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 %s\n", np->full_name);
  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 %s\n", of_irq->irq,
  67                        np->full_name);
  68                 return ret;
  69         }
  70
  71         clkevt->irq = of_irq->irq;
  72
  73         return 0;
  74 }
  75
  76 static __init void timer_clk_exit(struct of_timer_clk *of_clk)
  77 {
  78         of_clk->rate = 0;
  79         clk_disable_unprepare(of_clk->clk);
  80         clk_put(of_clk->clk);
  81 }
  82
  83 static __init int timer_clk_init(struct device_node *np,
  84                                  struct of_timer_clk *of_clk)
  85 {
  86         int ret;
  87
  88         of_clk->clk = of_clk->name ? of_clk_get_by_name(np, of_clk->name) :
  89                 of_clk_get(np, of_clk->index);
  90         if (IS_ERR(of_clk->clk)) {
  91                 pr_err("Failed to get clock for %s\n", np->full_name);
  92                 return PTR_ERR(of_clk->clk);
  93         }
  94
  95         ret = clk_prepare_enable(of_clk->clk);
  96         if (ret) {
  97                 pr_err("Failed for enable clock for %s\n", np->full_name);
  98                 goto out_clk_put;
  99         }
 100
 101         of_clk->rate = clk_get_rate(of_clk->clk);
 102         if (!of_clk->rate) {
 103                 ret = -EINVAL;
 104                 pr_err("Failed to get clock rate for %s\n", np->full_name);
 105                 goto out_clk_disable;
 106         }
 107
 108         of_clk->period = DIV_ROUND_UP(of_clk->rate, HZ);
 109 out:
 110         return ret;
 111
 112 out_clk_disable:
 113         clk_disable_unprepare(of_clk->clk);
 114 out_clk_put:
 115         clk_put(of_clk->clk);
 116
 117         goto out;
 118 }
 119
 120 static __init void timer_base_exit(struct of_timer_base *of_base)
 121 {
 122         iounmap(of_base->base);
 123 }
 124
 125 static __init int timer_base_init(struct device_node *np,
 126                                   struct of_timer_base *of_base)
 127 {
 128         const char *name = of_base->name ? of_base->name : np->full_name;
 129
 130         of_base->base = of_io_request_and_map(np, of_base->index, name);
 131         if (!of_base->base) {
 132                 pr_err("Failed to iomap (%s)\n", name);
 133                 return -ENXIO;
 134         }
 135
 136         return 0;
 137 }
 138
 139 int __init timer_of_init(struct device_node *np, struct timer_of *to)
 140 {
 141         int ret = -EINVAL;
 142         int flags = 0;
 143
 144         if (to->flags & TIMER_OF_BASE) {
 145                 ret = timer_base_init(np, &to->of_base);
 146                 if (ret)
 147                         goto out_fail;
 148                 flags |= TIMER_OF_BASE;
 149         }
 150
 151         if (to->flags & TIMER_OF_CLOCK) {
 152                 ret = timer_clk_init(np, &to->of_clk);
 153                 if (ret)
 154                         goto out_fail;
 155                 flags |= TIMER_OF_CLOCK;
 156         }
 157
 158         if (to->flags & TIMER_OF_IRQ) {
 159                 ret = timer_irq_init(np, &to->of_irq);
 160                 if (ret)
 161                         goto out_fail;
 162                 flags |= TIMER_OF_IRQ;
 163         }
 164
 165         if (!to->clkevt.name)
 166                 to->clkevt.name = np->name;
 167         return ret;
 168
 169 out_fail:
 170         if (flags & TIMER_OF_IRQ)
 171                 timer_irq_exit(&to->of_irq);
 172
 173         if (flags & TIMER_OF_CLOCK)
 174                 timer_clk_exit(&to->of_clk);
 175
 176         if (flags & TIMER_OF_BASE)
 177                 timer_base_exit(&to->of_base);
 178         return ret;
 179 }