drivers/clocksource/timer-of.c

   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 static __init void timer_irq_exit(struct of_timer_irq *of_irq)
  28 {
  29         struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
  30
  31         struct clock_event_device *clkevt = &to->clkevt;
  32
  33         of_irq->percpu ? free_percpu_irq(of_irq->irq, clkevt) :
  34                 free_irq(of_irq->irq, clkevt);
  35 }
  36
  37 static __init int timer_irq_init(struct device_node *np,
  38                                  struct of_timer_irq *of_irq)
  39 {
  40         int ret;
  41         struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
  42         struct clock_event_device *clkevt = &to->clkevt;
  43
  44         if (of_irq->name) {
  45                 of_irq->irq = ret = of_irq_get_byname(np, of_irq->name);
  46                 if (ret < 0) {
  47                         pr_err("Failed to get interrupt %s for %s\n",
  48                                of_irq->name, np->full_name);
  49                         return ret;
  50                 }
  51         } else  {
  52                 of_irq->irq = irq_of_parse_and_map(np, of_irq->index);
  53         }
  54         if (!of_irq->irq) {
  55                 pr_err("Failed to map interrupt for %pOF\n", np);
  56                 return -EINVAL;
  57         }
  58
  59         ret = of_irq->percpu ?
  60                 request_percpu_irq(of_irq->irq, of_irq->handler,
  61                                    np->full_name, clkevt) :
  62                 request_irq(of_irq->irq, of_irq->handler,
  63                             of_irq->flags ? of_irq->flags : IRQF_TIMER,
  64                             np->full_name, clkevt);
  65         if (ret) {
  66                 pr_err("Failed to request irq %d for %pOF\n", of_irq->irq, np);
  67                 return ret;
  68         }
  69
  70         clkevt->irq = of_irq->irq;
  71
  72         return 0;
  73 }
  74
  75 static __init void timer_clk_exit(struct of_timer_clk *of_clk)
  76 {
  77         of_clk->rate = 0;
  78         clk_disable_unprepare(of_clk->clk);
  79         clk_put(of_clk->clk);
  80 }
  81
  82 static __init int timer_clk_init(struct device_node *np,
  83                                  struct of_timer_clk *of_clk)
  84 {
  85         int ret;
  86
  87         of_clk->clk = of_clk->name ? of_clk_get_by_name(np, of_clk->name) :
  88                 of_clk_get(np, of_clk->index);
  89         if (IS_ERR(of_clk->clk)) {
  90                 pr_err("Failed to get clock for %pOF\n", np);
  91                 return PTR_ERR(of_clk->clk);
  92         }
  93
  94         ret = clk_prepare_enable(of_clk->clk);
  95         if (ret) {
  96                 pr_err("Failed for enable clock for %pOF\n", np);
  97                 goto out_clk_put;
  98         }
  99
 100         of_clk->rate = clk_get_rate(of_clk->clk);
 101         if (!of_clk->rate) {
 102                 ret = -EINVAL;
 103                 pr_err("Failed to get clock rate for %pOF\n", np);
 104                 goto out_clk_disable;
 105         }
 106
 107         of_clk->period = DIV_ROUND_UP(of_clk->rate, HZ);
 108 out:
 109         return ret;
 110
 111 out_clk_disable:
 112         clk_disable_unprepare(of_clk->clk);
 113 out_clk_put:
 114         clk_put(of_clk->clk);
 115
 116         goto out;
 117 }
 118
 119 static __init void timer_base_exit(struct of_timer_base *of_base)
 120 {
 121         iounmap(of_base->base);
 122 }
 123
 124 static __init int timer_base_init(struct device_node *np,
 125                                   struct of_timer_base *of_base)
 126 {
 127         const char *name = of_base->name ? of_base->name : np->full_name;
 128
 129         of_base->base = of_io_request_and_map(np, of_base->index, name);
 130         if (IS_ERR(of_base->base)) {
 131                 pr_err("Failed to iomap (%s)\n", name);
 132                 return PTR_ERR(of_base->base);
 133         }
 134
 135         return 0;
 136 }
 137
 138 int __init timer_of_init(struct device_node *np, struct timer_of *to)
 139 {
 140         int ret = -EINVAL;
 141         int flags = 0;
 142
 143         if (to->flags & TIMER_OF_BASE) {
 144                 ret = timer_base_init(np, &to->of_base);
 145                 if (ret)
 146                         goto out_fail;
 147                 flags |= TIMER_OF_BASE;
 148         }
 149
 150         if (to->flags & TIMER_OF_CLOCK) {
 151                 ret = timer_clk_init(np, &to->of_clk);
 152                 if (ret)
 153                         goto out_fail;
 154                 flags |= TIMER_OF_CLOCK;
 155         }
 156
 157         if (to->flags & TIMER_OF_IRQ) {
 158                 ret = timer_irq_init(np, &to->of_irq);
 159                 if (ret)
 160                         goto out_fail;
 161                 flags |= TIMER_OF_IRQ;
 162         }
 163
 164         if (!to->clkevt.name)
 165                 to->clkevt.name = np->name;
 166         return ret;
 167
 168 out_fail:
 169         if (flags & TIMER_OF_IRQ)
 170                 timer_irq_exit(&to->of_irq);
 171
 172         if (flags & TIMER_OF_CLOCK)
 173                 timer_clk_exit(&to->of_clk);
 174
 175         if (flags & TIMER_OF_BASE)
 176                 timer_base_exit(&to->of_base);
 177         return ret;
 178 }
 179
 180 /**
 181  * timer_of_cleanup - release timer_of ressources
 182  * @to: timer_of structure
 183  *
 184  * Release the ressources that has been used in timer_of_init().
 185  * This function should be called in init error cases
 186  */
 187 void __init timer_of_cleanup(struct timer_of *to)
 188 {
 189         if (to->flags & TIMER_OF_IRQ)
 190                 timer_irq_exit(&to->of_irq);
 191
 192         if (to->flags & TIMER_OF_CLOCK)
 193                 timer_clk_exit(&to->of_clk);
 194
 195         if (to->flags & TIMER_OF_BASE)
 196                 timer_base_exit(&to->of_base);
 197 }