// SPDX-License-Identifier: GPL-2.0-only
/*
 * The R_INTC in Allwinner A31 and newer SoCs manages several types of
 * interrupts, as shown below:
 *
 *             NMI IRQ                DIRECT IRQs           MUXED IRQs
 *              bit 0                  bits 1-15^           bits 19-31
 *
 *   +---------+                      +---------+    +---------+  +---------+
 *   | NMI Pad |                      |  IRQ d  |    |  IRQ m  |  | IRQ m+7 |
 *   +---------+                      +---------+    +---------+  +---------+
 *        |                             |     |         |    |      |    |
 *        |                             |     |         |    |......|    |
 * +------V------+ +------------+       |     |         | +--V------V--+ |
 * |   Invert/   | | Write 1 to |       |     |         | |  AND with  | |
 * | Edge Detect | | PENDING[0] |       |     |         | |  MUX[m/8]  | |
 * +-------------+ +------------+       |     |         | +------------+ |
 *            |       |                 |     |         |       |        |
 *         +--V-------V--+           +--V--+  |      +--V--+    |     +--V--+
 *         | Set    Reset|           | GIC |  |      | GIC |    |     | GIC |
 *         |    Latch    |           | SPI |  |      | SPI |... |  ...| SPI |
 *         +-------------+           | N+d |  |      |  m  |    |     | m+7 |
 *             |     |               +-----+  |      +-----+    |     +-----+
 *             |     |                        |                 |
 *     +-------V-+ +-V----------+   +---------V--+     +--------V--------+
 *     | GIC SPI | |  AND with  |   |  AND with  |     |    AND with     |
 *     | N (=32) | |  ENABLE[0] |   |  ENABLE[d] |     |  ENABLE[19+m/8] |
 *     +---------+ +------------+   +------------+     +-----------------+
 *                        |                |                    |
 *                 +------V-----+   +------V-----+     +--------V--------+
 *                 |    Read    |   |    Read    |     |     Read        |
 *                 | PENDING[0] |   | PENDING[d] |     | PENDING[19+m/8] |
 *                 +------------+   +------------+     +-----------------+
 *
 * ^ bits 16-18 are direct IRQs for peripherals with banked interrupts, such as
 *   the MSGBOX. These IRQs do not map to any GIC SPI.
 *
 * The H6 variant adds two more (banked) direct IRQs and implements the full
 * set of 128 mux bits. This requires a second set of top-level registers.
 */

#include <linux/bitmap.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/syscore_ops.h>

#include <dt-bindings/interrupt-controller/arm-gic.h>

#define SUN6I_NMI_CTRL                  (0x0c)
#define SUN6I_IRQ_PENDING(n)            (0x10 + 4 * (n))
#define SUN6I_IRQ_ENABLE(n)             (0x40 + 4 * (n))
#define SUN6I_MUX_ENABLE(n)             (0xc0 + 4 * (n))

#define SUN6I_NMI_SRC_TYPE_LEVEL_LOW    0
#define SUN6I_NMI_SRC_TYPE_EDGE_FALLING 1
#define SUN6I_NMI_SRC_TYPE_LEVEL_HIGH   2
#define SUN6I_NMI_SRC_TYPE_EDGE_RISING  3

#define SUN6I_NMI_BIT                   BIT(0)

#define SUN6I_NMI_NEEDS_ACK             ((void *)1)

#define SUN6I_NR_TOP_LEVEL_IRQS         64
#define SUN6I_NR_DIRECT_IRQS            16
#define SUN6I_NR_MUX_BITS               128

struct sun6i_r_intc_variant {
        u32             first_mux_irq;
        u32             nr_mux_irqs;
        u32             mux_valid[BITS_TO_U32(SUN6I_NR_MUX_BITS)];
};

static void __iomem *base;
static irq_hw_number_t nmi_hwirq;
static DECLARE_BITMAP(wake_irq_enabled, SUN6I_NR_TOP_LEVEL_IRQS);
static DECLARE_BITMAP(wake_mux_enabled, SUN6I_NR_MUX_BITS);
static DECLARE_BITMAP(wake_mux_valid, SUN6I_NR_MUX_BITS);

static void sun6i_r_intc_ack_nmi(void)
{
        writel_relaxed(SUN6I_NMI_BIT, base + SUN6I_IRQ_PENDING(0));
}

static void sun6i_r_intc_nmi_ack(struct irq_data *data)
{
        if (irqd_get_trigger_type(data) & IRQ_TYPE_EDGE_BOTH)
                sun6i_r_intc_ack_nmi();
        else
                data->chip_data = SUN6I_NMI_NEEDS_ACK;
}

static void sun6i_r_intc_nmi_eoi(struct irq_data *data)
{
        /* For oneshot IRQs, delay the ack until the IRQ is unmasked. */
        if (data->chip_data == SUN6I_NMI_NEEDS_ACK && !irqd_irq_masked(data)) {
                data->chip_data = NULL;
                sun6i_r_intc_ack_nmi();
        }

        irq_chip_eoi_parent(data);
}

static void sun6i_r_intc_nmi_unmask(struct irq_data *data)
{
        if (data->chip_data == SUN6I_NMI_NEEDS_ACK) {
                data->chip_data = NULL;
                sun6i_r_intc_ack_nmi();
        }

        irq_chip_unmask_parent(data);
}

static int sun6i_r_intc_nmi_set_type(struct irq_data *data, unsigned int type)
{
        u32 nmi_src_type;

        switch (type) {
        case IRQ_TYPE_EDGE_RISING:
                nmi_src_type = SUN6I_NMI_SRC_TYPE_EDGE_RISING;
                break;
        case IRQ_TYPE_EDGE_FALLING:
                nmi_src_type = SUN6I_NMI_SRC_TYPE_EDGE_FALLING;
                break;
        case IRQ_TYPE_LEVEL_HIGH:
                nmi_src_type = SUN6I_NMI_SRC_TYPE_LEVEL_HIGH;
                break;
        case IRQ_TYPE_LEVEL_LOW:
                nmi_src_type = SUN6I_NMI_SRC_TYPE_LEVEL_LOW;
                break;
        default:
                return -EINVAL;
        }

        writel_relaxed(nmi_src_type, base + SUN6I_NMI_CTRL);

        /*
         * The "External NMI" GIC input connects to a latch inside R_INTC, not
         * directly to the pin. So the GIC trigger type does not depend on the
         * NMI pin trigger type.
         */
        return irq_chip_set_type_parent(data, IRQ_TYPE_LEVEL_HIGH);
}

static int sun6i_r_intc_nmi_set_irqchip_state(struct irq_data *data,
                                              enum irqchip_irq_state which,
                                              bool state)
{
        if (which == IRQCHIP_STATE_PENDING && !state)
                sun6i_r_intc_ack_nmi();

        return irq_chip_set_parent_state(data, which, state);
}

static int sun6i_r_intc_irq_set_wake(struct irq_data *data, unsigned int on)
{
        unsigned long offset_from_nmi = data->hwirq - nmi_hwirq;

        if (offset_from_nmi < SUN6I_NR_DIRECT_IRQS)
                assign_bit(offset_from_nmi, wake_irq_enabled, on);
        else if (test_bit(data->hwirq, wake_mux_valid))
                assign_bit(data->hwirq, wake_mux_enabled, on);
        else
                /* Not wakeup capable. */
                return -EPERM;

        return 0;
}

static struct irq_chip sun6i_r_intc_nmi_chip = {
        .name                   = "sun6i-r-intc",
        .irq_ack                = sun6i_r_intc_nmi_ack,
        .irq_mask               = irq_chip_mask_parent,
        .irq_unmask             = sun6i_r_intc_nmi_unmask,
        .irq_eoi                = sun6i_r_intc_nmi_eoi,
        .irq_set_affinity       = irq_chip_set_affinity_parent,
        .irq_set_type           = sun6i_r_intc_nmi_set_type,
        .irq_set_irqchip_state  = sun6i_r_intc_nmi_set_irqchip_state,
        .irq_set_wake           = sun6i_r_intc_irq_set_wake,
        .flags                  = IRQCHIP_SET_TYPE_MASKED,
};

static struct irq_chip sun6i_r_intc_wakeup_chip = {
        .name                   = "sun6i-r-intc",
        .irq_mask               = irq_chip_mask_parent,
        .irq_unmask             = irq_chip_unmask_parent,
        .irq_eoi                = irq_chip_eoi_parent,
        .irq_set_affinity       = irq_chip_set_affinity_parent,
        .irq_set_type           = irq_chip_set_type_parent,
        .irq_set_wake           = sun6i_r_intc_irq_set_wake,
        .flags                  = IRQCHIP_SET_TYPE_MASKED,
};

static int sun6i_r_intc_domain_translate(struct irq_domain *domain,
                                         struct irq_fwspec *fwspec,
                                         unsigned long *hwirq,
                                         unsigned int *type)
{
        /* Accept the old two-cell binding for the NMI only. */
        if (fwspec->param_count == 2 && fwspec->param[0] == 0) {
                *hwirq = nmi_hwirq;
                *type  = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
                return 0;
        }

        /* Otherwise this binding should match the GIC SPI binding. */
        if (fwspec->param_count < 3)
                return -EINVAL;
        if (fwspec->param[0] != GIC_SPI)
                return -EINVAL;

        *hwirq = fwspec->param[1];
        *type  = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;

        return 0;
}

static int sun6i_r_intc_domain_alloc(struct irq_domain *domain,
                                     unsigned int virq,
                                     unsigned int nr_irqs, void *arg)
{
        struct irq_fwspec *fwspec = arg;
        struct irq_fwspec gic_fwspec;
        unsigned long hwirq;
        unsigned int type;
        int i, ret;

        ret = sun6i_r_intc_domain_translate(domain, fwspec, &hwirq, &type);
        if (ret)
                return ret;
        if (hwirq + nr_irqs > SUN6I_NR_MUX_BITS)
                return -EINVAL;

        /* Construct a GIC-compatible fwspec from this fwspec. */
        gic_fwspec = (struct irq_fwspec) {
                .fwnode      = domain->parent->fwnode,
                .param_count = 3,
                .param       = { GIC_SPI, hwirq, type },
        };

        ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &gic_fwspec);
        if (ret)
                return ret;

        for (i = 0; i < nr_irqs; ++i, ++hwirq, ++virq) {
                if (hwirq == nmi_hwirq) {
                        irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
                                                      &sun6i_r_intc_nmi_chip,
                                                      NULL);
                        irq_set_handler(virq, handle_fasteoi_ack_irq);
                } else {
                        irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
                                                      &sun6i_r_intc_wakeup_chip,
                                                      NULL);
                }
        }

        return 0;
}

static const struct irq_domain_ops sun6i_r_intc_domain_ops = {
        .translate      = sun6i_r_intc_domain_translate,
        .alloc          = sun6i_r_intc_domain_alloc,
        .free           = irq_domain_free_irqs_common,
};

static int sun6i_r_intc_suspend(void *data)
{
        u32 buf[BITS_TO_U32(MAX(SUN6I_NR_TOP_LEVEL_IRQS, SUN6I_NR_MUX_BITS))];
        int i;

        /* Wake IRQs are enabled during system sleep and shutdown. */
        bitmap_to_arr32(buf, wake_irq_enabled, SUN6I_NR_TOP_LEVEL_IRQS);
        for (i = 0; i < BITS_TO_U32(SUN6I_NR_TOP_LEVEL_IRQS); ++i)
                writel_relaxed(buf[i], base + SUN6I_IRQ_ENABLE(i));
        bitmap_to_arr32(buf, wake_mux_enabled, SUN6I_NR_MUX_BITS);
        for (i = 0; i < BITS_TO_U32(SUN6I_NR_MUX_BITS); ++i)
                writel_relaxed(buf[i], base + SUN6I_MUX_ENABLE(i));

        return 0;
}

static void sun6i_r_intc_resume(void *data)
{
        int i;

        /* Only the NMI is relevant during normal operation. */
        writel_relaxed(SUN6I_NMI_BIT, base + SUN6I_IRQ_ENABLE(0));
        for (i = 1; i < BITS_TO_U32(SUN6I_NR_TOP_LEVEL_IRQS); ++i)
                writel_relaxed(0, base + SUN6I_IRQ_ENABLE(i));
}

static void sun6i_r_intc_shutdown(void *data)
{
        sun6i_r_intc_suspend(data);
}

static const struct syscore_ops sun6i_r_intc_syscore_ops = {
        .suspend        = sun6i_r_intc_suspend,
        .resume         = sun6i_r_intc_resume,
        .shutdown       = sun6i_r_intc_shutdown,
};

static struct syscore sun6i_r_intc_syscore = {
        .ops = &sun6i_r_intc_syscore_ops,
};

static int __init sun6i_r_intc_init(struct device_node *node,
                                    struct device_node *parent,
                                    const struct sun6i_r_intc_variant *v)
{
        struct irq_domain *domain, *parent_domain;
        struct of_phandle_args nmi_parent;
        int ret;

        /* Extract the NMI hwirq number from the OF node. */
        ret = of_irq_parse_one(node, 0, &nmi_parent);
        if (ret)
                return ret;
        if (nmi_parent.args_count < 3 ||
            nmi_parent.args[0] != GIC_SPI ||
            nmi_parent.args[2] != IRQ_TYPE_LEVEL_HIGH)
                return -EINVAL;
        nmi_hwirq = nmi_parent.args[1];

        bitmap_set(wake_irq_enabled, v->first_mux_irq, v->nr_mux_irqs);
        bitmap_from_arr32(wake_mux_valid, v->mux_valid, SUN6I_NR_MUX_BITS);

        parent_domain = irq_find_host(parent);
        if (!parent_domain) {
                pr_err("%pOF: Failed to obtain parent domain\n", node);
                return -ENXIO;
        }

        base = of_io_request_and_map(node, 0, NULL);
        if (IS_ERR(base)) {
                pr_err("%pOF: Failed to map MMIO region\n", node);
                return PTR_ERR(base);
        }

        domain = irq_domain_create_hierarchy(parent_domain, 0, 0, of_fwnode_handle(node),
                                             &sun6i_r_intc_domain_ops, NULL);
        if (!domain) {
                pr_err("%pOF: Failed to allocate domain\n", node);
                iounmap(base);
                return -ENOMEM;
        }

        register_syscore(&sun6i_r_intc_syscore);

        sun6i_r_intc_ack_nmi();
        sun6i_r_intc_resume(NULL);

        return 0;
}

static const struct sun6i_r_intc_variant sun6i_a31_r_intc_variant __initconst = {
        .first_mux_irq  = 19,
        .nr_mux_irqs    = 13,
        .mux_valid      = { 0xffffffff, 0xfff80000, 0xffffffff, 0x0000000f },
};

static int __init sun6i_a31_r_intc_init(struct device_node *node,
                                        struct device_node *parent)
{
        return sun6i_r_intc_init(node, parent, &sun6i_a31_r_intc_variant);
}
IRQCHIP_DECLARE(sun6i_a31_r_intc, "allwinner,sun6i-a31-r-intc", sun6i_a31_r_intc_init);

static const struct sun6i_r_intc_variant sun50i_h6_r_intc_variant __initconst = {
        .first_mux_irq  = 21,
        .nr_mux_irqs    = 16,
        .mux_valid      = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff },
};

static int __init sun50i_h6_r_intc_init(struct device_node *node,
                                        struct device_node *parent)
{
        return sun6i_r_intc_init(node, parent, &sun50i_h6_r_intc_variant);
}
IRQCHIP_DECLARE(sun50i_h6_r_intc, "allwinner,sun50i-h6-r-intc", sun50i_h6_r_intc_init);