/*
 * Copyright (C) 2015 Freescale Semiconductor, Inc.
 *
 * 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/of_address.h>
#include <linux/of_irq.h>
#include <linux/slab.h>
#include <linux/irqchip.h>
#include <linux/syscore_ops.h>

#define IMR_NUM			4
#define GPC_MAX_IRQS            (IMR_NUM * 32)

#define GPC_IMR1_CORE0		0x30
#define GPC_IMR1_CORE1		0x40

struct gpcv2_irqchip_data {
	struct raw_spinlock	rlock;
	void __iomem		*gpc_base;
	u32			wakeup_sources[IMR_NUM];
	u32			saved_irq_mask[IMR_NUM];
	u32			cpu2wakeup;
};

static struct gpcv2_irqchip_data *imx_gpcv2_instance;

/*
 * Interface for the low level wakeup code.
 */
u32 imx_gpcv2_get_wakeup_source(u32 **sources)
{
	if (!imx_gpcv2_instance)
		return 0;

	if (sources)
		*sources = imx_gpcv2_instance->wakeup_sources;

	return IMR_NUM;
}

static int gpcv2_wakeup_source_save(void)
{
	struct gpcv2_irqchip_data *cd;
	void __iomem *reg;
	int i;

	cd = imx_gpcv2_instance;
	if (!cd)
		return 0;

	for (i = 0; i < IMR_NUM; i++) {
		reg = cd->gpc_base + cd->cpu2wakeup + i * 4;
		cd->saved_irq_mask[i] = readl_relaxed(reg);
		writel_relaxed(cd->wakeup_sources[i], reg);
	}

	return 0;
}

static void gpcv2_wakeup_source_restore(void)
{
	struct gpcv2_irqchip_data *cd;
	void __iomem *reg;
	int i;

	cd = imx_gpcv2_instance;
	if (!cd)
		return;

	for (i = 0; i < IMR_NUM; i++) {
		reg = cd->gpc_base + cd->cpu2wakeup + i * 4;
		writel_relaxed(cd->saved_irq_mask[i], reg);
	}
}

static struct syscore_ops imx_gpcv2_syscore_ops = {
	.suspend	= gpcv2_wakeup_source_save,
	.resume		= gpcv2_wakeup_source_restore,
};

static int imx_gpcv2_irq_set_wake(struct irq_data *d, unsigned int on)
{
	struct gpcv2_irqchip_data *cd = d->chip_data;
	unsigned int idx = d->hwirq / 32;
	unsigned long flags;
	void __iomem *reg;
	u32 mask, val;

	raw_spin_lock_irqsave(&cd->rlock, flags);
	reg = cd->gpc_base + cd->cpu2wakeup + idx * 4;
	mask = 1 << d->hwirq % 32;
	val = cd->wakeup_sources[idx];

	cd->wakeup_sources[idx] = on ? (val & ~mask) : (val | mask);
	raw_spin_unlock_irqrestore(&cd->rlock, flags);

	/*
	 * Do *not* call into the parent, as the GIC doesn't have any
	 * wake-up facility...
	 */

	return 0;
}

static void imx_gpcv2_irq_unmask(struct irq_data *d)
{
	struct gpcv2_irqchip_data *cd = d->chip_data;
	void __iomem *reg;
	u32 val;

	raw_spin_lock(&cd->rlock);
	reg = cd->gpc_base + cd->cpu2wakeup + d->hwirq / 32 * 4;
	val = readl_relaxed(reg);
	val &= ~(1 << d->hwirq % 32);
	writel_relaxed(val, reg);
	raw_spin_unlock(&cd->rlock);

	irq_chip_unmask_parent(d);
}

static void imx_gpcv2_irq_mask(struct irq_data *d)
{
	struct gpcv2_irqchip_data *cd = d->chip_data;
	void __iomem *reg;
	u32 val;

	raw_spin_lock(&cd->rlock);
	reg = cd->gpc_base + cd->cpu2wakeup + d->hwirq / 32 * 4;
	val = readl_relaxed(reg);
	val |= 1 << (d->hwirq % 32);
	writel_relaxed(val, reg);
	raw_spin_unlock(&cd->rlock);

	irq_chip_mask_parent(d);
}

static struct irq_chip gpcv2_irqchip_data_chip = {
	.name			= "GPCv2",
	.irq_eoi		= irq_chip_eoi_parent,
	.irq_mask		= imx_gpcv2_irq_mask,
	.irq_unmask		= imx_gpcv2_irq_unmask,
	.irq_set_wake		= imx_gpcv2_irq_set_wake,
	.irq_retrigger		= irq_chip_retrigger_hierarchy,
#ifdef CONFIG_SMP
	.irq_set_affinity	= irq_chip_set_affinity_parent,
#endif
};

static int imx_gpcv2_domain_xlate(struct irq_domain *domain,
				struct device_node *controller,
				const u32 *intspec,
				unsigned int intsize,
				unsigned long *out_hwirq,
				unsigned int *out_type)
{
	/* Shouldn't happen, really... */
	if (domain->of_node != controller)
		return -EINVAL;

	/* Not GIC compliant */
	if (intsize != 3)
		return -EINVAL;

	/* No PPI should point to this domain */
	if (intspec[0] != 0)
		return -EINVAL;

	*out_hwirq = intspec[1];
	*out_type = intspec[2];
	return 0;
}

static int imx_gpcv2_domain_alloc(struct irq_domain *domain,
				  unsigned int irq, unsigned int nr_irqs,
				  void *data)
{
	struct of_phandle_args *args = data;
	struct of_phandle_args parent_args;
	irq_hw_number_t hwirq;
	int i;

	/* Not GIC compliant */
	if (args->args_count != 3)
		return -EINVAL;

	/* No PPI should point to this domain */
	if (args->args[0] != 0)
		return -EINVAL;

	/* Can't deal with this */
	hwirq = args->args[1];
	if (hwirq >= GPC_MAX_IRQS)
		return -EINVAL;

	for (i = 0; i < nr_irqs; i++) {
		irq_domain_set_hwirq_and_chip(domain, irq + i, hwirq + i,
				&gpcv2_irqchip_data_chip, domain->host_data);
	}

	parent_args = *args;
	parent_args.np = domain->parent->of_node;
	return irq_domain_alloc_irqs_parent(domain, irq, nr_irqs, &parent_args);
}

static struct irq_domain_ops gpcv2_irqchip_data_domain_ops = {
	.xlate	= imx_gpcv2_domain_xlate,
	.alloc	= imx_gpcv2_domain_alloc,
	.free	= irq_domain_free_irqs_common,
};

static int __init imx_gpcv2_irqchip_init(struct device_node *node,
			       struct device_node *parent)
{
	struct irq_domain *parent_domain, *domain;
	struct gpcv2_irqchip_data *cd;
	int i;

	if (!parent) {
		pr_err("%s: no parent, giving up\n", node->full_name);
		return -ENODEV;
	}

	parent_domain = irq_find_host(parent);
	if (!parent_domain) {
		pr_err("%s: unable to get parent domain\n", node->full_name);
		return -ENXIO;
	}

	cd = kzalloc(sizeof(struct gpcv2_irqchip_data), GFP_KERNEL);
	if (!cd) {
		pr_err("kzalloc failed!\n");
		return -ENOMEM;
	}

	cd->gpc_base = of_iomap(node, 0);
	if (!cd->gpc_base) {
		pr_err("fsl-gpcv2: unable to map gpc registers\n");
		kfree(cd);
		return -ENOMEM;
	}

	domain = irq_domain_add_hierarchy(parent_domain, 0, GPC_MAX_IRQS,
				node, &gpcv2_irqchip_data_domain_ops, cd);
	if (!domain) {
		iounmap(cd->gpc_base);
		kfree(cd);
		return -ENOMEM;
	}
	irq_set_default_host(domain);

	/* Initially mask all interrupts */
	for (i = 0; i < IMR_NUM; i++) {
		writel_relaxed(~0, cd->gpc_base + GPC_IMR1_CORE0 + i * 4);
		writel_relaxed(~0, cd->gpc_base + GPC_IMR1_CORE1 + i * 4);
		cd->wakeup_sources[i] = ~0;
	}

	/* Let CORE0 as the default CPU to wake up by GPC */
	cd->cpu2wakeup = GPC_IMR1_CORE0;

	/*
	 * Due to hardware design failure, need to make sure GPR
	 * interrupt(#32) is unmasked during RUN mode to avoid entering
	 * DSM by mistake.
	 */
	writel_relaxed(~0x1, cd->gpc_base + cd->cpu2wakeup);

	imx_gpcv2_instance = cd;
	register_syscore_ops(&imx_gpcv2_syscore_ops);

	return 0;
}

IRQCHIP_DECLARE(imx_gpcv2, "fsl,imx7d-gpc", imx_gpcv2_irqchip_init);