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Russell King97a63ec2005-11-09 13:50:57 +00001/*
2 * linux/arch/arm/mach-realview/hotplug.c
3 *
4 * Copyright (C) 2002 ARM Ltd.
5 * All Rights Reserved
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11#include <linux/kernel.h>
12#include <linux/errno.h>
13#include <linux/smp.h>
Russell King97a63ec2005-11-09 13:50:57 +000014
Harry Fearnhamm8aa2da82008-12-01 14:54:56 +000015#include <asm/cacheflush.h>
16
Russell King97a63ec2005-11-09 13:50:57 +000017extern volatile int pen_release;
18
Russell King97a63ec2005-11-09 13:50:57 +000019static inline void cpu_enter_lowpower(void)
20{
21 unsigned int v;
22
Harry Fearnhamm8aa2da82008-12-01 14:54:56 +000023 flush_cache_all();
24 asm volatile(
Russell King97a63ec2005-11-09 13:50:57 +000025 " mcr p15, 0, %1, c7, c5, 0\n"
26 " mcr p15, 0, %1, c7, c10, 4\n"
27 /*
28 * Turn off coherency
29 */
30 " mrc p15, 0, %0, c1, c0, 1\n"
31 " bic %0, %0, #0x20\n"
32 " mcr p15, 0, %0, c1, c0, 1\n"
33 " mrc p15, 0, %0, c1, c0, 0\n"
Russell Kinge3d9c622010-12-19 11:36:33 +000034 " bic %0, %0, %2\n"
Russell King97a63ec2005-11-09 13:50:57 +000035 " mcr p15, 0, %0, c1, c0, 0\n"
36 : "=&r" (v)
Russell Kinge3d9c622010-12-19 11:36:33 +000037 : "r" (0), "Ir" (CR_C)
Russell King97a63ec2005-11-09 13:50:57 +000038 : "cc");
39}
40
41static inline void cpu_leave_lowpower(void)
42{
43 unsigned int v;
44
45 asm volatile( "mrc p15, 0, %0, c1, c0, 0\n"
Russell Kinge3d9c622010-12-19 11:36:33 +000046 " orr %0, %0, %1\n"
Russell King97a63ec2005-11-09 13:50:57 +000047 " mcr p15, 0, %0, c1, c0, 0\n"
48 " mrc p15, 0, %0, c1, c0, 1\n"
49 " orr %0, %0, #0x20\n"
50 " mcr p15, 0, %0, c1, c0, 1\n"
51 : "=&r" (v)
Russell Kinge3d9c622010-12-19 11:36:33 +000052 : "Ir" (CR_C)
Russell King97a63ec2005-11-09 13:50:57 +000053 : "cc");
54}
55
Russell Kingd4450262010-12-19 11:30:43 +000056static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
Russell King97a63ec2005-11-09 13:50:57 +000057{
58 /*
59 * there is no power-control hardware on this platform, so all
60 * we can do is put the core into WFI; this is safe as the calling
61 * code will have already disabled interrupts
62 */
63 for (;;) {
64 /*
65 * here's the WFI
66 */
67 asm(".word 0xe320f003\n"
68 :
69 :
70 : "memory", "cc");
71
Will Deacon4a139b62011-08-09 12:24:07 +010072 if (pen_release == cpu_logical_map(cpu)) {
Russell King97a63ec2005-11-09 13:50:57 +000073 /*
74 * OK, proper wakeup, we're done
75 */
76 break;
77 }
78
79 /*
Russell Kingd4450262010-12-19 11:30:43 +000080 * Getting here, means that we have come out of WFI without
Russell King97a63ec2005-11-09 13:50:57 +000081 * having been woken up - this shouldn't happen
82 *
Russell Kingd4450262010-12-19 11:30:43 +000083 * Just note it happening - when we're woken, we can report
84 * its occurrence.
Russell King97a63ec2005-11-09 13:50:57 +000085 */
Russell Kingd4450262010-12-19 11:30:43 +000086 (*spurious)++;
Russell King97a63ec2005-11-09 13:50:57 +000087 }
88}
89
90int platform_cpu_kill(unsigned int cpu)
91{
Russell King3c030be2010-11-30 11:07:35 +000092 return 1;
Russell King97a63ec2005-11-09 13:50:57 +000093}
94
95/*
96 * platform-specific code to shutdown a CPU
97 *
98 * Called with IRQs disabled
99 */
100void platform_cpu_die(unsigned int cpu)
101{
Russell Kingd4450262010-12-19 11:30:43 +0000102 int spurious = 0;
103
Russell King97a63ec2005-11-09 13:50:57 +0000104 /*
105 * we're ready for shutdown now, so do it
106 */
107 cpu_enter_lowpower();
Russell Kingd4450262010-12-19 11:30:43 +0000108 platform_do_lowpower(cpu, &spurious);
Russell King97a63ec2005-11-09 13:50:57 +0000109
110 /*
111 * bring this CPU back into the world of cache
112 * coherency, and then restore interrupts
113 */
114 cpu_leave_lowpower();
Russell Kingd4450262010-12-19 11:30:43 +0000115
116 if (spurious)
117 pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
Russell King97a63ec2005-11-09 13:50:57 +0000118}
119
Russell King8e2a43f2010-05-15 10:18:05 +0100120int platform_cpu_disable(unsigned int cpu)
Russell King97a63ec2005-11-09 13:50:57 +0000121{
122 /*
123 * we don't allow CPU 0 to be shutdown (it is still too special
124 * e.g. clock tick interrupts)
125 */
126 return cpu == 0 ? -EPERM : 0;
127}