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/*
* arch/arm/common/mcpm_entry.c -- entry point for multi-cluster PM
*
* Created by: Nicolas Pitre, March 2012
* Copyright: (C) 2012-2013 Linaro Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/irqflags.h>
#include <asm/mcpm.h>
#include <asm/cacheflush.h>
extern unsigned long mcpm_entry_vectors[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER];
void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr)
{
unsigned long val = ptr ? virt_to_phys(ptr) : 0;
mcpm_entry_vectors[cluster][cpu] = val;
sync_cache_w(&mcpm_entry_vectors[cluster][cpu]);
}
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static const struct mcpm_platform_ops *platform_ops;
int __init mcpm_platform_register(const struct mcpm_platform_ops *ops)
{
if (platform_ops)
return -EBUSY;
platform_ops = ops;
return 0;
}
int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster)
{
if (!platform_ops)
return -EUNATCH; /* try not to shadow power_up errors */
might_sleep();
return platform_ops->power_up(cpu, cluster);
}
typedef void (*phys_reset_t)(unsigned long);
void mcpm_cpu_power_down(void)
{
phys_reset_t phys_reset;
BUG_ON(!platform_ops);
BUG_ON(!irqs_disabled());
/*
* Do this before calling into the power_down method,
* as it might not always be safe to do afterwards.
*/
setup_mm_for_reboot();
platform_ops->power_down();
/*
* It is possible for a power_up request to happen concurrently
* with a power_down request for the same CPU. In this case the
* power_down method might not be able to actually enter a
* powered down state with the WFI instruction if the power_up
* method has removed the required reset condition. The
* power_down method is then allowed to return. We must perform
* a re-entry in the kernel as if the power_up method just had
* deasserted reset on the CPU.
*
* To simplify race issues, the platform specific implementation
* must accommodate for the possibility of unordered calls to
* power_down and power_up with a usage count. Therefore, if a
* call to power_up is issued for a CPU that is not down, then
* the next call to power_down must not attempt a full shutdown
* but only do the minimum (normally disabling L1 cache and CPU
* coherency) and return just as if a concurrent power_up request
* had happened as described above.
*/
phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
phys_reset(virt_to_phys(mcpm_entry_point));
/* should never get here */
BUG();
}
void mcpm_cpu_suspend(u64 expected_residency)
{
phys_reset_t phys_reset;
BUG_ON(!platform_ops);
BUG_ON(!irqs_disabled());
/* Very similar to mcpm_cpu_power_down() */
setup_mm_for_reboot();
platform_ops->suspend(expected_residency);
phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
phys_reset(virt_to_phys(mcpm_entry_point));
BUG();
}
int mcpm_cpu_powered_up(void)
{
if (!platform_ops)
return -EUNATCH;
if (platform_ops->powered_up)
platform_ops->powered_up();
return 0;
}