// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  linux/arch/arm/common/vic.c
 *
 *  Copyright (C) 1999 - 2003 ARM Limited
 *  Copyright (C) 2000 Deep Blue Solutions Ltd
 */

#include <linux/export.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.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 <linux/device.h>
#include <linux/amba/bus.h>
#include <linux/irqchip/arm-vic.h>

#include <asm/exception.h>
#include <asm/irq.h>

#define VIC_IRQ_STATUS                  0x00
#define VIC_FIQ_STATUS                  0x04
#define VIC_RAW_STATUS                  0x08
#define VIC_INT_SELECT                  0x0c    /* 1 = FIQ, 0 = IRQ */
#define VIC_INT_ENABLE                  0x10    /* 1 = enable, 0 = disable */
#define VIC_INT_ENABLE_CLEAR            0x14
#define VIC_INT_SOFT                    0x18
#define VIC_INT_SOFT_CLEAR              0x1c
#define VIC_PROTECT                     0x20
#define VIC_PL190_VECT_ADDR             0x30    /* PL190 only */
#define VIC_PL190_DEF_VECT_ADDR         0x34    /* PL190 only */

#define VIC_VECT_ADDR0                  0x100   /* 0 to 15 (0..31 PL192) */
#define VIC_VECT_CNTL0                  0x200   /* 0 to 15 (0..31 PL192) */
#define VIC_ITCR                        0x300   /* VIC test control register */

#define VIC_VECT_CNTL_ENABLE            (1 << 5)

#define VIC_PL192_VECT_ADDR             0xF00

/**
 * struct vic_device - VIC PM device
 * @parent_irq: The parent IRQ number of the VIC if cascaded, or 0.
 * @irq: The IRQ number for the base of the VIC.
 * @base: The register base for the VIC.
 * @valid_sources: A bitmask of valid interrupts
 * @resume_sources: A bitmask of interrupts for resume.
 * @resume_irqs: The IRQs enabled for resume.
 * @int_select: Save for VIC_INT_SELECT.
 * @int_enable: Save for VIC_INT_ENABLE.
 * @soft_int: Save for VIC_INT_SOFT.
 * @protect: Save for VIC_PROTECT.
 * @domain: The IRQ domain for the VIC.
 */
struct vic_device {
        void __iomem    *base;
        int             irq;
        u32             valid_sources;
        u32             resume_sources;
        u32             resume_irqs;
        u32             int_select;
        u32             int_enable;
        u32             soft_int;
        u32             protect;
        struct irq_domain *domain;
};

/* we cannot allocate memory when VICs are initially registered */
static struct vic_device vic_devices[CONFIG_ARM_VIC_NR];

static int vic_id;

static void vic_handle_irq(struct pt_regs *regs);

/**
 * vic_init2 - common initialisation code
 * @base: Base of the VIC.
 *
 * Common initialisation code for registration
 * and resume.
*/
static void vic_init2(void __iomem *base)
{
        int i;

        for (i = 0; i < 16; i++) {
                void __iomem *reg = base + VIC_VECT_CNTL0 + (i * 4);
                writel(VIC_VECT_CNTL_ENABLE | i, reg);
        }

        writel(32, base + VIC_PL190_DEF_VECT_ADDR);
}

#ifdef CONFIG_PM
static void resume_one_vic(struct vic_device *vic)
{
        void __iomem *base = vic->base;

        printk(KERN_DEBUG "%s: resuming vic at %p\n", __func__, base);

        /* re-initialise static settings */
        vic_init2(base);

        writel(vic->int_select, base + VIC_INT_SELECT);
        writel(vic->protect, base + VIC_PROTECT);

        /* set the enabled ints and then clear the non-enabled */
        writel(vic->int_enable, base + VIC_INT_ENABLE);
        writel(~vic->int_enable, base + VIC_INT_ENABLE_CLEAR);

        /* and the same for the soft-int register */

        writel(vic->soft_int, base + VIC_INT_SOFT);
        writel(~vic->soft_int, base + VIC_INT_SOFT_CLEAR);
}

static void vic_resume(void)
{
        int id;

        for (id = vic_id - 1; id >= 0; id--)
                resume_one_vic(vic_devices + id);
}

static void suspend_one_vic(struct vic_device *vic)
{
        void __iomem *base = vic->base;

        printk(KERN_DEBUG "%s: suspending vic at %p\n", __func__, base);

        vic->int_select = readl(base + VIC_INT_SELECT);
        vic->int_enable = readl(base + VIC_INT_ENABLE);
        vic->soft_int = readl(base + VIC_INT_SOFT);
        vic->protect = readl(base + VIC_PROTECT);

        /* set the interrupts (if any) that are used for
         * resuming the system */

        writel(vic->resume_irqs, base + VIC_INT_ENABLE);
        writel(~vic->resume_irqs, base + VIC_INT_ENABLE_CLEAR);
}

static int vic_suspend(void)
{
        int id;

        for (id = 0; id < vic_id; id++)
                suspend_one_vic(vic_devices + id);

        return 0;
}

static struct syscore_ops vic_syscore_ops = {
        .suspend        = vic_suspend,
        .resume         = vic_resume,
};

/**
 * vic_pm_init - initcall to register VIC pm
 *
 * This is called via late_initcall() to register
 * the resources for the VICs due to the early
 * nature of the VIC's registration.
*/
static int __init vic_pm_init(void)
{
        if (vic_id > 0)
                register_syscore_ops(&vic_syscore_ops);

        return 0;
}
late_initcall(vic_pm_init);
#endif /* CONFIG_PM */

static struct irq_chip vic_chip;

static int vic_irqdomain_map(struct irq_domain *d, unsigned int irq,
                             irq_hw_number_t hwirq)
{
        struct vic_device *v = d->host_data;

        /* Skip invalid IRQs, only register handlers for the real ones */
        if (!(v->valid_sources & (1 << hwirq)))
                return -EPERM;
        irq_set_chip_and_handler(irq, &vic_chip, handle_level_irq);
        irq_set_chip_data(irq, v->base);
        irq_set_probe(irq);
        return 0;
}

/*
 * Handle each interrupt in a single VIC.  Returns non-zero if we've
 * handled at least one interrupt.  This reads the status register
 * before handling each interrupt, which is necessary given that
 * handle_IRQ may briefly re-enable interrupts for soft IRQ handling.
 */
static int handle_one_vic(struct vic_device *vic, struct pt_regs *regs)
{
        u32 stat, irq;
        int handled = 0;

        while ((stat = readl_relaxed(vic->base + VIC_IRQ_STATUS))) {
                irq = ffs(stat) - 1;
                handle_domain_irq(vic->domain, irq, regs);
                handled = 1;
        }

        return handled;
}

static void vic_handle_irq_cascaded(struct irq_desc *desc)
{
        u32 stat, hwirq;
        struct irq_chip *host_chip = irq_desc_get_chip(desc);
        struct vic_device *vic = irq_desc_get_handler_data(desc);

        chained_irq_enter(host_chip, desc);

        while ((stat = readl_relaxed(vic->base + VIC_IRQ_STATUS))) {
                hwirq = ffs(stat) - 1;
                generic_handle_domain_irq(vic->domain, hwirq);
        }

        chained_irq_exit(host_chip, desc);
}

/*
 * Keep iterating over all registered VIC's until there are no pending
 * interrupts.
 */
static void __exception_irq_entry vic_handle_irq(struct pt_regs *regs)
{
        int i, handled;

        do {
                for (i = 0, handled = 0; i < vic_id; ++i)
                        handled |= handle_one_vic(&vic_devices[i], regs);
        } while (handled);
}

static const struct irq_domain_ops vic_irqdomain_ops = {
        .map = vic_irqdomain_map,
        .xlate = irq_domain_xlate_onetwocell,
};

/**
 * vic_register() - Register a VIC.
 * @base: The base address of the VIC.
 * @parent_irq: The parent IRQ if cascaded, else 0.
 * @irq: The base IRQ for the VIC.
 * @valid_sources: bitmask of valid interrupts
 * @resume_sources: bitmask of interrupts allowed for resume sources.
 * @node: The device tree node associated with the VIC.
 *
 * Register the VIC with the system device tree so that it can be notified
 * of suspend and resume requests and ensure that the correct actions are
 * taken to re-instate the settings on resume.
 *
 * This also configures the IRQ domain for the VIC.
 */
static void __init vic_register(void __iomem *base, unsigned int parent_irq,
                                unsigned int irq,
                                u32 valid_sources, u32 resume_sources,
                                struct device_node *node)
{
        struct vic_device *v;
        int i;

        if (vic_id >= ARRAY_SIZE(vic_devices)) {
                printk(KERN_ERR "%s: too few VICs, increase CONFIG_ARM_VIC_NR\n", __func__);
                return;
        }

        v = &vic_devices[vic_id];
        v->base = base;
        v->valid_sources = valid_sources;
        v->resume_sources = resume_sources;
        set_handle_irq(vic_handle_irq);
        vic_id++;

        if (parent_irq) {
                irq_set_chained_handler_and_data(parent_irq,
                                                 vic_handle_irq_cascaded, v);
        }

        v->domain = irq_domain_add_simple(node, fls(valid_sources), irq,
                                          &vic_irqdomain_ops, v);
        /* create an IRQ mapping for each valid IRQ */
        for (i = 0; i < fls(valid_sources); i++)
                if (valid_sources & (1 << i))
                        irq_create_mapping(v->domain, i);
        /* If no base IRQ was passed, figure out our allocated base */
        if (irq)
                v->irq = irq;
        else
                v->irq = irq_find_mapping(v->domain, 0);
}

static void vic_ack_irq(struct irq_data *d)
{
        void __iomem *base = irq_data_get_irq_chip_data(d);
        unsigned int irq = d->hwirq;
        writel(1 << irq, base + VIC_INT_ENABLE_CLEAR);
        /* moreover, clear the soft-triggered, in case it was the reason */
        writel(1 << irq, base + VIC_INT_SOFT_CLEAR);
}

static void vic_mask_irq(struct irq_data *d)
{
        void __iomem *base = irq_data_get_irq_chip_data(d);
        unsigned int irq = d->hwirq;
        writel(1 << irq, base + VIC_INT_ENABLE_CLEAR);
}

static void vic_unmask_irq(struct irq_data *d)
{
        void __iomem *base = irq_data_get_irq_chip_data(d);
        unsigned int irq = d->hwirq;
        writel(1 << irq, base + VIC_INT_ENABLE);
}

#if defined(CONFIG_PM)
static struct vic_device *vic_from_irq(unsigned int irq)
{
        struct vic_device *v = vic_devices;
        unsigned int base_irq = irq & ~31;
        int id;

        for (id = 0; id < vic_id; id++, v++) {
                if (v->irq == base_irq)
                        return v;
        }

        return NULL;
}

static int vic_set_wake(struct irq_data *d, unsigned int on)
{
        struct vic_device *v = vic_from_irq(d->irq);
        unsigned int off = d->hwirq;
        u32 bit = 1 << off;

        if (!v)
                return -EINVAL;

        if (!(bit & v->resume_sources))
                return -EINVAL;

        if (on)
                v->resume_irqs |= bit;
        else
                v->resume_irqs &= ~bit;

        return 0;
}
#else
#define vic_set_wake NULL
#endif /* CONFIG_PM */

static struct irq_chip vic_chip = {
        .name           = "VIC",
        .irq_ack        = vic_ack_irq,
        .irq_mask       = vic_mask_irq,
        .irq_unmask     = vic_unmask_irq,
        .irq_set_wake   = vic_set_wake,
};

static void __init vic_disable(void __iomem *base)
{
        writel(0, base + VIC_INT_SELECT);
        writel(0, base + VIC_INT_ENABLE);
        writel(~0, base + VIC_INT_ENABLE_CLEAR);
        writel(0, base + VIC_ITCR);
        writel(~0, base + VIC_INT_SOFT_CLEAR);
}

static void __init vic_clear_interrupts(void __iomem *base)
{
        unsigned int i;

        writel(0, base + VIC_PL190_VECT_ADDR);
        for (i = 0; i < 19; i++) {
                unsigned int value;

                value = readl(base + VIC_PL190_VECT_ADDR);
                writel(value, base + VIC_PL190_VECT_ADDR);
        }
}

/*
 * The PL190 cell from ARM has been modified by ST to handle 64 interrupts.
 * The original cell has 32 interrupts, while the modified one has 64,
 * replicating two blocks 0x00..0x1f in 0x20..0x3f. In that case
 * the probe function is called twice, with base set to offset 000
 *  and 020 within the page. We call this "second block".
 */
static void __init vic_init_st(void __iomem *base, unsigned int irq_start,
                               u32 vic_sources, struct device_node *node)
{
        unsigned int i;
        int vic_2nd_block = ((unsigned long)base & ~PAGE_MASK) != 0;

        /* Disable all interrupts initially. */
        vic_disable(base);

        /*
         * Make sure we clear all existing interrupts. The vector registers
         * in this cell are after the second block of general registers,
         * so we can address them using standard offsets, but only from
         * the second base address, which is 0x20 in the page
         */
        if (vic_2nd_block) {
                vic_clear_interrupts(base);

                /* ST has 16 vectors as well, but we don't enable them by now */
                for (i = 0; i < 16; i++) {
                        void __iomem *reg = base + VIC_VECT_CNTL0 + (i * 4);
                        writel(0, reg);
                }

                writel(32, base + VIC_PL190_DEF_VECT_ADDR);
        }

        vic_register(base, 0, irq_start, vic_sources, 0, node);
}

static void __init __vic_init(void __iomem *base, int parent_irq, int irq_start,
                              u32 vic_sources, u32 resume_sources,
                              struct device_node *node)
{
        unsigned int i;
        u32 cellid = 0;
        enum amba_vendor vendor;

        /* Identify which VIC cell this one is, by reading the ID */
        for (i = 0; i < 4; i++) {
                void __iomem *addr;
                addr = (void __iomem *)((u32)base & PAGE_MASK) + 0xfe0 + (i * 4);
                cellid |= (readl(addr) & 0xff) << (8 * i);
        }
        vendor = (cellid >> 12) & 0xff;
        printk(KERN_INFO "VIC @%p: id 0x%08x, vendor 0x%02x\n",
               base, cellid, vendor);

        switch(vendor) {
        case AMBA_VENDOR_ST:
                vic_init_st(base, irq_start, vic_sources, node);
                return;
        default:
                printk(KERN_WARNING "VIC: unknown vendor, continuing anyways\n");
                fallthrough;
        case AMBA_VENDOR_ARM:
                break;
        }

        /* Disable all interrupts initially. */
        vic_disable(base);

        /* Make sure we clear all existing interrupts */
        vic_clear_interrupts(base);

        vic_init2(base);

        vic_register(base, parent_irq, irq_start, vic_sources, resume_sources, node);
}

/**
 * vic_init() - initialise a vectored interrupt controller
 * @base: iomem base address
 * @irq_start: starting interrupt number, must be muliple of 32
 * @vic_sources: bitmask of interrupt sources to allow
 * @resume_sources: bitmask of interrupt sources to allow for resume
 */
void __init vic_init(void __iomem *base, unsigned int irq_start,
                     u32 vic_sources, u32 resume_sources)
{
        __vic_init(base, 0, irq_start, vic_sources, resume_sources, NULL);
}

#ifdef CONFIG_OF
static int __init vic_of_init(struct device_node *node,
                              struct device_node *parent)
{
        void __iomem *regs;
        u32 interrupt_mask = ~0;
        u32 wakeup_mask = ~0;
        int parent_irq;

        regs = of_iomap(node, 0);
        if (WARN_ON(!regs))
                return -EIO;

        of_property_read_u32(node, "valid-mask", &interrupt_mask);
        of_property_read_u32(node, "valid-wakeup-mask", &wakeup_mask);
        parent_irq = of_irq_get(node, 0);
        if (parent_irq < 0)
                parent_irq = 0;

        /*
         * Passing 0 as first IRQ makes the simple domain allocate descriptors
         */
        __vic_init(regs, parent_irq, 0, interrupt_mask, wakeup_mask, node);

        return 0;
}
IRQCHIP_DECLARE(arm_pl190_vic, "arm,pl190-vic", vic_of_init);
IRQCHIP_DECLARE(arm_pl192_vic, "arm,pl192-vic", vic_of_init);
IRQCHIP_DECLARE(arm_versatile_vic, "arm,versatile-vic", vic_of_init);
#endif /* CONFIG OF */