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/*
* linux/arch/arm/kernel/dma.c
*
* Copyright (C) 1995-2000 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Front-end to the DMA handling. This handles the allocation/freeing
* of DMA channels, and provides a unified interface to the machines
* DMA facilities.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <asm/dma.h>
#include <asm/mach/dma.h>
DEFINE_SPINLOCK(dma_spin_lock);
EXPORT_SYMBOL(dma_spin_lock);
static dma_t *dma_chan[MAX_DMA_CHANNELS];
static inline dma_t *dma_channel(unsigned int chan)
{
if (chan >= MAX_DMA_CHANNELS)
return NULL;
return dma_chan[chan];
}
int __init isa_dma_add(unsigned int chan, dma_t *dma)
{
if (!dma->d_ops)
return -EINVAL;
if (dma_chan[chan])
return -EBUSY;
dma_chan[chan] = dma;
return 0;
}
/*
* Request DMA channel
*
* On certain platforms, we have to allocate an interrupt as well...
*/
int request_dma(unsigned int chan, const char *device_id)
{
dma_t *dma = dma_channel(chan);
int ret;
if (!dma)
goto bad_dma;
if (xchg(&dma->lock, 1) != 0)
goto busy;
dma->device_id = device_id;
dma->active = 0;
dma->invalid = 1;
ret = 0;
if (dma->d_ops->request)
ret = dma->d_ops->request(chan, dma);
if (ret)
xchg(&dma->lock, 0);
return ret;
bad_dma:
printk(KERN_ERR "dma: trying to allocate DMA%d\n", chan);
return -EINVAL;
busy:
return -EBUSY;
}
EXPORT_SYMBOL(request_dma);
/*
* Free DMA channel
*
* On certain platforms, we have to free interrupt as well...
*/
void free_dma(unsigned int chan)
{
dma_t *dma = dma_channel(chan);
if (!dma)
goto bad_dma;
if (dma->active) {
printk(KERN_ERR "dma%d: freeing active DMA\n", chan);
dma->d_ops->disable(chan, dma);
dma->active = 0;
}
if (xchg(&dma->lock, 0) != 0) {
if (dma->d_ops->free)
dma->d_ops->free(chan, dma);
return;
}
printk(KERN_ERR "dma%d: trying to free free DMA\n", chan);
return;
bad_dma:
printk(KERN_ERR "dma: trying to free DMA%d\n", chan);
}
EXPORT_SYMBOL(free_dma);
/* Set DMA Scatter-Gather list
*/
void set_dma_sg (unsigned int chan, struct scatterlist *sg, int nr_sg)
{
dma_t *dma = dma_channel(chan);
if (dma->active)
printk(KERN_ERR "dma%d: altering DMA SG while "
"DMA active\n", chan);
dma->sg = sg;
dma->sgcount = nr_sg;
dma->invalid = 1;
}
EXPORT_SYMBOL(set_dma_sg);
/* Set DMA address
*
* Copy address to the structure, and set the invalid bit
*/
void __set_dma_addr (unsigned int chan, void *addr)
{
dma_t *dma = dma_channel(chan);
if (dma->active)
printk(KERN_ERR "dma%d: altering DMA address while "
"DMA active\n", chan);
dma->sg = NULL;
dma->addr = addr;
dma->invalid = 1;
}
EXPORT_SYMBOL(__set_dma_addr);
/* Set DMA byte count
*
* Copy address to the structure, and set the invalid bit
*/
void set_dma_count (unsigned int chan, unsigned long count)
{
dma_t *dma = dma_channel(chan);
if (dma->active)
printk(KERN_ERR "dma%d: altering DMA count while "
"DMA active\n", chan);
dma->sg = NULL;
dma->count = count;
dma->invalid = 1;
}
EXPORT_SYMBOL(set_dma_count);
/* Set DMA direction mode
*/
void set_dma_mode (unsigned int chan, dmamode_t mode)
{
dma_t *dma = dma_channel(chan);
if (dma->active)
printk(KERN_ERR "dma%d: altering DMA mode while "
"DMA active\n", chan);
dma->dma_mode = mode;
dma->invalid = 1;
}
EXPORT_SYMBOL(set_dma_mode);
/* Enable DMA channel
*/
void enable_dma (unsigned int chan)
{
dma_t *dma = dma_channel(chan);
if (!dma->lock)
goto free_dma;
if (dma->active == 0) {
dma->active = 1;
dma->d_ops->enable(chan, dma);
}
return;
free_dma:
printk(KERN_ERR "dma%d: trying to enable free DMA\n", chan);
BUG();
}
EXPORT_SYMBOL(enable_dma);
/* Disable DMA channel
*/
void disable_dma (unsigned int chan)
{
dma_t *dma = dma_channel(chan);
if (!dma->lock)
goto free_dma;
if (dma->active == 1) {
dma->active = 0;
dma->d_ops->disable(chan, dma);
}
return;
free_dma:
printk(KERN_ERR "dma%d: trying to disable free DMA\n", chan);
BUG();
}
EXPORT_SYMBOL(disable_dma);
/*
* Is the specified DMA channel active?
*/
int dma_channel_active(unsigned int chan)
{
dma_t *dma = dma_channel(chan);
return dma->active;
}
EXPORT_SYMBOL(dma_channel_active);
void set_dma_page(unsigned int chan, char pagenr)
{
printk(KERN_ERR "dma%d: trying to set_dma_page\n", chan);
}
EXPORT_SYMBOL(set_dma_page);
void set_dma_speed(unsigned int chan, int cycle_ns)
{
dma_t *dma = dma_channel(chan);
int ret = 0;
if (dma->d_ops->setspeed)
ret = dma->d_ops->setspeed(chan, dma, cycle_ns);
dma->speed = ret;
}
EXPORT_SYMBOL(set_dma_speed);
int get_dma_residue(unsigned int chan)
{
dma_t *dma = dma_channel(chan);
int ret = 0;
if (dma->d_ops->residue)
ret = dma->d_ops->residue(chan, dma);
return ret;
}
EXPORT_SYMBOL(get_dma_residue);
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