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
21 static unsigned int xfer_complete;
22 static int count;
23
pvr2_dma_interrupt(int irq,void * dev_id)24 static 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
pvr2_request_dma(struct dma_channel * chan)41 static 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
pvr2_get_dma_residue(struct dma_channel * chan)51 static int pvr2_get_dma_residue(struct dma_channel *chan)
52 {
53 return xfer_complete == 0;
54 }
55
pvr2_xfer_dma(struct dma_channel * chan)56 static 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
70 static struct irqaction pvr2_dma_irq = {
71 .name = "pvr2 DMA handler",
72 .handler = pvr2_dma_interrupt,
73 };
74
75 static 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
81 static 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
pvr2_dma_init(void)88 static 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
pvr2_dma_exit(void)96 static 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
103 subsys_initcall(pvr2_dma_init);
104 module_exit(pvr2_dma_exit);
105
106 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
107 MODULE_DESCRIPTION("NEC PowerVR 2 DMA driver");
108 MODULE_LICENSE("GPL");
109