arch/arm/mach-vexpress/reset.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2012 ARM Limited
  12  */
  13
  14 #include <linux/jiffies.h>
  15 #include <linux/of.h>
  16 #include <linux/of_device.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/stat.h>
  19 #include <linux/vexpress.h>
  20
  21 static void vexpress_reset_do(struct device *dev, const char *what)
  22 {
  23         int err = -ENOENT;
  24         struct vexpress_config_func *func =
  25                         vexpress_config_func_get_by_dev(dev);
  26
  27         if (func) {
  28                 unsigned long timeout;
  29
  30                 err = vexpress_config_write(func, 0, 0);
  31
  32                 timeout = jiffies + HZ;
  33                 while (time_before(jiffies, timeout))
  34                         cpu_relax();
  35         }
  36
  37         dev_emerg(dev, "Unable to %s (%d)\n", what, err);
  38 }
  39
  40 static struct device *vexpress_power_off_device;
  41
  42 void vexpress_power_off(void)
  43 {
  44         vexpress_reset_do(vexpress_power_off_device, "power off");
  45 }
  46
  47 static struct device *vexpress_restart_device;
  48
  49 void vexpress_restart(char str, const char *cmd)
  50 {
  51         vexpress_reset_do(vexpress_restart_device, "restart");
  52 }
  53
  54 static ssize_t vexpress_reset_active_show(struct device *dev,
  55                 struct device_attribute *attr, char *buf)
  56 {
  57         return sprintf(buf, "%d\n", vexpress_restart_device == dev);
  58 }
  59
  60 static ssize_t vexpress_reset_active_store(struct device *dev,
  61                 struct device_attribute *attr, const char *buf, size_t count)
  62 {
  63         long value;
  64         int err = kstrtol(buf, 0, &value);
  65
  66         if (!err && value)
  67                 vexpress_restart_device = dev;
  68
  69         return err ? err : count;
  70 }
  71
  72 DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
  73                 vexpress_reset_active_store);
  74
  75
  76 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
  77
  78 static struct of_device_id vexpress_reset_of_match[] = {
  79         {
  80                 .compatible = "arm,vexpress-reset",
  81                 .data = (void *)FUNC_RESET,
  82         }, {
  83                 .compatible = "arm,vexpress-shutdown",
  84                 .data = (void *)FUNC_SHUTDOWN
  85         }, {
  86                 .compatible = "arm,vexpress-reboot",
  87                 .data = (void *)FUNC_REBOOT
  88         },
  89         {}
  90 };
  91
  92 static int vexpress_reset_probe(struct platform_device *pdev)
  93 {
  94         enum vexpress_reset_func func;
  95         const struct of_device_id *match =
  96                         of_match_device(vexpress_reset_of_match, &pdev->dev);
  97
  98         if (match)
  99                 func = (enum vexpress_reset_func)match->data;
 100         else
 101                 func = pdev->id_entry->driver_data;
 102
 103         switch (func) {
 104         case FUNC_SHUTDOWN:
 105                 vexpress_power_off_device = &pdev->dev;
 106                 break;
 107         case FUNC_RESET:
 108                 if (!vexpress_restart_device)
 109                         vexpress_restart_device = &pdev->dev;
 110                 device_create_file(&pdev->dev, &dev_attr_active);
 111                 break;
 112         case FUNC_REBOOT:
 113                 vexpress_restart_device = &pdev->dev;
 114                 device_create_file(&pdev->dev, &dev_attr_active);
 115                 break;
 116         };
 117
 118         return 0;
 119 }
 120
 121 static const struct platform_device_id vexpress_reset_id_table[] = {
 122         { .name = "vexpress-reset", .driver_data = FUNC_RESET, },
 123         { .name = "vexpress-shutdown", .driver_data = FUNC_SHUTDOWN, },
 124         { .name = "vexpress-reboot", .driver_data = FUNC_REBOOT, },
 125         {}
 126 };
 127
 128 static struct platform_driver vexpress_reset_driver = {
 129         .probe = vexpress_reset_probe,
 130         .driver = {
 131                 .name = "vexpress-reset",
 132                 .of_match_table = vexpress_reset_of_match,
 133         },
 134         .id_table = vexpress_reset_id_table,
 135 };
 136
 137 static int __init vexpress_reset_init(void)
 138 {
 139         return platform_driver_register(&vexpress_reset_driver);
 140 }
 141 device_initcall(vexpress_reset_init);