1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * dice_hwdep.c - a part of driver for DICE based devices
4 *
5 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
6 * Copyright (c) 2014 Takashi Sakamoto <o-takashi@sakamocchi.jp>
7 */
8
9#include "dice.h"
10
11static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf,
12 long count, loff_t *offset)
13{
14 struct snd_dice *dice = hwdep->private_data;
15 DEFINE_WAIT(wait);
16 union snd_firewire_event event;
17
18 spin_lock_irq(lock: &dice->lock);
19
20 while (!dice->dev_lock_changed && dice->notification_bits == 0) {
21 prepare_to_wait(wq_head: &dice->hwdep_wait, wq_entry: &wait, TASK_INTERRUPTIBLE);
22 spin_unlock_irq(lock: &dice->lock);
23 schedule();
24 finish_wait(wq_head: &dice->hwdep_wait, wq_entry: &wait);
25 if (signal_pending(current))
26 return -ERESTARTSYS;
27 spin_lock_irq(lock: &dice->lock);
28 }
29
30 memset(&event, 0, sizeof(event));
31 if (dice->dev_lock_changed) {
32 event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
33 event.lock_status.status = dice->dev_lock_count > 0;
34 dice->dev_lock_changed = false;
35
36 count = min_t(long, count, sizeof(event.lock_status));
37 } else {
38 event.dice_notification.type =
39 SNDRV_FIREWIRE_EVENT_DICE_NOTIFICATION;
40 event.dice_notification.notification = dice->notification_bits;
41 dice->notification_bits = 0;
42
43 count = min_t(long, count, sizeof(event.dice_notification));
44 }
45
46 spin_unlock_irq(lock: &dice->lock);
47
48 if (copy_to_user(to: buf, from: &event, n: count))
49 return -EFAULT;
50
51 return count;
52}
53
54static __poll_t hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
55 poll_table *wait)
56{
57 struct snd_dice *dice = hwdep->private_data;
58
59 poll_wait(filp: file, wait_address: &dice->hwdep_wait, p: wait);
60
61 guard(spinlock_irq)(l: &dice->lock);
62 if (dice->dev_lock_changed || dice->notification_bits != 0)
63 return EPOLLIN | EPOLLRDNORM;
64 else
65 return 0;
66}
67
68static int hwdep_get_info(struct snd_dice *dice, void __user *arg)
69{
70 struct fw_device *dev = fw_parent_device(dice->unit);
71 struct snd_firewire_get_info info;
72
73 memset(&info, 0, sizeof(info));
74 info.type = SNDRV_FIREWIRE_TYPE_DICE;
75 info.card = dev->card->index;
76 *(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
77 *(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
78 strscpy(info.device_name, dev_name(&dev->device),
79 sizeof(info.device_name));
80
81 if (copy_to_user(to: arg, from: &info, n: sizeof(info)))
82 return -EFAULT;
83
84 return 0;
85}
86
87static int hwdep_lock(struct snd_dice *dice)
88{
89 guard(spinlock_irq)(l: &dice->lock);
90
91 if (dice->dev_lock_count == 0) {
92 dice->dev_lock_count = -1;
93 return 0;
94 } else {
95 return -EBUSY;
96 }
97}
98
99static int hwdep_unlock(struct snd_dice *dice)
100{
101 guard(spinlock_irq)(l: &dice->lock);
102
103 if (dice->dev_lock_count == -1) {
104 dice->dev_lock_count = 0;
105 return 0;
106 } else {
107 return -EBADFD;
108 }
109}
110
111static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
112{
113 struct snd_dice *dice = hwdep->private_data;
114
115 guard(spinlock_irq)(l: &dice->lock);
116 if (dice->dev_lock_count == -1)
117 dice->dev_lock_count = 0;
118
119 return 0;
120}
121
122static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
123 unsigned int cmd, unsigned long arg)
124{
125 struct snd_dice *dice = hwdep->private_data;
126
127 switch (cmd) {
128 case SNDRV_FIREWIRE_IOCTL_GET_INFO:
129 return hwdep_get_info(dice, arg: (void __user *)arg);
130 case SNDRV_FIREWIRE_IOCTL_LOCK:
131 return hwdep_lock(dice);
132 case SNDRV_FIREWIRE_IOCTL_UNLOCK:
133 return hwdep_unlock(dice);
134 default:
135 return -ENOIOCTLCMD;
136 }
137}
138
139#ifdef CONFIG_COMPAT
140static int hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
141 unsigned int cmd, unsigned long arg)
142{
143 return hwdep_ioctl(hwdep, file, cmd,
144 arg: (unsigned long)compat_ptr(uptr: arg));
145}
146#else
147#define hwdep_compat_ioctl NULL
148#endif
149
150int snd_dice_create_hwdep(struct snd_dice *dice)
151{
152 static const struct snd_hwdep_ops ops = {
153 .read = hwdep_read,
154 .release = hwdep_release,
155 .poll = hwdep_poll,
156 .ioctl = hwdep_ioctl,
157 .ioctl_compat = hwdep_compat_ioctl,
158 };
159 struct snd_hwdep *hwdep;
160 int err;
161
162 err = snd_hwdep_new(card: dice->card, id: "DICE", device: 0, rhwdep: &hwdep);
163 if (err < 0)
164 return err;
165 strscpy(hwdep->name, "DICE");
166 hwdep->iface = SNDRV_HWDEP_IFACE_FW_DICE;
167 hwdep->ops = ops;
168 hwdep->private_data = dice;
169 hwdep->exclusive = true;
170
171 return 0;
172}
173

source code of linux/sound/firewire/dice/dice-hwdep.c