arch/arm/mach-imx/cpuidle.c

   1 /*
   2  * Copyright 2012 Freescale Semiconductor, Inc.
   3  * Copyright 2012 Linaro Ltd.
   4  *
   5  * The code contained herein is licensed under the GNU General Public
   6  * License. You may obtain a copy of the GNU General Public License
   7  * Version 2 or later at the following locations:
   8  *
   9  * http://www.opensource.org/licenses/gpl-license.html
  10  * http://www.gnu.org/copyleft/gpl.html
  11  */
  12
  13 #include <linux/cpuidle.h>
  14 #include <linux/err.h>
  15 #include <linux/hrtimer.h>
  16 #include <linux/io.h>
  17 #include <linux/kernel.h>
  18 #include <linux/slab.h>
  19
  20 static struct cpuidle_device __percpu * imx_cpuidle_devices;
  21
  22 static void __init imx_cpuidle_devices_uninit(void)
  23 {
  24         int cpu_id;
  25         struct cpuidle_device *dev;
  26
  27         for_each_possible_cpu(cpu_id) {
  28                 dev = per_cpu_ptr(imx_cpuidle_devices, cpu_id);
  29                 cpuidle_unregister_device(dev);
  30         }
  31
  32         free_percpu(imx_cpuidle_devices);
  33 }
  34
  35 int __init imx_cpuidle_init(struct cpuidle_driver *drv)
  36 {
  37         struct cpuidle_device *dev;
  38         int cpu_id, ret;
  39
  40         if (drv->state_count > CPUIDLE_STATE_MAX) {
  41                 pr_err("%s: state_count exceeds maximum\n", __func__);
  42                 return -EINVAL;
  43         }
  44
  45         ret = cpuidle_register_driver(drv);
  46         if (ret) {
  47                 pr_err("%s: Failed to register cpuidle driver with error: %d\n",
  48                          __func__, ret);
  49                 return ret;
  50         }
  51
  52         imx_cpuidle_devices = alloc_percpu(struct cpuidle_device);
  53         if (imx_cpuidle_devices == NULL) {
  54                 ret = -ENOMEM;
  55                 goto unregister_drv;
  56         }
  57
  58         /* initialize state data for each cpuidle_device */
  59         for_each_possible_cpu(cpu_id) {
  60                 dev = per_cpu_ptr(imx_cpuidle_devices, cpu_id);
  61                 dev->cpu = cpu_id;
  62                 dev->state_count = drv->state_count;
  63
  64                 ret = cpuidle_register_device(dev);
  65                 if (ret) {
  66                         pr_err("%s: Failed to register cpu %u, error: %d\n",
  67                                 __func__, cpu_id, ret);
  68                         goto uninit;
  69                 }
  70         }
  71
  72         return 0;
  73
  74 uninit:
  75         imx_cpuidle_devices_uninit();
  76
  77 unregister_drv:
  78         cpuidle_unregister_driver(drv);
  79         return ret;
  80 }