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  */
22 static __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  */
50 static __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(np, 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(np, 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(of_irq->irq, of_irq->handler,
74 				   np->full_name, clkevt) :
75 		request_irq(of_irq->irq, of_irq->handler,
76 			    of_irq->flags ? of_irq->flags : IRQF_TIMER,
77 			    np->full_name, 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  */
94 static __init void timer_of_clk_exit(struct of_timer_clk *of_clk)
95 {
96 	of_clk->rate = 0;
97 	clk_disable_unprepare(of_clk->clk);
98 	clk_put(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  */
110 static __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, of_clk->name) :
116 		of_clk_get(np, of_clk->index);
117 	if (IS_ERR(of_clk->clk)) {
118 		ret = PTR_ERR(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(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(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);
138 out:
139 	return ret;
140 
141 out_clk_disable:
142 	clk_disable_unprepare(of_clk->clk);
143 out_clk_put:
144 	clk_put(of_clk->clk);
145 
146 	goto out;
147 }
148 
149 static __init void timer_of_base_exit(struct of_timer_base *of_base)
150 {
151 	iounmap(of_base->base);
152 }
153 
154 static __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(np, of_base->index, of_base->name) :
159 		of_iomap(np, of_base->index);
160 	if (IS_ERR(of_base->base)) {
161 		pr_err("Failed to iomap (%s)\n", of_base->name);
162 		return PTR_ERR(of_base->base);
163 	}
164 
165 	return 0;
166 }
167 
168 int __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, &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, &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, &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 
201 out_fail:
202 	if (flags & TIMER_OF_IRQ)
203 		timer_of_irq_exit(&to->of_irq);
204 
205 	if (flags & TIMER_OF_CLOCK)
206 		timer_of_clk_exit(&to->of_clk);
207 
208 	if (flags & TIMER_OF_BASE)
209 		timer_of_base_exit(&to->of_base);
210 	return ret;
211 }
212 
213 /**
214  * timer_of_cleanup - release timer_of ressources
215  * @to: timer_of structure
216  *
217  * Release the ressources that has been used in timer_of_init().
218  * This function should be called in init error cases
219  */
220 void __init timer_of_cleanup(struct timer_of *to)
221 {
222 	if (to->flags & TIMER_OF_IRQ)
223 		timer_of_irq_exit(&to->of_irq);
224 
225 	if (to->flags & TIMER_OF_CLOCK)
226 		timer_of_clk_exit(&to->of_clk);
227 
228 	if (to->flags & TIMER_OF_BASE)
229 		timer_of_base_exit(&to->of_base);
230 }
231