bebob_hwdep.c

  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
 18static long
 19hwdep_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
 52static __poll_t
 53hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait)
 54{
 55	struct snd_bebob *bebob = hwdep->private_data;
 56
 57	poll_wait(file, &bebob->hwdep_wait, wait);
 58
 59	guard(spinlock_irq)(&bebob->lock);
 60	if (bebob->dev_lock_changed)
 61		return EPOLLIN | EPOLLRDNORM;
 62	else
 63		return 0;
 64}
 65
 66static int
 67hwdep_get_info(struct snd_bebob *bebob, void __user *arg)
 68{
 69	struct fw_device *dev = fw_parent_device(bebob->unit);
 70	struct snd_firewire_get_info info;
 71
 72	memset(&info, 0, sizeof(info));
 73	info.type = SNDRV_FIREWIRE_TYPE_BEBOB;
 74	info.card = dev->card->index;
 75	*(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
 76	*(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
 77	strscpy(info.device_name, dev_name(&dev->device),
 78		sizeof(info.device_name));
 79
 80	if (copy_to_user(arg, &info, sizeof(info)))
 81		return -EFAULT;
 82
 83	return 0;
 84}
 85
 86static int
 87hwdep_lock(struct snd_bebob *bebob)
 88{
 89	guard(spinlock_irq)(&bebob->lock);
 90
 91	if (bebob->dev_lock_count == 0) {
 92		bebob->dev_lock_count = -1;
 93		return 0;
 94	} else {
 95		return -EBUSY;
 96	}
 97}
 98
 99static int
100hwdep_unlock(struct snd_bebob *bebob)
101{
102	guard(spinlock_irq)(&bebob->lock);
103
104	if (bebob->dev_lock_count == -1) {
105		bebob->dev_lock_count = 0;
106		return 0;
107	} else {
108		return -EBADFD;
109	}
110}
111
112static int
113hwdep_release(struct snd_hwdep *hwdep, struct file *file)
114{
115	struct snd_bebob *bebob = hwdep->private_data;
116
117	guard(spinlock_irq)(&bebob->lock);
118	if (bebob->dev_lock_count == -1)
119		bebob->dev_lock_count = 0;
120
121	return 0;
122}
123
124static int
125hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
126	    unsigned int cmd, unsigned long arg)
127{
128	struct snd_bebob *bebob = hwdep->private_data;
129
130	switch (cmd) {
131	case SNDRV_FIREWIRE_IOCTL_GET_INFO:
132		return hwdep_get_info(bebob, (void __user *)arg);
133	case SNDRV_FIREWIRE_IOCTL_LOCK:
134		return hwdep_lock(bebob);
135	case SNDRV_FIREWIRE_IOCTL_UNLOCK:
136		return hwdep_unlock(bebob);
137	default:
138		return -ENOIOCTLCMD;
139	}
140}
141
142#ifdef CONFIG_COMPAT
143static int
144hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
145		   unsigned int cmd, unsigned long arg)
146{
147	return hwdep_ioctl(hwdep, file, cmd,
148			   (unsigned long)compat_ptr(arg));
149}
150#else
151#define hwdep_compat_ioctl NULL
152#endif
153
154int snd_bebob_create_hwdep_device(struct snd_bebob *bebob)
155{
156	static const struct snd_hwdep_ops ops = {
157		.read		= hwdep_read,
158		.release	= hwdep_release,
159		.poll		= hwdep_poll,
160		.ioctl		= hwdep_ioctl,
161		.ioctl_compat	= hwdep_compat_ioctl,
162	};
163	struct snd_hwdep *hwdep;
164	int err;
165
166	err = snd_hwdep_new(bebob->card, "BeBoB", 0, &hwdep);
167	if (err < 0)
168		goto end;
169	strscpy(hwdep->name, "BeBoB");
170	hwdep->iface = SNDRV_HWDEP_IFACE_FW_BEBOB;
171	hwdep->ops = ops;
172	hwdep->private_data = bebob;
173	hwdep->exclusive = true;
174end:
175	return err;
176}
177