1 /*
2 * Cloned from 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
12 #include <linux/kernel.h>
13 #include <linux/errno.h>
14 #include <linux/smp.h>
15 #include <linux/io.h>
16
17 #include <asm/cacheflush.h>
18 #include <asm/cp15.h>
19 #include <asm/smp_plat.h>
20
21 #include "common.h"
22 #include "regs-pmu.h"
23
cpu_leave_lowpower(void)24 static inline void cpu_leave_lowpower(void)
25 {
26 unsigned int v;
27
28 asm volatile(
29 "mrc p15, 0, %0, c1, c0, 0\n"
30 " orr %0, %0, %1\n"
31 " mcr p15, 0, %0, c1, c0, 0\n"
32 " mrc p15, 0, %0, c1, c0, 1\n"
33 " orr %0, %0, %2\n"
34 " mcr p15, 0, %0, c1, c0, 1\n"
35 : "=&r" (v)
36 : "Ir" (CR_C), "Ir" (0x40)
37 : "cc");
38 }
39
platform_do_lowpower(unsigned int cpu,int * spurious)40 static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
41 {
42 u32 mpidr = cpu_logical_map(cpu);
43 u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);
44
45 for (;;) {
46
47 /* Turn the CPU off on next WFI instruction. */
48 exynos_cpu_power_down(core_id);
49
50 wfi();
51
52 if (pen_release == core_id) {
53 /*
54 * OK, proper wakeup, we're done
55 */
56 break;
57 }
58
59 /*
60 * Getting here, means that we have come out of WFI without
61 * having been woken up - this shouldn't happen
62 *
63 * Just note it happening - when we're woken, we can report
64 * its occurrence.
65 */
66 (*spurious)++;
67 }
68 }
69
70 /*
71 * platform-specific code to shutdown a CPU
72 *
73 * Called with IRQs disabled
74 */
exynos_cpu_die(unsigned int cpu)75 void __ref exynos_cpu_die(unsigned int cpu)
76 {
77 int spurious = 0;
78
79 v7_exit_coherency_flush(louis);
80
81 platform_do_lowpower(cpu, &spurious);
82
83 /*
84 * bring this CPU back into the world of cache
85 * coherency, and then restore interrupts
86 */
87 cpu_leave_lowpower();
88
89 if (spurious)
90 pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
91 }
92