// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2012 Regents of the University of California
 * Copyright (C) 2017 SiFive
 * Copyright (C) 2018 Christoph Hellwig
 */

#include <linux/interrupt.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/scs.h>
#include <linux/seq_file.h>
#include <asm/sbi.h>
#include <asm/smp.h>
#include <asm/softirq_stack.h>
#include <asm/stacktrace.h>

static struct fwnode_handle *(*__get_intc_node)(void);

void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void))
{
        __get_intc_node = fn;
}

struct fwnode_handle *riscv_get_intc_hwnode(void)
{
        if (__get_intc_node)
                return __get_intc_node();

        return NULL;
}
EXPORT_SYMBOL_GPL(riscv_get_intc_hwnode);

/**
 * riscv_get_hart_index() - get hart index for interrupt delivery
 * @fwnode: interrupt controller node
 * @logical_index: index within the "interrupts-extended" property
 * @hart_index: filled with the hart index to use
 *
 * RISC-V uses term "hart index" for its interrupt controllers, for the
 * purpose of the interrupt routing to destination harts.
 * It may be arbitrary numbers assigned to each destination hart in context
 * of the particular interrupt domain.
 *
 * These numbers encoded in the optional property "riscv,hart-indexes"
 * that should contain hart index for each interrupt destination in the same
 * order as in the "interrupts-extended" property. If this property
 * not exist, it assumed equal to the logical index, i.e. index within the
 * "interrupts-extended" property.
 *
 * Return: error code
 */
int riscv_get_hart_index(struct fwnode_handle *fwnode, u32 logical_index,
                         u32 *hart_index)
{
        static const char *prop_hart_index = "riscv,hart-indexes";
        struct device_node *np = to_of_node(fwnode);

        if (!np || !of_property_present(np, prop_hart_index)) {
                *hart_index = logical_index;
                return 0;
        }

        return of_property_read_u32_index(np, prop_hart_index,
                                          logical_index, hart_index);
}

#ifdef CONFIG_IRQ_STACKS
#include <asm/irq_stack.h>

DECLARE_PER_CPU(ulong *, irq_shadow_call_stack_ptr);

#ifdef CONFIG_SHADOW_CALL_STACK
DEFINE_PER_CPU(ulong *, irq_shadow_call_stack_ptr);
#endif

static void init_irq_scs(void)
{
        int cpu;

        if (!scs_is_enabled())
                return;

        for_each_possible_cpu(cpu)
                per_cpu(irq_shadow_call_stack_ptr, cpu) =
                        scs_alloc(cpu_to_node(cpu));
}

DEFINE_PER_CPU(ulong *, irq_stack_ptr);

#ifdef CONFIG_VMAP_STACK
static void init_irq_stacks(void)
{
        int cpu;
        ulong *p;

        for_each_possible_cpu(cpu) {
                p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, cpu_to_node(cpu));
                per_cpu(irq_stack_ptr, cpu) = p;
        }
}
#else
/* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
DEFINE_PER_CPU_ALIGNED(ulong [IRQ_STACK_SIZE/sizeof(ulong)], irq_stack);

static void init_irq_stacks(void)
{
        int cpu;

        for_each_possible_cpu(cpu)
                per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
}
#endif /* CONFIG_VMAP_STACK */

#ifdef CONFIG_SOFTIRQ_ON_OWN_STACK
static void ___do_softirq(struct pt_regs *regs)
{
        __do_softirq();
}

void do_softirq_own_stack(void)
{
        if (on_thread_stack())
                call_on_irq_stack(NULL, ___do_softirq);
        else
                __do_softirq();
}
#endif /* CONFIG_SOFTIRQ_ON_OWN_STACK */

#else
static void init_irq_scs(void) {}
static void init_irq_stacks(void) {}
#endif /* CONFIG_IRQ_STACKS */

int arch_show_interrupts(struct seq_file *p, int prec)
{
        show_ipi_stats(p, prec);
        return 0;
}

void __init init_IRQ(void)
{
        init_irq_scs();
        init_irq_stacks();
        irqchip_init();
        if (!handle_arch_irq)
                panic("No interrupt controller found.");
        sbi_ipi_init();
}