Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq
[linux-2.6] / arch / sh / drivers / dma / dma-pvr2.c
1 /*
2  * arch/sh/boards/dreamcast/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 <asm/mach/sysasic.h>
17 #include <asm/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
24 static irqreturn_t pvr2_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
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
41 static int pvr2_request_dma(struct dma_channel *chan)
42 {
43         if (ctrl_inl(PVR2_DMA_MODE) != 0)
44                 return -EBUSY;
45
46         ctrl_outl(0, PVR2_DMA_LMMODE0);
47
48         return 0;
49 }
50
51 static int pvr2_get_dma_residue(struct dma_channel *chan)
52 {
53         return xfer_complete == 0;
54 }
55
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         ctrl_outl(chan->dar, PVR2_DMA_ADDR);
64         ctrl_outl(chan->count, PVR2_DMA_COUNT);
65         ctrl_outl(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         .flags          = IRQF_DISABLED,
74 };
75
76 static struct dma_ops pvr2_dma_ops = {
77         .request        = pvr2_request_dma,
78         .get_residue    = pvr2_get_dma_residue,
79         .xfer           = pvr2_xfer_dma,
80 };
81
82 static struct dma_info pvr2_dma_info = {
83         .name           = "pvr2_dmac",
84         .nr_channels    = 1,
85         .ops            = &pvr2_dma_ops,
86         .flags          = DMAC_CHANNELS_TEI_CAPABLE,
87 };
88
89 static int __init pvr2_dma_init(void)
90 {
91         setup_irq(HW_EVENT_PVR2_DMA, &pvr2_dma_irq);
92         request_dma(PVR2_CASCADE_CHAN, "pvr2 cascade");
93
94         return register_dmac(&pvr2_dma_info);
95 }
96
97 static void __exit pvr2_dma_exit(void)
98 {
99         free_dma(PVR2_CASCADE_CHAN);
100         free_irq(HW_EVENT_PVR2_DMA, 0);
101         unregister_dmac(&pvr2_dma_info);
102 }
103
104 subsys_initcall(pvr2_dma_init);
105 module_exit(pvr2_dma_exit);
106
107 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
108 MODULE_DESCRIPTION("NEC PowerVR 2 DMA driver");
109 MODULE_LICENSE("GPL");