/*
 * 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_translate(struct irq_domain *d,
                                      struct irq_fwspec *fwspec,
                                      unsigned long *hwirq,
                                      unsigned int *type)
{
        if (is_of_node(fwspec->fwnode)) {
                if (fwspec->param_count != 3)
                        return -EINVAL;

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

                *hwirq = fwspec->param[1];
                *type = fwspec->param[2];
                return 0;
        }

        return -EINVAL;
}

static int imx_gpcv2_domain_alloc(struct irq_domain *domain,
                                  unsigned int irq, unsigned int nr_irqs,
                                  void *data)
{
        struct irq_fwspec *fwspec = data;
        struct irq_fwspec parent_fwspec;
        irq_hw_number_t hwirq;
        unsigned int type;
        int err;
        int i;

        err = imx_gpcv2_domain_translate(domain, fwspec, &hwirq, &type);
        if (err)
                return err;

        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_fwspec = *fwspec;
        parent_fwspec.fwnode = domain->parent->fwnode;
        return irq_domain_alloc_irqs_parent(domain, irq, nr_irqs,
                                            &parent_fwspec);
}

static const struct irq_domain_ops gpcv2_irqchip_data_domain_ops = {
        .translate      = imx_gpcv2_domain_translate,
        .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;
        }

        raw_spin_lock_init(&cd->rlock);

        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);

        /*
         * Clear the OF_POPULATED flag set in of_irq_init so that
         * later the GPC power domain driver will not be skipped.
         */
        of_node_clear_flag(node, OF_POPULATED);
        return 0;
}

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