// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2009 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB
 * Copyright (C) 2009 Konrad Eisele (konrad@gaisler.com) Aeroflex Gaisler AB
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/interrupt.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>

#include <asm/oplib.h>
#include <asm/timer.h>
#include <asm/prom.h>
#include <asm/leon.h>
#include <asm/leon_amba.h>
#include <asm/traps.h>
#include <asm/cacheflush.h>
#include <asm/smp.h>
#include <asm/setup.h>

#include "kernel.h"
#include "prom.h"
#include "irq.h"

struct leon3_irqctrl_regs_map *leon3_irqctrl_regs; /* interrupt controller base address */
struct leon3_gptimer_regs_map *leon3_gptimer_regs; /* timer controller base address */

int leondebug_irq_disable;
int leon_debug_irqout;
static volatile u32 dummy_master_l10_counter;
unsigned long amba_system_id;
static DEFINE_SPINLOCK(leon_irq_lock);

static unsigned long leon3_gptimer_idx; /* Timer Index (0..6) within Timer Core */
static unsigned long leon3_gptimer_ackmask; /* For clearing pending bit */
unsigned long leon3_gptimer_irq; /* interrupt controller irq number */
unsigned int sparc_leon_eirq;
#define LEON_IMASK(cpu) (&leon3_irqctrl_regs->mask[cpu])
#define LEON_IACK (&leon3_irqctrl_regs->iclear)
#define LEON_DO_ACK_HW 1

/* Return the last ACKed IRQ by the Extended IRQ controller. It has already
 * been (automatically) ACKed when the CPU takes the trap.
 */
static inline unsigned int leon_eirq_get(int cpu)
{
        return LEON3_BYPASS_LOAD_PA(&leon3_irqctrl_regs->intid[cpu]) & 0x1f;
}

/* Handle one or multiple IRQs from the extended interrupt controller */
static void leon_handle_ext_irq(struct irq_desc *desc)
{
        unsigned int eirq;
        struct irq_bucket *p;
        int cpu = sparc_leon3_cpuid();

        eirq = leon_eirq_get(cpu);
        p = irq_map[eirq];
        if ((eirq & 0x10) && p && p->irq) /* bit4 tells if IRQ happened */
                generic_handle_irq(p->irq);
}

/* The extended IRQ controller has been found, this function registers it */
static void leon_eirq_setup(unsigned int eirq)
{
        unsigned long mask, oldmask;
        unsigned int veirq;

        if (eirq < 1 || eirq > 0xf) {
                printk(KERN_ERR "LEON EXT IRQ NUMBER BAD: %d\n", eirq);
                return;
        }

        veirq = leon_build_device_irq(eirq, leon_handle_ext_irq, "extirq", 0);

        /*
         * Unmask the Extended IRQ, the IRQs routed through the Ext-IRQ
         * controller have a mask-bit of their own, so this is safe.
         */
        irq_link(veirq);
        mask = 1 << eirq;
        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(boot_cpu_id));
        LEON3_BYPASS_STORE_PA(LEON_IMASK(boot_cpu_id), (oldmask | mask));
        sparc_leon_eirq = eirq;
}

unsigned long leon_get_irqmask(unsigned int irq)
{
        unsigned long mask;

        if (!irq || ((irq > 0xf) && !sparc_leon_eirq)
            || ((irq > 0x1f) && sparc_leon_eirq)) {
                printk(KERN_ERR
                       "leon_get_irqmask: false irq number: %d\n", irq);
                mask = 0;
        } else {
                mask = LEON_HARD_INT(irq);
        }
        return mask;
}

#ifdef CONFIG_SMP
static int irq_choose_cpu(const struct cpumask *affinity)
{
        unsigned int cpu = cpumask_first_and(affinity, cpu_online_mask);

        if (cpumask_subset(cpu_online_mask, affinity) || cpu >= nr_cpu_ids)
                return boot_cpu_id;
        else
                return cpu;
}
#else
#define irq_choose_cpu(affinity) boot_cpu_id
#endif

static int leon_set_affinity(struct irq_data *data, const struct cpumask *dest,
                             bool force)
{
        unsigned long mask, oldmask, flags;
        int oldcpu, newcpu;

        mask = (unsigned long)data->chip_data;
        oldcpu = irq_choose_cpu(irq_data_get_affinity_mask(data));
        newcpu = irq_choose_cpu(dest);

        if (oldcpu == newcpu)
                goto out;

        /* unmask on old CPU first before enabling on the selected CPU */
        spin_lock_irqsave(&leon_irq_lock, flags);
        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(oldcpu));
        LEON3_BYPASS_STORE_PA(LEON_IMASK(oldcpu), (oldmask & ~mask));
        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(newcpu));
        LEON3_BYPASS_STORE_PA(LEON_IMASK(newcpu), (oldmask | mask));
        spin_unlock_irqrestore(&leon_irq_lock, flags);
out:
        return IRQ_SET_MASK_OK;
}

static void leon_unmask_irq(struct irq_data *data)
{
        unsigned long mask, oldmask, flags;
        int cpu;

        mask = (unsigned long)data->chip_data;
        cpu = irq_choose_cpu(irq_data_get_affinity_mask(data));
        spin_lock_irqsave(&leon_irq_lock, flags);
        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(cpu));
        LEON3_BYPASS_STORE_PA(LEON_IMASK(cpu), (oldmask | mask));
        spin_unlock_irqrestore(&leon_irq_lock, flags);
}

static void leon_mask_irq(struct irq_data *data)
{
        unsigned long mask, oldmask, flags;
        int cpu;

        mask = (unsigned long)data->chip_data;
        cpu = irq_choose_cpu(irq_data_get_affinity_mask(data));
        spin_lock_irqsave(&leon_irq_lock, flags);
        oldmask = LEON3_BYPASS_LOAD_PA(LEON_IMASK(cpu));
        LEON3_BYPASS_STORE_PA(LEON_IMASK(cpu), (oldmask & ~mask));
        spin_unlock_irqrestore(&leon_irq_lock, flags);
}

static unsigned int leon_startup_irq(struct irq_data *data)
{
        irq_link(data->irq);
        leon_unmask_irq(data);
        return 0;
}

static void leon_shutdown_irq(struct irq_data *data)
{
        leon_mask_irq(data);
        irq_unlink(data->irq);
}

/* Used by external level sensitive IRQ handlers on the LEON: ACK IRQ ctrl */
static void leon_eoi_irq(struct irq_data *data)
{
        unsigned long mask = (unsigned long)data->chip_data;

        if (mask & LEON_DO_ACK_HW)
                LEON3_BYPASS_STORE_PA(LEON_IACK, mask & ~LEON_DO_ACK_HW);
}

static struct irq_chip leon_irq = {
        .name                   = "leon",
        .irq_startup            = leon_startup_irq,
        .irq_shutdown           = leon_shutdown_irq,
        .irq_mask               = leon_mask_irq,
        .irq_unmask             = leon_unmask_irq,
        .irq_eoi                = leon_eoi_irq,
        .irq_set_affinity       = leon_set_affinity,
};

/*
 * Build a LEON IRQ for the edge triggered LEON IRQ controller:
 *  Edge (normal) IRQ           - handle_simple_irq, ack=DON'T-CARE, never ack
 *  Level IRQ (PCI|Level-GPIO)  - handle_fasteoi_irq, ack=1, ack after ISR
 *  Per-CPU Edge                - handle_percpu_irq, ack=0
 */
unsigned int leon_build_device_irq(unsigned int real_irq,
                                    irq_flow_handler_t flow_handler,
                                    const char *name, int do_ack)
{
        unsigned int irq;
        unsigned long mask;
        struct irq_desc *desc;

        irq = 0;
        mask = leon_get_irqmask(real_irq);
        if (mask == 0)
                goto out;

        irq = irq_alloc(real_irq, real_irq);
        if (irq == 0)
                goto out;

        if (do_ack)
                mask |= LEON_DO_ACK_HW;

        desc = irq_to_desc(irq);
        if (!desc || !desc->handle_irq || desc->handle_irq == handle_bad_irq) {
                irq_set_chip_and_handler_name(irq, &leon_irq,
                                              flow_handler, name);
                irq_set_chip_data(irq, (void *)mask);
        }

out:
        return irq;
}

static unsigned int _leon_build_device_irq(struct platform_device *op,
                                           unsigned int real_irq)
{
        return leon_build_device_irq(real_irq, handle_simple_irq, "edge", 0);
}

void leon_update_virq_handling(unsigned int virq,
                              irq_flow_handler_t flow_handler,
                              const char *name, int do_ack)
{
        unsigned long mask = (unsigned long)irq_get_chip_data(virq);

        mask &= ~LEON_DO_ACK_HW;
        if (do_ack)
                mask |= LEON_DO_ACK_HW;

        irq_set_chip_and_handler_name(virq, &leon_irq,
                                      flow_handler, name);
        irq_set_chip_data(virq, (void *)mask);
}

static u32 leon_cycles_offset(void)
{
        u32 rld, val, ctrl, off;

        rld = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].rld);
        val = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].val);
        ctrl = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl);
        if (LEON3_GPTIMER_CTRL_ISPENDING(ctrl)) {
                val = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].val);
                off = 2 * rld - val;
        } else {
                off = rld - val;
        }

        return off;
}

#ifdef CONFIG_SMP

/* smp clockevent irq */
static irqreturn_t leon_percpu_timer_ce_interrupt(int irq, void *unused)
{
        struct clock_event_device *ce;
        int cpu = smp_processor_id();

        leon_clear_profile_irq(cpu);

        if (cpu == boot_cpu_id)
                timer_interrupt(irq, NULL);

        ce = &per_cpu(sparc32_clockevent, cpu);

        irq_enter();
        if (ce->event_handler)
                ce->event_handler(ce);
        irq_exit();

        return IRQ_HANDLED;
}

#endif /* CONFIG_SMP */

void __init leon_init_timers(void)
{
        int irq, eirq;
        struct device_node *rootnp, *np, *nnp;
        struct property *pp;
        int len;
        int icsel;
        int ampopts;
        int err;
        u32 config;
        u32 ctrl;

        sparc_config.get_cycles_offset = leon_cycles_offset;
        sparc_config.cs_period = 1000000 / HZ;
        sparc_config.features |= FEAT_L10_CLOCKSOURCE;

#ifndef CONFIG_SMP
        sparc_config.features |= FEAT_L10_CLOCKEVENT;
#endif

        leondebug_irq_disable = 0;
        leon_debug_irqout = 0;
        master_l10_counter = (u32 __iomem *)&dummy_master_l10_counter;
        dummy_master_l10_counter = 0;

        rootnp = of_find_node_by_path("/ambapp0");
        if (!rootnp)
                goto bad;

        /* Find System ID: GRLIB build ID and optional CHIP ID */
        pp = of_find_property(rootnp, "systemid", &len);
        if (pp)
                amba_system_id = *(unsigned long *)pp->value;

        /* Find IRQMP IRQ Controller Registers base adr otherwise bail out */
        np = of_find_node_by_name(rootnp, "GAISLER_IRQMP");
        if (!np) {
                np = of_find_node_by_name(rootnp, "01_00d");
                if (!np)
                        goto bad;
        }
        pp = of_find_property(np, "reg", &len);
        if (!pp)
                goto bad;
        leon3_irqctrl_regs = *(struct leon3_irqctrl_regs_map **)pp->value;

        /* Find GPTIMER Timer Registers base address otherwise bail out. */
        nnp = rootnp;

retry:
        np = of_find_node_by_name(nnp, "GAISLER_GPTIMER");
        if (!np) {
                np = of_find_node_by_name(nnp, "01_011");
                if (!np)
                        goto bad;
        }

        ampopts = 0;
        pp = of_find_property(np, "ampopts", &len);
        if (pp) {
                ampopts = *(int *)pp->value;
                if (ampopts == 0) {
                        /* Skip this instance, resource already
                         * allocated by other OS */
                        nnp = np;
                        goto retry;
                }
        }

        /* Select Timer-Instance on Timer Core. Default is zero */
        leon3_gptimer_idx = ampopts & 0x7;

        pp = of_find_property(np, "reg", &len);
        if (pp)
                leon3_gptimer_regs = *(struct leon3_gptimer_regs_map **)
                                        pp->value;
        pp = of_find_property(np, "interrupts", &len);
        if (pp)
                leon3_gptimer_irq = *(unsigned int *)pp->value;

        if (!(leon3_gptimer_regs && leon3_irqctrl_regs && leon3_gptimer_irq))
                goto bad;

        ctrl = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl);
        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
                              ctrl | LEON3_GPTIMER_CTRL_PENDING);
        ctrl = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl);

        if ((ctrl & LEON3_GPTIMER_CTRL_PENDING) != 0)
                leon3_gptimer_ackmask = ~LEON3_GPTIMER_CTRL_PENDING;
        else
                leon3_gptimer_ackmask = ~0;

        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].val, 0);
        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].rld,
                                (((1000000 / HZ) - 1)));
        LEON3_BYPASS_STORE_PA(
                        &leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl, 0);

        /*
         * The IRQ controller may (if implemented) consist of multiple
         * IRQ controllers, each mapped on a 4Kb boundary.
         * Each CPU may be routed to different IRQCTRLs, however
         * we assume that all CPUs (in SMP system) is routed to the
         * same IRQ Controller, and for non-SMP only one IRQCTRL is
         * accessed anyway.
         * In AMP systems, Linux must run on CPU0 for the time being.
         */
        icsel = LEON3_BYPASS_LOAD_PA(&leon3_irqctrl_regs->icsel[boot_cpu_id/8]);
        icsel = (icsel >> ((7 - (boot_cpu_id&0x7)) * 4)) & 0xf;
        leon3_irqctrl_regs += icsel;

        /* Mask all IRQs on boot-cpu IRQ controller */
        LEON3_BYPASS_STORE_PA(&leon3_irqctrl_regs->mask[boot_cpu_id], 0);

        /* Probe extended IRQ controller */
        eirq = (LEON3_BYPASS_LOAD_PA(&leon3_irqctrl_regs->mpstatus)
                >> 16) & 0xf;
        if (eirq != 0)
                leon_eirq_setup(eirq);

#ifdef CONFIG_SMP
        {
                unsigned long flags;

                /*
                 * In SMP, sun4m adds a IPI handler to IRQ trap handler that
                 * LEON never must take, sun4d and LEON overwrites the branch
                 * with a NOP.
                 */
                local_irq_save(flags);
                patchme_maybe_smp_msg[0] = 0x01000000; /* NOP out the branch */
                local_ops->cache_all();
                local_irq_restore(flags);
        }
#endif

        config = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->config);
        if (config & (1 << LEON3_GPTIMER_SEPIRQ))
                leon3_gptimer_irq += leon3_gptimer_idx;
        else if ((config & LEON3_GPTIMER_TIMERS) > 1)
                pr_warn("GPTIMER uses shared irqs, using other timers of the same core will fail.\n");

#ifdef CONFIG_SMP
        /* Install per-cpu IRQ handler for broadcasted ticker */
        irq = leon_build_device_irq(leon3_gptimer_irq, handle_percpu_irq,
                                    "per-cpu", 0);
        err = request_irq(irq, leon_percpu_timer_ce_interrupt,
                          IRQF_PERCPU | IRQF_TIMER, "timer", NULL);
#else
        irq = _leon_build_device_irq(NULL, leon3_gptimer_irq);
        err = request_irq(irq, timer_interrupt, IRQF_TIMER, "timer", NULL);
#endif
        if (err) {
                pr_err("Unable to attach timer IRQ%d\n", irq);
                prom_halt();
        }
        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
                              LEON3_GPTIMER_EN |
                              LEON3_GPTIMER_RL |
                              LEON3_GPTIMER_LD |
                              LEON3_GPTIMER_IRQEN);
        return;
bad:
        printk(KERN_ERR "No Timer/irqctrl found\n");
        BUG();
        return;
}

static void leon_clear_clock_irq(void)
{
        u32 ctrl;

        ctrl = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl);
        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
                              ctrl & leon3_gptimer_ackmask);
}

static void leon_load_profile_irq(int cpu, unsigned int limit)
{
}

#ifdef CONFIG_SMP
void leon_clear_profile_irq(int cpu)
{
}

void leon_enable_irq_cpu(unsigned int irq_nr, unsigned int cpu)
{
        unsigned long mask, flags, *addr;
        mask = leon_get_irqmask(irq_nr);
        spin_lock_irqsave(&leon_irq_lock, flags);
        addr = (unsigned long *)LEON_IMASK(cpu);
        LEON3_BYPASS_STORE_PA(addr, (LEON3_BYPASS_LOAD_PA(addr) | mask));
        spin_unlock_irqrestore(&leon_irq_lock, flags);
}

#endif

void __init leon_init_IRQ(void)
{
        sparc_config.init_timers      = leon_init_timers;
        sparc_config.build_device_irq = _leon_build_device_irq;
        sparc_config.clock_rate       = 1000000;
        sparc_config.clear_clock_irq  = leon_clear_clock_irq;
        sparc_config.load_profile_irq = leon_load_profile_irq;
}