1 /* linux arch/arm/mach-exynos4/hotplug.c
2 *
3 * Cloned from linux/arch/arm/mach-realview/hotplug.c
4 *
5 * Copyright (C) 2002 ARM Ltd.
6 * All Rights Reserved
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/smp.h>
16 #include <linux/io.h>
17
18 #include <asm/cacheflush.h>
19 #include <asm/smp_plat.h>
20
21 #include <mach/regs-pmu.h>
22
23 extern volatile int pen_release;
24
cpu_enter_lowpower(void)25 static inline void cpu_enter_lowpower(void)
26 {
27 unsigned int v;
28
29 flush_cache_all();
30 asm volatile(
31 " mcr p15, 0, %1, c7, c5, 0\n"
32 " mcr p15, 0, %1, c7, c10, 4\n"
33 /*
34 * Turn off coherency
35 */
36 " mrc p15, 0, %0, c1, c0, 1\n"
37 " bic %0, %0, %3\n"
38 " mcr p15, 0, %0, c1, c0, 1\n"
39 " mrc p15, 0, %0, c1, c0, 0\n"
40 " bic %0, %0, %2\n"
41 " mcr p15, 0, %0, c1, c0, 0\n"
42 : "=&r" (v)
43 : "r" (0), "Ir" (CR_C), "Ir" (0x40)
44 : "cc");
45 }
46
cpu_leave_lowpower(void)47 static inline void cpu_leave_lowpower(void)
48 {
49 unsigned int v;
50
51 asm volatile(
52 "mrc p15, 0, %0, c1, c0, 0\n"
53 " orr %0, %0, %1\n"
54 " mcr p15, 0, %0, c1, c0, 0\n"
55 " mrc p15, 0, %0, c1, c0, 1\n"
56 " orr %0, %0, %2\n"
57 " mcr p15, 0, %0, c1, c0, 1\n"
58 : "=&r" (v)
59 : "Ir" (CR_C), "Ir" (0x40)
60 : "cc");
61 }
62
platform_do_lowpower(unsigned int cpu,int * spurious)63 static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
64 {
65 for (;;) {
66
67 /* make cpu1 to be turned off at next WFI command */
68 if (cpu == 1)
69 __raw_writel(0, S5P_ARM_CORE1_CONFIGURATION);
70
71 /*
72 * here's the WFI
73 */
74 asm(".word 0xe320f003\n"
75 :
76 :
77 : "memory", "cc");
78
79 if (pen_release == cpu_logical_map(cpu)) {
80 /*
81 * OK, proper wakeup, we're done
82 */
83 break;
84 }
85
86 /*
87 * Getting here, means that we have come out of WFI without
88 * having been woken up - this shouldn't happen
89 *
90 * Just note it happening - when we're woken, we can report
91 * its occurrence.
92 */
93 (*spurious)++;
94 }
95 }
96
platform_cpu_kill(unsigned int cpu)97 int platform_cpu_kill(unsigned int cpu)
98 {
99 return 1;
100 }
101
102 /*
103 * platform-specific code to shutdown a CPU
104 *
105 * Called with IRQs disabled
106 */
platform_cpu_die(unsigned int cpu)107 void platform_cpu_die(unsigned int cpu)
108 {
109 int spurious = 0;
110
111 /*
112 * we're ready for shutdown now, so do it
113 */
114 cpu_enter_lowpower();
115 platform_do_lowpower(cpu, &spurious);
116
117 /*
118 * bring this CPU back into the world of cache
119 * coherency, and then restore interrupts
120 */
121 cpu_leave_lowpower();
122
123 if (spurious)
124 pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
125 }
126
platform_cpu_disable(unsigned int cpu)127 int platform_cpu_disable(unsigned int cpu)
128 {
129 /*
130 * we don't allow CPU 0 to be shutdown (it is still too special
131 * e.g. clock tick interrupts)
132 */
133 return cpu == 0 ? -EPERM : 0;
134 }
135