xref: /openbmc/linux/sound/core/misc.c (revision baf2c002)
1  // SPDX-License-Identifier: GPL-2.0-or-later
2  /*
3   *  Misc and compatibility things
4   *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5   */
6  
7  #include <linux/init.h>
8  #include <linux/export.h>
9  #include <linux/moduleparam.h>
10  #include <linux/time.h>
11  #include <linux/slab.h>
12  #include <linux/ioport.h>
13  #include <linux/fs.h>
14  #include <sound/core.h>
15  
16  #ifdef CONFIG_SND_DEBUG
17  
18  #ifdef CONFIG_SND_DEBUG_VERBOSE
19  #define DEFAULT_DEBUG_LEVEL	2
20  #else
21  #define DEFAULT_DEBUG_LEVEL	1
22  #endif
23  
24  static int debug = DEFAULT_DEBUG_LEVEL;
25  module_param(debug, int, 0644);
26  MODULE_PARM_DESC(debug, "Debug level (0 = disable)");
27  
28  #endif /* CONFIG_SND_DEBUG */
29  
30  void release_and_free_resource(struct resource *res)
31  {
32  	if (res) {
33  		release_resource(res);
34  		kfree(res);
35  	}
36  }
37  EXPORT_SYMBOL(release_and_free_resource);
38  
39  #ifdef CONFIG_SND_VERBOSE_PRINTK
40  /* strip the leading path if the given path is absolute */
41  static const char *sanity_file_name(const char *path)
42  {
43  	if (*path == '/')
44  		return strrchr(path, '/') + 1;
45  	else
46  		return path;
47  }
48  #endif
49  
50  #if defined(CONFIG_SND_DEBUG) || defined(CONFIG_SND_VERBOSE_PRINTK)
51  void __snd_printk(unsigned int level, const char *path, int line,
52  		  const char *format, ...)
53  {
54  	va_list args;
55  #ifdef CONFIG_SND_VERBOSE_PRINTK
56  	int kern_level;
57  	struct va_format vaf;
58  	char verbose_fmt[] = KERN_DEFAULT "ALSA %s:%d %pV";
59  	bool level_found = false;
60  #endif
61  
62  #ifdef CONFIG_SND_DEBUG
63  	if (debug < level)
64  		return;
65  #endif
66  
67  	va_start(args, format);
68  #ifdef CONFIG_SND_VERBOSE_PRINTK
69  	vaf.fmt = format;
70  	vaf.va = &args;
71  
72  	while ((kern_level = printk_get_level(vaf.fmt)) != 0) {
73  		const char *end_of_header = printk_skip_level(vaf.fmt);
74  
75  		/* Ignore KERN_CONT. We print filename:line for each piece. */
76  		if (kern_level >= '0' && kern_level <= '7') {
77  			memcpy(verbose_fmt, vaf.fmt, end_of_header - vaf.fmt);
78  			level_found = true;
79  		}
80  
81  		vaf.fmt = end_of_header;
82  	}
83  
84  	if (!level_found && level)
85  		memcpy(verbose_fmt, KERN_DEBUG, sizeof(KERN_DEBUG) - 1);
86  
87  	printk(verbose_fmt, sanity_file_name(path), line, &vaf);
88  #else
89  	vprintk(format, args);
90  #endif
91  	va_end(args);
92  }
93  EXPORT_SYMBOL_GPL(__snd_printk);
94  #endif
95  
96  #ifdef CONFIG_PCI
97  #include <linux/pci.h>
98  /**
99   * snd_pci_quirk_lookup_id - look up a PCI SSID quirk list
100   * @vendor: PCI SSV id
101   * @device: PCI SSD id
102   * @list: quirk list, terminated by a null entry
103   *
104   * Look through the given quirk list and finds a matching entry
105   * with the same PCI SSID.  When subdevice is 0, all subdevice
106   * values may match.
107   *
108   * Returns the matched entry pointer, or NULL if nothing matched.
109   */
110  const struct snd_pci_quirk *
111  snd_pci_quirk_lookup_id(u16 vendor, u16 device,
112  			const struct snd_pci_quirk *list)
113  {
114  	const struct snd_pci_quirk *q;
115  
116  	for (q = list; q->subvendor || q->subdevice; q++) {
117  		if (q->subvendor != vendor)
118  			continue;
119  		if (!q->subdevice ||
120  		    (device & q->subdevice_mask) == q->subdevice)
121  			return q;
122  	}
123  	return NULL;
124  }
125  EXPORT_SYMBOL(snd_pci_quirk_lookup_id);
126  
127  /**
128   * snd_pci_quirk_lookup - look up a PCI SSID quirk list
129   * @pci: pci_dev handle
130   * @list: quirk list, terminated by a null entry
131   *
132   * Look through the given quirk list and finds a matching entry
133   * with the same PCI SSID.  When subdevice is 0, all subdevice
134   * values may match.
135   *
136   * Returns the matched entry pointer, or NULL if nothing matched.
137   */
138  const struct snd_pci_quirk *
139  snd_pci_quirk_lookup(struct pci_dev *pci, const struct snd_pci_quirk *list)
140  {
141  	if (!pci)
142  		return NULL;
143  	return snd_pci_quirk_lookup_id(pci->subsystem_vendor,
144  				       pci->subsystem_device,
145  				       list);
146  }
147  EXPORT_SYMBOL(snd_pci_quirk_lookup);
148  #endif
149  
150  /*
151   * Deferred async signal helpers
152   *
153   * Below are a few helper functions to wrap the async signal handling
154   * in the deferred work.  The main purpose is to avoid the messy deadlock
155   * around tasklist_lock and co at the kill_fasync() invocation.
156   * fasync_helper() and kill_fasync() are replaced with snd_fasync_helper()
157   * and snd_kill_fasync(), respectively.  In addition, snd_fasync_free() has
158   * to be called at releasing the relevant file object.
159   */
160  struct snd_fasync {
161  	struct fasync_struct *fasync;
162  	int signal;
163  	int poll;
164  	int on;
165  	struct list_head list;
166  };
167  
168  static DEFINE_SPINLOCK(snd_fasync_lock);
169  static LIST_HEAD(snd_fasync_list);
170  
171  static void snd_fasync_work_fn(struct work_struct *work)
172  {
173  	struct snd_fasync *fasync;
174  
175  	spin_lock_irq(&snd_fasync_lock);
176  	while (!list_empty(&snd_fasync_list)) {
177  		fasync = list_first_entry(&snd_fasync_list, struct snd_fasync, list);
178  		list_del_init(&fasync->list);
179  		spin_unlock_irq(&snd_fasync_lock);
180  		if (fasync->on)
181  			kill_fasync(&fasync->fasync, fasync->signal, fasync->poll);
182  		spin_lock_irq(&snd_fasync_lock);
183  	}
184  	spin_unlock_irq(&snd_fasync_lock);
185  }
186  
187  static DECLARE_WORK(snd_fasync_work, snd_fasync_work_fn);
188  
189  int snd_fasync_helper(int fd, struct file *file, int on,
190  		      struct snd_fasync **fasyncp)
191  {
192  	struct snd_fasync *fasync = NULL;
193  
194  	if (on) {
195  		fasync = kzalloc(sizeof(*fasync), GFP_KERNEL);
196  		if (!fasync)
197  			return -ENOMEM;
198  		INIT_LIST_HEAD(&fasync->list);
199  	}
200  
201  	spin_lock_irq(&snd_fasync_lock);
202  	if (*fasyncp) {
203  		kfree(fasync);
204  		fasync = *fasyncp;
205  	} else {
206  		if (!fasync) {
207  			spin_unlock_irq(&snd_fasync_lock);
208  			return 0;
209  		}
210  		*fasyncp = fasync;
211  	}
212  	fasync->on = on;
213  	spin_unlock_irq(&snd_fasync_lock);
214  	return fasync_helper(fd, file, on, &fasync->fasync);
215  }
216  EXPORT_SYMBOL_GPL(snd_fasync_helper);
217  
218  void snd_kill_fasync(struct snd_fasync *fasync, int signal, int poll)
219  {
220  	unsigned long flags;
221  
222  	if (!fasync || !fasync->on)
223  		return;
224  	spin_lock_irqsave(&snd_fasync_lock, flags);
225  	fasync->signal = signal;
226  	fasync->poll = poll;
227  	list_move(&fasync->list, &snd_fasync_list);
228  	schedule_work(&snd_fasync_work);
229  	spin_unlock_irqrestore(&snd_fasync_lock, flags);
230  }
231  EXPORT_SYMBOL_GPL(snd_kill_fasync);
232  
233  void snd_fasync_free(struct snd_fasync *fasync)
234  {
235  	if (!fasync)
236  		return;
237  	fasync->on = 0;
238  	flush_work(&snd_fasync_work);
239  	kfree(fasync);
240  }
241  EXPORT_SYMBOL_GPL(snd_fasync_free);
242