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         of_irq->irq = of_irq->name ? of_irq_get_byname(np, of_irq->name):
  45                 irq_of_parse_and_map(np, of_irq->index);
  46         if (!of_irq->irq) {
  47                 pr_err("Failed to map interrupt for %s\n", np->full_name);
  48                 return -EINVAL;
  49         }
  50
  51         ret = of_irq->percpu ?
  52                 request_percpu_irq(of_irq->irq, of_irq->handler,
  53                                    np->full_name, clkevt) :
  54                 request_irq(of_irq->irq, of_irq->handler,
  55                             of_irq->flags ? of_irq->flags : IRQF_TIMER,
  56                             np->full_name, clkevt);
  57         if (ret) {
  58                 pr_err("Failed to request irq %d for %s\n", of_irq->irq,
  59                        np->full_name);
  60                 return ret;
  61         }
  62
  63         clkevt->irq = of_irq->irq;
  64
  65         return 0;
  66 }
  67
  68 static __init void timer_clk_exit(struct of_timer_clk *of_clk)
  69 {
  70         of_clk->rate = 0;
  71         clk_disable_unprepare(of_clk->clk);
  72         clk_put(of_clk->clk);
  73 }
  74
  75 static __init int timer_clk_init(struct device_node *np,
  76                                  struct of_timer_clk *of_clk)
  77 {
  78         int ret;
  79
  80         of_clk->clk = of_clk->name ? of_clk_get_by_name(np, of_clk->name) :
  81                 of_clk_get(np, of_clk->index);
  82         if (IS_ERR(of_clk->clk)) {
  83                 pr_err("Failed to get clock for %s\n", np->full_name);
  84                 return PTR_ERR(of_clk->clk);
  85         }
  86
  87         ret = clk_prepare_enable(of_clk->clk);
  88         if (ret) {
  89                 pr_err("Failed for enable clock for %s\n", np->full_name);
  90                 goto out_clk_put;
  91         }
  92
  93         of_clk->rate = clk_get_rate(of_clk->clk);
  94         if (!of_clk->rate) {
  95                 ret = -EINVAL;
  96                 pr_err("Failed to get clock rate for %s\n", np->full_name);
  97                 goto out_clk_disable;
  98         }
  99
 100         of_clk->period = DIV_ROUND_UP(of_clk->rate, HZ);
 101 out:
 102         return ret;
 103
 104 out_clk_disable:
 105         clk_disable_unprepare(of_clk->clk);
 106 out_clk_put:
 107         clk_put(of_clk->clk);
 108
 109         goto out;
 110 }
 111
 112 static __init void timer_base_exit(struct of_timer_base *of_base)
 113 {
 114         iounmap(of_base->base);
 115 }
 116
 117 static __init int timer_base_init(struct device_node *np,
 118                                   struct of_timer_base *of_base)
 119 {
 120         const char *name = of_base->name ? of_base->name : np->full_name;
 121
 122         of_base->base = of_io_request_and_map(np, of_base->index, name);
 123         if (!of_base->base) {
 124                 pr_err("Failed to iomap (%s)\n", name);
 125                 return -ENXIO;
 126         }
 127
 128         return 0;
 129 }
 130
 131 int __init timer_of_init(struct device_node *np, struct timer_of *to)
 132 {
 133         int ret = -EINVAL;
 134         int flags = 0;
 135
 136         if (to->flags & TIMER_OF_BASE) {
 137                 ret = timer_base_init(np, &to->of_base);
 138                 if (ret)
 139                         goto out_fail;
 140                 flags |= TIMER_OF_BASE;
 141         }
 142
 143         if (to->flags & TIMER_OF_CLOCK) {
 144                 ret = timer_clk_init(np, &to->of_clk);
 145                 if (ret)
 146                         goto out_fail;
 147                 flags |= TIMER_OF_CLOCK;
 148         }
 149
 150         if (to->flags & TIMER_OF_IRQ) {
 151                 ret = timer_irq_init(np, &to->of_irq);
 152                 if (ret)
 153                         goto out_fail;
 154                 flags |= TIMER_OF_IRQ;
 155         }
 156
 157         if (!to->clkevt.name)
 158                 to->clkevt.name = np->name;
 159         return ret;
 160
 161 out_fail:
 162         if (flags & TIMER_OF_IRQ)
 163                 timer_irq_exit(&to->of_irq);
 164
 165         if (flags & TIMER_OF_CLOCK)
 166                 timer_clk_exit(&to->of_clk);
 167
 168         if (flags & TIMER_OF_BASE)
 169                 timer_base_exit(&to->of_base);
 170         return ret;
 171 }