root/arch/x86/kernel/i8237.c

DEFINITIONS

1. i8237A_resume
2. i8237A_suspend
3. i8237A_init_sysfs

/*
 * 8237A DMA controller suspend functions.
 *
 * Written by Pierre Ossman, 2005.
 *
 * 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.
 */

#include <linux/init.h>
#include <linux/sysdev.h>

#include <asm/dma.h>

/*
 * This module just handles suspend/resume issues with the
 * 8237A DMA controller (used for ISA and LPC).
 * Allocation is handled in kernel/dma.c and normal usage is
 * in asm/dma.h.
 */

static int i8237A_resume(struct sys_device *dev)
{
        unsigned long flags;
        int i;

        flags = claim_dma_lock();

        dma_outb(DMA1_RESET_REG, 0);
        dma_outb(DMA2_RESET_REG, 0);

        for (i = 0;i < 8;i++) {
                set_dma_addr(i, 0x000000);
                /* DMA count is a bit weird so this is not 0 */
                set_dma_count(i, 1);
        }

        /* Enable cascade DMA or channel 0-3 won't work */
        enable_dma(4);

        release_dma_lock(flags);

        return 0;
}

static int i8237A_suspend(struct sys_device *dev, pm_message_t state)
{
        return 0;
}

static struct sysdev_class i8237_sysdev_class = {
        .name = "i8237",
        .suspend = i8237A_suspend,
        .resume = i8237A_resume,
};

static struct sys_device device_i8237A = {
        .id     = 0,
        .cls    = &i8237_sysdev_class,
};

static int __init i8237A_init_sysfs(void)
{
        int error = sysdev_class_register(&i8237_sysdev_class);
        if (!error)
                error = sysdev_register(&device_i8237A);
        return error;
}

device_initcall(i8237A_init_sysfs);