1/*
2 * arch/sh/drivers/dma/dma-pvr2.c
3 *
4 * NEC PowerVR 2 (Dreamcast) DMA support
5 *
6 * Copyright (C) 2003, 2004  Paul Mundt
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License.  See the file "COPYING" in the main directory of this archive
10 * for more details.
11 */
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/interrupt.h>
16#include <mach/sysasic.h>
17#include <mach/dma.h>
18#include <asm/dma.h>
19#include <asm/io.h>
20
21static unsigned int xfer_complete;
22static int count;
23
24static irqreturn_t pvr2_dma_interrupt(int irq, void *dev_id)
25{
26	if (get_dma_residue(PVR2_CASCADE_CHAN)) {
27		printk(KERN_WARNING "DMA: SH DMAC did not complete transfer "
28		       "on channel %d, waiting..\n", PVR2_CASCADE_CHAN);
29		dma_wait_for_completion(PVR2_CASCADE_CHAN);
30	}
31
32	if (count++ < 10)
33		pr_debug("Got a pvr2 dma interrupt for channel %d\n",
34			 irq - HW_EVENT_PVR2_DMA);
35
36	xfer_complete = 1;
37
38	return IRQ_HANDLED;
39}
40
41static int pvr2_request_dma(struct dma_channel *chan)
42{
43	if (__raw_readl(PVR2_DMA_MODE) != 0)
44		return -EBUSY;
45
46	__raw_writel(0, PVR2_DMA_LMMODE0);
47
48	return 0;
49}
50
51static int pvr2_get_dma_residue(struct dma_channel *chan)
52{
53	return xfer_complete == 0;
54}
55
56static int pvr2_xfer_dma(struct dma_channel *chan)
57{
58	if (chan->sar || !chan->dar)
59		return -EINVAL;
60
61	xfer_complete = 0;
62
63	__raw_writel(chan->dar, PVR2_DMA_ADDR);
64	__raw_writel(chan->count, PVR2_DMA_COUNT);
65	__raw_writel(chan->mode & DMA_MODE_MASK, PVR2_DMA_MODE);
66
67	return 0;
68}
69
70static struct irqaction pvr2_dma_irq = {
71	.name		= "pvr2 DMA handler",
72	.handler	= pvr2_dma_interrupt,
73};
74
75static struct dma_ops pvr2_dma_ops = {
76	.request	= pvr2_request_dma,
77	.get_residue	= pvr2_get_dma_residue,
78	.xfer		= pvr2_xfer_dma,
79};
80
81static struct dma_info pvr2_dma_info = {
82	.name		= "pvr2_dmac",
83	.nr_channels	= 1,
84	.ops		= &pvr2_dma_ops,
85	.flags		= DMAC_CHANNELS_TEI_CAPABLE,
86};
87
88static int __init pvr2_dma_init(void)
89{
90	setup_irq(HW_EVENT_PVR2_DMA, &pvr2_dma_irq);
91	request_dma(PVR2_CASCADE_CHAN, "pvr2 cascade");
92
93	return register_dmac(&pvr2_dma_info);
94}
95
96static void __exit pvr2_dma_exit(void)
97{
98	free_dma(PVR2_CASCADE_CHAN);
99	free_irq(HW_EVENT_PVR2_DMA, 0);
100	unregister_dmac(&pvr2_dma_info);
101}
102
103subsys_initcall(pvr2_dma_init);
104module_exit(pvr2_dma_exit);
105
106MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
107MODULE_DESCRIPTION("NEC PowerVR 2 DMA driver");
108MODULE_LICENSE("GPL");
109