2 * linux/arch/arm/mach-realview/hotplug.c
4 * Copyright (C) 2002 ARM Ltd.
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.
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/smp.h>
15 #include <asm/cacheflush.h>
17 static inline void cpu_enter_lowpower(void)
23 " mcr p15, 0, %1, c7, c5, 0\n"
24 " mcr p15, 0, %1, c7, c10, 4\n"
28 " mrc p15, 0, %0, c1, c0, 1\n"
29 " bic %0, %0, #0x20\n"
30 " mcr p15, 0, %0, c1, c0, 1\n"
31 " mrc p15, 0, %0, c1, c0, 0\n"
32 " bic %0, %0, #0x04\n"
33 " mcr p15, 0, %0, c1, c0, 0\n"
39 static inline void cpu_leave_lowpower(void)
44 "mrc p15, 0, %0, c1, c0, 0\n"
45 " orr %0, %0, #0x04\n"
46 " mcr p15, 0, %0, c1, c0, 0\n"
47 " mrc p15, 0, %0, c1, c0, 1\n"
48 " orr %0, %0, #0x20\n"
49 " mcr p15, 0, %0, c1, c0, 1\n"
55 static inline void platform_do_lowpower(unsigned int cpu)
58 * there is no power-control hardware on this platform, so all
59 * we can do is put the core into WFI; this is safe as the calling
60 * code will have already disabled interrupts
66 asm(".word 0xe320f003\n"
71 /*if (pen_release == cpu) {*/
73 * OK, proper wakeup, we're done
79 * getting here, means that we have come out of WFI without
80 * having been woken up - this shouldn't happen
82 * The trouble is, letting people know about this is not really
83 * possible, since we are currently running incoherently, and
84 * therefore cannot safely call printk() or anything else
87 printk(KERN_WARN "CPU%u: spurious wakeup call\n", cpu);
92 int platform_cpu_kill(unsigned int cpu)
98 * platform-specific code to shutdown a CPU
100 * Called with IRQs disabled
102 void platform_cpu_die(unsigned int cpu)
105 * we're ready for shutdown now, so do it
107 cpu_enter_lowpower();
108 platform_do_lowpower(cpu);
111 * bring this CPU back into the world of cache
112 * coherency, and then restore interrupts
114 cpu_leave_lowpower();
117 int platform_cpu_disable(unsigned int cpu)
120 * we don't allow CPU 0 to be shutdown (it is still too special
121 * e.g. clock tick interrupts)
123 return cpu == 0 ? -EPERM : 0;