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/clocksource.h> 14 #include <linux/delay.h> 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/irqchip.h> 18 #include <linux/of_address.h> 19 #include <linux/of_irq.h> 20 #include <linux/of_platform.h> 21 #include <linux/io.h> 22 23 #include <linux/clk/sunxi.h> 24 25 #include <asm/mach/arch.h> 26 #include <asm/mach/map.h> 27 #include <asm/system_misc.h> 28 29 #include "sunxi.h" 30 31 #define SUN4I_WATCHDOG_CTRL_REG 0x00 32 #define SUN4I_WATCHDOG_CTRL_RESTART (1 << 0) 33 #define SUN4I_WATCHDOG_MODE_REG 0x04 34 #define SUN4I_WATCHDOG_MODE_ENABLE (1 << 0) 35 #define SUN4I_WATCHDOG_MODE_RESET_ENABLE (1 << 1) 36 37 static void __iomem *wdt_base; 38 39 static void sun4i_restart(char mode, const char *cmd) 40 { 41 if (!wdt_base) 42 return; 43 44 /* Enable timer and set reset bit in the watchdog */ 45 writel(SUN4I_WATCHDOG_MODE_ENABLE | SUN4I_WATCHDOG_MODE_RESET_ENABLE, 46 wdt_base + SUN4I_WATCHDOG_MODE_REG); 47 48 /* 49 * Restart the watchdog. The default (and lowest) interval 50 * value for the watchdog is 0.5s. 51 */ 52 writel(SUN4I_WATCHDOG_CTRL_RESTART, wdt_base + SUN4I_WATCHDOG_CTRL_REG); 53 54 while (1) { 55 mdelay(5); 56 writel(SUN4I_WATCHDOG_MODE_ENABLE | SUN4I_WATCHDOG_MODE_RESET_ENABLE, 57 wdt_base + SUN4I_WATCHDOG_MODE_REG); 58 } 59 } 60 61 static struct of_device_id sunxi_restart_ids[] = { 62 { .compatible = "allwinner,sun4i-wdt", .data = sun4i_restart }, 63 { /*sentinel*/ } 64 }; 65 66 static void sunxi_setup_restart(void) 67 { 68 const struct of_device_id *of_id; 69 struct device_node *np; 70 71 np = of_find_matching_node(NULL, sunxi_restart_ids); 72 if (WARN(!np, "unable to setup watchdog restart")) 73 return; 74 75 wdt_base = of_iomap(np, 0); 76 WARN(!wdt_base, "failed to map watchdog base address"); 77 78 of_id = of_match_node(sunxi_restart_ids, np); 79 WARN(!of_id, "restart function not available"); 80 81 arm_pm_restart = of_id->data; 82 } 83 84 static struct map_desc sunxi_io_desc[] __initdata = { 85 { 86 .virtual = (unsigned long) SUNXI_REGS_VIRT_BASE, 87 .pfn = __phys_to_pfn(SUNXI_REGS_PHYS_BASE), 88 .length = SUNXI_REGS_SIZE, 89 .type = MT_DEVICE, 90 }, 91 }; 92 93 void __init sunxi_map_io(void) 94 { 95 iotable_init(sunxi_io_desc, ARRAY_SIZE(sunxi_io_desc)); 96 } 97 98 static void __init sunxi_timer_init(void) 99 { 100 sunxi_init_clocks(); 101 clocksource_of_init(); 102 } 103 104 static void __init sunxi_dt_init(void) 105 { 106 sunxi_setup_restart(); 107 108 of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL); 109 } 110 111 static const char * const sunxi_board_dt_compat[] = { 112 "allwinner,sun4i-a10", 113 "allwinner,sun5i-a13", 114 NULL, 115 }; 116 117 DT_MACHINE_START(SUNXI_DT, "Allwinner A1X (Device Tree)") 118 .init_machine = sunxi_dt_init, 119 .map_io = sunxi_map_io, 120 .init_irq = irqchip_init, 121 .init_time = sunxi_timer_init, 122 .dt_compat = sunxi_board_dt_compat, 123 MACHINE_END 124