summaryrefslogtreecommitdiff
path: root/arch/sh/drivers/dma/dma-sh.c
blob: f63721ed86c273fc20864fe107e0877e88d3b65c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
/*
 * arch/sh/drivers/dma/dma-sh.c
 *
 * SuperH On-chip DMAC Support
 *
 * Copyright (C) 2000 Takashi YOSHII
 * Copyright (C) 2003, 2004 Paul Mundt
 * Copyright (C) 2005 Andriy Skulysh
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <asm/dreamcast/dma.h>
#include <asm/dma.h>
#include <asm/io.h>
#include "dma-sh.h"



#ifdef CONFIG_CPU_SH4
static struct ipr_data dmae_ipr_map[] = {
	{ DMAE_IRQ, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
};
#endif
static struct ipr_data dmte_ipr_map[] = {
	/*
	 * Normally we could just do DMTE0_IRQ + chan outright, though in the
	 * case of the 7751R, the DMTE IRQs for channels > 4 start right above
	 * the SCIF
	 */
	{ DMTE0_IRQ + 0, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
	{ DMTE0_IRQ + 1, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
	{ DMTE0_IRQ + 2, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
	{ DMTE0_IRQ + 3, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
	{ DMTE4_IRQ + 0, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
	{ DMTE4_IRQ + 1, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
	{ DMTE4_IRQ + 2, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
	{ DMTE4_IRQ + 3, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY },
};

static inline unsigned int get_dmte_irq(unsigned int chan)
{
	unsigned int irq = 0;
	if (chan < ARRAY_SIZE(dmte_ipr_map))
		irq = dmte_ipr_map[chan].irq;
	return irq;
}

/*
 * We determine the correct shift size based off of the CHCR transmit size
 * for the given channel. Since we know that it will take:
 *
 *	info->count >> ts_shift[transmit_size]
 *
 * iterations to complete the transfer.
 */
static inline unsigned int calc_xmit_shift(struct dma_channel *chan)
{
	u32 chcr = ctrl_inl(CHCR[chan->chan]);

	return ts_shift[(chcr & CHCR_TS_MASK)>>CHCR_TS_SHIFT];
}

/*
 * The transfer end interrupt must read the chcr register to end the
 * hardware interrupt active condition.
 * Besides that it needs to waken any waiting process, which should handle
 * setting up the next transfer.
 */
static irqreturn_t dma_tei(int irq, void *dev_id)
{
	struct dma_channel *chan = dev_id;
	u32 chcr;

	chcr = ctrl_inl(CHCR[chan->chan]);

	if (!(chcr & CHCR_TE))
		return IRQ_NONE;

	chcr &= ~(CHCR_IE | CHCR_DE);
	ctrl_outl(chcr, CHCR[chan->chan]);

	wake_up(&chan->wait_queue);

	return IRQ_HANDLED;
}

static int sh_dmac_request_dma(struct dma_channel *chan)
{
	if (unlikely(!chan->flags & DMA_TEI_CAPABLE))
		return 0;

	return request_irq(get_dmte_irq(chan->chan), dma_tei,
			   IRQF_DISABLED, chan->dev_id, chan);
}

static void sh_dmac_free_dma(struct dma_channel *chan)
{
	free_irq(get_dmte_irq(chan->chan), chan);
}

static void
sh_dmac_configure_channel(struct dma_channel *chan, unsigned long chcr)
{
	if (!chcr)
		chcr = RS_DUAL | CHCR_IE;

	if (chcr & CHCR_IE) {
		chcr &= ~CHCR_IE;
		chan->flags |= DMA_TEI_CAPABLE;
	} else {
		chan->flags &= ~DMA_TEI_CAPABLE;
	}

	ctrl_outl(chcr, CHCR[chan->chan]);

	chan->flags |= DMA_CONFIGURED;
}

static void sh_dmac_enable_dma(struct dma_channel *chan)
{
	int irq;
	u32 chcr;

	chcr = ctrl_inl(CHCR[chan->chan]);
	chcr |= CHCR_DE;

	if (chan->flags & DMA_TEI_CAPABLE)
		chcr |= CHCR_IE;

	ctrl_outl(chcr, CHCR[chan->chan]);

	if (chan->flags & DMA_TEI_CAPABLE) {
		irq = get_dmte_irq(chan->chan);
		enable_irq(irq);
	}
}

static void sh_dmac_disable_dma(struct dma_channel *chan)
{
	int irq;
	u32 chcr;

	if (chan->flags & DMA_TEI_CAPABLE) {
		irq = get_dmte_irq(chan->chan);
		disable_irq(irq);
	}

	chcr = ctrl_inl(CHCR[chan->chan]);
	chcr &= ~(CHCR_DE | CHCR_TE | CHCR_IE);
	ctrl_outl(chcr, CHCR[chan->chan]);
}

static int sh_dmac_xfer_dma(struct dma_channel *chan)
{
	/*
	 * If we haven't pre-configured the channel with special flags, use
	 * the defaults.
	 */
	if (unlikely(!(chan->flags & DMA_CONFIGURED)))
		sh_dmac_configure_channel(chan, 0);

	sh_dmac_disable_dma(chan);

	/*
	 * Single-address mode usage note!
	 *
	 * It's important that we don't accidentally write any value to SAR/DAR
	 * (this includes 0) that hasn't been directly specified by the user if
	 * we're in single-address mode.
	 *
	 * In this case, only one address can be defined, anything else will
	 * result in a DMA address error interrupt (at least on the SH-4),
	 * which will subsequently halt the transfer.
	 *
	 * Channel 2 on the Dreamcast is a special case, as this is used for
	 * cascading to the PVR2 DMAC. In this case, we still need to write
	 * SAR and DAR, regardless of value, in order for cascading to work.
	 */
	if (chan->sar || (mach_is_dreamcast() &&
			  chan->chan == PVR2_CASCADE_CHAN))
		ctrl_outl(chan->sar, SAR[chan->chan]);
	if (chan->dar || (mach_is_dreamcast() &&
			  chan->chan == PVR2_CASCADE_CHAN))
		ctrl_outl(chan->dar, DAR[chan->chan]);

	ctrl_outl(chan->count >> calc_xmit_shift(chan), DMATCR[chan->chan]);

	sh_dmac_enable_dma(chan);

	return 0;
}

static int sh_dmac_get_dma_residue(struct dma_channel *chan)
{
	if (!(ctrl_inl(CHCR[chan->chan]) & CHCR_DE))
		return 0;

	return ctrl_inl(DMATCR[chan->chan]) << calc_xmit_shift(chan);
}

#ifdef CONFIG_CPU_SUBTYPE_SH7780
#define dmaor_read_reg()	ctrl_inw(DMAOR)
#define dmaor_write_reg(data)	ctrl_outw(data, DMAOR)
#else
#define dmaor_read_reg()	ctrl_inl(DMAOR)
#define dmaor_write_reg(data)	ctrl_outl(data, DMAOR)
#endif

static inline int dmaor_reset(void)
{
	unsigned long dmaor = dmaor_read_reg();

	/* Try to clear the error flags first, incase they are set */
	dmaor &= ~(DMAOR_NMIF | DMAOR_AE);
	dmaor_write_reg(dmaor);

	dmaor |= DMAOR_INIT;
	dmaor_write_reg(dmaor);

	/* See if we got an error again */
	if ((dmaor_read_reg() & (DMAOR_AE | DMAOR_NMIF))) {
		printk(KERN_ERR "dma-sh: Can't initialize DMAOR.\n");
		return -EINVAL;
	}

	return 0;
}

#if defined(CONFIG_CPU_SH4)
static irqreturn_t dma_err(int irq, void *dummy)
{
	dmaor_reset();
	disable_irq(irq);

	return IRQ_HANDLED;
}
#endif

static struct dma_ops sh_dmac_ops = {
	.request	= sh_dmac_request_dma,
	.free		= sh_dmac_free_dma,
	.get_residue	= sh_dmac_get_dma_residue,
	.xfer		= sh_dmac_xfer_dma,
	.configure	= sh_dmac_configure_channel,
};

static struct dma_info sh_dmac_info = {
	.name		= "sh_dmac",
	.nr_channels	= CONFIG_NR_ONCHIP_DMA_CHANNELS,
	.ops		= &sh_dmac_ops,
	.flags		= DMAC_CHANNELS_TEI_CAPABLE,
};

static int __init sh_dmac_init(void)
{
	struct dma_info *info = &sh_dmac_info;
	int i;

#ifdef CONFIG_CPU_SH4
	make_ipr_irq(dmae_ipr_map, ARRAY_SIZE(dmae_ipr_map));
	i = request_irq(DMAE_IRQ, dma_err, IRQF_DISABLED, "DMAC Address Error", 0);
	if (unlikely(i < 0))
		return i;
#endif

	i = info->nr_channels;
	if (i > ARRAY_SIZE(dmte_ipr_map))
		i = ARRAY_SIZE(dmte_ipr_map);
	make_ipr_irq(dmte_ipr_map, i);

	/*
	 * Initialize DMAOR, and clean up any error flags that may have
	 * been set.
	 */
	i = dmaor_reset();
	if (unlikely(i != 0))
		return i;

	return register_dmac(info);
}

static void __exit sh_dmac_exit(void)
{
#ifdef CONFIG_CPU_SH4
	free_irq(DMAE_IRQ, 0);
#endif
	unregister_dmac(&sh_dmac_info);
}

subsys_initcall(sh_dmac_init);
module_exit(sh_dmac_exit);

MODULE_AUTHOR("Takashi YOSHII, Paul Mundt, Andriy Skulysh");
MODULE_DESCRIPTION("SuperH On-Chip DMAC Support");
MODULE_LICENSE("GPL");