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 	if (bebob->dev_lock_changed) {
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 		count = min_t(long, count, sizeof(event.lock_status));
45 	}
46 
47 	spin_unlock_irq(&bebob->lock);
48 
49 	if (copy_to_user(buf, &event, count))
50 		return -EFAULT;
51 
52 	return count;
53 }
54 
55 static __poll_t
56 hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait)
57 {
58 	struct snd_bebob *bebob = hwdep->private_data;
59 	__poll_t events;
60 
61 	poll_wait(file, &bebob->hwdep_wait, wait);
62 
63 	spin_lock_irq(&bebob->lock);
64 	if (bebob->dev_lock_changed)
65 		events = EPOLLIN | EPOLLRDNORM;
66 	else
67 		events = 0;
68 	spin_unlock_irq(&bebob->lock);
69 
70 	return events;
71 }
72 
73 static int
74 hwdep_get_info(struct snd_bebob *bebob, void __user *arg)
75 {
76 	struct fw_device *dev = fw_parent_device(bebob->unit);
77 	struct snd_firewire_get_info info;
78 
79 	memset(&info, 0, sizeof(info));
80 	info.type = SNDRV_FIREWIRE_TYPE_BEBOB;
81 	info.card = dev->card->index;
82 	*(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
83 	*(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
84 	strlcpy(info.device_name, dev_name(&dev->device),
85 		sizeof(info.device_name));
86 
87 	if (copy_to_user(arg, &info, sizeof(info)))
88 		return -EFAULT;
89 
90 	return 0;
91 }
92 
93 static int
94 hwdep_lock(struct snd_bebob *bebob)
95 {
96 	int err;
97 
98 	spin_lock_irq(&bebob->lock);
99 
100 	if (bebob->dev_lock_count == 0) {
101 		bebob->dev_lock_count = -1;
102 		err = 0;
103 	} else {
104 		err = -EBUSY;
105 	}
106 
107 	spin_unlock_irq(&bebob->lock);
108 
109 	return err;
110 }
111 
112 static int
113 hwdep_unlock(struct snd_bebob *bebob)
114 {
115 	int err;
116 
117 	spin_lock_irq(&bebob->lock);
118 
119 	if (bebob->dev_lock_count == -1) {
120 		bebob->dev_lock_count = 0;
121 		err = 0;
122 	} else {
123 		err = -EBADFD;
124 	}
125 
126 	spin_unlock_irq(&bebob->lock);
127 
128 	return err;
129 }
130 
131 static int
132 hwdep_release(struct snd_hwdep *hwdep, struct file *file)
133 {
134 	struct snd_bebob *bebob = hwdep->private_data;
135 
136 	spin_lock_irq(&bebob->lock);
137 	if (bebob->dev_lock_count == -1)
138 		bebob->dev_lock_count = 0;
139 	spin_unlock_irq(&bebob->lock);
140 
141 	return 0;
142 }
143 
144 static int
145 hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
146 	    unsigned int cmd, unsigned long arg)
147 {
148 	struct snd_bebob *bebob = hwdep->private_data;
149 
150 	switch (cmd) {
151 	case SNDRV_FIREWIRE_IOCTL_GET_INFO:
152 		return hwdep_get_info(bebob, (void __user *)arg);
153 	case SNDRV_FIREWIRE_IOCTL_LOCK:
154 		return hwdep_lock(bebob);
155 	case SNDRV_FIREWIRE_IOCTL_UNLOCK:
156 		return hwdep_unlock(bebob);
157 	default:
158 		return -ENOIOCTLCMD;
159 	}
160 }
161 
162 #ifdef CONFIG_COMPAT
163 static int
164 hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
165 		   unsigned int cmd, unsigned long arg)
166 {
167 	return hwdep_ioctl(hwdep, file, cmd,
168 			   (unsigned long)compat_ptr(arg));
169 }
170 #else
171 #define hwdep_compat_ioctl NULL
172 #endif
173 
174 int snd_bebob_create_hwdep_device(struct snd_bebob *bebob)
175 {
176 	static const struct snd_hwdep_ops ops = {
177 		.read		= hwdep_read,
178 		.release	= hwdep_release,
179 		.poll		= hwdep_poll,
180 		.ioctl		= hwdep_ioctl,
181 		.ioctl_compat	= hwdep_compat_ioctl,
182 	};
183 	struct snd_hwdep *hwdep;
184 	int err;
185 
186 	err = snd_hwdep_new(bebob->card, "BeBoB", 0, &hwdep);
187 	if (err < 0)
188 		goto end;
189 	strcpy(hwdep->name, "BeBoB");
190 	hwdep->iface = SNDRV_HWDEP_IFACE_FW_BEBOB;
191 	hwdep->ops = ops;
192 	hwdep->private_data = bebob;
193 	hwdep->exclusive = true;
194 end:
195 	return err;
196 }
197 
198