/*
 * Sunxi platform smp source file.
 * It contains platform specific fucntions needed for the linux smp kernel.
 *
 * Copyright (c) Allwinner.  All rights reserved.
 * Sugar (shuge@allwinnertech.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/delay.h>
#include <asm/cacheflush.h>
#include <asm/io.h>

#include "platsmp.h"

static cpumask_t dead_cpus;

int sunxi_cpu_kill(unsigned int cpu)
{
	int k, tmp_cpu = get_cpu();

	put_cpu();
	pr_debug("%s: cpu%d try to kill cpu%d\n", __func__, tmp_cpu, cpu);

	for (k = 0; k < 1000; k++) {
		if (cpumask_test_cpu(cpu, &dead_cpus)) {
			if (sunxi_is_wfi_mode(cpu)) {
				sunxi_disable_cpu(cpu);
				pr_debug("%s: cpu%d is killed!\n",
						__func__, cpu);
#ifdef CONFIG_ARM_SUNXI_CPUIDLE
				sunxi_idle_cpux_flag_valid(cpu, 1);
#endif
				return 1;
			}
		}

		mdelay(1);
	}

	pr_err("%s: try to kill cpu%d failed!\n", __func__, cpu);
	return 0;
}

int sunxi_cpu_disable(unsigned int cpu)
{
	cpumask_clear_cpu(cpu, &dead_cpus);
	return cpu == 0 ? -EPERM : 0;
}

void sunxi_cpu_die(unsigned int cpu)
{
	unsigned long actlr;

	cpumask_set_cpu(cpu, &dead_cpus);

#ifdef CONFIG_ARM_SUNXI_CPUIDLE
	sunxi_idle_cpux_flag_set(cpu, 1);
#endif

	/* step1: disable the data cache */
	asm("mrc p15, 0, %0, c1, c0, 0" : "=r" (actlr));
	actlr &= ~(1<<2);
	asm volatile("mcr p15, 0, %0, c1, c0, 0\n" : : "r" (actlr));

	/* step2: clean and ivalidate L1 cache */
	flush_cache_all();

	/* step3: execute a CLREX instruction */
	asm("clrex" : : : "memory", "cc");

	/* step4: switch cpu from SMP mode to AMP mode,
	 * aim is to disable cache coherency
	 */
	asm("mrc p15, 0, %0, c1, c0, 1" : "=r" (actlr));
	actlr &= ~(1<<6);
	asm volatile("mcr p15, 0, %0, c1, c0, 1\n" : : "r" (actlr));

	/* step5: execute an ISB instruction */
	isb();

	/* step6: execute a DSB instruction  */
	dsb();

	/* step7: execute a WFI instruction */
	while (1)
		asm("wfi" : : : "memory", "cc");
}