, loff_t *pos)
125 struct goldfish_audio *data = fp->private_data;
126 unsigned long irq_flags;
130 if (!data->read_supported)
134 length = (count > READ_BUFFER_SIZE ? READ_BUFFER_SIZE : count);
135 audio_write(data, AUDIO_START_READ, length);
137 wait_event_interruptible(data->wait, data->buffer_status &
138 AUDIO_INT_READ_BUFFER_FULL);
140 spin_lock_irqsave(&data->lock, irq_flags);
141 data->buffer_status &= ~AUDIO_INT_READ_BUFFER_FULL;
142 spin_unlock_irqrestore(&data->lock, irq_flags);
144 length = audio_read(data, AUDIO_READ_BUFFER_AVAILABLE);
146 /* copy data to user space */
147 if (copy_to_user(buf, data->read_buffer, length))
157 static ssize_t goldfish_audio_write(struct file *fp, const char __user *buf,
158 size_t count, loff_t *pos)
160 struct goldfish_audio *data = fp->private_data;
161 unsigned long irq_flags;
166 ssize_t copy = count;
168 if (copy > WRITE_BUFFER_SIZE)
169 copy = WRITE_BUFFER_SIZE;
170 wait_event_interruptible(data->wait, data->buffer_status &
171 (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
172 AUDIO_INT_WRITE_BUFFER_2_EMPTY));
174 if ((data->buffer_status & AUDIO_INT_WRITE_BUFFER_1_EMPTY) != 0)
175 kbuf = data->write_buffer1;
177 kbuf = data->write_buffer2;
179 /* copy from user space to the appropriate buffer */
180 if (copy_from_user(kbuf, buf, copy)) {
185 spin_lock_irqsave(&data->lock, irq_flags);
187 * clear the buffer empty flag, and signal the emulator
188 * to start writing the buffer
190 if (kbuf == data->write_buffer1) {
191 data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_1_EMPTY;
192 audio_write(data, AUDIO_WRITE_BUFFER_1, copy);
194 data->buffer_status &= ~AUDIO_INT_WRITE_BUFFER_2_EMPTY;
195 audio_write(data, AUDIO_WRITE_BUFFER_2, copy);
197 spin_unlock_irqrestore(&data->lock, irq_flags);
206 static int goldfish_audio_open(struct inode *ip, struct file *fp)
211 if (atomic_inc_return(&open_count) == 1) {
212 fp->private_data = audio_data;
213 audio_data->buffer_status = (AUDIO_INT_WRITE_BUFFER_1_EMPTY |
214 AUDIO_INT_WRITE_BUFFER_2_EMPTY);
215 audio_write(audio_data, AUDIO_INT_ENABLE, AUDIO_INT_MASK);
219 atomic_dec(&open_count);
223 static int goldfish_audio_release(struct inode *ip, struct file *fp)
225 atomic_dec(&open_count);
226 /* FIXME: surely this is wrong for the multi-opened case */
227 audio_write(audio_data, AUDIO_INT_ENABLE, 0);
231 static long goldfish_audio_ioctl(struct file *fp, unsigned int cmd,
234 /* temporary workaround, until we switch to the ALSA API */
241 static irqreturn_t goldfish_audio_interrupt(int irq, void *dev_id)
243 unsigned long irq_flags;
244 struct goldfish_audio *data = dev_id;
247 spin_lock_irqsave(&data->lock, irq_flags);
249 /* read buffer status flags */
250 status = audio_read(data, AUDIO_INT_STATUS);
251 status &= AUDIO_INT_MASK;
253 * if buffers are newly empty, wake up blocked
254 * goldfish_audio_write() call
257 data->buffer_status = status;
258 wake_up(&data->wait);
261 spin_unlock_irqrestore(&data->lock, irq_flags);
262 return status ? IRQ_HANDLED : IRQ_NONE;
265 /* file operations for /dev/eac */
266 static const struct file_operations goldfish_audio_fops = {
267 .owner = THIS_MODULE,
268 .read = goldfish_audio_read,
269 .write = goldfish_audio_write,
270 .open = goldfish_audio_open,
271 .release = goldfish_audio_release,
272 .unlocked_ioctl = goldfish_audio_ioctl,
275 static struct miscdevice goldfish_audio_device = {
276 .minor = MISC_DYNAMIC_MINOR,
278 .fops = &goldfish_audio_fops,
281 static int goldfish_audio_probe(struct platform_device *pdev)
285 struct goldfish_audio *data;
288 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
291 spin_lock_init(&data->lock);
292 init_waitqueue_head(&data->wait);
293 platform_set_drvdata(pdev, data);
295 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
297 dev_err(&pdev->dev, "platform_get_resource failed\n");
300 data->reg_base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
304 data->irq = platform_get_irq(pdev, 0);
307 data->buffer_virt = dmam_alloc_coherent(&pdev->dev,
308 COMBINED_BUFFER_SIZE,
309 &buf_addr, GFP_KERNEL);
310 if (!data->buffer_virt) {
311 dev_err(&pdev->dev, "allocate buffer failed\n");
314 data->buffer_phys = buf_addr;
315 data->write_buffer1 = data->buffer_virt;
316 data->write_buffer2 = data->buffer_virt + WRITE_BUFFER_SIZE;
317 data->read_buffer = data->buffer_virt + 2 * WRITE_BUFFER_SIZE;
319 ret = devm_request_irq(&pdev->dev, data->irq, goldfish_audio_interrupt,
320 IRQF_SHARED, pdev->name, data);
322 dev_err(&pdev->dev, "request_irq failed\n");
326 ret = misc_register(&goldfish_audio_device);
329 "misc_register returned %d in goldfish_audio_init\n",
334 audio_write64(data, AUDIO_SET_WRITE_BUFFER_1,
335 AUDIO_SET_WRITE_BUFFER_1_HIGH, buf_addr);
336 buf_addr += WRITE_BUFFER_SIZE;
338 audio_write64(data, AUDIO_SET_WRITE_BUFFER_2,
339 AUDIO_SET_WRITE_BUFFER_2_HIGH, buf_addr);
341 buf_addr += WRITE_BUFFER_SIZE;
343 data->read_supported = audio_read(data, AUDIO_READ_SUPPORTED);
344 if (data->read_supported)
345 audio_write64(data, AUDIO_SET_READ_BUFFER,
346 AUDIO_SET_READ_BUFFER_HIGH, buf_addr);
352 static int goldfish_audio_remove(struct platform_device *pdev)
354 misc_deregister(&goldfish_audio_device);
359 static const struct of_device_id goldfish_audio_of_match[] = {
360 { .compatible = "google,goldfish-audio", },
363 MODULE_DEVICE_TABLE(of, goldfish_audio_of_match);
366 static const struct acpi_device_id goldfish_audio_acpi_match[] = {
370 MODULE_DEVICE_TABLE(acpi, goldfish_audio_acpi_match);
373 static struct platform_driver goldfish_audio_driver = {
374 .probe = goldfish_audio_probe,
375 .remove = goldfish_audio_remove,
377 .name = "goldfish_audio",
378 .of_match_table = goldfish_audio_of_match,
379 .acpi_match_table = ACPI_PTR(goldfish_audio_acpi_match),
383 module_platform_driver(goldfish_audio_driver);