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/*
* linux/arch/unicore32/kernel/dma.c
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
* Copyright (C) 2001-2010 Guan Xuetao
*
* 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 <mach/hardware.h>
#include <mach/dma.h>
struct dma_channel {
char *name;
puv3_dma_prio prio;
void (*irq_handler)(int, void *);
void (*err_handler)(int, void *);
void *data;
};
static struct dma_channel dma_channels[MAX_DMA_CHANNELS];
int puv3_request_dma(char *name, puv3_dma_prio prio,
void (*irq_handler)(int, void *),
void (*err_handler)(int, void *),
void *data)
{
unsigned long flags;
int i, found = 0;
/* basic sanity checks */
if (!name)
return -EINVAL;
local_irq_save(flags);
do {
/* try grabbing a DMA channel with the requested priority */
for (i = 0; i < MAX_DMA_CHANNELS; i++) {
if ((dma_channels[i].prio == prio) &&
!dma_channels[i].name) {
found = 1;
break;
}
}
/* if requested prio group is full, try a hier priority */
} while (!found && prio--);
if (found) {
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;
}
EXPORT_SYMBOL(puv3_request_dma);
void puv3_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",
__func__, dma_ch);
return;
}
local_irq_save(flags);
dma_channels[dma_ch].name = NULL;
dma_channels[dma_ch].err_handler = NULL;
local_irq_restore(flags);
}
EXPORT_SYMBOL(puv3_free_dma);
static irqreturn_t dma_irq_handler(int irq, void *dev_id)
{
int i, dint = DMAC_ITCSR;
for (i = 0; i < MAX_DMA_CHANNELS; i++) {
if (dint & DMAC_CHANNEL(i)) {
struct dma_channel *channel = &dma_channels[i];
/* Clear TC interrupt of channel i */
DMAC_ITCCR = DMAC_CHANNEL(i);
DMAC_ITCCR = 0;
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);
}
}
}
return IRQ_HANDLED;
}
static irqreturn_t dma_err_handler(int irq, void *dev_id)
{
int i, dint = DMAC_IESR;
for (i = 0; i < MAX_DMA_CHANNELS; i++) {
if (dint & DMAC_CHANNEL(i)) {
struct dma_channel *channel = &dma_channels[i];
/* Clear Err interrupt of channel i */
DMAC_IECR = DMAC_CHANNEL(i);
DMAC_IECR = 0;
if (channel->name && channel->err_handler) {
channel->err_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);
}
}
}
return IRQ_HANDLED;
}
int __init puv3_init_dma(void)
{
int i, ret;
/* dma channel priorities on v8 processors:
* ch 0 - 1 <--> (0) DMA_PRIO_HIGH
* ch 2 - 3 <--> (1) DMA_PRIO_MEDIUM
* ch 4 - 5 <--> (2) DMA_PRIO_LOW
*/
for (i = 0; i < MAX_DMA_CHANNELS; i++) {
puv3_stop_dma(i);
dma_channels[i].name = NULL;
dma_channels[i].prio = min((i & 0x7) >> 1, DMA_PRIO_LOW);
}
ret = request_irq(IRQ_DMA, dma_irq_handler, 0, "DMA", NULL);
if (ret) {
printk(KERN_CRIT "Can't register IRQ for DMA\n");
return ret;
}
ret = request_irq(IRQ_DMAERR, dma_err_handler, 0, "DMAERR", NULL);
if (ret) {
printk(KERN_CRIT "Can't register IRQ for DMAERR\n");
free_irq(IRQ_DMA, "DMA");
return ret;
}
return 0;
}
postcore_initcall(puv3_init_dma);
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