nmi.c

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/*
 * SDK7786 FPGA NMI Support.
 *
 * 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 <linux/init.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <mach/fpga.h>

enum {
    NMI_MODE_MANUAL,
    NMI_MODE_AUX,
    NMI_MODE_MASKED,
    NMI_MODE_ANY,
    NMI_MODE_UNKNOWN,
};

/*
 * Default to the manual NMI switch.
 */
static unsigned int __initdata nmi_mode = NMI_MODE_ANY;

static int __init nmi_mode_setup(char *str)
{
    if (!str)
        return 0;

    if (strcmp(str, "manual") == 0)
        nmi_mode = NMI_MODE_MANUAL;
    else if (strcmp(str, "aux") == 0)
        nmi_mode = NMI_MODE_AUX;
    else if (strcmp(str, "masked") == 0)
        nmi_mode = NMI_MODE_MASKED;
    else if (strcmp(str, "any") == 0)
        nmi_mode = NMI_MODE_ANY;
    else {
        nmi_mode = NMI_MODE_UNKNOWN;
        pr_warning("Unknown NMI mode %s\n", str);
    }

    printk("Set NMI mode to %d\n", nmi_mode);
    return 0;
}
early_param("nmi_mode", nmi_mode_setup);

void __init sdk7786_nmi_init(void)
{
    unsigned int source, mask, tmp;

    switch (nmi_mode) {
    case NMI_MODE_MANUAL:
        source = NMISR_MAN_NMI;
        mask = NMIMR_MAN_NMIM;
        break;
    case NMI_MODE_AUX:
        source = NMISR_AUX_NMI;
        mask = NMIMR_AUX_NMIM;
        break;
    case NMI_MODE_ANY:
        source = NMISR_MAN_NMI | NMISR_AUX_NMI;
        mask = NMIMR_MAN_NMIM | NMIMR_AUX_NMIM;
        break;
    case NMI_MODE_MASKED:
    case NMI_MODE_UNKNOWN:
    default:
        source = mask = 0;
        break;
    }

    /* Set the NMI source */
    tmp = fpga_read_reg(NMISR);
    tmp &= ~NMISR_MASK;
    tmp |= source;
    fpga_write_reg(tmp, NMISR);

    /* And the IRQ masking */
    fpga_write_reg(NMIMR_MASK ^ mask, NMIMR);
}