linux/arch/arm/mach-ux500/hotplug.c
Will Deacon eb50439b92 ARM: 7293/1: logical_cpu_map: decouple CPU mapping from SMP
It turns out that the logical CPU mapping is useful even when !CONFIG_SMP
for manipulation of devices like interrupt and power controllers when
running a UP kernel on a CPU other than 0. This can happen when kexecing
a UP image from an SMP kernel.

In the future, multi-cluster systems running AMP configurations will
require something similar for mapping cluster IDs, so it makes sense to
decouple this logic in preparation for this support.

Acked-by: Yang Bai <hamo.by@gmail.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reported-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-01-23 10:20:05 +00:00

61 lines
1.1 KiB
C

/*
* Copyright (C) STMicroelectronics 2009
* Copyright (C) ST-Ericsson SA 2010
*
* License Terms: GNU General Public License v2
* Based on ARM realview platform
*
* Author: Sundar Iyer <sundar.iyer@stericsson.com>
*
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/smp.h>
#include <asm/cacheflush.h>
#include <asm/smp_plat.h>
extern volatile int pen_release;
static inline void platform_do_lowpower(unsigned int cpu)
{
flush_cache_all();
/* we put the platform to just WFI */
for (;;) {
__asm__ __volatile__("dsb\n\t" "wfi\n\t"
: : : "memory");
if (pen_release == cpu_logical_map(cpu)) {
/*
* OK, proper wakeup, we're done
*/
break;
}
}
}
int platform_cpu_kill(unsigned int cpu)
{
return 1;
}
/*
* platform-specific code to shutdown a CPU
*
* Called with IRQs disabled
*/
void platform_cpu_die(unsigned int cpu)
{
/* directly enter low power state, skipping secure registers */
platform_do_lowpower(cpu);
}
int platform_cpu_disable(unsigned int cpu)
{
/*
* we don't allow CPU 0 to be shutdown (it is still too special
* e.g. clock tick interrupts)
*/
return cpu == 0 ? -EPERM : 0;
}