795312e763
Reset the ISA DMA controller into a known state after a suspend. Primary concern was reenabling the cascading DMA channel (4). Signed-off-by: Pierre Ossman <drzeus@drzeus.cx> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
/*
|
|
* i8237.c: 8237A DMA controller suspend functions.
|
|
*
|
|
* Written by Pierre Ossman, 2005.
|
|
*/
|
|
|
|
#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 = {
|
|
set_kset_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);
|