1/*
2 * 8237A DMA controller suspend functions.
3 *
4 * Written by Pierre Ossman, 2005.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or (at
9 * your option) any later version.
10 */
11
12#include <linux/init.h>
13#include <linux/syscore_ops.h>
14
15#include <asm/dma.h>
16
17/*
18 * This module just handles suspend/resume issues with the
19 * 8237A DMA controller (used for ISA and LPC).
20 * Allocation is handled in kernel/dma.c and normal usage is
21 * in asm/dma.h.
22 */
23
24static void i8237A_resume(void)
25{
26	unsigned long flags;
27	int i;
28
29	flags = claim_dma_lock();
30
31	dma_outb(0, DMA1_RESET_REG);
32	dma_outb(0, DMA2_RESET_REG);
33
34	for (i = 0; i < 8; i++) {
35		set_dma_addr(i, 0x000000);
36		/* DMA count is a bit weird so this is not 0 */
37		set_dma_count(i, 1);
38	}
39
40	/* Enable cascade DMA or channel 0-3 won't work */
41	enable_dma(4);
42
43	release_dma_lock(flags);
44}
45
46static struct syscore_ops i8237_syscore_ops = {
47	.resume		= i8237A_resume,
48};
49
50static int __init i8237A_init_ops(void)
51{
52	register_syscore_ops(&i8237_syscore_ops);
53	return 0;
54}
55device_initcall(i8237A_init_ops);
56