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/*
* arch/sh/drivers/dma/dma-g2.c
*
* G2 bus DMA support
*
* Copyright (C) 2003 - 2006 Paul Mundt
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <asm/cacheflush.h>
#include <mach/sysasic.h>
#include <mach/dma.h>
#include <asm/dma.h>
struct g2_channel {
unsigned long g2_addr; /* G2 bus address */
unsigned long root_addr; /* Root bus (SH-4) address */
unsigned long size; /* Size (in bytes), 32-byte aligned */
unsigned long direction; /* Transfer direction */
unsigned long ctrl; /* Transfer control */
unsigned long chan_enable; /* Channel enable */
unsigned long xfer_enable; /* Transfer enable */
unsigned long xfer_stat; /* Transfer status */
} __attribute__ ((aligned(32)));
struct g2_status {
unsigned long g2_addr;
unsigned long root_addr;
unsigned long size;
unsigned long status;
} __attribute__ ((aligned(16)));
struct g2_dma_info {
struct g2_channel channel[G2_NR_DMA_CHANNELS];
unsigned long pad1[G2_NR_DMA_CHANNELS];
unsigned long wait_state;
unsigned long pad2[10];
unsigned long magic;
struct g2_status status[G2_NR_DMA_CHANNELS];
} __attribute__ ((aligned(256)));
static volatile struct g2_dma_info *g2_dma = (volatile struct g2_dma_info *)0xa05f7800;
#define g2_bytes_remaining(i) \
((g2_dma->channel[i].size - \
g2_dma->status[i].size) & 0x0fffffff)
static irqreturn_t g2_dma_interrupt(int irq, void *dev_id)
{
int i;
for (i = 0; i < G2_NR_DMA_CHANNELS; i++) {
if (g2_dma->status[i].status & 0x20000000) {
unsigned int bytes = g2_bytes_remaining(i);
if (likely(bytes == 0)) {
struct dma_info *info = dev_id;
struct dma_channel *chan = info->channels + i;
wake_up(&chan->wait_queue);
return IRQ_HANDLED;
}
}
}
return IRQ_NONE;
}
static int g2_enable_dma(struct dma_channel *chan)
{
unsigned int chan_nr = chan->chan;
g2_dma->channel[chan_nr].chan_enable = 1;
g2_dma->channel[chan_nr].xfer_enable = 1;
return 0;
}
static int g2_disable_dma(struct dma_channel *chan)
{
unsigned int chan_nr = chan->chan;
g2_dma->channel[chan_nr].chan_enable = 0;
g2_dma->channel[chan_nr].xfer_enable = 0;
return 0;
}
static int g2_xfer_dma(struct dma_channel *chan)
{
unsigned int chan_nr = chan->chan;
if (chan->sar & 31) {
printk("g2dma: unaligned source 0x%lx\n", chan->sar);
return -EINVAL;
}
if (chan->dar & 31) {
printk("g2dma: unaligned dest 0x%lx\n", chan->dar);
return -EINVAL;
}
/* Align the count */
if (chan->count & 31)
chan->count = (chan->count + (32 - 1)) & ~(32 - 1);
/* Fixup destination */
chan->dar += 0xa0800000;
/* Fixup direction */
chan->mode = !chan->mode;
flush_icache_range((unsigned long)chan->sar, chan->count);
g2_disable_dma(chan);
g2_dma->channel[chan_nr].g2_addr = chan->dar & 0x1fffffe0;
g2_dma->channel[chan_nr].root_addr = chan->sar & 0x1fffffe0;
g2_dma->channel[chan_nr].size = (chan->count & ~31) | 0x80000000;
g2_dma->channel[chan_nr].direction = chan->mode;
/*
* bit 0 - ???
* bit 1 - if set, generate a hardware event on transfer completion
* bit 2 - ??? something to do with suspend?
*/
g2_dma->channel[chan_nr].ctrl = 5; /* ?? */
g2_enable_dma(chan);
/* debug cruft */
pr_debug("count, sar, dar, mode, ctrl, chan, xfer: %ld, 0x%08lx, "
"0x%08lx, %ld, %ld, %ld, %ld\n",
g2_dma->channel[chan_nr].size,
g2_dma->channel[chan_nr].root_addr,
g2_dma->channel[chan_nr].g2_addr,
g2_dma->channel[chan_nr].direction,
g2_dma->channel[chan_nr].ctrl,
g2_dma->channel[chan_nr].chan_enable,
g2_dma->channel[chan_nr].xfer_enable);
return 0;
}
static int g2_get_residue(struct dma_channel *chan)
{
return g2_bytes_remaining(chan->chan);
}
static struct dma_ops g2_dma_ops = {
.xfer = g2_xfer_dma,
.get_residue = g2_get_residue,
};
static struct dma_info g2_dma_info = {
.name = "g2_dmac",
.nr_channels = 4,
.ops = &g2_dma_ops,
.flags = DMAC_CHANNELS_TEI_CAPABLE,
};
static int __init g2_dma_init(void)
{
int ret;
ret = request_irq(HW_EVENT_G2_DMA, g2_dma_interrupt, IRQF_DISABLED,
"g2 DMA handler", &g2_dma_info);
if (unlikely(ret))
return -EINVAL;
/* Magic */
g2_dma->wait_state = 27;
g2_dma->magic = 0x4659404f;
ret = register_dmac(&g2_dma_info);
if (unlikely(ret != 0))
free_irq(HW_EVENT_G2_DMA, 0);
return ret;
}
static void __exit g2_dma_exit(void)
{
free_irq(HW_EVENT_G2_DMA, 0);
unregister_dmac(&g2_dma_info);
}
subsys_initcall(g2_dma_init);
module_exit(g2_dma_exit);
MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
MODULE_DESCRIPTION("G2 bus DMA driver");
MODULE_LICENSE("GPL");
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