eb50439b92
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>
61 lines
1.1 KiB
C
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;
|
|
}
|