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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>
Russell King15d07dc2012-03-28 18:30:01 +010016#include <asm/cp15.h>
Will Deaconeb504392012-01-20 12:01:12 +010017#include <asm/smp_plat.h>
Harry Fearnhamm8aa2da82008-12-01 14:54:56 +000018
Russell King97a63ec2005-11-09 13:50:57 +000019extern volatile int pen_release;
20
Russell King97a63ec2005-11-09 13:50:57 +000021static inline void cpu_enter_lowpower(void)
22{
23 unsigned int v;
24
Harry Fearnhamm8aa2da82008-12-01 14:54:56 +000025 flush_cache_all();
26 asm volatile(
Russell King97a63ec2005-11-09 13:50:57 +000027 " mcr p15, 0, %1, c7, c5, 0\n"
28 " mcr p15, 0, %1, c7, c10, 4\n"
29 /*
30 * Turn off coherency
31 */
32 " mrc p15, 0, %0, c1, c0, 1\n"
33 " bic %0, %0, #0x20\n"
34 " mcr p15, 0, %0, c1, c0, 1\n"
35 " mrc p15, 0, %0, c1, c0, 0\n"
Russell Kinge3d9c622010-12-19 11:36:33 +000036 " bic %0, %0, %2\n"
Russell King97a63ec2005-11-09 13:50:57 +000037 " mcr p15, 0, %0, c1, c0, 0\n"
38 : "=&r" (v)
Russell Kinge3d9c622010-12-19 11:36:33 +000039 : "r" (0), "Ir" (CR_C)
Russell King97a63ec2005-11-09 13:50:57 +000040 : "cc");
41}
42
43static inline void cpu_leave_lowpower(void)
44{
45 unsigned int v;
46
47 asm volatile( "mrc p15, 0, %0, c1, c0, 0\n"
Russell Kinge3d9c622010-12-19 11:36:33 +000048 " orr %0, %0, %1\n"
Russell King97a63ec2005-11-09 13:50:57 +000049 " mcr p15, 0, %0, c1, c0, 0\n"
50 " mrc p15, 0, %0, c1, c0, 1\n"
51 " orr %0, %0, #0x20\n"
52 " mcr p15, 0, %0, c1, c0, 1\n"
53 : "=&r" (v)
Russell Kinge3d9c622010-12-19 11:36:33 +000054 : "Ir" (CR_C)
Russell King97a63ec2005-11-09 13:50:57 +000055 : "cc");
56}
57
Russell Kingd4450262010-12-19 11:30:43 +000058static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
Russell King97a63ec2005-11-09 13:50:57 +000059{
60 /*
61 * there is no power-control hardware on this platform, so all
62 * we can do is put the core into WFI; this is safe as the calling
63 * code will have already disabled interrupts
64 */
65 for (;;) {
66 /*
67 * here's the WFI
68 */
69 asm(".word 0xe320f003\n"
70 :
71 :
72 : "memory", "cc");
73
Will Deacon4a139b62011-08-09 12:24:07 +010074 if (pen_release == cpu_logical_map(cpu)) {
Russell King97a63ec2005-11-09 13:50:57 +000075 /*
76 * OK, proper wakeup, we're done
77 */
78 break;
79 }
80
81 /*
Russell Kingd4450262010-12-19 11:30:43 +000082 * Getting here, means that we have come out of WFI without
Russell King97a63ec2005-11-09 13:50:57 +000083 * having been woken up - this shouldn't happen
84 *
Russell Kingd4450262010-12-19 11:30:43 +000085 * Just note it happening - when we're woken, we can report
86 * its occurrence.
Russell King97a63ec2005-11-09 13:50:57 +000087 */
Russell Kingd4450262010-12-19 11:30:43 +000088 (*spurious)++;
Russell King97a63ec2005-11-09 13:50:57 +000089 }
90}
91
92int platform_cpu_kill(unsigned int cpu)
93{
Russell King3c030be2010-11-30 11:07:35 +000094 return 1;
Russell King97a63ec2005-11-09 13:50:57 +000095}
96
97/*
98 * platform-specific code to shutdown a CPU
99 *
100 * Called with IRQs disabled
101 */
102void platform_cpu_die(unsigned int cpu)
103{
Russell Kingd4450262010-12-19 11:30:43 +0000104 int spurious = 0;
105
Russell King97a63ec2005-11-09 13:50:57 +0000106 /*
107 * we're ready for shutdown now, so do it
108 */
109 cpu_enter_lowpower();
Russell Kingd4450262010-12-19 11:30:43 +0000110 platform_do_lowpower(cpu, &spurious);
Russell King97a63ec2005-11-09 13:50:57 +0000111
112 /*
113 * bring this CPU back into the world of cache
114 * coherency, and then restore interrupts
115 */
116 cpu_leave_lowpower();
Russell Kingd4450262010-12-19 11:30:43 +0000117
118 if (spurious)
119 pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
Russell King97a63ec2005-11-09 13:50:57 +0000120}
121
Russell King8e2a43f2010-05-15 10:18:05 +0100122int platform_cpu_disable(unsigned int cpu)
Russell King97a63ec2005-11-09 13:50:57 +0000123{
124 /*
125 * we don't allow CPU 0 to be shutdown (it is still too special
126 * e.g. clock tick interrupts)
127 */
128 return cpu == 0 ? -EPERM : 0;
129}