mpic_msi.c

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/*
 * Copyright 2006-2007, Michael Ellerman, IBM Corporation.
 *
 * 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; version 2 of the
 * License.
 *
 */

#include <linux/irq.h>
#include <linux/bitmap.h>
#include <linux/msi.h>
#include <asm/mpic.h>
#include <asm/prom.h>
#include <asm/hw_irq.h>
#include <asm/ppc-pci.h>
#include <asm/msi_bitmap.h>

#include <sysdev/mpic.h>

void mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)
{
    /* The mpic calls this even when there is no allocator setup */
    if (!mpic->msi_bitmap.bitmap)
        return;

    msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, hwirq);
}

#ifdef CONFIG_MPIC_U3_HT_IRQS
static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
{
    irq_hw_number_t hwirq;
    const struct irq_domain_ops *ops = mpic->irqhost->ops;
    struct device_node *np;
    int flags, index, i;
    struct of_irq oirq;

    pr_debug("mpic: found U3, guessing msi allocator setup\n");

    /* Reserve source numbers we know are reserved in the HW.
     *
     * This is a bit of a mix of U3 and U4 reserves but that's going
     * to work fine, we have plenty enugh numbers left so let's just
     * mark anything we don't like reserved.
     */
    for (i = 0;   i < 8;   i++)
        msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);

    for (i = 42;  i < 46;  i++)
        msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);

    for (i = 100; i < 105; i++)
        msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);

    for (i = 124; i < mpic->num_sources; i++)
        msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);


    np = NULL;
    while ((np = of_find_all_nodes(np))) {
        pr_debug("mpic: mapping hwirqs for %s\n", np->full_name);

        index = 0;
        while (of_irq_map_one(np, index++, &oirq) == 0) {
            ops->xlate(mpic->irqhost, NULL, oirq.specifier,
                        oirq.size, &hwirq, &flags);
            msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, hwirq);
        }
    }

    return 0;
}
#else
static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)
{
    return -1;
}
#endif

int mpic_msi_init_allocator(struct mpic *mpic)
{
    int rc;

    rc = msi_bitmap_alloc(&mpic->msi_bitmap, mpic->num_sources,
                  mpic->irqhost->of_node);
    if (rc)
        return rc;

    rc = msi_bitmap_reserve_dt_hwirqs(&mpic->msi_bitmap);
    if (rc > 0) {
        if (mpic->flags & MPIC_U3_HT_IRQS)
            rc = mpic_msi_reserve_u3_hwirqs(mpic);

        if (rc) {
            msi_bitmap_free(&mpic->msi_bitmap);
            return rc;
        }
    }

    return 0;
}