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 	event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
39 	event.lock_status.status = (ff->dev_lock_count > 0);
40 	ff->dev_lock_changed = false;
41 
42 	count = min_t(long, count, sizeof(event.lock_status));
43 
44 	spin_unlock_irq(&ff->lock);
45 
46 	if (copy_to_user(buf, &event, count))
47 		return -EFAULT;
48 
49 	return count;
50 }
51 
52 static __poll_t hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
53 			       poll_table *wait)
54 {
55 	struct snd_ff *ff = hwdep->private_data;
56 	__poll_t events;
57 
58 	poll_wait(file, &ff->hwdep_wait, wait);
59 
60 	spin_lock_irq(&ff->lock);
61 	if (ff->dev_lock_changed)
62 		events = EPOLLIN | EPOLLRDNORM;
63 	else
64 		events = 0;
65 	spin_unlock_irq(&ff->lock);
66 
67 	return events;
68 }
69 
70 static int hwdep_get_info(struct snd_ff *ff, void __user *arg)
71 {
72 	struct fw_device *dev = fw_parent_device(ff->unit);
73 	struct snd_firewire_get_info info;
74 
75 	memset(&info, 0, sizeof(info));
76 	info.type = SNDRV_FIREWIRE_TYPE_FIREFACE;
77 	info.card = dev->card->index;
78 	*(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
79 	*(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
80 	strscpy(info.device_name, dev_name(&dev->device),
81 		sizeof(info.device_name));
82 
83 	if (copy_to_user(arg, &info, sizeof(info)))
84 		return -EFAULT;
85 
86 	return 0;
87 }
88 
89 static int hwdep_lock(struct snd_ff *ff)
90 {
91 	int err;
92 
93 	spin_lock_irq(&ff->lock);
94 
95 	if (ff->dev_lock_count == 0) {
96 		ff->dev_lock_count = -1;
97 		err = 0;
98 	} else {
99 		err = -EBUSY;
100 	}
101 
102 	spin_unlock_irq(&ff->lock);
103 
104 	return err;
105 }
106 
107 static int hwdep_unlock(struct snd_ff *ff)
108 {
109 	int err;
110 
111 	spin_lock_irq(&ff->lock);
112 
113 	if (ff->dev_lock_count == -1) {
114 		ff->dev_lock_count = 0;
115 		err = 0;
116 	} else {
117 		err = -EBADFD;
118 	}
119 
120 	spin_unlock_irq(&ff->lock);
121 
122 	return err;
123 }
124 
125 static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
126 {
127 	struct snd_ff *ff = hwdep->private_data;
128 
129 	spin_lock_irq(&ff->lock);
130 	if (ff->dev_lock_count == -1)
131 		ff->dev_lock_count = 0;
132 	spin_unlock_irq(&ff->lock);
133 
134 	return 0;
135 }
136 
137 static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
138 		       unsigned int cmd, unsigned long arg)
139 {
140 	struct snd_ff *ff = hwdep->private_data;
141 
142 	switch (cmd) {
143 	case SNDRV_FIREWIRE_IOCTL_GET_INFO:
144 		return hwdep_get_info(ff, (void __user *)arg);
145 	case SNDRV_FIREWIRE_IOCTL_LOCK:
146 		return hwdep_lock(ff);
147 	case SNDRV_FIREWIRE_IOCTL_UNLOCK:
148 		return hwdep_unlock(ff);
149 	default:
150 		return -ENOIOCTLCMD;
151 	}
152 }
153 
154 #ifdef CONFIG_COMPAT
155 static int hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
156 			      unsigned int cmd, unsigned long arg)
157 {
158 	return hwdep_ioctl(hwdep, file, cmd,
159 			   (unsigned long)compat_ptr(arg));
160 }
161 #else
162 #define hwdep_compat_ioctl NULL
163 #endif
164 
165 int snd_ff_create_hwdep_devices(struct snd_ff *ff)
166 {
167 	static const struct snd_hwdep_ops hwdep_ops = {
168 		.read		= hwdep_read,
169 		.release	= hwdep_release,
170 		.poll		= hwdep_poll,
171 		.ioctl		= hwdep_ioctl,
172 		.ioctl_compat	= hwdep_compat_ioctl,
173 	};
174 	struct snd_hwdep *hwdep;
175 	int err;
176 
177 	err = snd_hwdep_new(ff->card, ff->card->driver, 0, &hwdep);
178 	if (err < 0)
179 		return err;
180 
181 	strcpy(hwdep->name, ff->card->driver);
182 	hwdep->iface = SNDRV_HWDEP_IFACE_FW_FIREFACE;
183 	hwdep->ops = hwdep_ops;
184 	hwdep->private_data = ff;
185 	hwdep->exclusive = true;
186 
187 	return 0;
188 }
189