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/sunxi_timer.h> 21 22 #include <linux/irqchip/sunxi.h> 23 24 #include <asm/mach/arch.h> 25 #include <asm/mach/map.h> 26 27 #include "sunxi.h" 28 29 #define WATCHDOG_CTRL_REG 0x00 30 #define WATCHDOG_CTRL_RESTART (1 << 0) 31 #define WATCHDOG_MODE_REG 0x04 32 #define WATCHDOG_MODE_ENABLE (1 << 0) 33 #define WATCHDOG_MODE_RESET_ENABLE (1 << 1) 34 35 static void __iomem *wdt_base; 36 37 static void sunxi_setup_restart(void) 38 { 39 struct device_node *np = of_find_compatible_node(NULL, NULL, 40 "allwinner,sunxi-wdt"); 41 if (WARN(!np, "unable to setup watchdog restart")) 42 return; 43 44 wdt_base = of_iomap(np, 0); 45 WARN(!wdt_base, "failed to map watchdog base address"); 46 } 47 48 static void sunxi_restart(char mode, const char *cmd) 49 { 50 if (!wdt_base) 51 return; 52 53 /* Enable timer and set reset bit in the watchdog */ 54 writel(WATCHDOG_MODE_ENABLE | WATCHDOG_MODE_RESET_ENABLE, 55 wdt_base + WATCHDOG_MODE_REG); 56 57 /* 58 * Restart the watchdog. The default (and lowest) interval 59 * value for the watchdog is 0.5s. 60 */ 61 writel(WATCHDOG_CTRL_RESTART, wdt_base + WATCHDOG_CTRL_REG); 62 63 while (1) { 64 mdelay(5); 65 writel(WATCHDOG_MODE_ENABLE | WATCHDOG_MODE_RESET_ENABLE, 66 wdt_base + WATCHDOG_MODE_REG); 67 } 68 } 69 70 static struct map_desc sunxi_io_desc[] __initdata = { 71 { 72 .virtual = (unsigned long) SUNXI_REGS_VIRT_BASE, 73 .pfn = __phys_to_pfn(SUNXI_REGS_PHYS_BASE), 74 .length = SUNXI_REGS_SIZE, 75 .type = MT_DEVICE, 76 }, 77 }; 78 79 void __init sunxi_map_io(void) 80 { 81 iotable_init(sunxi_io_desc, ARRAY_SIZE(sunxi_io_desc)); 82 } 83 84 static void __init sunxi_dt_init(void) 85 { 86 sunxi_setup_restart(); 87 88 of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL); 89 } 90 91 static const char * const sunxi_board_dt_compat[] = { 92 "allwinner,sun4i-a10", 93 "allwinner,sun5i-a13", 94 NULL, 95 }; 96 97 DT_MACHINE_START(SUNXI_DT, "Allwinner A1X (Device Tree)") 98 .init_machine = sunxi_dt_init, 99 .map_io = sunxi_map_io, 100 .init_irq = sunxi_init_irq, 101 .handle_irq = sunxi_handle_irq, 102 .restart = sunxi_restart, 103 .init_time = &sunxi_timer_init, 104 .dt_compat = sunxi_board_dt_compat, 105 MACHINE_END 106