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(cmd: 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 | |