1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/sh/drivers/dma/dma-pvr2.c
4 *
5 * NEC PowerVR 2 (Dreamcast) DMA support
6 *
7 * Copyright (C) 2003, 2004 Paul Mundt
8 */
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
13 #include <mach/sysasic.h>
14 #include <mach/dma.h>
15 #include <asm/dma.h>
16 #include <asm/io.h>
17
18 static unsigned int xfer_complete;
19 static int count;
20
pvr2_dma_interrupt(int irq,void * dev_id)21 static irqreturn_t pvr2_dma_interrupt(int irq, void *dev_id)
22 {
23 if (get_dma_residue(PVR2_CASCADE_CHAN)) {
24 printk(KERN_WARNING "DMA: SH DMAC did not complete transfer "
25 "on channel %d, waiting..\n", PVR2_CASCADE_CHAN);
26 dma_wait_for_completion(PVR2_CASCADE_CHAN);
27 }
28
29 if (count++ < 10)
30 pr_debug("Got a pvr2 dma interrupt for channel %d\n",
31 irq - HW_EVENT_PVR2_DMA);
32
33 xfer_complete = 1;
34
35 return IRQ_HANDLED;
36 }
37
pvr2_request_dma(struct dma_channel * chan)38 static int pvr2_request_dma(struct dma_channel *chan)
39 {
40 if (__raw_readl(PVR2_DMA_MODE) != 0)
41 return -EBUSY;
42
43 __raw_writel(0, PVR2_DMA_LMMODE0);
44
45 return 0;
46 }
47
pvr2_get_dma_residue(struct dma_channel * chan)48 static int pvr2_get_dma_residue(struct dma_channel *chan)
49 {
50 return xfer_complete == 0;
51 }
52
pvr2_xfer_dma(struct dma_channel * chan)53 static int pvr2_xfer_dma(struct dma_channel *chan)
54 {
55 if (chan->sar || !chan->dar)
56 return -EINVAL;
57
58 xfer_complete = 0;
59
60 __raw_writel(chan->dar, PVR2_DMA_ADDR);
61 __raw_writel(chan->count, PVR2_DMA_COUNT);
62 __raw_writel(chan->mode & DMA_MODE_MASK, PVR2_DMA_MODE);
63
64 return 0;
65 }
66
67 static struct dma_ops pvr2_dma_ops = {
68 .request = pvr2_request_dma,
69 .get_residue = pvr2_get_dma_residue,
70 .xfer = pvr2_xfer_dma,
71 };
72
73 static struct dma_info pvr2_dma_info = {
74 .name = "pvr2_dmac",
75 .nr_channels = 1,
76 .ops = &pvr2_dma_ops,
77 .flags = DMAC_CHANNELS_TEI_CAPABLE,
78 };
79
pvr2_dma_init(void)80 static int __init pvr2_dma_init(void)
81 {
82 if (request_irq(HW_EVENT_PVR2_DMA, pvr2_dma_interrupt, 0,
83 "pvr2 DMA handler", NULL))
84 pr_err("Failed to register pvr2 DMA handler interrupt\n");
85 request_dma(PVR2_CASCADE_CHAN, "pvr2 cascade");
86
87 return register_dmac(&pvr2_dma_info);
88 }
89
pvr2_dma_exit(void)90 static void __exit pvr2_dma_exit(void)
91 {
92 free_dma(PVR2_CASCADE_CHAN);
93 free_irq(HW_EVENT_PVR2_DMA, 0);
94 unregister_dmac(&pvr2_dma_info);
95 }
96
97 subsys_initcall(pvr2_dma_init);
98 module_exit(pvr2_dma_exit);
99
100 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
101 MODULE_DESCRIPTION("NEC PowerVR 2 DMA driver");
102 MODULE_LICENSE("GPL v2");
103