2 * Device Tree support for Allwinner A1X SoCs
4 * Copyright (C) 2012 Maxime Ripard
6 * Maxime Ripard <maxime.ripard@free-electrons.com>
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.
13 #include <linux/clocksource.h>
14 #include <linux/delay.h>
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/of_address.h>
18 #include <linux/of_irq.h>
19 #include <linux/of_platform.h>
22 #include <linux/clk/sunxi.h>
24 #include <asm/mach/arch.h>
25 #include <asm/mach/map.h>
26 #include <asm/system_misc.h>
28 #define SUN4I_WATCHDOG_CTRL_REG 0x00
29 #define SUN4I_WATCHDOG_CTRL_RESTART (1 << 0)
30 #define SUN4I_WATCHDOG_MODE_REG 0x04
31 #define SUN4I_WATCHDOG_MODE_ENABLE (1 << 0)
32 #define SUN4I_WATCHDOG_MODE_RESET_ENABLE (1 << 1)
34 static void __iomem *wdt_base;
36 static void sun4i_restart(char mode, const char *cmd)
41 /* Enable timer and set reset bit in the watchdog */
42 writel(SUN4I_WATCHDOG_MODE_ENABLE | SUN4I_WATCHDOG_MODE_RESET_ENABLE,
43 wdt_base + SUN4I_WATCHDOG_MODE_REG);
46 * Restart the watchdog. The default (and lowest) interval
47 * value for the watchdog is 0.5s.
49 writel(SUN4I_WATCHDOG_CTRL_RESTART, wdt_base + SUN4I_WATCHDOG_CTRL_REG);
53 writel(SUN4I_WATCHDOG_MODE_ENABLE | SUN4I_WATCHDOG_MODE_RESET_ENABLE,
54 wdt_base + SUN4I_WATCHDOG_MODE_REG);
58 static struct of_device_id sunxi_restart_ids[] = {
59 { .compatible = "allwinner,sun4i-wdt", .data = sun4i_restart },
63 static void sunxi_setup_restart(void)
65 const struct of_device_id *of_id;
66 struct device_node *np;
68 np = of_find_matching_node(NULL, sunxi_restart_ids);
69 if (WARN(!np, "unable to setup watchdog restart"))
72 wdt_base = of_iomap(np, 0);
73 WARN(!wdt_base, "failed to map watchdog base address");
75 of_id = of_match_node(sunxi_restart_ids, np);
76 WARN(!of_id, "restart function not available");
78 arm_pm_restart = of_id->data;
81 static void __init sunxi_timer_init(void)
84 clocksource_of_init();
87 static void __init sunxi_dt_init(void)
89 sunxi_setup_restart();
91 of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
94 static const char * const sunxi_board_dt_compat[] = {
95 "allwinner,sun4i-a10",
96 "allwinner,sun5i-a10s",
97 "allwinner,sun5i-a13",
101 DT_MACHINE_START(SUNXI_DT, "Allwinner A1X (Device Tree)")
102 .init_machine = sunxi_dt_init,
103 .init_time = sunxi_timer_init,
104 .dt_compat = sunxi_board_dt_compat,