arch/microblaze/kernel/reset.c

   1 /*
   2  * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
   3  * Copyright (C) 2009 PetaLogix
   4  *
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License. See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/of_platform.h>
  12 #include <asm/prom.h>
  13
  14 /* Trigger specific functions */
  15 #ifdef CONFIG_GPIOLIB
  16
  17 #include <linux/of_gpio.h>
  18
  19 static int handle; /* reset pin handle */
  20 static unsigned int reset_val;
  21
  22 static int of_reset_gpio_handle(void)
  23 {
  24         int ret; /* variable which stored handle reset gpio pin */
  25         struct device_node *root; /* root node */
  26         struct device_node *gpio; /* gpio node */
  27         struct gpio_chip *gc;
  28         u32 flags;
  29         const void *gpio_spec;
  30
  31         /* find out root node */
  32         root = of_find_node_by_path("/");
  33
  34         /* give me handle for gpio node to be possible allocate pin */
  35         ret = of_parse_phandles_with_args(root, "hard-reset-gpios",
  36                                 "#gpio-cells", 0, &gpio, &gpio_spec);
  37         if (ret) {
  38                 pr_debug("%s: can't parse gpios property\n", __func__);
  39                 goto err0;
  40         }
  41
  42         gc = of_node_to_gpiochip(gpio);
  43         if (!gc) {
  44                 pr_debug("%s: gpio controller %s isn't registered\n",
  45                          root->full_name, gpio->full_name);
  46                 ret = -ENODEV;
  47                 goto err1;
  48         }
  49
  50         ret = gc->of_xlate(gc, root, gpio_spec, &flags);
  51         if (ret < 0)
  52                 goto err1;
  53
  54         ret += gc->base;
  55 err1:
  56         of_node_put(gpio);
  57 err0:
  58         pr_debug("%s exited with status %d\n", __func__, ret);
  59         return ret;
  60 }
  61
  62 void of_platform_reset_gpio_probe(void)
  63 {
  64         int ret;
  65         handle = of_reset_gpio_handle();
  66
  67         if (!gpio_is_valid(handle)) {
  68                 printk(KERN_INFO "Skipping unavailable RESET gpio %d (%s)\n",
  69                                 handle, "reset");
  70         }
  71
  72         ret = gpio_request(handle, "reset");
  73         if (ret < 0) {
  74                 printk(KERN_INFO "GPIO pin is already allocated\n");
  75                 return;
  76         }
  77
  78         /* get current setup value */
  79         reset_val = gpio_get_value(handle);
  80         /* FIXME maybe worth to perform any action */
  81         pr_debug("Reset: Gpio output state: 0x%x\n", reset_val);
  82
  83         /* Setup GPIO as output */
  84         ret = gpio_direction_output(handle, 0);
  85         if (ret < 0)
  86                 goto err;
  87
  88         /* Setup output direction */
  89         gpio_set_value(handle, 0);
  90
  91         printk(KERN_INFO "RESET: Registered gpio device: %d, current val: %d\n",
  92                                                         handle, reset_val);
  93         return;
  94 err:
  95         gpio_free(handle);
  96         return;
  97 }
  98
  99
 100 static void gpio_system_reset(void)
 101 {
 102         gpio_set_value(handle, 1 - reset_val);
 103 }
 104 #else
 105 #define gpio_system_reset() do {} while (0)
 106 void of_platform_reset_gpio_probe(void)
 107 {
 108         return;
 109 }
 110 #endif
 111
 112 void machine_restart(char *cmd)
 113 {
 114         printk(KERN_NOTICE "Machine restart...\n");
 115         gpio_system_reset();
 116         dump_stack();
 117         while (1)
 118                 ;
 119 }
 120
 121 void machine_shutdown(void)
 122 {
 123         printk(KERN_NOTICE "Machine shutdown...\n");
 124         while (1)
 125                 ;
 126 }
 127
 128 void machine_halt(void)
 129 {
 130         printk(KERN_NOTICE "Machine halt...\n");
 131         while (1)
 132                 ;
 133 }
 134
 135 void machine_power_off(void)
 136 {
 137         printk(KERN_NOTICE "Machine power off...\n");
 138         while (1)
 139                 ;
 140 }