Linux Kernel  3.7.1
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reset.c
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1 /*
2  * This program is free software; you can redistribute it and/or modify it
3  * under the terms of the GNU General Public License version 2 as published
4  * by the Free Software Foundation.
5  *
6  * Copyright (C) 2010 John Crispin <[email protected]>
7  */
8 
9 #include <linux/init.h>
10 #include <linux/io.h>
11 #include <linux/ioport.h>
12 #include <linux/pm.h>
13 #include <linux/export.h>
14 #include <linux/delay.h>
15 #include <linux/of_address.h>
16 #include <linux/of_platform.h>
17 
18 #include <asm/reboot.h>
19 
20 #include <lantiq_soc.h>
21 
22 #include "../prom.h"
23 
24 #define ltq_rcu_w32(x, y) ltq_w32((x), ltq_rcu_membase + (y))
25 #define ltq_rcu_r32(x) ltq_r32(ltq_rcu_membase + (x))
26 
27 /* reset request register */
28 #define RCU_RST_REQ 0x0010
29 /* reset status register */
30 #define RCU_RST_STAT 0x0014
31 
32 /* reboot bit */
33 #define RCU_RD_SRST BIT(30)
34 /* reset cause */
35 #define RCU_STAT_SHIFT 26
36 /* boot selection */
37 #define RCU_BOOT_SEL_SHIFT 26
38 #define RCU_BOOT_SEL_MASK 0x7
39 
40 /* remapped base addr of the reset control unit */
41 static void __iomem *ltq_rcu_membase;
42 
43 /* This function is used by the watchdog driver */
44 int ltq_reset_cause(void)
45 {
47  return val >> RCU_STAT_SHIFT;
48 }
50 
51 /* allow platform code to find out what source we booted from */
52 unsigned char ltq_boot_select(void)
53 {
55  return (val >> RCU_BOOT_SEL_SHIFT) & RCU_BOOT_SEL_MASK;
56 }
57 
58 /* reset a io domain for u micro seconds */
59 void ltq_reset_once(unsigned int module, ulong u)
60 {
62  udelay(u);
64 }
65 
66 static void ltq_machine_restart(char *command)
67 {
70  unreachable();
71 }
72 
73 static void ltq_machine_halt(void)
74 {
76  unreachable();
77 }
78 
79 static void ltq_machine_power_off(void)
80 {
82  unreachable();
83 }
84 
85 static int __init mips_reboot_setup(void)
86 {
87  struct resource res;
88  struct device_node *np =
89  of_find_compatible_node(NULL, NULL, "lantiq,rcu-xway");
90 
91  /* check if all the reset register range is available */
92  if (!np)
93  panic("Failed to load reset resources from devicetree");
94 
95  if (of_address_to_resource(np, 0, &res))
96  panic("Failed to get rcu memory range");
97 
98  if (request_mem_region(res.start, resource_size(&res), res.name) < 0)
99  pr_err("Failed to request rcu memory");
100 
101  ltq_rcu_membase = ioremap_nocache(res.start, resource_size(&res));
102  if (!ltq_rcu_membase)
103  panic("Failed to remap core memory");
104 
105  _machine_restart = ltq_machine_restart;
106  _machine_halt = ltq_machine_halt;
107  pm_power_off = ltq_machine_power_off;
108 
109  return 0;
110 }
111 
112 arch_initcall(mips_reboot_setup);