/*
 * linux/arch/xtensa/kernel/irq.c
 *
 * Xtensa built-in interrupt controller and some generic functions copied
 * from i386.
 *
 * Copyright (C) 2002 - 2013 Tensilica, Inc.
 * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 *
 *
 * Chris Zankel <chris@zankel.net>
 * Kevin Chea
 *
 */

#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel_stat.h>
#include <linux/irqchip.h>
#include <linux/irqchip/xtensa-mx.h>
#include <linux/irqchip/xtensa-pic.h>
#include <linux/irqdomain.h>
#include <linux/of.h>

#include <asm/mxregs.h>
#include <asm/uaccess.h>
#include <asm/platform.h>

atomic_t irq_err_count;

asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
{
        int irq = irq_find_mapping(NULL, hwirq);

        if (hwirq >= NR_IRQS) {
                printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
                                __func__, hwirq);
        }

#ifdef CONFIG_DEBUG_STACKOVERFLOW
        /* Debugging check for stack overflow: is there less than 1KB free? */
        {
                unsigned long sp;

                __asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
                sp &= THREAD_SIZE - 1;

                if (unlikely(sp < (sizeof(thread_info) + 1024)))
                        printk("Stack overflow in do_IRQ: %ld\n",
                               sp - sizeof(struct thread_info));
        }
#endif
        generic_handle_irq(irq);
}

int arch_show_interrupts(struct seq_file *p, int prec)
{
#ifdef CONFIG_SMP
        show_ipi_list(p, prec);
#endif
        seq_printf(p, "%*s: ", prec, "ERR");
        seq_printf(p, "%10u\n", atomic_read(&irq_err_count));
        return 0;
}

int xtensa_irq_domain_xlate(const u32 *intspec, unsigned int intsize,
                unsigned long int_irq, unsigned long ext_irq,
                unsigned long *out_hwirq, unsigned int *out_type)
{
        if (WARN_ON(intsize < 1 || intsize > 2))
                return -EINVAL;
        if (intsize == 2 && intspec[1] == 1) {
                int_irq = xtensa_map_ext_irq(ext_irq);
                if (int_irq < XCHAL_NUM_INTERRUPTS)
                        *out_hwirq = int_irq;
                else
                        return -EINVAL;
        } else {
                *out_hwirq = int_irq;
        }
        *out_type = IRQ_TYPE_NONE;
        return 0;
}

int xtensa_irq_map(struct irq_domain *d, unsigned int irq,
                irq_hw_number_t hw)
{
        struct irq_chip *irq_chip = d->host_data;
        u32 mask = 1 << hw;

        if (mask & XCHAL_INTTYPE_MASK_SOFTWARE) {
                irq_set_chip_and_handler_name(irq, irq_chip,
                                handle_simple_irq, "level");
                irq_set_status_flags(irq, IRQ_LEVEL);
        } else if (mask & XCHAL_INTTYPE_MASK_EXTERN_EDGE) {
                irq_set_chip_and_handler_name(irq, irq_chip,
                                handle_edge_irq, "edge");
                irq_clear_status_flags(irq, IRQ_LEVEL);
        } else if (mask & XCHAL_INTTYPE_MASK_EXTERN_LEVEL) {
                irq_set_chip_and_handler_name(irq, irq_chip,
                                handle_level_irq, "level");
                irq_set_status_flags(irq, IRQ_LEVEL);
        } else if (mask & XCHAL_INTTYPE_MASK_TIMER) {
                irq_set_chip_and_handler_name(irq, irq_chip,
                                handle_percpu_irq, "timer");
                irq_clear_status_flags(irq, IRQ_LEVEL);
        } else {/* XCHAL_INTTYPE_MASK_WRITE_ERROR */
                /* XCHAL_INTTYPE_MASK_NMI */
                irq_set_chip_and_handler_name(irq, irq_chip,
                                handle_level_irq, "level");
                irq_set_status_flags(irq, IRQ_LEVEL);
        }
        return 0;
}

unsigned xtensa_map_ext_irq(unsigned ext_irq)
{
        unsigned mask = XCHAL_INTTYPE_MASK_EXTERN_EDGE |
                XCHAL_INTTYPE_MASK_EXTERN_LEVEL;
        unsigned i;

        for (i = 0; mask; ++i, mask >>= 1) {
                if ((mask & 1) && ext_irq-- == 0)
                        return i;
        }
        return XCHAL_NUM_INTERRUPTS;
}

unsigned xtensa_get_ext_irq_no(unsigned irq)
{
        unsigned mask = (XCHAL_INTTYPE_MASK_EXTERN_EDGE |
                XCHAL_INTTYPE_MASK_EXTERN_LEVEL) &
                ((1u << irq) - 1);
        return hweight32(mask);
}

void __init init_IRQ(void)
{
#ifdef CONFIG_OF
        irqchip_init();
#else
#ifdef CONFIG_HAVE_SMP
        xtensa_mx_init_legacy(NULL);
#else
        xtensa_pic_init_legacy(NULL);
#endif
#endif

#ifdef CONFIG_SMP
        ipi_init();
#endif
        variant_init_irq();
}

#ifdef CONFIG_HOTPLUG_CPU
/*
 * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 * the affinity settings do not allow other CPUs, force them onto any
 * available CPU.
 */
void migrate_irqs(void)
{
        unsigned int i, cpu = smp_processor_id();

        for_each_active_irq(i) {
                struct irq_data *data = irq_get_irq_data(i);
                unsigned int newcpu;

                if (irqd_is_per_cpu(data))
                        continue;

                if (!cpumask_test_cpu(cpu, data->affinity))
                        continue;

                newcpu = cpumask_any_and(data->affinity, cpu_online_mask);

                if (newcpu >= nr_cpu_ids) {
                        pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
                                            i, cpu);

                        cpumask_setall(data->affinity);
                }
                irq_set_affinity(i, data->affinity);
        }
}
#endif /* CONFIG_HOTPLUG_CPU */