/*
 * Platform information definitions.
 *
 * Copied from arch/ppc/syslib/cpm2_pic.c with minor subsequent updates
 * to make in work in arch/powerpc/. Original (c) belongs to Dan Malek.
 *
 * Author:  Vitaly Bordug <vbordug@ru.mvista.com>
 *
 * 1999-2001 (c) Dan Malek <dan@embeddedalley.com>
 * 2006 (c) MontaVista Software, Inc.
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

/* The CPM2 internal interrupt controller.  It is usually
 * the only interrupt controller.
 * There are two 32-bit registers (high/low) for up to 64
 * possible interrupts.
 *
 * Now, the fun starts.....Interrupt Numbers DO NOT MAP
 * in a simple arithmetic fashion to mask or pending registers.
 * That is, interrupt 4 does not map to bit position 4.
 * We create two tables, indexed by vector number, to indicate
 * which register to use and which bit in the register to use.
 */

#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>

#include <asm/immap_cpm2.h>
#include <asm/io.h>

#include "cpm2_pic.h"

/* External IRQS */
#define CPM2_IRQ_EXT1           19
#define CPM2_IRQ_EXT7           25

/* Port C IRQS */
#define CPM2_IRQ_PORTC15        48
#define CPM2_IRQ_PORTC0         63

static intctl_cpm2_t __iomem *cpm2_intctl;

static struct irq_domain *cpm2_pic_host;
static unsigned long ppc_cached_irq_mask[2]; /* 2 32-bit registers */

static const u_char irq_to_siureg[] = {
        1, 1, 1, 1, 1, 1, 1, 1,
        1, 1, 1, 1, 1, 1, 1, 1,
        0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0,
        1, 1, 1, 1, 1, 1, 1, 1,
        1, 1, 1, 1, 1, 1, 1, 1,
        0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0
};

/* bit numbers do not match the docs, these are precomputed so the bit for
 * a given irq is (1 << irq_to_siubit[irq]) */
static const u_char irq_to_siubit[] = {
         0, 15, 14, 13, 12, 11, 10,  9,
         8,  7,  6,  5,  4,  3,  2,  1,
         2,  1,  0, 14, 13, 12, 11, 10,
         9,  8,  7,  6,  5,  4,  3,  0,
        31, 30, 29, 28, 27, 26, 25, 24,
        23, 22, 21, 20, 19, 18, 17, 16,
        16, 17, 18, 19, 20, 21, 22, 23,
        24, 25, 26, 27, 28, 29, 30, 31,
};

static void cpm2_mask_irq(struct irq_data *d)
{
        int     bit, word;
        unsigned int irq_nr = irqd_to_hwirq(d);

        bit = irq_to_siubit[irq_nr];
        word = irq_to_siureg[irq_nr];

        ppc_cached_irq_mask[word] &= ~(1 << bit);
        out_be32(&cpm2_intctl->ic_simrh + word, ppc_cached_irq_mask[word]);
}

static void cpm2_unmask_irq(struct irq_data *d)
{
        int     bit, word;
        unsigned int irq_nr = irqd_to_hwirq(d);

        bit = irq_to_siubit[irq_nr];
        word = irq_to_siureg[irq_nr];

        ppc_cached_irq_mask[word] |= 1 << bit;
        out_be32(&cpm2_intctl->ic_simrh + word, ppc_cached_irq_mask[word]);
}

static void cpm2_ack(struct irq_data *d)
{
        int     bit, word;
        unsigned int irq_nr = irqd_to_hwirq(d);

        bit = irq_to_siubit[irq_nr];
        word = irq_to_siureg[irq_nr];

        out_be32(&cpm2_intctl->ic_sipnrh + word, 1 << bit);
}

static void cpm2_end_irq(struct irq_data *d)
{
        int     bit, word;
        unsigned int irq_nr = irqd_to_hwirq(d);

        bit = irq_to_siubit[irq_nr];
        word = irq_to_siureg[irq_nr];

        ppc_cached_irq_mask[word] |= 1 << bit;
        out_be32(&cpm2_intctl->ic_simrh + word, ppc_cached_irq_mask[word]);

        /*
         * Work around large numbers of spurious IRQs on PowerPC 82xx
         * systems.
         */
        mb();
}

static int cpm2_set_irq_type(struct irq_data *d, unsigned int flow_type)
{
        unsigned int src = irqd_to_hwirq(d);
        unsigned int vold, vnew, edibit;

        /* Port C interrupts are either IRQ_TYPE_EDGE_FALLING or
         * IRQ_TYPE_EDGE_BOTH (default).  All others are IRQ_TYPE_EDGE_FALLING
         * or IRQ_TYPE_LEVEL_LOW (default)
         */
        if (src >= CPM2_IRQ_PORTC15 && src <= CPM2_IRQ_PORTC0) {
                if (flow_type == IRQ_TYPE_NONE)
                        flow_type = IRQ_TYPE_EDGE_BOTH;

                if (flow_type != IRQ_TYPE_EDGE_BOTH &&
                    flow_type != IRQ_TYPE_EDGE_FALLING)
                        goto err_sense;
        } else {
                if (flow_type == IRQ_TYPE_NONE)
                        flow_type = IRQ_TYPE_LEVEL_LOW;

                if (flow_type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_LEVEL_HIGH))
                        goto err_sense;
        }

        irqd_set_trigger_type(d, flow_type);
        if (flow_type & IRQ_TYPE_LEVEL_LOW)
                irq_set_handler_locked(d, handle_level_irq);
        else
                irq_set_handler_locked(d, handle_edge_irq);

        /* internal IRQ senses are LEVEL_LOW
         * EXT IRQ and Port C IRQ senses are programmable
         */
        if (src >= CPM2_IRQ_EXT1 && src <= CPM2_IRQ_EXT7)
                        edibit = (14 - (src - CPM2_IRQ_EXT1));
        else
                if (src >= CPM2_IRQ_PORTC15 && src <= CPM2_IRQ_PORTC0)
                        edibit = (31 - (CPM2_IRQ_PORTC0 - src));
                else
                        return (flow_type & IRQ_TYPE_LEVEL_LOW) ?
                                IRQ_SET_MASK_OK_NOCOPY : -EINVAL;

        vold = in_be32(&cpm2_intctl->ic_siexr);

        if ((flow_type & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_FALLING)
                vnew = vold | (1 << edibit);
        else
                vnew = vold & ~(1 << edibit);

        if (vold != vnew)
                out_be32(&cpm2_intctl->ic_siexr, vnew);
        return IRQ_SET_MASK_OK_NOCOPY;

err_sense:
        pr_err("CPM2 PIC: sense type 0x%x not supported\n", flow_type);
        return -EINVAL;
}

static struct irq_chip cpm2_pic = {
        .name = "CPM2 SIU",
        .irq_mask = cpm2_mask_irq,
        .irq_unmask = cpm2_unmask_irq,
        .irq_ack = cpm2_ack,
        .irq_eoi = cpm2_end_irq,
        .irq_set_type = cpm2_set_irq_type,
        .flags = IRQCHIP_EOI_IF_HANDLED,
};

unsigned int cpm2_get_irq(void)
{
        int irq;
        unsigned long bits;

       /* For CPM2, read the SIVEC register and shift the bits down
         * to get the irq number.         */
        bits = in_be32(&cpm2_intctl->ic_sivec);
        irq = bits >> 26;

        if (irq == 0)
                return(-1);
        return irq_find_mapping(cpm2_pic_host, irq);
}

static int cpm2_pic_host_map(struct irq_domain *h, unsigned int virq,
                          irq_hw_number_t hw)
{
        pr_debug("cpm2_pic_host_map(%d, 0x%lx)\n", virq, hw);

        irq_set_status_flags(virq, IRQ_LEVEL);
        irq_set_chip_and_handler(virq, &cpm2_pic, handle_level_irq);
        return 0;
}

static const struct irq_domain_ops cpm2_pic_host_ops = {
        .map = cpm2_pic_host_map,
        .xlate = irq_domain_xlate_onetwocell,
};

void cpm2_pic_init(struct device_node *node)
{
        int i;

        cpm2_intctl = &cpm2_immr->im_intctl;

        /* Clear the CPM IRQ controller, in case it has any bits set
         * from the bootloader
         */

        /* Mask out everything */

        out_be32(&cpm2_intctl->ic_simrh, 0x00000000);
        out_be32(&cpm2_intctl->ic_simrl, 0x00000000);

        wmb();

        /* Ack everything */
        out_be32(&cpm2_intctl->ic_sipnrh, 0xffffffff);
        out_be32(&cpm2_intctl->ic_sipnrl, 0xffffffff);
        wmb();

        /* Dummy read of the vector */
        i = in_be32(&cpm2_intctl->ic_sivec);
        rmb();

        /* Initialize the default interrupt mapping priorities,
         * in case the boot rom changed something on us.
         */
        out_be16(&cpm2_intctl->ic_sicr, 0);
        out_be32(&cpm2_intctl->ic_scprrh, 0x05309770);
        out_be32(&cpm2_intctl->ic_scprrl, 0x05309770);

        /* create a legacy host */
        cpm2_pic_host = irq_domain_create_linear(of_fwnode_handle(node), 64,
                                                 &cpm2_pic_host_ops, NULL);
        if (cpm2_pic_host == NULL) {
                printk(KERN_ERR "CPM2 PIC: failed to allocate irq host!\n");
                return;
        }
}