1 /* $NetBSD: linux_irq_work.c,v 1.2 2021/12/19 11:50:54 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2021 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __KERNEL_RCSID(0, "$NetBSD: linux_irq_work.c,v 1.2 2021/12/19 11:50:54 riastradh Exp $");
34
35 #include <sys/param.h>
36
37 #include <sys/atomic.h>
38 #include <sys/intr.h>
39 #include <sys/kmem.h>
40 #include <sys/mutex.h>
41 #include <sys/percpu.h>
42 #include <sys/queue.h>
43
44 #include <linux/irq_work.h>
45
46 struct irq_work_cpu {
47 kmutex_t iwc_lock;
48 SIMPLEQ_HEAD(, irq_work) iwc_todo;
49 };
50
51 enum {
52 IRQ_WORK_PENDING = 1,
53 };
54
55 static struct percpu *irq_work_percpu;
56 static void *irq_work_sih __read_mostly;
57
58 static void
irq_work_intr(void * cookie)59 irq_work_intr(void *cookie)
60 {
61 struct irq_work_cpu *const *iwcp, *iwc;
62 SIMPLEQ_HEAD(, irq_work) todo = SIMPLEQ_HEAD_INITIALIZER(todo);
63 struct irq_work *iw, *next;
64
65 iwcp = percpu_getref(irq_work_percpu);
66 iwc = *iwcp;
67 mutex_spin_enter(&iwc->iwc_lock);
68 SIMPLEQ_CONCAT(&todo, &iwc->iwc_todo);
69 mutex_spin_exit(&iwc->iwc_lock);
70 percpu_putref(irq_work_percpu);
71
72 SIMPLEQ_FOREACH_SAFE(iw, &todo, iw_entry, next) {
73 atomic_store_relaxed(&iw->iw_flags, 0);
74 (*iw->func)(iw);
75 }
76 }
77
78 static void
irq_work_cpu_init(void * ptr,void * cookie,struct cpu_info * ci)79 irq_work_cpu_init(void *ptr, void *cookie, struct cpu_info *ci)
80 {
81 struct irq_work_cpu **iwcp = ptr, *iwc;
82
83 iwc = *iwcp = kmem_zalloc(sizeof(*iwc), KM_SLEEP);
84 mutex_init(&iwc->iwc_lock, MUTEX_DEFAULT, IPL_HIGH);
85 SIMPLEQ_INIT(&iwc->iwc_todo);
86 }
87
88 static void
irq_work_cpu_fini(void * ptr,void * cookie,struct cpu_info * ci)89 irq_work_cpu_fini(void *ptr, void *cookie, struct cpu_info *ci)
90 {
91 struct irq_work_cpu **iwcp = ptr, *iwc = *iwcp;
92
93 KASSERT(SIMPLEQ_EMPTY(&iwc->iwc_todo));
94 mutex_destroy(&iwc->iwc_lock);
95 kmem_free(iwc, sizeof(*iwc));
96 }
97
98 void
linux_irq_work_init(void)99 linux_irq_work_init(void)
100 {
101
102 irq_work_percpu = percpu_create(sizeof(struct irq_work_cpu),
103 irq_work_cpu_init, irq_work_cpu_fini, NULL);
104 irq_work_sih = softint_establish(SOFTINT_SERIAL|SOFTINT_MPSAFE,
105 irq_work_intr, NULL);
106 }
107
108 void
linux_irq_work_fini(void)109 linux_irq_work_fini(void)
110 {
111
112 softint_disestablish(irq_work_sih);
113 percpu_free(irq_work_percpu, sizeof(struct irq_work_cpu));
114 }
115
116 void
init_irq_work(struct irq_work * iw,void (* func)(struct irq_work *))117 init_irq_work(struct irq_work *iw, void (*func)(struct irq_work *))
118 {
119
120 iw->iw_flags = 0;
121 iw->func = func;
122 }
123
124 bool
irq_work_queue(struct irq_work * iw)125 irq_work_queue(struct irq_work *iw)
126 {
127 struct irq_work_cpu *const *iwcp, *iwc;
128
129 if (atomic_swap_uint(&iw->iw_flags, IRQ_WORK_PENDING)
130 & IRQ_WORK_PENDING)
131 return false;
132
133 iwcp = percpu_getref(irq_work_percpu);
134 iwc = *iwcp;
135 mutex_spin_enter(&iwc->iwc_lock);
136 SIMPLEQ_INSERT_TAIL(&iwc->iwc_todo, iw, iw_entry);
137 mutex_spin_exit(&iwc->iwc_lock);
138 softint_schedule(irq_work_sih);
139 percpu_putref(irq_work_percpu);
140
141 return true;
142 }
143