drivers/clocksource/timer-of.c

   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 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  */
 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 }