1/*
2 *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
3 *  Original Copyright (C) 1995  Linus Torvalds
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9#include <linux/cpu.h>
10#include <linux/delay.h>
11#include <linux/reboot.h>
12
13#include <asm/cacheflush.h>
14#include <asm/idmap.h>
15
16#include "reboot.h"
17
18typedef void (*phys_reset_t)(unsigned long);
19
20/*
21 * Function pointers to optional machine specific functions
22 */
23void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
24void (*pm_power_off)(void);
25EXPORT_SYMBOL(pm_power_off);
26
27/*
28 * A temporary stack to use for CPU reset. This is static so that we
29 * don't clobber it with the identity mapping. When running with this
30 * stack, any references to the current task *will not work* so you
31 * should really do as little as possible before jumping to your reset
32 * code.
33 */
34static u64 soft_restart_stack[16];
35
36static void __soft_restart(void *addr)
37{
38	phys_reset_t phys_reset;
39
40	/* Take out a flat memory mapping. */
41	setup_mm_for_reboot();
42
43	/* Clean and invalidate caches */
44	flush_cache_all();
45
46	/* Turn off caching */
47	cpu_proc_fin();
48
49	/* Push out any further dirty data, and ensure cache is empty */
50	flush_cache_all();
51
52	/* Switch to the identity mapping. */
53	phys_reset = (phys_reset_t)(unsigned long)virt_to_idmap(cpu_reset);
54	phys_reset((unsigned long)addr);
55
56	/* Should never get here. */
57	BUG();
58}
59
60void _soft_restart(unsigned long addr, bool disable_l2)
61{
62	u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
63
64	/* Disable interrupts first */
65	raw_local_irq_disable();
66	local_fiq_disable();
67
68	/* Disable the L2 if we're the last man standing. */
69	if (disable_l2)
70		outer_disable();
71
72	/* Change to the new stack and continue with the reset. */
73	call_with_stack(__soft_restart, (void *)addr, (void *)stack);
74
75	/* Should never get here. */
76	BUG();
77}
78
79void soft_restart(unsigned long addr)
80{
81	_soft_restart(addr, num_online_cpus() == 1);
82}
83
84/*
85 * Called by kexec, immediately prior to machine_kexec().
86 *
87 * This must completely disable all secondary CPUs; simply causing those CPUs
88 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
89 * kexec'd kernel to use any and all RAM as it sees fit, without having to
90 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
91 * functionality embodied in disable_nonboot_cpus() to achieve this.
92 */
93void machine_shutdown(void)
94{
95	disable_nonboot_cpus();
96}
97
98/*
99 * Halting simply requires that the secondary CPUs stop performing any
100 * activity (executing tasks, handling interrupts). smp_send_stop()
101 * achieves this.
102 */
103void machine_halt(void)
104{
105	local_irq_disable();
106	smp_send_stop();
107
108	local_irq_disable();
109	while (1);
110}
111
112/*
113 * Power-off simply requires that the secondary CPUs stop performing any
114 * activity (executing tasks, handling interrupts). smp_send_stop()
115 * achieves this. When the system power is turned off, it will take all CPUs
116 * with it.
117 */
118void machine_power_off(void)
119{
120	local_irq_disable();
121	smp_send_stop();
122
123	if (pm_power_off)
124		pm_power_off();
125}
126
127/*
128 * Restart requires that the secondary CPUs stop performing any activity
129 * while the primary CPU resets the system. Systems with a single CPU can
130 * use soft_restart() as their machine descriptor's .restart hook, since that
131 * will cause the only available CPU to reset. Systems with multiple CPUs must
132 * provide a HW restart implementation, to ensure that all CPUs reset at once.
133 * This is required so that any code running after reset on the primary CPU
134 * doesn't have to co-ordinate with other CPUs to ensure they aren't still
135 * executing pre-reset code, and using RAM that the primary CPU's code wishes
136 * to use. Implementing such co-ordination would be essentially impossible.
137 */
138void machine_restart(char *cmd)
139{
140	local_irq_disable();
141	smp_send_stop();
142
143	if (arm_pm_restart)
144		arm_pm_restart(reboot_mode, cmd);
145	else
146		do_kernel_restart(cmd);
147
148	/* Give a grace period for failure to restart of 1s */
149	mdelay(1000);
150
151	/* Whoops - the platform was unable to reboot. Tell the user! */
152	printk("Reboot failed -- System halted\n");
153	local_irq_disable();
154	while (1);
155}
156