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