pm.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * loongson-specific suspend support
 *
 *  Copyright (C) 2009 Lemote Inc.
 *  Author: Wu Zhangjin <[email protected]>
 */
#include <linux/suspend.h>
#include <linux/interrupt.h>
#include <linux/pm.h>

#include <asm/i8259.h>
#include <asm/mipsregs.h>

#include <loongson.h>

static unsigned int __maybe_unused cached_master_mask;	/* i8259A */
static unsigned int __maybe_unused cached_slave_mask;
static unsigned int __maybe_unused cached_bonito_irq_mask; /* bonito */

void arch_suspend_disable_irqs(void)
{
	/* disable all mips events */
	local_irq_disable();

#ifdef CONFIG_I8259
	/* disable all events of i8259A */
	cached_slave_mask = inb(PIC_SLAVE_IMR);
	cached_master_mask = inb(PIC_MASTER_IMR);

	outb(0xff, PIC_SLAVE_IMR);
	inb(PIC_SLAVE_IMR);
	outb(0xff, PIC_MASTER_IMR);
	inb(PIC_MASTER_IMR);
#endif
	/* disable all events of bonito */
	cached_bonito_irq_mask = LOONGSON_INTEN;
	LOONGSON_INTENCLR = 0xffff;
	(void)LOONGSON_INTENCLR;
}

void arch_suspend_enable_irqs(void)
{
	/* enable all mips events */
	local_irq_enable();
#ifdef CONFIG_I8259
	/* only enable the cached events of i8259A */
	outb(cached_slave_mask, PIC_SLAVE_IMR);
	outb(cached_master_mask, PIC_MASTER_IMR);
#endif
	/* enable all cached events of bonito */
	LOONGSON_INTENSET = cached_bonito_irq_mask;
	(void)LOONGSON_INTENSET;
}

/*
 * Setup the board-specific events for waking up loongson from wait mode
 */
void __weak setup_wakeup_events(void)
{
}

/*
 * Check wakeup events
 */
int __weak wakeup_loongson(void)
{
	return 1;
}

/*
 * If the events are really what we want to wakeup the CPU, wake it up
 * otherwise put the CPU asleep again.
 */
static void wait_for_wakeup_events(void)
{
	while (!wakeup_loongson())
		writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG);
}

/*
 * Stop all perf counters
 *
 * $24 is the control register of Loongson perf counter
 */
static inline void stop_perf_counters(void)
{
	__write_64bit_c0_register($24, 0, 0);
}


static void loongson_suspend_enter(void)
{
	unsigned int cached_cpu_freq;

	/* setup wakeup events via enabling the IRQs */
	setup_wakeup_events();

	stop_perf_counters();

	cached_cpu_freq = readl(LOONGSON_CHIPCFG);

	/* Put CPU into wait mode */
	writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG);

	/* wait for the given events to wakeup cpu from wait mode */
	wait_for_wakeup_events();

	writel(cached_cpu_freq, LOONGSON_CHIPCFG);

	mmiowb();
}

void __weak mach_suspend(void)
{
}

void __weak mach_resume(void)
{
}

static int loongson_pm_enter(suspend_state_t state)
{
	mach_suspend();

	/* processor specific suspend */
	loongson_suspend_enter();

	mach_resume();

	return 0;
}

static int loongson_pm_valid_state(suspend_state_t state)
{
	switch (state) {
	case PM_SUSPEND_ON:
	case PM_SUSPEND_STANDBY:
	case PM_SUSPEND_MEM:
		return 1;

	default:
		return 0;
	}
}

static const struct platform_suspend_ops loongson_pm_ops = {
	.valid	= loongson_pm_valid_state,
	.enter	= loongson_pm_enter,
};

static int __init loongson_pm_init(void)
{
	suspend_set_ops(&loongson_pm_ops);

	return 0;
}
arch_initcall(loongson_pm_init);