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" }, 94 { .compatible = "allwinner,sun6i-wdt" }, 95 { /*sentinel*/ } 96 }; 97 98 static void sunxi_setup_restart(void) 99 { 100 struct device_node *np; 101 102 np = of_find_matching_node(NULL, sunxi_restart_ids); 103 if (WARN(!np, "unable to setup watchdog restart")) 104 return; 105 106 wdt_base = of_iomap(np, 0); 107 WARN(!wdt_base, "failed to map watchdog base address"); 108 } 109 110 static void __init sunxi_dt_init(void) 111 { 112 sunxi_setup_restart(); 113 114 of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL); 115 } 116 117 static const char * const sunxi_board_dt_compat[] = { 118 "allwinner,sun4i-a10", 119 "allwinner,sun5i-a10s", 120 "allwinner,sun5i-a13", 121 NULL, 122 }; 123 124 DT_MACHINE_START(SUNXI_DT, "Allwinner A1X (Device Tree)") 125 .init_machine = sunxi_dt_init, 126 .dt_compat = sunxi_board_dt_compat, 127 .restart = sun4i_restart, 128 MACHINE_END 129 130 static const char * const sun6i_board_dt_compat[] = { 131 "allwinner,sun6i-a31", 132 NULL, 133 }; 134 135 DT_MACHINE_START(SUN6I_DT, "Allwinner sun6i (A31) Family") 136 .init_machine = sunxi_dt_init, 137 .dt_compat = sun6i_board_dt_compat, 138 .restart = sun6i_restart, 139 MACHINE_END 140 141 static const char * const sun7i_board_dt_compat[] = { 142 "allwinner,sun7i-a20", 143 NULL, 144 }; 145 146 DT_MACHINE_START(SUN7I_DT, "Allwinner sun7i (A20) Family") 147 .init_machine = sunxi_dt_init, 148 .dt_compat = sun7i_board_dt_compat, 149 .restart = sun4i_restart, 150 MACHINE_END 151