1 /*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2001, 06 by Ralf Baechle (ralf@linux-mips.org)
7 * Copyright (C) 2001 MIPS Technologies, Inc.
8 */
9 #include <linux/kernel.h>
10 #include <linux/export.h>
11 #include <linux/pm.h>
12 #include <linux/types.h>
13 #include <linux/reboot.h>
14 #include <linux/delay.h>
15
16 #include <asm/compiler.h>
17 #include <asm/idle.h>
18 #include <asm/mipsregs.h>
19 #include <asm/reboot.h>
20
21 /*
22 * Urgs ... Too many MIPS machines to handle this in a generic way.
23 * So handle all using function pointers to machine specific
24 * functions.
25 */
26 void (*_machine_restart)(char *command);
27 void (*_machine_halt)(void);
28 void (*pm_power_off)(void);
29
30 EXPORT_SYMBOL(pm_power_off);
31
32 static void machine_hang(void)
33 {
34 /*
35 * We're hanging the system so we don't want to be interrupted anymore.
36 * Any interrupt handlers that ran would at best be useless & at worst
37 * go awry because the system isn't in a functional state.
38 */
39 local_irq_disable();
40
41 /*
42 * Mask all interrupts, giving us a better chance of remaining in the
43 * low power wait state.
44 */
45 clear_c0_status(ST0_IM);
46
47 while (true) {
48 if (cpu_has_mips_r) {
49 /*
50 * We know that the wait instruction is supported so
51 * make use of it directly, leaving interrupts
52 * disabled.
53 */
54 asm volatile(
55 ".set push\n\t"
56 ".set " MIPS_ISA_ARCH_LEVEL "\n\t"
57 "wait\n\t"
58 ".set pop");
59 } else if (cpu_wait) {
60 /*
61 * Try the cpu_wait() callback. This isn't ideal since
62 * it'll re-enable interrupts, but that ought to be
63 * harmless given that they're all masked.
64 */
65 cpu_wait();
66 local_irq_disable();
67 } else {
68 /*
69 * We're going to burn some power running round the
70 * loop, but we don't really have a choice. This isn't
71 * a path we should expect to run for long during
72 * typical use anyway.
73 */
74 }
75
76 /*
77 * In most modern MIPS CPUs interrupts will cause the wait
78 * instruction to graduate even when disabled, and in some
79 * cases even when masked. In order to prevent a timer
80 * interrupt from continuously taking us out of the low power
81 * wait state, we clear any pending timer interrupt here.
82 */
83 if (cpu_has_counter)
84 write_c0_compare(0);
85 }
86 }
87
88 void machine_restart(char *command)
89 {
90 if (_machine_restart)
91 _machine_restart(command);
92
93 #ifdef CONFIG_SMP
94 preempt_disable();
95 smp_send_stop();
96 #endif
97 do_kernel_restart(command);
98 mdelay(1000);
99 pr_emerg("Reboot failed -- System halted\n");
100 machine_hang();
101 }
102
103 void machine_halt(void)
104 {
105 if (_machine_halt)
106 _machine_halt();
107
108 #ifdef CONFIG_SMP
109 preempt_disable();
110 smp_send_stop();
111 #endif
112 machine_hang();
113 }
114
115 void machine_power_off(void)
116 {
117 do_kernel_power_off();
118
119 #ifdef CONFIG_SMP
120 preempt_disable();
121 smp_send_stop();
122 #endif
123 machine_hang();
124 }
125
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.