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/*
* linux/arch/arm/mach-imx/dma.c
*
* imx DMA registration and IRQ dispatching
*
* 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.
*
* 03/03/2004 Sascha Hauer <sascha@saschahauer.de>
* initial version heavily inspired by
* linux/arch/arm/mach-pxa/dma.c
*/
#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>
static struct dma_channel {
char *name;
void (*irq_handler) (int, void *, struct pt_regs *);
void (*err_handler) (int, void *, struct pt_regs *);
void *data;
} dma_channels[11];
/* set err_handler to NULL to have the standard info-only error handler */
int
imx_request_dma(char *name, imx_dma_prio prio,
void (*irq_handler) (int, void *, struct pt_regs *),
void (*err_handler) (int, void *, struct pt_regs *), void *data)
{
unsigned long flags;
int i, found = 0;
/* basic sanity checks */
if (!name || !irq_handler)
return -EINVAL;
local_irq_save(flags);
/* try grabbing a DMA channel with the requested priority */
for (i = prio; i < prio + (prio == DMA_PRIO_LOW) ? 8 : 4; i++) {
if (!dma_channels[i].name) {
found = 1;
break;
}
}
if (!found) {
/* requested prio group is full, try hier priorities */
for (i = prio - 1; i >= 0; i--) {
if (!dma_channels[i].name) {
found = 1;
break;
}
}
}
if (found) {
DIMR &= ~(1 << i);
dma_channels[i].name = name;
dma_channels[i].irq_handler = irq_handler;
dma_channels[i].err_handler = err_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
imx_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);
DIMR &= ~(1 << dma_ch);
dma_channels[dma_ch].name = NULL;
local_irq_restore(flags);
}
static irqreturn_t
dma_err_handler(int irq, void *dev_id, struct pt_regs *regs)
{
int i, disr = DISR;
struct dma_channel *channel;
unsigned int err_mask = DBTOSR | DRTOSR | DSESR | DBOSR;
DISR = disr;
for (i = 0; i < 11; i++) {
channel = &dma_channels[i];
if ( (err_mask & 1<<i) && channel->name && channel->err_handler) {
channel->err_handler(i, channel->data, regs);
continue;
}
if (DBTOSR & (1 << i)) {
printk(KERN_WARNING
"Burst timeout on channel %d (%s)\n",
i, channel->name);
DBTOSR |= (1 << i);
}
if (DRTOSR & (1 << i)) {
printk(KERN_WARNING
"Request timeout on channel %d (%s)\n",
i, channel->name);
DRTOSR |= (1 << i);
}
if (DSESR & (1 << i)) {
printk(KERN_WARNING
"Transfer timeout on channel %d (%s)\n",
i, channel->name);
DSESR |= (1 << i);
}
if (DBOSR & (1 << i)) {
printk(KERN_WARNING
"Buffer overflow timeout on channel %d (%s)\n",
i, channel->name);
DBOSR |= (1 << i);
}
}
return IRQ_HANDLED;
}
static irqreturn_t
dma_irq_handler(int irq, void *dev_id, struct pt_regs *regs)
{
int i, disr = DISR;
DISR = disr;
for (i = 0; i < 11; i++) {
if (disr & (1 << i)) {
struct dma_channel *channel = &dma_channels[i];
if (channel->name && channel->irq_handler) {
channel->irq_handler(i, channel->data, regs);
} 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);
}
}
}
return IRQ_HANDLED;
}
static int __init
imx_dma_init(void)
{
int ret;
/* reset DMA module */
DCR = DCR_DRST;
ret = request_irq(DMA_INT, dma_irq_handler, 0, "DMA", NULL);
if (ret) {
printk(KERN_CRIT "Wow! Can't register IRQ for DMA\n");
return ret;
}
ret = request_irq(DMA_ERR, dma_err_handler, 0, "DMA", NULL);
if (ret) {
printk(KERN_CRIT "Wow! Can't register ERRIRQ for DMA\n");
free_irq(DMA_INT, NULL);
}
/* enable DMA module */
DCR = DCR_DEN;
/* clear all interrupts */
DISR = 0x3ff;
/* enable interrupts */
DIMR = 0;
return ret;
}
arch_initcall(imx_dma_init);
EXPORT_SYMBOL(imx_request_dma);
EXPORT_SYMBOL(imx_free_dma);
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