msm: platsmp: snapshot of the smp ops

/*

 *  Copyright (C) 2002 ARM Ltd.

 *  All Rights Reserved

 *  Copyright (c) 2011-2014, 2016, 2018, The Linux Foundation.

 *  All rights reserved.

 *

 * 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/errno.h>

#include <linux/smp.h>

#include <linux/cpu.h>

#include <linux/notifier.h>

#include <soc/qcom/spm.h>

#include <soc/qcom/pm.h>

#include <linux/irqchip/arm-gic.h>

#include <asm/smp_plat.h>

#include <asm/vfp.h>

#include <soc/qcom/jtag.h>

static cpumask_t cpu_dying_mask;

static DEFINE_PER_CPU(unsigned int, warm_boot_flag);

static inline void cpu_enter_lowpower(void)

{

}

static inline void cpu_leave_lowpower(void)

{

}

static inline void platform_do_lowpower(unsigned int cpu, int *spurious)

{

	/* Just enter wfi for now. TODO: Properly shut off the cpu. */

	for (;;) {

		lpm_cpu_hotplug_enter(cpu);

		if (pen_release == cpu_logical_map(cpu)) {

			/*

			 * OK, proper wakeup, we're done

			 */

			break;

		}

		/*

		 * getting here, means that we have come out of WFI without

		 * having been woken up - this shouldn't happen

		 *

		 * The trouble is, letting people know about this is not really

		 * possible, since we are currently running incoherently, and

		 * therefore cannot safely call printk() or anything else

		 * Read the pending interrupts to understand why we woke up

		 */

#ifdef CONFIG_MSM_PM

		gic_show_pending_irq();

#endif

		(*spurious)++;

	}

}

int msm_cpu_kill(unsigned int cpu)

{

	int ret = 0;

	if (cpumask_test_and_clear_cpu(cpu, &cpu_dying_mask))

		ret = msm_pm_wait_cpu_shutdown(cpu);

	return ret ? 0 : 1;

}

/*

 * platform-specific code to shutdown a CPU

 *

 * Called with IRQs disabled

 */

void __ref msm_cpu_die(unsigned int cpu)

{

	int spurious = 0;

	if (unlikely(cpu != smp_processor_id())) {

		pr_crit("%s: running on %u, should be %u\n",

			__func__, smp_processor_id(), cpu);

		WARN_ON(cpu);

	}

	/*

	 * we're ready for shutdown now, so do it

	 */

	cpu_enter_lowpower();

	platform_do_lowpower(cpu, &spurious);

	pr_debug("CPU%u: %s: normal wakeup\n", cpu, __func__);

	cpu_leave_lowpower();

	if (spurious)

		pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);

}

static int hotplug_dying_callback(struct notifier_block *nfb,

				unsigned long action, void *hcpu)

{

	switch (action & (~CPU_TASKS_FROZEN)) {

	case CPU_DYING:

		cpumask_set_cpu((unsigned long)hcpu, &cpu_dying_mask);

		break;

	default:

		break;

	}

	return NOTIFY_OK;

}

static struct notifier_block hotplug_dying_notifier = {

	.notifier_call = hotplug_dying_callback,

};

int msm_platform_secondary_init(unsigned int cpu)

{

	int ret;

	unsigned int *warm_boot = &__get_cpu_var(warm_boot_flag);

	if (!(*warm_boot)) {

		*warm_boot = 1;

		/*

		 * All CPU0 boots are considered warm boots (restore needed)

		 * since CPU0 is the system boot CPU and never cold-booted

		 * by the kernel.

		 */

		if (cpu)

			return 0;

	}

	msm_jtag_restore_state();

#if defined(CONFIG_VFP) && defined(CONFIG_CPU_PM)

	vfp_pm_resume();

#endif

	ret = msm_spm_set_low_power_mode(MSM_SPM_MODE_CLOCK_GATING, false);

	return ret;

}

static int __init init_hotplug_dying(void)

{

	return register_hotcpu_notifier(&hotplug_dying_notifier);

}

early_initcall(init_hotplug_dying);