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
18static unsigned int xfer_complete;
19static int count;
20
21static irqreturn_t pvr2_dma_interrupt(int irq, void *dev_id)
22{
23 if (get_dma_residue(dmanr: 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
38static int pvr2_request_dma(struct dma_channel *chan)
39{
40 if (__raw_readl(addr: PVR2_DMA_MODE) != 0)
41 return -EBUSY;
42
43 __raw_writel(val: 0, addr: PVR2_DMA_LMMODE0);
44
45 return 0;
46}
47
48static int pvr2_get_dma_residue(struct dma_channel *chan)
49{
50 return xfer_complete == 0;
51}
52
53static 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(val: chan->dar, addr: PVR2_DMA_ADDR);
61 __raw_writel(val: chan->count, addr: PVR2_DMA_COUNT);
62 __raw_writel(val: chan->mode & DMA_MODE_MASK, addr: PVR2_DMA_MODE);
63
64 return 0;
65}
66
67static 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
73static 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
80static int __init pvr2_dma_init(void)
81{
82 if (request_irq(irq: HW_EVENT_PVR2_DMA, handler: pvr2_dma_interrupt, flags: 0,
83 name: "pvr2 DMA handler", NULL))
84 pr_err("Failed to register pvr2 DMA handler interrupt\n");
85 request_dma(dmanr: PVR2_CASCADE_CHAN, device_id: "pvr2 cascade");
86
87 return register_dmac(&pvr2_dma_info);
88}
89
90static void __exit pvr2_dma_exit(void)
91{
92 free_dma(dmanr: PVR2_CASCADE_CHAN);
93 free_irq(HW_EVENT_PVR2_DMA, 0);
94 unregister_dmac(&pvr2_dma_info);
95}
96
97subsys_initcall(pvr2_dma_init);
98module_exit(pvr2_dma_exit);
99
100MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
101MODULE_DESCRIPTION("NEC PowerVR 2 DMA driver");
102MODULE_LICENSE("GPL v2");
103

source code of linux/arch/sh/drivers/dma/dma-pvr2.c