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 #include <asm/system_misc.h> 22 23 static void vexpress_reset_do(struct device *dev, const char *what) 24 { 25 int err = -ENOENT; 26 struct vexpress_config_func *func = 27 vexpress_config_func_get_by_dev(dev); 28 29 if (func) { 30 unsigned long timeout; 31 32 err = vexpress_config_write(func, 0, 0); 33 34 timeout = jiffies + HZ; 35 while (time_before(jiffies, timeout)) 36 cpu_relax(); 37 } 38 39 dev_emerg(dev, "Unable to %s (%d)\n", what, err); 40 } 41 42 static struct device *vexpress_power_off_device; 43 44 static void vexpress_power_off(void) 45 { 46 vexpress_reset_do(vexpress_power_off_device, "power off"); 47 } 48 49 static struct device *vexpress_restart_device; 50 51 static void vexpress_restart(enum reboot_mode reboot_mode, const char *cmd) 52 { 53 vexpress_reset_do(vexpress_restart_device, "restart"); 54 } 55 56 static ssize_t vexpress_reset_active_show(struct device *dev, 57 struct device_attribute *attr, char *buf) 58 { 59 return sprintf(buf, "%d\n", vexpress_restart_device == dev); 60 } 61 62 static ssize_t vexpress_reset_active_store(struct device *dev, 63 struct device_attribute *attr, const char *buf, size_t count) 64 { 65 long value; 66 int err = kstrtol(buf, 0, &value); 67 68 if (!err && value) 69 vexpress_restart_device = dev; 70 71 return err ? err : count; 72 } 73 74 DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show, 75 vexpress_reset_active_store); 76 77 78 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT }; 79 80 static struct of_device_id vexpress_reset_of_match[] = { 81 { 82 .compatible = "arm,vexpress-reset", 83 .data = (void *)FUNC_RESET, 84 }, { 85 .compatible = "arm,vexpress-shutdown", 86 .data = (void *)FUNC_SHUTDOWN 87 }, { 88 .compatible = "arm,vexpress-reboot", 89 .data = (void *)FUNC_REBOOT 90 }, 91 {} 92 }; 93 94 static int vexpress_reset_probe(struct platform_device *pdev) 95 { 96 enum vexpress_reset_func func; 97 const struct of_device_id *match = 98 of_match_device(vexpress_reset_of_match, &pdev->dev); 99 100 if (match) 101 func = (enum vexpress_reset_func)match->data; 102 else 103 func = pdev->id_entry->driver_data; 104 105 switch (func) { 106 case FUNC_SHUTDOWN: 107 vexpress_power_off_device = &pdev->dev; 108 pm_power_off = vexpress_power_off; 109 break; 110 case FUNC_RESET: 111 if (!vexpress_restart_device) 112 vexpress_restart_device = &pdev->dev; 113 arm_pm_restart = vexpress_restart; 114 device_create_file(&pdev->dev, &dev_attr_active); 115 break; 116 case FUNC_REBOOT: 117 vexpress_restart_device = &pdev->dev; 118 arm_pm_restart = vexpress_restart; 119 device_create_file(&pdev->dev, &dev_attr_active); 120 break; 121 }; 122 123 return 0; 124 } 125 126 static const struct platform_device_id vexpress_reset_id_table[] = { 127 { .name = "vexpress-reset", .driver_data = FUNC_RESET, }, 128 { .name = "vexpress-shutdown", .driver_data = FUNC_SHUTDOWN, }, 129 { .name = "vexpress-reboot", .driver_data = FUNC_REBOOT, }, 130 {} 131 }; 132 133 static struct platform_driver vexpress_reset_driver = { 134 .probe = vexpress_reset_probe, 135 .driver = { 136 .name = "vexpress-reset", 137 .of_match_table = vexpress_reset_of_match, 138 }, 139 .id_table = vexpress_reset_id_table, 140 }; 141 142 static int __init vexpress_reset_init(void) 143 { 144 return platform_driver_register(&vexpress_reset_driver); 145 } 146 device_initcall(vexpress_reset_init); 147