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