2 * linux/arch/arm/mach-spear13xx/hotplug.c
4 * Copyright (C) 2012 ST Microelectronics Ltd.
5 * Deepak Sikri <deepak.sikri@st.com>
7 * based upon linux/arch/arm/mach-realview/hotplug.c
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/smp.h>
16 #include <asm/cacheflush.h>
18 #include <asm/smp_plat.h>
20 extern volatile int pen_release;
22 static inline void cpu_enter_lowpower(void)
28 " mcr p15, 0, %1, c7, c5, 0\n"
33 " mrc p15, 0, %0, c1, c0, 1\n"
34 " bic %0, %0, #0x20\n"
35 " mcr p15, 0, %0, c1, c0, 1\n"
36 " mrc p15, 0, %0, c1, c0, 0\n"
38 " mcr p15, 0, %0, c1, c0, 0\n"
40 : "r" (0), "Ir" (CR_C)
44 static inline void cpu_leave_lowpower(void)
48 asm volatile("mrc p15, 0, %0, c1, c0, 0\n"
50 " mcr p15, 0, %0, c1, c0, 0\n"
51 " mrc p15, 0, %0, c1, c0, 1\n"
52 " orr %0, %0, #0x20\n"
53 " mcr p15, 0, %0, c1, c0, 1\n"
59 static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
64 if (pen_release == cpu) {
66 * OK, proper wakeup, we're done
72 * Getting here, means that we have come out of WFI without
73 * having been woken up - this shouldn't happen
75 * Just note it happening - when we're woken, we can report
82 int platform_cpu_kill(unsigned int cpu)
88 * platform-specific code to shutdown a CPU
90 * Called with IRQs disabled
92 void __cpuinit platform_cpu_die(unsigned int cpu)
97 * we're ready for shutdown now, so do it
100 platform_do_lowpower(cpu, &spurious);
103 * bring this CPU back into the world of cache
104 * coherency, and then restore interrupts
106 cpu_leave_lowpower();
109 pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
112 int platform_cpu_disable(unsigned int cpu)
115 * we don't allow CPU 0 to be shutdown (it is still too special
116 * e.g. clock tick interrupts)
118 return cpu == 0 ? -EPERM : 0;