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/*
* linux/arch/arm/mach-pxa/dma.c
*
* PXA DMA registration and IRQ dispatching
*
* Author: Nicolas Pitre
* Created: Nov 15, 2001
* Copyright: MontaVista Software Inc.
*
* 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.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/dma.h>
#include <asm/arch/pxa-regs.h>
static struct dma_channel {
char *name;
void (*irq_handler)(int, void *);
void *data;
} dma_channels[PXA_DMA_CHANNELS];
int pxa_request_dma (char *name, pxa_dma_prio prio,
void (*irq_handler)(int, void *),
void *data)
{
unsigned long flags;
int i, found = 0;
/* basic sanity checks */
if (!name || !irq_handler)
return -EINVAL;
local_irq_save(flags);
do {
/* try grabbing a DMA channel with the requested priority */
pxa_for_each_dma_prio (i, prio) {
if (!dma_channels[i].name) {
found = 1;
break;
}
}
/* if requested prio group is full, try a hier priority */
} while (!found && prio--);
if (found) {
DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
dma_channels[i].name = name;
dma_channels[i].irq_handler = irq_handler;
dma_channels[i].data = data;
} else {
printk (KERN_WARNING "No more available DMA channels for %s\n", name);
i = -ENODEV;
}
local_irq_restore(flags);
return i;
}
void pxa_free_dma (int dma_ch)
{
unsigned long flags;
if (!dma_channels[dma_ch].name) {
printk (KERN_CRIT
"%s: trying to free channel %d which is already freed\n",
__FUNCTION__, dma_ch);
return;
}
local_irq_save(flags);
DCSR(dma_ch) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
dma_channels[dma_ch].name = NULL;
local_irq_restore(flags);
}
static irqreturn_t dma_irq_handler(int irq, void *dev_id)
{
int i, dint = DINT;
for (i = 0; i < PXA_DMA_CHANNELS; i++) {
if (dint & (1 << i)) {
struct dma_channel *channel = &dma_channels[i];
if (channel->name && channel->irq_handler) {
channel->irq_handler(i, channel->data);
} else {
/*
* IRQ for an unregistered DMA channel:
* let's clear the interrupts and disable it.
*/
printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i);
DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
}
}
}
return IRQ_HANDLED;
}
static int __init pxa_dma_init (void)
{
int ret;
ret = request_irq (IRQ_DMA, dma_irq_handler, 0, "DMA", NULL);
if (ret)
printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n");
return ret;
}
arch_initcall(pxa_dma_init);
EXPORT_SYMBOL(pxa_request_dma);
EXPORT_SYMBOL(pxa_free_dma);
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