![Eric Miao](/assets/img/avatar_default.png)
1. introduce folder of 'arch/arm/plat-pxa' for common code across different PXA processor families 2. initially moved DMA code into plat-pxa 3. common code in <mach/dma.h> moved into <plat/dma.h>, new processors should implement its own <mach/dma.h>, provide the following required definitions and '#include <plat/dma.h>' in the end: - DMAC_REGS_VIRT for mapped virtual address of the DMA registers' physical I/O memory Signed-off-by: Eric Miao <eric.miao@marvell.com>
145 lines
3.3 KiB
C
145 lines
3.3 KiB
C
/*
|
|
* linux/arch/arm/plat-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 <mach/hardware.h>
|
|
#include <mach/dma.h>
|
|
|
|
struct dma_channel {
|
|
char *name;
|
|
pxa_dma_prio prio;
|
|
void (*irq_handler)(int, void *);
|
|
void *data;
|
|
};
|
|
|
|
static struct dma_channel *dma_channels;
|
|
static int num_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 */
|
|
for (i = 0; i < num_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) {
|
|
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",
|
|
__func__, 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 < num_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;
|
|
}
|
|
|
|
int __init pxa_init_dma(int irq, int num_ch)
|
|
{
|
|
int i, ret;
|
|
|
|
dma_channels = kzalloc(sizeof(struct dma_channel) * num_ch, GFP_KERNEL);
|
|
if (dma_channels == NULL)
|
|
return -ENOMEM;
|
|
|
|
/* dma channel priorities on pxa2xx processors:
|
|
* ch 0 - 3, 16 - 19 <--> (0) DMA_PRIO_HIGH
|
|
* ch 4 - 7, 20 - 23 <--> (1) DMA_PRIO_MEDIUM
|
|
* ch 8 - 15, 24 - 31 <--> (2) DMA_PRIO_LOW
|
|
*/
|
|
for (i = 0; i < num_ch; i++) {
|
|
DCSR(i) = 0;
|
|
dma_channels[i].prio = min((i & 0xf) >> 2, DMA_PRIO_LOW);
|
|
}
|
|
|
|
ret = request_irq(irq, dma_irq_handler, IRQF_DISABLED, "DMA", NULL);
|
|
if (ret) {
|
|
printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n");
|
|
kfree(dma_channels);
|
|
return ret;
|
|
}
|
|
|
|
num_dma_channels = num_ch;
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(pxa_request_dma);
|
|
EXPORT_SYMBOL(pxa_free_dma);
|