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