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 /**
  28  * timer_of_irq_exit - Release the interrupt
  29  * @of_irq: an of_timer_irq structure pointer
  30  *
  31  * Free the irq resource
  32  */
  33 static __init void timer_of_irq_exit(struct of_timer_irq *of_irq)
  34 {
  35         struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
  36
  37         struct clock_event_device *clkevt = &to->clkevt;
  38
  39         of_irq->percpu ? free_percpu_irq(of_irq->irq, clkevt) :
  40                 free_irq(of_irq->irq, clkevt);
  41 }
  42
  43 /**
  44  * timer_of_irq_init - Request the interrupt
  45  * @np: a device tree node pointer
  46  * @of_irq: an of_timer_irq structure pointer
  47  *
  48  * Get the interrupt number from the DT from its definition and
  49  * request it. The interrupt is gotten by falling back the following way:
  50  *
  51  * - Get interrupt number by name
  52  * - Get interrupt number by index
  53  *
  54  * When the interrupt is per CPU, 'request_percpu_irq()' is called,
  55  * otherwise 'request_irq()' is used.
  56  *
  57  * Returns 0 on success, < 0 otherwise
  58  */
  59 static __init int timer_of_irq_init(struct device_node *np,
  60                                     struct of_timer_irq *of_irq)
  61 {
  62         int ret;
  63         struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
  64         struct clock_event_device *clkevt = &to->clkevt;
  65
  66         if (of_irq->name) {
  67                 of_irq->irq = ret = of_irq_get_byname(np, of_irq->name);
  68                 if (ret < 0) {
  69                         pr_err("Failed to get interrupt %s for %s\n",
  70                                of_irq->name, np->full_name);
  71                         return ret;
  72                 }
  73         } else  {
  74                 of_irq->irq = irq_of_parse_and_map(np, of_irq->index);
  75         }
  76         if (!of_irq->irq) {
  77                 pr_err("Failed to map interrupt for %pOF\n", np);
  78                 return -EINVAL;
  79         }
  80
  81         ret = of_irq->percpu ?
  82                 request_percpu_irq(of_irq->irq, of_irq->handler,
  83                                    np->full_name, clkevt) :
  84                 request_irq(of_irq->irq, of_irq->handler,
  85                             of_irq->flags ? of_irq->flags : IRQF_TIMER,
  86                             np->full_name, clkevt);
  87         if (ret) {
  88                 pr_err("Failed to request irq %d for %pOF\n", of_irq->irq, np);
  89                 return ret;
  90         }
  91
  92         clkevt->irq = of_irq->irq;
  93
  94         return 0;
  95 }
  96
  97 /**
  98  * timer_of_clk_exit - Release the clock resources
  99  * @of_clk: a of_timer_clk structure pointer
 100  *
 101  * Disables and releases the refcount on the clk
 102  */
 103 static __init void timer_of_clk_exit(struct of_timer_clk *of_clk)
 104 {
 105         of_clk->rate = 0;
 106         clk_disable_unprepare(of_clk->clk);
 107         clk_put(of_clk->clk);
 108 }
 109
 110 /**
 111  * timer_of_clk_init - Initialize the clock resources
 112  * @np: a device tree node pointer
 113  * @of_clk: a of_timer_clk structure pointer
 114  *
 115  * Get the clock by name or by index, enable it and get the rate
 116  *
 117  * Returns 0 on success, < 0 otherwise
 118  */
 119 static __init int timer_of_clk_init(struct device_node *np,
 120                                     struct of_timer_clk *of_clk)
 121 {
 122         int ret;
 123
 124         of_clk->clk = of_clk->name ? of_clk_get_by_name(np, of_clk->name) :
 125                 of_clk_get(np, of_clk->index);
 126         if (IS_ERR(of_clk->clk)) {
 127                 pr_err("Failed to get clock for %pOF\n", np);
 128                 return PTR_ERR(of_clk->clk);
 129         }
 130
 131         ret = clk_prepare_enable(of_clk->clk);
 132         if (ret) {
 133                 pr_err("Failed for enable clock for %pOF\n", np);
 134                 goto out_clk_put;
 135         }
 136
 137         of_clk->rate = clk_get_rate(of_clk->clk);
 138         if (!of_clk->rate) {
 139                 ret = -EINVAL;
 140                 pr_err("Failed to get clock rate for %pOF\n", np);
 141                 goto out_clk_disable;
 142         }
 143
 144         of_clk->period = DIV_ROUND_UP(of_clk->rate, HZ);
 145 out:
 146         return ret;
 147
 148 out_clk_disable:
 149         clk_disable_unprepare(of_clk->clk);
 150 out_clk_put:
 151         clk_put(of_clk->clk);
 152
 153         goto out;
 154 }
 155
 156 static __init void timer_of_base_exit(struct of_timer_base *of_base)
 157 {
 158         iounmap(of_base->base);
 159 }
 160
 161 static __init int timer_of_base_init(struct device_node *np,
 162                                      struct of_timer_base *of_base)
 163 {
 164         of_base->base = of_base->name ?
 165                 of_io_request_and_map(np, of_base->index, of_base->name) :
 166                 of_iomap(np, of_base->index);
 167         if (IS_ERR(of_base->base)) {
 168                 pr_err("Failed to iomap (%s)\n", of_base->name);
 169                 return PTR_ERR(of_base->base);
 170         }
 171
 172         return 0;
 173 }
 174
 175 int __init timer_of_init(struct device_node *np, struct timer_of *to)
 176 {
 177         int ret = -EINVAL;
 178         int flags = 0;
 179
 180         if (to->flags & TIMER_OF_BASE) {
 181                 ret = timer_of_base_init(np, &to->of_base);
 182                 if (ret)
 183                         goto out_fail;
 184                 flags |= TIMER_OF_BASE;
 185         }
 186
 187         if (to->flags & TIMER_OF_CLOCK) {
 188                 ret = timer_of_clk_init(np, &to->of_clk);
 189                 if (ret)
 190                         goto out_fail;
 191                 flags |= TIMER_OF_CLOCK;
 192         }
 193
 194         if (to->flags & TIMER_OF_IRQ) {
 195                 ret = timer_of_irq_init(np, &to->of_irq);
 196                 if (ret)
 197                         goto out_fail;
 198                 flags |= TIMER_OF_IRQ;
 199         }
 200
 201         if (!to->clkevt.name)
 202                 to->clkevt.name = np->name;
 203
 204         to->np = np;
 205
 206         return ret;
 207
 208 out_fail:
 209         if (flags & TIMER_OF_IRQ)
 210                 timer_of_irq_exit(&to->of_irq);
 211
 212         if (flags & TIMER_OF_CLOCK)
 213                 timer_of_clk_exit(&to->of_clk);
 214
 215         if (flags & TIMER_OF_BASE)
 216                 timer_of_base_exit(&to->of_base);
 217         return ret;
 218 }
 219
 220 /**
 221  * timer_of_cleanup - release timer_of ressources
 222  * @to: timer_of structure
 223  *
 224  * Release the ressources that has been used in timer_of_init().
 225  * This function should be called in init error cases
 226  */
 227 void __init timer_of_cleanup(struct timer_of *to)
 228 {
 229         if (to->flags & TIMER_OF_IRQ)
 230                 timer_of_irq_exit(&to->of_irq);
 231
 232         if (to->flags & TIMER_OF_CLOCK)
 233                 timer_of_clk_exit(&to->of_clk);
 234
 235         if (to->flags & TIMER_OF_BASE)
 236                 timer_of_base_exit(&to->of_base);
 237 }