/*++
	linux/arch/arm/mach-wmt/platsmp.c

	Copyright (c) 2013  WonderMedia Technologies, Inc.

	Copyright (C) 2002 ARM Ltd.
	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 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.
	You should have received a copy of the GNU General Public License along with
	this program.  If not, see <http://www.gnu.org/licenses/>.

	WonderMedia Technologies, Inc.
	10F, 529, Chung-Cheng Road, Hsin-Tien, Taipei 231, R.O.C.
--*/
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/jiffies.h>
#include <linux/smp.h>
#include <linux/io.h>

#include <linux/syscore_ops.h>

#include <asm/cacheflush.h>
#include <asm/hardware/gic.h>
#include <asm/smp_plat.h>
#include <asm/smp_scu.h>

#include <mach/hardware.h>

extern void wmt_secondary_startup(void);

#define CPU1_BOOT_REG		HSP7_ADDR
/*
 * control for which core is the next to come out of the secondary
 * boot "holding pen"
 */

volatile int __cpuinitdata pen_release = -1;

/*
 * Write pen_release in a way that is guaranteed to be visible to all
 * observers, irrespective of whether they're taking part in coherency
 * or not.  This is necessary for the hotplug code to work reliably.
 */
static void write_pen_release(int val)
{
	pen_release = val;
	smp_wmb();
	__cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
	outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
}

static void __iomem *scu_base_addr(void)
{
	return (void __iomem *)(MPCORE_PRIVATE_MEM);
}

static DEFINE_SPINLOCK(boot_lock);

void __cpuinit platform_secondary_init(unsigned int cpu)
{
	/*
	 * if any interrupts are already enabled for the primary
	 * core (e.g. timer irq), then they will not have been enabled
	 * for us: do so
	 */
	gic_secondary_init(0);

	/*
	 * let the primary processor know we're out of the
	 * pen, then head off into the C entry point
	 */
	write_pen_release(-1);

	/*
	 * Synchronise with the boot thread.
	 */
	spin_lock(&boot_lock);
	spin_unlock(&boot_lock);
}

int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
{
	unsigned long timeout;

	/*
	 * Set synchronisation state between this boot processor
	 * and the secondary one
	 */
	spin_lock(&boot_lock);

	/*
	 * This is really belt and braces; we hold unintended secondary
	 * CPUs in the holding pen until we're ready for them.  However,
	 * since we haven't sent them a soft interrupt, they shouldn't
	 * be there.
	 */
	write_pen_release(cpu_logical_map(cpu));

	/*
	 * Send the secondary CPU a soft interrupt, thereby causing
	 * the boot monitor to read the system wide flags register,
	 * and branch to the address found there.
	 */

	timeout = jiffies + (1 * HZ);
	while (time_before(jiffies, timeout)) {
		smp_rmb();

		__raw_writel(virt_to_phys(wmt_secondary_startup),
			CPU1_BOOT_REG);
		gic_raise_softirq(cpumask_of(cpu), 1);

		if (pen_release == -1)
			break;

		udelay(10);
	}

	/*
	 * now the secondary core is starting up let it run its
	 * calibrations, then wait for it to finish
	 */
	spin_unlock(&boot_lock);

	return pen_release != -1 ? -ENOSYS : 0;
}

/*
 * Initialise the CPU possible map early - this describes the CPUs
 * which may be present or become present in the system.
 */

void __init smp_init_cpus(void)
{
	void __iomem *scu_base = scu_base_addr();
	unsigned int i, ncores;

	ncores = scu_base ? scu_get_core_count(scu_base) : 1;

	/* sanity check */
	if (ncores > nr_cpu_ids) {
		pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
			ncores, nr_cpu_ids);
		ncores = nr_cpu_ids;
	}

	for (i = 0; i < ncores; i++)
		set_cpu_possible(i, true);

	set_smp_cross_call(gic_raise_softirq);
}

void __init platform_smp_prepare_cpus(unsigned int max_cpus)
{
	*(volatile unsigned int *)MPCORE_PRIVATE_MEM |= BIT5 | BIT6;
	scu_enable(scu_base_addr());

	/*
	 * Write the address of secondary startup into the
	 * system-wide flags register. The boot monitor waits
	 * until it receives a soft interrupt, and then the
	 * secondary CPU branches to this address.
	 */
	__raw_writel(virt_to_phys(wmt_secondary_startup),
			CPU1_BOOT_REG);
}

static int wmt_pm_suspend(void)
{
	return 0;
}

static void wmt_pm_resume(void)
{
#ifdef CONFIG_SMP
	*(volatile unsigned int *)MPCORE_PRIVATE_MEM |= BIT5 | BIT6;
	scu_enable(scu_base_addr());
#endif
	return;
}

static struct syscore_ops wmt_pm_syscore_ops = {
	.suspend	= wmt_pm_suspend,
	.resume		= wmt_pm_resume,
};

static __init int wmt_pm_syscore_init(void)
{
	register_syscore_ops(&wmt_pm_syscore_ops);
	return 0;
}
arch_initcall(wmt_pm_syscore_init);