/*
 * Support for 'media5200-platform' compatible boards.
 *
 * Copyright (C) 2008 Secret Lab Technologies Ltd.
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 * Description:
 * This code implements support for the Freescape Media5200 platform
 * (built around the MPC5200 SoC).
 *
 * Notable characteristic of the Media5200 is the presence of an FPGA
 * that has all external IRQ lines routed through it.  This file implements
 * a cascaded interrupt controller driver which attaches itself to the
 * Virtual IRQ subsystem after the primary mpc5200 interrupt controller
 * is initialized.
 *
 */

#undef DEBUG

#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <asm/time.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/mpc52xx.h>

static const struct of_device_id mpc5200_gpio_ids[] __initconst = {
        { .compatible = "fsl,mpc5200-gpio", },
        { .compatible = "mpc5200-gpio", },
        {}
};

/* FPGA register set */
#define MEDIA5200_IRQ_ENABLE (0x40c)
#define MEDIA5200_IRQ_STATUS (0x410)
#define MEDIA5200_NUM_IRQS   (6)
#define MEDIA5200_IRQ_SHIFT  (32 - MEDIA5200_NUM_IRQS)

struct media5200_irq {
        void __iomem *regs;
        spinlock_t lock;
        struct irq_domain *irqhost;
};
struct media5200_irq media5200_irq;

static void media5200_irq_unmask(struct irq_data *d)
{
        unsigned long flags;
        u32 val;

        spin_lock_irqsave(&media5200_irq.lock, flags);
        val = in_be32(media5200_irq.regs + MEDIA5200_IRQ_ENABLE);
        val |= 1 << (MEDIA5200_IRQ_SHIFT + irqd_to_hwirq(d));
        out_be32(media5200_irq.regs + MEDIA5200_IRQ_ENABLE, val);
        spin_unlock_irqrestore(&media5200_irq.lock, flags);
}

static void media5200_irq_mask(struct irq_data *d)
{
        unsigned long flags;
        u32 val;

        spin_lock_irqsave(&media5200_irq.lock, flags);
        val = in_be32(media5200_irq.regs + MEDIA5200_IRQ_ENABLE);
        val &= ~(1 << (MEDIA5200_IRQ_SHIFT + irqd_to_hwirq(d)));
        out_be32(media5200_irq.regs + MEDIA5200_IRQ_ENABLE, val);
        spin_unlock_irqrestore(&media5200_irq.lock, flags);
}

static struct irq_chip media5200_irq_chip = {
        .name = "Media5200 FPGA",
        .irq_unmask = media5200_irq_unmask,
        .irq_mask = media5200_irq_mask,
        .irq_mask_ack = media5200_irq_mask,
};

void media5200_irq_cascade(unsigned int virq, struct irq_desc *desc)
{
        struct irq_chip *chip = irq_desc_get_chip(desc);
        int sub_virq, val;
        u32 status, enable;

        /* Mask off the cascaded IRQ */
        raw_spin_lock(&desc->lock);
        chip->irq_mask(&desc->irq_data);
        raw_spin_unlock(&desc->lock);

        /* Ask the FPGA for IRQ status.  If 'val' is 0, then no irqs
         * are pending.  'ffs()' is 1 based */
        status = in_be32(media5200_irq.regs + MEDIA5200_IRQ_ENABLE);
        enable = in_be32(media5200_irq.regs + MEDIA5200_IRQ_STATUS);
        val = ffs((status & enable) >> MEDIA5200_IRQ_SHIFT);
        if (val) {
                sub_virq = irq_linear_revmap(media5200_irq.irqhost, val - 1);
                /* pr_debug("%s: virq=%i s=%.8x e=%.8x hwirq=%i subvirq=%i\n",
                 *          __func__, virq, status, enable, val - 1, sub_virq);
                 */
                generic_handle_irq(sub_virq);
        }

        /* Processing done; can reenable the cascade now */
        raw_spin_lock(&desc->lock);
        chip->irq_ack(&desc->irq_data);
        if (!irqd_irq_disabled(&desc->irq_data))
                chip->irq_unmask(&desc->irq_data);
        raw_spin_unlock(&desc->lock);
}

static int media5200_irq_map(struct irq_domain *h, unsigned int virq,
                             irq_hw_number_t hw)
{
        pr_debug("%s: h=%p, virq=%i, hwirq=%i\n", __func__, h, virq, (int)hw);
        irq_set_chip_data(virq, &media5200_irq);
        irq_set_chip_and_handler(virq, &media5200_irq_chip, handle_level_irq);
        irq_set_status_flags(virq, IRQ_LEVEL);
        return 0;
}

static int media5200_irq_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)
{
        if (intsize != 2)
                return -1;

        pr_debug("%s: bank=%i, number=%i\n", __func__, intspec[0], intspec[1]);
        *out_hwirq = intspec[1];
        *out_flags = IRQ_TYPE_NONE;
        return 0;
}

static const struct irq_domain_ops media5200_irq_ops = {
        .map = media5200_irq_map,
        .xlate = media5200_irq_xlate,
};

/*
 * Setup Media5200 IRQ mapping
 */
static void __init media5200_init_irq(void)
{
        struct device_node *fpga_np;
        int cascade_virq;

        /* First setup the regular MPC5200 interrupt controller */
        mpc52xx_init_irq();

        /* Now find the FPGA IRQ */
        fpga_np = of_find_compatible_node(NULL, NULL, "fsl,media5200-fpga");
        if (!fpga_np)
                goto out;
        pr_debug("%s: found fpga node: %s\n", __func__, fpga_np->full_name);

        media5200_irq.regs = of_iomap(fpga_np, 0);
        if (!media5200_irq.regs)
                goto out;
        pr_debug("%s: mapped to %p\n", __func__, media5200_irq.regs);

        cascade_virq = irq_of_parse_and_map(fpga_np, 0);
        if (!cascade_virq)
                goto out;
        pr_debug("%s: cascaded on virq=%i\n", __func__, cascade_virq);

        /* Disable all FPGA IRQs */
        out_be32(media5200_irq.regs + MEDIA5200_IRQ_ENABLE, 0);

        spin_lock_init(&media5200_irq.lock);

        media5200_irq.irqhost = irq_domain_add_linear(fpga_np,
                        MEDIA5200_NUM_IRQS, &media5200_irq_ops, &media5200_irq);
        if (!media5200_irq.irqhost)
                goto out;
        pr_debug("%s: allocated irqhost\n", __func__);

        irq_set_handler_data(cascade_virq, &media5200_irq);
        irq_set_chained_handler(cascade_virq, media5200_irq_cascade);

        return;

 out:
        pr_err("Could not find Media5200 FPGA; PCI interrupts will not work\n");
}

/*
 * Setup the architecture
 */
static void __init media5200_setup_arch(void)
{

        struct device_node *np;
        struct mpc52xx_gpio __iomem *gpio;
        u32 port_config;

        if (ppc_md.progress)
                ppc_md.progress("media5200_setup_arch()", 0);

        /* Map important registers from the internal memory map */
        mpc52xx_map_common_devices();

        /* Some mpc5200 & mpc5200b related configuration */
        mpc5200_setup_xlb_arbiter();

        mpc52xx_setup_pci();

        np = of_find_matching_node(NULL, mpc5200_gpio_ids);
        gpio = of_iomap(np, 0);
        of_node_put(np);
        if (!gpio) {
                printk(KERN_ERR "%s() failed. expect abnormal behavior\n",
                       __func__);
                return;
        }

        /* Set port config */
        port_config = in_be32(&gpio->port_config);

        port_config &= ~0x03000000;     /* ATA CS is on csb_4/5         */
        port_config |=  0x01000000;

        out_be32(&gpio->port_config, port_config);

        /* Unmap zone */
        iounmap(gpio);

}

/* list of the supported boards */
static const char * const board[] __initconst = {
        "fsl,media5200",
        NULL
};

/*
 * Called very early, MMU is off, device-tree isn't unflattened
 */
static int __init media5200_probe(void)
{
        return of_flat_dt_match(of_get_flat_dt_root(), board);
}

define_machine(media5200_platform) {
        .name           = "media5200-platform",
        .probe          = media5200_probe,
        .setup_arch     = media5200_setup_arch,
        .init           = mpc52xx_declare_of_platform_devices,
        .init_IRQ       = media5200_init_irq,
        .get_irq        = mpc52xx_get_irq,
        .restart        = mpc52xx_restart,
        .calibrate_decr = generic_calibrate_decr,
};