// SPDX-License-Identifier: GPL-2.0
/*
 * SS1000/SC2000 interrupt handling.
 *
 *  Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 *  Heavily based on arch/sparc/kernel/irq.c.
 */

#include <linux/kernel_stat.h>
#include <linux/slab.h>
#include <linux/seq_file.h>

#include <asm/timer.h>
#include <asm/traps.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/sbi.h>
#include <asm/cacheflush.h>
#include <asm/setup.h>
#include <asm/oplib.h>

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

/* Sun4d interrupts fall roughly into two categories.  SBUS and
 * cpu local.  CPU local interrupts cover the timer interrupts
 * and whatnot, and we encode those as normal PILs between
 * 0 and 15.
 * SBUS interrupts are encodes as a combination of board, level and slot.
 */

struct sun4d_handler_data {
        unsigned int cpuid;    /* target cpu */
        unsigned int real_irq; /* interrupt level */
};


static unsigned int sun4d_encode_irq(int board, int lvl, int slot)
{
        return (board + 1) << 5 | (lvl << 2) | slot;
}

struct sun4d_timer_regs {
        u32     l10_timer_limit;
        u32     l10_cur_countx;
        u32     l10_limit_noclear;
        u32     ctrl;
        u32     l10_cur_count;
};

static struct sun4d_timer_regs __iomem *sun4d_timers;

#define SUN4D_TIMER_IRQ        10

/* Specify which cpu handle interrupts from which board.
 * Index is board - value is cpu.
 */
static unsigned char board_to_cpu[32];

static int pil_to_sbus[] = {
        0,
        0,
        1,
        2,
        0,
        3,
        0,
        4,
        0,
        5,
        0,
        6,
        0,
        7,
        0,
        0,
};

/* Exported for sun4d_smp.c */
DEFINE_SPINLOCK(sun4d_imsk_lock);

/* SBUS interrupts are encoded integers including the board number
 * (plus one), the SBUS level, and the SBUS slot number.  Sun4D
 * IRQ dispatch is done by:
 *
 * 1) Reading the BW local interrupt table in order to get the bus
 *    interrupt mask.
 *
 *    This table is indexed by SBUS interrupt level which can be
 *    derived from the PIL we got interrupted on.
 *
 * 2) For each bus showing interrupt pending from #1, read the
 *    SBI interrupt state register.  This will indicate which slots
 *    have interrupts pending for that SBUS interrupt level.
 *
 * 3) Call the genreric IRQ support.
 */
static void sun4d_sbus_handler_irq(int sbusl)
{
        unsigned int bus_mask;
        unsigned int sbino, slot;
        unsigned int sbil;

        bus_mask = bw_get_intr_mask(sbusl) & 0x3ffff;
        bw_clear_intr_mask(sbusl, bus_mask);

        sbil = (sbusl << 2);
        /* Loop for each pending SBI */
        for (sbino = 0; bus_mask; sbino++, bus_mask >>= 1) {
                unsigned int idx, mask;

                if (!(bus_mask & 1))
                        continue;
                /* XXX This seems to ACK the irq twice.  acquire_sbi()
                 * XXX uses swap, therefore this writes 0xf << sbil,
                 * XXX then later release_sbi() will write the individual
                 * XXX bits which were set again.
                 */
                mask = acquire_sbi(SBI2DEVID(sbino), 0xf << sbil);
                mask &= (0xf << sbil);

                /* Loop for each pending SBI slot */
                slot = (1 << sbil);
                for (idx = 0; mask != 0; idx++, slot <<= 1) {
                        unsigned int pil;
                        struct irq_bucket *p;

                        if (!(mask & slot))
                                continue;

                        mask &= ~slot;
                        pil = sun4d_encode_irq(sbino, sbusl, idx);

                        p = irq_map[pil];
                        while (p) {
                                struct irq_bucket *next;

                                next = p->next;
                                generic_handle_irq(p->irq);
                                p = next;
                        }
                        release_sbi(SBI2DEVID(sbino), slot);
                }
        }
}

void sun4d_handler_irq(unsigned int pil, struct pt_regs *regs)
{
        struct pt_regs *old_regs;
        /* SBUS IRQ level (1 - 7) */
        int sbusl = pil_to_sbus[pil];

        /* FIXME: Is this necessary?? */
        cc_get_ipen();

        cc_set_iclr(1 << pil);

#ifdef CONFIG_SMP
        /*
         * Check IPI data structures after IRQ has been cleared. Hard and Soft
         * IRQ can happen at the same time, so both cases are always handled.
         */
        if (pil == SUN4D_IPI_IRQ)
                sun4d_ipi_interrupt();
#endif

        old_regs = set_irq_regs(regs);
        irq_enter();
        if (sbusl == 0) {
                /* cpu interrupt */
                struct irq_bucket *p;

                p = irq_map[pil];
                while (p) {
                        struct irq_bucket *next;

                        next = p->next;
                        generic_handle_irq(p->irq);
                        p = next;
                }
        } else {
                /* SBUS interrupt */
                sun4d_sbus_handler_irq(sbusl);
        }
        irq_exit();
        set_irq_regs(old_regs);
}


static void sun4d_mask_irq(struct irq_data *data)
{
        struct sun4d_handler_data *handler_data = irq_data_get_irq_handler_data(data);
        unsigned int real_irq;
#ifdef CONFIG_SMP
        int cpuid = handler_data->cpuid;
        unsigned long flags;
#endif
        real_irq = handler_data->real_irq;
#ifdef CONFIG_SMP
        spin_lock_irqsave(&sun4d_imsk_lock, flags);
        cc_set_imsk_other(cpuid, cc_get_imsk_other(cpuid) | (1 << real_irq));
        spin_unlock_irqrestore(&sun4d_imsk_lock, flags);
#else
        cc_set_imsk(cc_get_imsk() | (1 << real_irq));
#endif
}

static void sun4d_unmask_irq(struct irq_data *data)
{
        struct sun4d_handler_data *handler_data = irq_data_get_irq_handler_data(data);
        unsigned int real_irq;
#ifdef CONFIG_SMP
        int cpuid = handler_data->cpuid;
        unsigned long flags;
#endif
        real_irq = handler_data->real_irq;

#ifdef CONFIG_SMP
        spin_lock_irqsave(&sun4d_imsk_lock, flags);
        cc_set_imsk_other(cpuid, cc_get_imsk_other(cpuid) & ~(1 << real_irq));
        spin_unlock_irqrestore(&sun4d_imsk_lock, flags);
#else
        cc_set_imsk(cc_get_imsk() & ~(1 << real_irq));
#endif
}

static unsigned int sun4d_startup_irq(struct irq_data *data)
{
        irq_link(data->irq);
        sun4d_unmask_irq(data);
        return 0;
}

static void sun4d_shutdown_irq(struct irq_data *data)
{
        sun4d_mask_irq(data);
        irq_unlink(data->irq);
}

static struct irq_chip sun4d_irq = {
        .name           = "sun4d",
        .irq_startup    = sun4d_startup_irq,
        .irq_shutdown   = sun4d_shutdown_irq,
        .irq_unmask     = sun4d_unmask_irq,
        .irq_mask       = sun4d_mask_irq,
};

#ifdef CONFIG_SMP
/* Setup IRQ distribution scheme. */
void __init sun4d_distribute_irqs(void)
{
        struct device_node *dp;

        int cpuid = cpu_logical_map(1);

        if (cpuid == -1)
                cpuid = cpu_logical_map(0);
        for_each_node_by_name(dp, "sbi") {
                int devid = of_getintprop_default(dp, "device-id", 0);
                int board = of_getintprop_default(dp, "board#", 0);
                board_to_cpu[board] = cpuid;
                set_sbi_tid(devid, cpuid << 3);
        }
        printk(KERN_ERR "All sbus IRQs directed to CPU%d\n", cpuid);
}
#endif

static void sun4d_clear_clock_irq(void)
{
        sbus_readl(&sun4d_timers->l10_timer_limit);
}

static void sun4d_load_profile_irq(int cpu, unsigned int limit)
{
        unsigned int value = limit ? timer_value(limit) : 0;
        bw_set_prof_limit(cpu, value);
}

static void __init sun4d_load_profile_irqs(void)
{
        int cpu = 0, mid;

        while (!cpu_find_by_instance(cpu, NULL, &mid)) {
                sun4d_load_profile_irq(mid >> 3, 0);
                cpu++;
        }
}

static unsigned int _sun4d_build_device_irq(unsigned int real_irq,
                                            unsigned int pil,
                                            unsigned int board)
{
        struct sun4d_handler_data *handler_data;
        unsigned int irq;

        irq = irq_alloc(real_irq, pil);
        if (irq == 0) {
                prom_printf("IRQ: allocate for %d %d %d failed\n",
                        real_irq, pil, board);
                goto err_out;
        }

        handler_data = irq_get_handler_data(irq);
        if (unlikely(handler_data))
                goto err_out;

        handler_data = kzalloc(sizeof(struct sun4d_handler_data), GFP_ATOMIC);
        if (unlikely(!handler_data)) {
                prom_printf("IRQ: kzalloc(sun4d_handler_data) failed.\n");
                prom_halt();
        }
        handler_data->cpuid    = board_to_cpu[board];
        handler_data->real_irq = real_irq;
        irq_set_chip_and_handler_name(irq, &sun4d_irq,
                                      handle_level_irq, "level");
        irq_set_handler_data(irq, handler_data);

err_out:
        return irq;
}



static unsigned int sun4d_build_device_irq(struct platform_device *op,
                                           unsigned int real_irq)
{
        struct device_node *dp = op->dev.of_node;
        struct device_node *board_parent, *bus = dp->parent;
        char *bus_connection;
        const struct linux_prom_registers *regs;
        unsigned int pil;
        unsigned int irq;
        int board, slot;
        int sbusl;

        irq = real_irq;
        while (bus) {
                if (!strcmp(bus->name, "sbi")) {
                        bus_connection = "io-unit";
                        break;
                }

                if (!strcmp(bus->name, "bootbus")) {
                        bus_connection = "cpu-unit";
                        break;
                }

                bus = bus->parent;
        }
        if (!bus)
                goto err_out;

        regs = of_get_property(dp, "reg", NULL);
        if (!regs)
                goto err_out;

        slot = regs->which_io;

        /*
         * If Bus nodes parent is not io-unit/cpu-unit or the io-unit/cpu-unit
         * lacks a "board#" property, something is very wrong.
         */
        if (!bus->parent || strcmp(bus->parent->name, bus_connection)) {
                printk(KERN_ERR "%s: Error, parent is not %s.\n",
                        bus->full_name, bus_connection);
                goto err_out;
        }
        board_parent = bus->parent;
        board = of_getintprop_default(board_parent, "board#", -1);
        if (board == -1) {
                printk(KERN_ERR "%s: Error, lacks board# property.\n",
                        board_parent->full_name);
                goto err_out;
        }

        sbusl = pil_to_sbus[real_irq];
        if (sbusl)
                pil = sun4d_encode_irq(board, sbusl, slot);
        else
                pil = real_irq;

        irq = _sun4d_build_device_irq(real_irq, pil, board);
err_out:
        return irq;
}

static unsigned int sun4d_build_timer_irq(unsigned int board,
                                          unsigned int real_irq)
{
        return _sun4d_build_device_irq(real_irq, real_irq, board);
}


static void __init sun4d_fixup_trap_table(void)
{
#ifdef CONFIG_SMP
        unsigned long flags;
        struct tt_entry *trap_table = &sparc_ttable[SP_TRAP_IRQ1 + (14 - 1)];

        /* Adjust so that we jump directly to smp4d_ticker */
        lvl14_save[2] += smp4d_ticker - real_irq_entry;

        /* For SMP we use the level 14 ticker, however the bootup code
         * has copied the firmware's level 14 vector into the boot cpu's
         * trap table, we must fix this now or we get squashed.
         */
        local_irq_save(flags);
        patchme_maybe_smp_msg[0] = 0x01000000; /* NOP out the branch */
        trap_table->inst_one = lvl14_save[0];
        trap_table->inst_two = lvl14_save[1];
        trap_table->inst_three = lvl14_save[2];
        trap_table->inst_four = lvl14_save[3];
        local_ops->cache_all();
        local_irq_restore(flags);
#endif
}

static void __init sun4d_init_timers(void)
{
        struct device_node *dp;
        struct resource res;
        unsigned int irq;
        const u32 *reg;
        int err;
        int board;

        dp = of_find_node_by_name(NULL, "cpu-unit");
        if (!dp) {
                prom_printf("sun4d_init_timers: Unable to find cpu-unit\n");
                prom_halt();
        }

        /* Which cpu-unit we use is arbitrary, we can view the bootbus timer
         * registers via any cpu's mapping.  The first 'reg' property is the
         * bootbus.
         */
        reg = of_get_property(dp, "reg", NULL);
        if (!reg) {
                prom_printf("sun4d_init_timers: No reg property\n");
                prom_halt();
        }

        board = of_getintprop_default(dp, "board#", -1);
        if (board == -1) {
                prom_printf("sun4d_init_timers: No board# property on cpu-unit\n");
                prom_halt();
        }

        of_node_put(dp);

        res.start = reg[1];
        res.end = reg[2] - 1;
        res.flags = reg[0] & 0xff;
        sun4d_timers = of_ioremap(&res, BW_TIMER_LIMIT,
                                  sizeof(struct sun4d_timer_regs), "user timer");
        if (!sun4d_timers) {
                prom_printf("sun4d_init_timers: Can't map timer regs\n");
                prom_halt();
        }

#ifdef CONFIG_SMP
        sparc_config.cs_period = SBUS_CLOCK_RATE * 2;  /* 2 seconds */
#else
        sparc_config.cs_period = SBUS_CLOCK_RATE / HZ; /* 1/HZ sec  */
        sparc_config.features |= FEAT_L10_CLOCKEVENT;
#endif
        sparc_config.features |= FEAT_L10_CLOCKSOURCE;
        sbus_writel(timer_value(sparc_config.cs_period),
                    &sun4d_timers->l10_timer_limit);

        master_l10_counter = &sun4d_timers->l10_cur_count;

        irq = sun4d_build_timer_irq(board, SUN4D_TIMER_IRQ);
        err = request_irq(irq, timer_interrupt, IRQF_TIMER, "timer", NULL);
        if (err) {
                prom_printf("sun4d_init_timers: request_irq() failed with %d\n",
                             err);
                prom_halt();
        }
        sun4d_load_profile_irqs();
        sun4d_fixup_trap_table();
}

void __init sun4d_init_sbi_irq(void)
{
        struct device_node *dp;
        int target_cpu;

        target_cpu = boot_cpu_id;
        for_each_node_by_name(dp, "sbi") {
                int devid = of_getintprop_default(dp, "device-id", 0);
                int board = of_getintprop_default(dp, "board#", 0);
                unsigned int mask;

                set_sbi_tid(devid, target_cpu << 3);
                board_to_cpu[board] = target_cpu;

                /* Get rid of pending irqs from PROM */
                mask = acquire_sbi(devid, 0xffffffff);
                if (mask) {
                        printk(KERN_ERR "Clearing pending IRQs %08x on SBI %d\n",
                               mask, board);
                        release_sbi(devid, mask);
                }
        }
}

void __init sun4d_init_IRQ(void)
{
        local_irq_disable();

        sparc_config.init_timers      = sun4d_init_timers;
        sparc_config.build_device_irq = sun4d_build_device_irq;
        sparc_config.clock_rate       = SBUS_CLOCK_RATE;
        sparc_config.clear_clock_irq  = sun4d_clear_clock_irq;
        sparc_config.load_profile_irq = sun4d_load_profile_irq;

        /* Cannot enable interrupts until OBP ticker is disabled. */
}