1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2017, Linaro Ltd. All rights reserved.
4 *
5 * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
6 */
7#include <linux/clk.h>
8#include <linux/interrupt.h>
9#include <linux/of.h>
10#include <linux/of_address.h>
11#include <linux/of_irq.h>
12#include <linux/slab.h>
13
14#include "timer-of.h"
15
16/**
17 * timer_of_irq_exit - Release the interrupt
18 * @of_irq: an of_timer_irq structure pointer
19 *
20 * Free the irq resource
21 */
22static __init void timer_of_irq_exit(struct of_timer_irq *of_irq)
23{
24 struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
25
26 struct clock_event_device *clkevt = &to->clkevt;
27
28 if (of_irq->percpu)
29 free_percpu_irq(of_irq->irq, clkevt);
30 else
31 free_irq(of_irq->irq, clkevt);
32}
33
34/**
35 * timer_of_irq_init - Request the interrupt
36 * @np: a device tree node pointer
37 * @of_irq: an of_timer_irq structure pointer
38 *
39 * Get the interrupt number from the DT from its definition and
40 * request it. The interrupt is gotten by falling back the following way:
41 *
42 * - Get interrupt number by name
43 * - Get interrupt number by index
44 *
45 * When the interrupt is per CPU, 'request_percpu_irq()' is called,
46 * otherwise 'request_irq()' is used.
47 *
48 * Returns 0 on success, < 0 otherwise
49 */
50static __init int timer_of_irq_init(struct device_node *np,
51 struct of_timer_irq *of_irq)
52{
53 int ret;
54 struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
55 struct clock_event_device *clkevt = &to->clkevt;
56
57 if (of_irq->name) {
58 of_irq->irq = ret = of_irq_get_byname(dev: np, name: of_irq->name);
59 if (ret < 0) {
60 pr_err("Failed to get interrupt %s for %pOF\n",
61 of_irq->name, np);
62 return ret;
63 }
64 } else {
65 of_irq->irq = irq_of_parse_and_map(node: np, index: of_irq->index);
66 }
67 if (!of_irq->irq) {
68 pr_err("Failed to map interrupt for %pOF\n", np);
69 return -EINVAL;
70 }
71
72 ret = of_irq->percpu ?
73 request_percpu_irq(irq: of_irq->irq, handler: of_irq->handler,
74 devname: np->full_name, percpu_dev_id: clkevt) :
75 request_irq(irq: of_irq->irq, handler: of_irq->handler,
76 flags: of_irq->flags ? of_irq->flags : IRQF_TIMER,
77 name: np->full_name, dev: clkevt);
78 if (ret) {
79 pr_err("Failed to request irq %d for %pOF\n", of_irq->irq, np);
80 return ret;
81 }
82
83 clkevt->irq = of_irq->irq;
84
85 return 0;
86}
87
88/**
89 * timer_of_clk_exit - Release the clock resources
90 * @of_clk: a of_timer_clk structure pointer
91 *
92 * Disables and releases the refcount on the clk
93 */
94static __init void timer_of_clk_exit(struct of_timer_clk *of_clk)
95{
96 of_clk->rate = 0;
97 clk_disable_unprepare(clk: of_clk->clk);
98 clk_put(clk: of_clk->clk);
99}
100
101/**
102 * timer_of_clk_init - Initialize the clock resources
103 * @np: a device tree node pointer
104 * @of_clk: a of_timer_clk structure pointer
105 *
106 * Get the clock by name or by index, enable it and get the rate
107 *
108 * Returns 0 on success, < 0 otherwise
109 */
110static __init int timer_of_clk_init(struct device_node *np,
111 struct of_timer_clk *of_clk)
112{
113 int ret;
114
115 of_clk->clk = of_clk->name ? of_clk_get_by_name(np, name: of_clk->name) :
116 of_clk_get(np, index: of_clk->index);
117 if (IS_ERR(ptr: of_clk->clk)) {
118 ret = PTR_ERR(ptr: of_clk->clk);
119 if (ret != -EPROBE_DEFER)
120 pr_err("Failed to get clock for %pOF\n", np);
121 goto out;
122 }
123
124 ret = clk_prepare_enable(clk: of_clk->clk);
125 if (ret) {
126 pr_err("Failed for enable clock for %pOF\n", np);
127 goto out_clk_put;
128 }
129
130 of_clk->rate = clk_get_rate(clk: of_clk->clk);
131 if (!of_clk->rate) {
132 ret = -EINVAL;
133 pr_err("Failed to get clock rate for %pOF\n", np);
134 goto out_clk_disable;
135 }
136
137 of_clk->period = DIV_ROUND_UP(of_clk->rate, HZ);
138out:
139 return ret;
140
141out_clk_disable:
142 clk_disable_unprepare(clk: of_clk->clk);
143out_clk_put:
144 clk_put(clk: of_clk->clk);
145
146 goto out;
147}
148
149static __init void timer_of_base_exit(struct of_timer_base *of_base)
150{
151 iounmap(addr: of_base->base);
152}
153
154static __init int timer_of_base_init(struct device_node *np,
155 struct of_timer_base *of_base)
156{
157 of_base->base = of_base->name ?
158 of_io_request_and_map(device: np, index: of_base->index, name: of_base->name) :
159 of_iomap(node: np, index: of_base->index);
160 if (IS_ERR_OR_NULL(ptr: of_base->base)) {
161 pr_err("Failed to iomap (%s:%s)\n", np->name, of_base->name);
162 return of_base->base ? PTR_ERR(ptr: of_base->base) : -ENOMEM;
163 }
164
165 return 0;
166}
167
168int __init timer_of_init(struct device_node *np, struct timer_of *to)
169{
170 int ret = -EINVAL;
171 int flags = 0;
172
173 if (to->flags & TIMER_OF_BASE) {
174 ret = timer_of_base_init(np, of_base: &to->of_base);
175 if (ret)
176 goto out_fail;
177 flags |= TIMER_OF_BASE;
178 }
179
180 if (to->flags & TIMER_OF_CLOCK) {
181 ret = timer_of_clk_init(np, of_clk: &to->of_clk);
182 if (ret)
183 goto out_fail;
184 flags |= TIMER_OF_CLOCK;
185 }
186
187 if (to->flags & TIMER_OF_IRQ) {
188 ret = timer_of_irq_init(np, of_irq: &to->of_irq);
189 if (ret)
190 goto out_fail;
191 flags |= TIMER_OF_IRQ;
192 }
193
194 if (!to->clkevt.name)
195 to->clkevt.name = np->full_name;
196
197 to->np = np;
198
199 return ret;
200
201out_fail:
202 if (flags & TIMER_OF_IRQ)
203 timer_of_irq_exit(of_irq: &to->of_irq);
204
205 if (flags & TIMER_OF_CLOCK)
206 timer_of_clk_exit(of_clk: &to->of_clk);
207
208 if (flags & TIMER_OF_BASE)
209 timer_of_base_exit(of_base: &to->of_base);
210 return ret;
211}
212
213/**
214 * timer_of_cleanup - release timer_of resources
215 * @to: timer_of structure
216 *
217 * Release the resources that has been used in timer_of_init().
218 * This function should be called in init error cases
219 */
220void __init timer_of_cleanup(struct timer_of *to)
221{
222 if (to->flags & TIMER_OF_IRQ)
223 timer_of_irq_exit(of_irq: &to->of_irq);
224
225 if (to->flags & TIMER_OF_CLOCK)
226 timer_of_clk_exit(of_clk: &to->of_clk);
227
228 if (to->flags & TIMER_OF_BASE)
229 timer_of_base_exit(of_base: &to->of_base);
230}
231

source code of linux/drivers/clocksource/timer-of.c