1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ff-hwdep.c - a part of driver for RME Fireface series
4  *
5  * Copyright (c) 2015-2017 Takashi Sakamoto
6  */
7 
8 /*
9  * This codes give three functionality.
10  *
11  * 1.get firewire node information
12  * 2.get notification about starting/stopping stream
13  * 3.lock/unlock stream
14  */
15 
16 #include "ff.h"
17 
18 static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
19 		       loff_t *offset)
20 {
21 	struct snd_ff *ff = hwdep->private_data;
22 	DEFINE_WAIT(wait);
23 	union snd_firewire_event event;
24 
25 	spin_lock_irq(&ff->lock);
26 
27 	while (!ff->dev_lock_changed) {
28 		prepare_to_wait(&ff->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
29 		spin_unlock_irq(&ff->lock);
30 		schedule();
31 		finish_wait(&ff->hwdep_wait, &wait);
32 		if (signal_pending(current))
33 			return -ERESTARTSYS;
34 		spin_lock_irq(&ff->lock);
35 	}
36 
37 	memset(&event, 0, sizeof(event));
38 	if (ff->dev_lock_changed) {
39 		event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
40 		event.lock_status.status = (ff->dev_lock_count > 0);
41 		ff->dev_lock_changed = false;
42 
43 		count = min_t(long, count, sizeof(event.lock_status));
44 	}
45 
46 	spin_unlock_irq(&ff->lock);
47 
48 	if (copy_to_user(buf, &event, count))
49 		return -EFAULT;
50 
51 	return count;
52 }
53 
54 static __poll_t hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
55 			       poll_table *wait)
56 {
57 	struct snd_ff *ff = hwdep->private_data;
58 	__poll_t events;
59 
60 	poll_wait(file, &ff->hwdep_wait, wait);
61 
62 	spin_lock_irq(&ff->lock);
63 	if (ff->dev_lock_changed)
64 		events = EPOLLIN | EPOLLRDNORM;
65 	else
66 		events = 0;
67 	spin_unlock_irq(&ff->lock);
68 
69 	return events;
70 }
71 
72 static int hwdep_get_info(struct snd_ff *ff, void __user *arg)
73 {
74 	struct fw_device *dev = fw_parent_device(ff->unit);
75 	struct snd_firewire_get_info info;
76 
77 	memset(&info, 0, sizeof(info));
78 	info.type = SNDRV_FIREWIRE_TYPE_FIREFACE;
79 	info.card = dev->card->index;
80 	*(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
81 	*(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
82 	strlcpy(info.device_name, dev_name(&dev->device),
83 		sizeof(info.device_name));
84 
85 	if (copy_to_user(arg, &info, sizeof(info)))
86 		return -EFAULT;
87 
88 	return 0;
89 }
90 
91 static int hwdep_lock(struct snd_ff *ff)
92 {
93 	int err;
94 
95 	spin_lock_irq(&ff->lock);
96 
97 	if (ff->dev_lock_count == 0) {
98 		ff->dev_lock_count = -1;
99 		err = 0;
100 	} else {
101 		err = -EBUSY;
102 	}
103 
104 	spin_unlock_irq(&ff->lock);
105 
106 	return err;
107 }
108 
109 static int hwdep_unlock(struct snd_ff *ff)
110 {
111 	int err;
112 
113 	spin_lock_irq(&ff->lock);
114 
115 	if (ff->dev_lock_count == -1) {
116 		ff->dev_lock_count = 0;
117 		err = 0;
118 	} else {
119 		err = -EBADFD;
120 	}
121 
122 	spin_unlock_irq(&ff->lock);
123 
124 	return err;
125 }
126 
127 static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
128 {
129 	struct snd_ff *ff = hwdep->private_data;
130 
131 	spin_lock_irq(&ff->lock);
132 	if (ff->dev_lock_count == -1)
133 		ff->dev_lock_count = 0;
134 	spin_unlock_irq(&ff->lock);
135 
136 	return 0;
137 }
138 
139 static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
140 		       unsigned int cmd, unsigned long arg)
141 {
142 	struct snd_ff *ff = hwdep->private_data;
143 
144 	switch (cmd) {
145 	case SNDRV_FIREWIRE_IOCTL_GET_INFO:
146 		return hwdep_get_info(ff, (void __user *)arg);
147 	case SNDRV_FIREWIRE_IOCTL_LOCK:
148 		return hwdep_lock(ff);
149 	case SNDRV_FIREWIRE_IOCTL_UNLOCK:
150 		return hwdep_unlock(ff);
151 	default:
152 		return -ENOIOCTLCMD;
153 	}
154 }
155 
156 #ifdef CONFIG_COMPAT
157 static int hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
158 			      unsigned int cmd, unsigned long arg)
159 {
160 	return hwdep_ioctl(hwdep, file, cmd,
161 			   (unsigned long)compat_ptr(arg));
162 }
163 #else
164 #define hwdep_compat_ioctl NULL
165 #endif
166 
167 int snd_ff_create_hwdep_devices(struct snd_ff *ff)
168 {
169 	static const struct snd_hwdep_ops hwdep_ops = {
170 		.read		= hwdep_read,
171 		.release	= hwdep_release,
172 		.poll		= hwdep_poll,
173 		.ioctl		= hwdep_ioctl,
174 		.ioctl_compat	= hwdep_compat_ioctl,
175 	};
176 	struct snd_hwdep *hwdep;
177 	int err;
178 
179 	err = snd_hwdep_new(ff->card, ff->card->driver, 0, &hwdep);
180 	if (err < 0)
181 		return err;
182 
183 	strcpy(hwdep->name, ff->card->driver);
184 	hwdep->iface = SNDRV_HWDEP_IFACE_FW_FIREFACE;
185 	hwdep->ops = hwdep_ops;
186 	hwdep->private_data = ff;
187 	hwdep->exclusive = true;
188 
189 	return 0;
190 }
191