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/*
* linux/arch/arm/kernel/dma.c
*
* Copyright (C) 1995-1998 Russell King
*
* Front-end to the DMA handling. You must provide the following
* architecture-specific routines:
*
* int arch_request_dma(dmach_t channel, dma_t *dma, const char *dev_id);
* void arch_free_dma(dmach_t channel, dma_t *dma);
* void arch_enable_dma(dmach_t channel, dma_t *dma);
* void arch_disable_dma(dmach_t channel, dma_t *dma);
* int arch_get_dma_residue(dmach_t channel, dma_t *dma);
*
* Moved DMA resource allocation here...
*/
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/malloc.h>
#include <linux/mman.h>
#include <linux/init.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/spinlock.h>
/* A note on resource allocation:
*
* All drivers needing DMA channels, should allocate and release them
* through the public routines `request_dma()' and `free_dma()'.
*
* In order to avoid problems, all processes should allocate resources in
* the same sequence and release them in the reverse order.
*
* So, when allocating DMAs and IRQs, first allocate the IRQ, then the DMA.
* When releasing them, first release the DMA, then release the IRQ.
* If you don't, you may cause allocation requests to fail unnecessarily.
* This doesn't really matter now, but it will once we get real semaphores
* in the kernel.
*/
spinlock_t dma_spin_lock = SPIN_LOCK_UNLOCKED;
#include "dma.h"
const char dma_str[] = "%s: dma %d not supported\n";
static dma_t dma_chan[MAX_DMA_CHANNELS];
/* Get dma list
* for /proc/dma
*/
int get_dma_list(char *buf)
{
int i, len = 0;
for (i = 0; i < MAX_DMA_CHANNELS; i++) {
if (dma_chan[i].lock)
len += sprintf(buf + len, "%2d: %s\n",
i, dma_chan[i].device_id);
}
return len;
}
/* Request DMA channel
*
* On certain platforms, we have to allocate an interrupt as well...
*/
int request_dma(dmach_t channel, const char *device_id)
{
if (channel < MAX_DMA_CHANNELS) {
int ret;
if (xchg(&dma_chan[channel].lock, 1) != 0)
return -EBUSY;
ret = arch_request_dma(channel, &dma_chan[channel], device_id);
if (!ret) {
dma_chan[channel].device_id = device_id;
dma_chan[channel].active = 0;
dma_chan[channel].invalid = 1;
} else
xchg(&dma_chan[channel].lock, 0);
return ret;
} else {
printk (KERN_ERR "Trying to allocate DMA%d\n", channel);
return -EINVAL;
}
}
/* Free DMA channel
*
* On certain platforms, we have to free interrupt as well...
*/
void free_dma(dmach_t channel)
{
if (channel >= MAX_DMA_CHANNELS) {
printk (KERN_ERR "Trying to free DMA%d\n", channel);
return;
}
if (xchg(&dma_chan[channel].lock, 0) == 0) {
if (dma_chan[channel].active) {
printk (KERN_ERR "Freeing active DMA%d\n", channel);
arch_disable_dma(channel, &dma_chan[channel]);
dma_chan[channel].active = 0;
}
printk (KERN_ERR "Trying to free free DMA%d\n", channel);
return;
}
arch_free_dma(channel, &dma_chan[channel]);
}
/* Set DMA Scatter-Gather list
*/
void set_dma_sg (dmach_t channel, dmasg_t *sg, int nr_sg)
{
dma_chan[channel].sg = sg;
dma_chan[channel].sgcount = nr_sg;
dma_chan[channel].invalid = 1;
}
/* Set DMA address
*
* Copy address to the structure, and set the invalid bit
*/
void set_dma_addr (dmach_t channel, unsigned long physaddr)
{
if (dma_chan[channel].active)
printk(KERN_ERR "set_dma_addr: altering DMA%d"
" address while DMA active\n",
channel);
dma_chan[channel].sg = &dma_chan[channel].buf;
dma_chan[channel].sgcount = 1;
dma_chan[channel].buf.address = physaddr;
dma_chan[channel].invalid = 1;
}
/* Set DMA byte count
*
* Copy address to the structure, and set the invalid bit
*/
void set_dma_count (dmach_t channel, unsigned long count)
{
if (dma_chan[channel].active)
printk(KERN_ERR "set_dma_count: altering DMA%d"
" count while DMA active\n",
channel);
dma_chan[channel].sg = &dma_chan[channel].buf;
dma_chan[channel].sgcount = 1;
dma_chan[channel].buf.length = count;
dma_chan[channel].invalid = 1;
}
/* Set DMA direction mode
*/
void set_dma_mode (dmach_t channel, dmamode_t mode)
{
if (dma_chan[channel].active)
printk(KERN_ERR "set_dma_mode: altering DMA%d"
" mode while DMA active\n",
channel);
dma_chan[channel].dma_mode = mode;
dma_chan[channel].invalid = 1;
}
/* Enable DMA channel
*/
void enable_dma (dmach_t channel)
{
if (dma_chan[channel].lock) {
if (dma_chan[channel].active == 0) {
dma_chan[channel].active = 1;
arch_enable_dma(channel, &dma_chan[channel]);
}
} else
printk (KERN_ERR "Trying to enable free DMA%d\n", channel);
}
/* Disable DMA channel
*/
void disable_dma (dmach_t channel)
{
if (dma_chan[channel].lock) {
if (dma_chan[channel].active == 1) {
dma_chan[channel].active = 0;
arch_disable_dma(channel, &dma_chan[channel]);
}
} else
printk (KERN_ERR "Trying to disable free DMA%d\n", channel);
}
int get_dma_residue(dmach_t channel)
{
return arch_get_dma_residue(channel, &dma_chan[channel]);
}
EXPORT_SYMBOL(dma_str);
EXPORT_SYMBOL(enable_dma);
EXPORT_SYMBOL(disable_dma);
EXPORT_SYMBOL(set_dma_addr);
EXPORT_SYMBOL(set_dma_count);
EXPORT_SYMBOL(set_dma_mode);
EXPORT_SYMBOL(get_dma_residue);
EXPORT_SYMBOL(set_dma_sg);
__initfunc(void init_dma(void))
{
arch_dma_init(dma_chan);
}
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