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724117b7 | 1 | // SPDX-License-Identifier: GPL-2.0 |
fcc6ab33 SO |
2 | /* |
3 | * Functions for registration of I/O interruption subclasses on s390. | |
4 | * | |
5 | * Copyright IBM Corp. 2008 | |
6 | * Authors: Sebastian Ott <sebott@linux.vnet.ibm.com> | |
7 | */ | |
8 | ||
9 | #include <linux/spinlock.h> | |
10 | #include <linux/module.h> | |
11 | #include <asm/isc.h> | |
12 | ||
13 | static unsigned int isc_refs[MAX_ISC + 1]; | |
14 | static DEFINE_SPINLOCK(isc_ref_lock); | |
15 | ||
16 | ||
17 | /** | |
18 | * isc_register - register an I/O interruption subclass. | |
19 | * @isc: I/O interruption subclass to register | |
20 | * | |
21 | * The number of users for @isc is increased. If this is the first user to | |
22 | * register @isc, the corresponding I/O interruption subclass mask is enabled. | |
23 | * | |
24 | * Context: | |
25 | * This function must not be called in interrupt context. | |
26 | */ | |
27 | void isc_register(unsigned int isc) | |
28 | { | |
29 | if (isc > MAX_ISC) { | |
30 | WARN_ON(1); | |
31 | return; | |
32 | } | |
33 | ||
34 | spin_lock(&isc_ref_lock); | |
35 | if (isc_refs[isc] == 0) | |
36 | ctl_set_bit(6, 31 - isc); | |
37 | isc_refs[isc]++; | |
38 | spin_unlock(&isc_ref_lock); | |
39 | } | |
40 | EXPORT_SYMBOL_GPL(isc_register); | |
41 | ||
42 | /** | |
43 | * isc_unregister - unregister an I/O interruption subclass. | |
44 | * @isc: I/O interruption subclass to unregister | |
45 | * | |
46 | * The number of users for @isc is decreased. If this is the last user to | |
47 | * unregister @isc, the corresponding I/O interruption subclass mask is | |
48 | * disabled. | |
49 | * Note: This function must not be called if isc_register() hasn't been called | |
50 | * before by the driver for @isc. | |
51 | * | |
52 | * Context: | |
53 | * This function must not be called in interrupt context. | |
54 | */ | |
55 | void isc_unregister(unsigned int isc) | |
56 | { | |
57 | spin_lock(&isc_ref_lock); | |
58 | /* check for misuse */ | |
59 | if (isc > MAX_ISC || isc_refs[isc] == 0) { | |
60 | WARN_ON(1); | |
61 | goto out_unlock; | |
62 | } | |
63 | if (isc_refs[isc] == 1) | |
64 | ctl_clear_bit(6, 31 - isc); | |
65 | isc_refs[isc]--; | |
66 | out_unlock: | |
67 | spin_unlock(&isc_ref_lock); | |
68 | } | |
69 | EXPORT_SYMBOL_GPL(isc_unregister); |