balancing.c

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/*
 * Support for hardware-managed IRQ auto-distribution.
 *
 * Copyright (C) 2010  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include "internals.h"

static unsigned long dist_handle[INTC_NR_IRQS];

void intc_balancing_enable(unsigned int irq)
{
    struct intc_desc_int *d = get_intc_desc(irq);
    unsigned long handle = dist_handle[irq];
    unsigned long addr;

    if (irq_balancing_disabled(irq) || !handle)
        return;

    addr = INTC_REG(d, _INTC_ADDR_D(handle), 0);
    intc_reg_fns[_INTC_FN(handle)](addr, handle, 1);
}

void intc_balancing_disable(unsigned int irq)
{
    struct intc_desc_int *d = get_intc_desc(irq);
    unsigned long handle = dist_handle[irq];
    unsigned long addr;

    if (irq_balancing_disabled(irq) || !handle)
        return;

    addr = INTC_REG(d, _INTC_ADDR_D(handle), 0);
    intc_reg_fns[_INTC_FN(handle)](addr, handle, 0);
}

static unsigned int intc_dist_data(struct intc_desc *desc,
                   struct intc_desc_int *d,
                   intc_enum enum_id)
{
    struct intc_mask_reg *mr = desc->hw.mask_regs;
    unsigned int i, j, fn, mode;
    unsigned long reg_e, reg_d;

    for (i = 0; mr && enum_id && i < desc->hw.nr_mask_regs; i++) {
        mr = desc->hw.mask_regs + i;

        /*
         * Skip this entry if there's no auto-distribution
         * register associated with it.
         */
        if (!mr->dist_reg)
            continue;

        for (j = 0; j < ARRAY_SIZE(mr->enum_ids); j++) {
            if (mr->enum_ids[j] != enum_id)
                continue;

            fn = REG_FN_MODIFY_BASE;
            mode = MODE_ENABLE_REG;
            reg_e = mr->dist_reg;
            reg_d = mr->dist_reg;

            fn += (mr->reg_width >> 3) - 1;
            return _INTC_MK(fn, mode,
                    intc_get_reg(d, reg_e),
                    intc_get_reg(d, reg_d),
                    1,
                    (mr->reg_width - 1) - j);
        }
    }

    /*
     * It's possible we've gotten here with no distribution options
     * available for the IRQ in question, so we just skip over those.
     */
    return 0;
}

void intc_set_dist_handle(unsigned int irq, struct intc_desc *desc,
              struct intc_desc_int *d, intc_enum id)
{
    unsigned long flags;

    /*
     * Nothing to do for this IRQ.
     */
    if (!desc->hw.mask_regs)
        return;

    raw_spin_lock_irqsave(&intc_big_lock, flags);
    dist_handle[irq] = intc_dist_data(desc, d, id);
    raw_spin_unlock_irqrestore(&intc_big_lock, flags);
}