1/*
2 * Copyright (c) 2017, Linaro Ltd. All rights reserved.
3 *
4 * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18#include <linux/clk.h>
19#include <linux/interrupt.h>
20#include <linux/of.h>
21#include <linux/of_address.h>
22#include <linux/of_irq.h>
23#include <linux/slab.h>
24
25#include "timer-of.h"
26
27/**
28 * timer_of_irq_exit - Release the interrupt
29 * @of_irq: an of_timer_irq structure pointer
30 *
31 * Free the irq resource
32 */
33static __init void timer_of_irq_exit(struct of_timer_irq *of_irq)
34{
35 struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
36
37 struct clock_event_device *clkevt = &to->clkevt;
38
39 of_irq->percpu ? free_percpu_irq(of_irq->irq, clkevt) :
40 free_irq(of_irq->irq, clkevt);
41}
42
43/**
44 * timer_of_irq_init - Request the interrupt
45 * @np: a device tree node pointer
46 * @of_irq: an of_timer_irq structure pointer
47 *
48 * Get the interrupt number from the DT from its definition and
49 * request it. The interrupt is gotten by falling back the following way:
50 *
51 * - Get interrupt number by name
52 * - Get interrupt number by index
53 *
54 * When the interrupt is per CPU, 'request_percpu_irq()' is called,
55 * otherwise 'request_irq()' is used.
56 *
57 * Returns 0 on success, < 0 otherwise
58 */
59static __init int timer_of_irq_init(struct device_node *np,
60 struct of_timer_irq *of_irq)
61{
62 int ret;
63 struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
64 struct clock_event_device *clkevt = &to->clkevt;
65
66 if (of_irq->name) {
67 of_irq->irq = ret = of_irq_get_byname(np, of_irq->name);
68 if (ret < 0) {
69 pr_err("Failed to get interrupt %s for %s\n",
70 of_irq->name, np->full_name);
71 return ret;
72 }
73 } else {
74 of_irq->irq = irq_of_parse_and_map(np, of_irq->index);
75 }
76 if (!of_irq->irq) {
77 pr_err("Failed to map interrupt for %pOF\n", np);
78 return -EINVAL;
79 }
80
81 ret = of_irq->percpu ?
82 request_percpu_irq(of_irq->irq, of_irq->handler,
83 np->full_name, clkevt) :
84 request_irq(of_irq->irq, of_irq->handler,
85 of_irq->flags ? of_irq->flags : IRQF_TIMER,
86 np->full_name, clkevt);
87 if (ret) {
88 pr_err("Failed to request irq %d for %pOF\n", of_irq->irq, np);
89 return ret;
90 }
91
92 clkevt->irq = of_irq->irq;
93
94 return 0;
95}
96
97/**
98 * timer_of_clk_exit - Release the clock resources
99 * @of_clk: a of_timer_clk structure pointer
100 *
101 * Disables and releases the refcount on the clk
102 */
103static __init void timer_of_clk_exit(struct of_timer_clk *of_clk)
104{
105 of_clk->rate = 0;
106 clk_disable_unprepare(of_clk->clk);
107 clk_put(of_clk->clk);
108}
109
110/**
111 * timer_of_clk_init - Initialize the clock resources
112 * @np: a device tree node pointer
113 * @of_clk: a of_timer_clk structure pointer
114 *
115 * Get the clock by name or by index, enable it and get the rate
116 *
117 * Returns 0 on success, < 0 otherwise
118 */
119static __init int timer_of_clk_init(struct device_node *np,
120 struct of_timer_clk *of_clk)
121{
122 int ret;
123
124 of_clk->clk = of_clk->name ? of_clk_get_by_name(np, of_clk->name) :
125 of_clk_get(np, of_clk->index);
126 if (IS_ERR(of_clk->clk)) {
127 pr_err("Failed to get clock for %pOF\n", np);
128 return PTR_ERR(of_clk->clk);
129 }
130
131 ret = clk_prepare_enable(of_clk->clk);
132 if (ret) {
133 pr_err("Failed for enable clock for %pOF\n", np);
134 goto out_clk_put;
135 }
136
137 of_clk->rate = clk_get_rate(of_clk->clk);
138 if (!of_clk->rate) {
139 ret = -EINVAL;
140 pr_err("Failed to get clock rate for %pOF\n", np);
141 goto out_clk_disable;
142 }
143
144 of_clk->period = DIV_ROUND_UP(of_clk->rate, HZ);
145out:
146 return ret;
147
148out_clk_disable:
149 clk_disable_unprepare(of_clk->clk);
150out_clk_put:
151 clk_put(of_clk->clk);
152
153 goto out;
154}
155
156static __init void timer_of_base_exit(struct of_timer_base *of_base)
157{
158 iounmap(of_base->base);
159}
160
161static __init int timer_of_base_init(struct device_node *np,
162 struct of_timer_base *of_base)
163{
164 of_base->base = of_base->name ?
165 of_io_request_and_map(np, of_base->index, of_base->name) :
166 of_iomap(np, of_base->index);
167 if (IS_ERR(of_base->base)) {
168 pr_err("Failed to iomap (%s)\n", of_base->name);
169 return PTR_ERR(of_base->base);
170 }
171
172 return 0;
173}
174
175int __init timer_of_init(struct device_node *np, struct timer_of *to)
176{
177 int ret = -EINVAL;
178 int flags = 0;
179
180 if (to->flags & TIMER_OF_BASE) {
181 ret = timer_of_base_init(np, &to->of_base);
182 if (ret)
183 goto out_fail;
184 flags |= TIMER_OF_BASE;
185 }
186
187 if (to->flags & TIMER_OF_CLOCK) {
188 ret = timer_of_clk_init(np, &to->of_clk);
189 if (ret)
190 goto out_fail;
191 flags |= TIMER_OF_CLOCK;
192 }
193
194 if (to->flags & TIMER_OF_IRQ) {
195 ret = timer_of_irq_init(np, &to->of_irq);
196 if (ret)
197 goto out_fail;
198 flags |= TIMER_OF_IRQ;
199 }
200
201 if (!to->clkevt.name)
202 to->clkevt.name = np->name;
203
204 to->np = np;
205
206 return ret;
207
208out_fail:
209 if (flags & TIMER_OF_IRQ)
210 timer_of_irq_exit(&to->of_irq);
211
212 if (flags & TIMER_OF_CLOCK)
213 timer_of_clk_exit(&to->of_clk);
214
215 if (flags & TIMER_OF_BASE)
216 timer_of_base_exit(&to->of_base);
217 return ret;
218}
219
220/**
221 * timer_of_cleanup - release timer_of ressources
222 * @to: timer_of structure
223 *
224 * Release the ressources that has been used in timer_of_init().
225 * This function should be called in init error cases
226 */
227void __init timer_of_cleanup(struct timer_of *to)
228{
229 if (to->flags & TIMER_OF_IRQ)
230 timer_of_irq_exit(&to->of_irq);
231
232 if (to->flags & TIMER_OF_CLOCK)
233 timer_of_clk_exit(&to->of_clk);
234
235 if (to->flags & TIMER_OF_BASE)
236 timer_of_base_exit(&to->of_base);
237}
238