#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/irq.h>
#include <linux/dma-mapping.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/8xx_immap.h>

#include "pic.h"


#define PIC_VEC_SPURRIOUS      15

static struct irq_domain *mpc8xx_pic_host;
static unsigned long mpc8xx_cached_irq_mask;
static sysconf8xx_t __iomem *siu_reg;

static inline unsigned long mpc8xx_irqd_to_bit(struct irq_data *d)
{
        return 0x80000000 >> irqd_to_hwirq(d);
}

static void mpc8xx_unmask_irq(struct irq_data *d)
{
        mpc8xx_cached_irq_mask |= mpc8xx_irqd_to_bit(d);
        out_be32(&siu_reg->sc_simask, mpc8xx_cached_irq_mask);
}

static void mpc8xx_mask_irq(struct irq_data *d)
{
        mpc8xx_cached_irq_mask &= ~mpc8xx_irqd_to_bit(d);
        out_be32(&siu_reg->sc_simask, mpc8xx_cached_irq_mask);
}

static void mpc8xx_ack(struct irq_data *d)
{
        out_be32(&siu_reg->sc_sipend, mpc8xx_irqd_to_bit(d));
}

static void mpc8xx_end_irq(struct irq_data *d)
{
        mpc8xx_cached_irq_mask |= mpc8xx_irqd_to_bit(d);
        out_be32(&siu_reg->sc_simask, mpc8xx_cached_irq_mask);
}

static int mpc8xx_set_irq_type(struct irq_data *d, unsigned int flow_type)
{
        /* only external IRQ senses are programmable */
        if ((flow_type & IRQ_TYPE_EDGE_FALLING) && !(irqd_to_hwirq(d) & 1)) {
                unsigned int siel = in_be32(&siu_reg->sc_siel);
                siel |= mpc8xx_irqd_to_bit(d);
                out_be32(&siu_reg->sc_siel, siel);
                irq_set_handler_locked(d, handle_edge_irq);
        }
        return 0;
}

static struct irq_chip mpc8xx_pic = {
        .name = "8XX SIU",
        .irq_unmask = mpc8xx_unmask_irq,
        .irq_mask = mpc8xx_mask_irq,
        .irq_ack = mpc8xx_ack,
        .irq_eoi = mpc8xx_end_irq,
        .irq_set_type = mpc8xx_set_irq_type,
};

unsigned int mpc8xx_get_irq(void)
{
        int irq;

        /* For MPC8xx, read the SIVEC register and shift the bits down
         * to get the irq number.
         */
        irq = in_be32(&siu_reg->sc_sivec) >> 26;

        if (irq == PIC_VEC_SPURRIOUS)
                return 0;

        return irq_find_mapping(mpc8xx_pic_host, irq);

}

static int mpc8xx_pic_host_map(struct irq_domain *h, unsigned int virq,
                          irq_hw_number_t hw)
{
        pr_debug("mpc8xx_pic_host_map(%d, 0x%lx)\n", virq, hw);

        /* Set default irq handle */
        irq_set_chip_and_handler(virq, &mpc8xx_pic, handle_level_irq);
        return 0;
}


static int mpc8xx_pic_host_xlate(struct irq_domain *h, struct device_node *ct,
                            const u32 *intspec, unsigned int intsize,
                            irq_hw_number_t *out_hwirq, unsigned int *out_flags)
{
        static unsigned char map_pic_senses[4] = {
                IRQ_TYPE_EDGE_RISING,
                IRQ_TYPE_LEVEL_LOW,
                IRQ_TYPE_LEVEL_HIGH,
                IRQ_TYPE_EDGE_FALLING,
        };

        if (intspec[0] > 0x1f)
                return 0;

        *out_hwirq = intspec[0];
        if (intsize > 1 && intspec[1] < 4)
                *out_flags = map_pic_senses[intspec[1]];
        else
                *out_flags = IRQ_TYPE_NONE;

        return 0;
}


static const struct irq_domain_ops mpc8xx_pic_host_ops = {
        .map = mpc8xx_pic_host_map,
        .xlate = mpc8xx_pic_host_xlate,
};

void __init mpc8xx_pic_init(void)
{
        struct resource res;
        struct device_node *np;
        int ret;

        np = of_find_compatible_node(NULL, NULL, "fsl,pq1-pic");
        if (np == NULL)
                np = of_find_node_by_type(NULL, "mpc8xx-pic");
        if (np == NULL) {
                printk(KERN_ERR "Could not find fsl,pq1-pic node\n");
                return;
        }

        ret = of_address_to_resource(np, 0, &res);
        if (ret)
                goto out;

        siu_reg = ioremap(res.start, resource_size(&res));
        if (!siu_reg)
                goto out;

        mpc8xx_pic_host = irq_domain_create_linear(of_fwnode_handle(np), 64,
                                                   &mpc8xx_pic_host_ops, NULL);
        if (!mpc8xx_pic_host)
                printk(KERN_ERR "MPC8xx PIC: failed to allocate irq host!\n");

out:
        of_node_put(np);
}