1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * bebob_hwdep.c - a part of driver for BeBoB based devices
4  *
5  * Copyright (c) 2013-2014 Takashi Sakamoto
6  */
7 
8 /*
9  * This codes give three functionality.
10  *
11  * 1.get firewire node infomation
12  * 2.get notification about starting/stopping stream
13  * 3.lock/unlock stream
14  */
15 
16 #include "bebob.h"
17 
18 static long
19 hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
20 	   loff_t *offset)
21 {
22 	struct snd_bebob *bebob = hwdep->private_data;
23 	DEFINE_WAIT(wait);
24 	union snd_firewire_event event;
25 
26 	spin_lock_irq(&bebob->lock);
27 
28 	while (!bebob->dev_lock_changed) {
29 		prepare_to_wait(&bebob->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
30 		spin_unlock_irq(&bebob->lock);
31 		schedule();
32 		finish_wait(&bebob->hwdep_wait, &wait);
33 		if (signal_pending(current))
34 			return -ERESTARTSYS;
35 		spin_lock_irq(&bebob->lock);
36 	}
37 
38 	memset(&event, 0, sizeof(event));
39 	count = min_t(long, count, sizeof(event.lock_status));
40 	event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
41 	event.lock_status.status = (bebob->dev_lock_count > 0);
42 	bebob->dev_lock_changed = false;
43 
44 	spin_unlock_irq(&bebob->lock);
45 
46 	if (copy_to_user(buf, &event, count))
47 		return -EFAULT;
48 
49 	return count;
50 }
51 
52 static __poll_t
53 hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait)
54 {
55 	struct snd_bebob *bebob = hwdep->private_data;
56 	__poll_t events;
57 
58 	poll_wait(file, &bebob->hwdep_wait, wait);
59 
60 	spin_lock_irq(&bebob->lock);
61 	if (bebob->dev_lock_changed)
62 		events = EPOLLIN | EPOLLRDNORM;
63 	else
64 		events = 0;
65 	spin_unlock_irq(&bebob->lock);
66 
67 	return events;
68 }
69 
70 static int
71 hwdep_get_info(struct snd_bebob *bebob, void __user *arg)
72 {
73 	struct fw_device *dev = fw_parent_device(bebob->unit);
74 	struct snd_firewire_get_info info;
75 
76 	memset(&info, 0, sizeof(info));
77 	info.type = SNDRV_FIREWIRE_TYPE_BEBOB;
78 	info.card = dev->card->index;
79 	*(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
80 	*(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
81 	strscpy(info.device_name, dev_name(&dev->device),
82 		sizeof(info.device_name));
83 
84 	if (copy_to_user(arg, &info, sizeof(info)))
85 		return -EFAULT;
86 
87 	return 0;
88 }
89 
90 static int
91 hwdep_lock(struct snd_bebob *bebob)
92 {
93 	int err;
94 
95 	spin_lock_irq(&bebob->lock);
96 
97 	if (bebob->dev_lock_count == 0) {
98 		bebob->dev_lock_count = -1;
99 		err = 0;
100 	} else {
101 		err = -EBUSY;
102 	}
103 
104 	spin_unlock_irq(&bebob->lock);
105 
106 	return err;
107 }
108 
109 static int
110 hwdep_unlock(struct snd_bebob *bebob)
111 {
112 	int err;
113 
114 	spin_lock_irq(&bebob->lock);
115 
116 	if (bebob->dev_lock_count == -1) {
117 		bebob->dev_lock_count = 0;
118 		err = 0;
119 	} else {
120 		err = -EBADFD;
121 	}
122 
123 	spin_unlock_irq(&bebob->lock);
124 
125 	return err;
126 }
127 
128 static int
129 hwdep_release(struct snd_hwdep *hwdep, struct file *file)
130 {
131 	struct snd_bebob *bebob = hwdep->private_data;
132 
133 	spin_lock_irq(&bebob->lock);
134 	if (bebob->dev_lock_count == -1)
135 		bebob->dev_lock_count = 0;
136 	spin_unlock_irq(&bebob->lock);
137 
138 	return 0;
139 }
140 
141 static int
142 hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
143 	    unsigned int cmd, unsigned long arg)
144 {
145 	struct snd_bebob *bebob = hwdep->private_data;
146 
147 	switch (cmd) {
148 	case SNDRV_FIREWIRE_IOCTL_GET_INFO:
149 		return hwdep_get_info(bebob, (void __user *)arg);
150 	case SNDRV_FIREWIRE_IOCTL_LOCK:
151 		return hwdep_lock(bebob);
152 	case SNDRV_FIREWIRE_IOCTL_UNLOCK:
153 		return hwdep_unlock(bebob);
154 	default:
155 		return -ENOIOCTLCMD;
156 	}
157 }
158 
159 #ifdef CONFIG_COMPAT
160 static int
161 hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
162 		   unsigned int cmd, unsigned long arg)
163 {
164 	return hwdep_ioctl(hwdep, file, cmd,
165 			   (unsigned long)compat_ptr(arg));
166 }
167 #else
168 #define hwdep_compat_ioctl NULL
169 #endif
170 
171 int snd_bebob_create_hwdep_device(struct snd_bebob *bebob)
172 {
173 	static const struct snd_hwdep_ops ops = {
174 		.read		= hwdep_read,
175 		.release	= hwdep_release,
176 		.poll		= hwdep_poll,
177 		.ioctl		= hwdep_ioctl,
178 		.ioctl_compat	= hwdep_compat_ioctl,
179 	};
180 	struct snd_hwdep *hwdep;
181 	int err;
182 
183 	err = snd_hwdep_new(bebob->card, "BeBoB", 0, &hwdep);
184 	if (err < 0)
185 		goto end;
186 	strcpy(hwdep->name, "BeBoB");
187 	hwdep->iface = SNDRV_HWDEP_IFACE_FW_BEBOB;
188 	hwdep->ops = ops;
189 	hwdep->private_data = bebob;
190 	hwdep->exclusive = true;
191 end:
192 	return err;
193 }
194 
195