arch/arm/mach-sunxi/sunxi.c

   1 /*
   2  * Device Tree support for Allwinner A1X SoCs
   3  *
   4  * Copyright (C) 2012 Maxime Ripard
   5  *
   6  * Maxime Ripard <maxime.ripard@free-electrons.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2.  This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/of_address.h>
  17 #include <linux/of_irq.h>
  18 #include <linux/of_platform.h>
  19 #include <linux/io.h>
  20 #include <linux/reboot.h>
  21
  22 #include <asm/mach/arch.h>
  23 #include <asm/mach/map.h>
  24 #include <asm/system_misc.h>
  25
  26 #define SUN4I_WATCHDOG_CTRL_REG         0x00
  27 #define SUN4I_WATCHDOG_CTRL_RESTART             BIT(0)
  28 #define SUN4I_WATCHDOG_MODE_REG         0x04
  29 #define SUN4I_WATCHDOG_MODE_ENABLE              BIT(0)
  30 #define SUN4I_WATCHDOG_MODE_RESET_ENABLE        BIT(1)
  31
  32 #define SUN6I_WATCHDOG1_IRQ_REG         0x00
  33 #define SUN6I_WATCHDOG1_CTRL_REG        0x10
  34 #define SUN6I_WATCHDOG1_CTRL_RESTART            BIT(0)
  35 #define SUN6I_WATCHDOG1_CONFIG_REG      0x14
  36 #define SUN6I_WATCHDOG1_CONFIG_RESTART          BIT(0)
  37 #define SUN6I_WATCHDOG1_CONFIG_IRQ              BIT(1)
  38 #define SUN6I_WATCHDOG1_MODE_REG        0x18
  39 #define SUN6I_WATCHDOG1_MODE_ENABLE             BIT(0)
  40
  41 static void __iomem *wdt_base;
  42
  43 static void sun4i_restart(enum reboot_mode mode, const char *cmd)
  44 {
  45         if (!wdt_base)
  46                 return;
  47
  48         /* Enable timer and set reset bit in the watchdog */
  49         writel(SUN4I_WATCHDOG_MODE_ENABLE | SUN4I_WATCHDOG_MODE_RESET_ENABLE,
  50                wdt_base + SUN4I_WATCHDOG_MODE_REG);
  51
  52         /*
  53          * Restart the watchdog. The default (and lowest) interval
  54          * value for the watchdog is 0.5s.
  55          */
  56         writel(SUN4I_WATCHDOG_CTRL_RESTART, wdt_base + SUN4I_WATCHDOG_CTRL_REG);
  57
  58         while (1) {
  59                 mdelay(5);
  60                 writel(SUN4I_WATCHDOG_MODE_ENABLE | SUN4I_WATCHDOG_MODE_RESET_ENABLE,
  61                        wdt_base + SUN4I_WATCHDOG_MODE_REG);
  62         }
  63 }
  64
  65 static void sun6i_restart(enum reboot_mode mode, const char *cmd)
  66 {
  67         if (!wdt_base)
  68                 return;
  69
  70         /* Disable interrupts */
  71         writel(0, wdt_base + SUN6I_WATCHDOG1_IRQ_REG);
  72
  73         /* We want to disable the IRQ and just reset the whole system */
  74         writel(SUN6I_WATCHDOG1_CONFIG_RESTART,
  75                 wdt_base + SUN6I_WATCHDOG1_CONFIG_REG);
  76
  77         /* Enable timer. The default and lowest interval value is 0.5s */
  78         writel(SUN6I_WATCHDOG1_MODE_ENABLE,
  79                 wdt_base + SUN6I_WATCHDOG1_MODE_REG);
  80
  81         /* Restart the watchdog. */
  82         writel(SUN6I_WATCHDOG1_CTRL_RESTART,
  83                 wdt_base + SUN6I_WATCHDOG1_CTRL_REG);
  84
  85         while (1) {
  86                 mdelay(5);
  87                 writel(SUN6I_WATCHDOG1_MODE_ENABLE,
  88                         wdt_base + SUN6I_WATCHDOG1_MODE_REG);
  89         }
  90 }
  91
  92 static struct of_device_id sunxi_restart_ids[] = {
  93         { .compatible = "allwinner,sun4i-wdt", .data = sun4i_restart },
  94         { .compatible = "allwinner,sun6i-wdt", .data = sun6i_restart },
  95         { /*sentinel*/ }
  96 };
  97
  98 static void sunxi_setup_restart(void)
  99 {
 100         const struct of_device_id *of_id;
 101         struct device_node *np;
 102
 103         np = of_find_matching_node(NULL, sunxi_restart_ids);
 104         if (WARN(!np, "unable to setup watchdog restart"))
 105                 return;
 106
 107         wdt_base = of_iomap(np, 0);
 108         WARN(!wdt_base, "failed to map watchdog base address");
 109
 110         of_id = of_match_node(sunxi_restart_ids, np);
 111         WARN(!of_id, "restart function not available");
 112
 113         arm_pm_restart = of_id->data;
 114 }
 115
 116 static void __init sunxi_dt_init(void)
 117 {
 118         sunxi_setup_restart();
 119
 120         of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 121 }
 122
 123 static const char * const sunxi_board_dt_compat[] = {
 124         "allwinner,sun4i-a10",
 125         "allwinner,sun5i-a10s",
 126         "allwinner,sun5i-a13",
 127         "allwinner,sun6i-a31",
 128         "allwinner,sun7i-a20",
 129         NULL,
 130 };
 131
 132 DT_MACHINE_START(SUNXI_DT, "Allwinner A1X (Device Tree)")
 133         .init_machine   = sunxi_dt_init,
 134         .dt_compat      = sunxi_board_dt_compat,
 135 MACHINE_END