xref: /openbmc/linux/arch/arm/mach-sunxi/sunxi.c (revision 31b90347)
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