aboutsummaryrefslogtreecommitdiff
path: root/arch/hexagon/kernel/dma.c
blob: e711ace62fdf9b60eb93d97cf0de193d936cce35 (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
/*
 * DMA implementation for Hexagon
 *
 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include <linux/dma-mapping.h>
#include <linux/bootmem.h>
#include <linux/genalloc.h>
#include <asm/dma-mapping.h>

struct dma_map_ops *dma_ops;
EXPORT_SYMBOL(dma_ops);

int bad_dma_address;  /*  globals are automatically initialized to zero  */

int dma_supported(struct device *dev, u64 mask)
{
	if (mask == DMA_BIT_MASK(32))
		return 1;
	else
		return 0;
}
EXPORT_SYMBOL(dma_supported);

int dma_set_mask(struct device *dev, u64 mask)
{
	if (!dev->dma_mask || !dma_supported(dev, mask))
		return -EIO;

	*dev->dma_mask = mask;

	return 0;
}
EXPORT_SYMBOL(dma_set_mask);

static struct gen_pool *coherent_pool;


/* Allocates from a pool of uncached memory that was reserved at boot time */

void *hexagon_dma_alloc_coherent(struct device *dev, size_t size,
				 dma_addr_t *dma_addr, gfp_t flag)
{
	void *ret;

	if (coherent_pool == NULL) {
		coherent_pool = gen_pool_create(PAGE_SHIFT, -1);

		if (coherent_pool == NULL)
			panic("Can't create %s() memory pool!", __func__);
		else
			gen_pool_add(coherent_pool,
				(PAGE_OFFSET + (max_low_pfn << PAGE_SHIFT)),
				hexagon_coherent_pool_size, -1);
	}

	ret = (void *) gen_pool_alloc(coherent_pool, size);

	if (ret) {
		memset(ret, 0, size);
		*dma_addr = (dma_addr_t) (ret - PAGE_OFFSET);
	} else
		*dma_addr = ~0;

	return ret;
}

static void hexagon_free_coherent(struct device *dev, size_t size, void *vaddr,
				  dma_addr_t dma_addr)
{
	gen_pool_free(coherent_pool, (unsigned long) vaddr, size);
}

static int check_addr(const char *name, struct device *hwdev,
		      dma_addr_t bus, size_t size)
{
	if (hwdev && hwdev->dma_mask && !dma_capable(hwdev, bus, size)) {
		if (*hwdev->dma_mask >= DMA_BIT_MASK(32))
			printk(KERN_ERR
				"%s: overflow %Lx+%zu of device mask %Lx\n",
				name, (long long)bus, size,
				(long long)*hwdev->dma_mask);
		return 0;
	}
	return 1;
}

static int hexagon_map_sg(struct device *hwdev, struct scatterlist *sg,
			  int nents, enum dma_data_direction dir,
			  struct dma_attrs *attrs)
{
	struct scatterlist *s;
	int i;

	WARN_ON(nents == 0 || sg[0].length == 0);

	for_each_sg(sg, s, nents, i) {
		s->dma_address = sg_phys(s);
		if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
			return 0;

		s->dma_length = s->length;

		flush_dcache_range(PAGE_OFFSET + s->dma_address,
				   PAGE_OFFSET + s->dma_address + s->length);
	}

	return nents;
}

/*
 * address is virtual
 */
static inline void dma_sync(void *addr, size_t size,
			    enum dma_data_direction dir)
{
	switch (dir) {
	case DMA_TO_DEVICE:
		hexagon_clean_dcache_range((unsigned long) addr,
		(unsigned long) addr + size);
		break;
	case DMA_FROM_DEVICE:
		hexagon_inv_dcache_range((unsigned long) addr,
		(unsigned long) addr + size);
		break;
	case DMA_BIDIRECTIONAL:
		flush_dcache_range((unsigned long) addr,
		(unsigned long) addr + size);
		break;
	default:
		BUG();
	}
}

static inline void *dma_addr_to_virt(dma_addr_t dma_addr)
{
	return phys_to_virt((unsigned long) dma_addr);
}

/**
 * hexagon_map_page() - maps an address for device DMA
 * @dev:	pointer to DMA device
 * @page:	pointer to page struct of DMA memory
 * @offset:	offset within page
 * @size:	size of memory to map
 * @dir:	transfer direction
 * @attrs:	pointer to DMA attrs (not used)
 *
 * Called to map a memory address to a DMA address prior
 * to accesses to/from device.
 *
 * We don't particularly have many hoops to jump through
 * so far.  Straight translation between phys and virtual.
 *
 * DMA is not cache coherent so sync is necessary; this
 * seems to be a convenient place to do it.
 *
 */
static dma_addr_t hexagon_map_page(struct device *dev, struct page *page,
				   unsigned long offset, size_t size,
				   enum dma_data_direction dir,
				   struct dma_attrs *attrs)
{
	dma_addr_t bus = page_to_phys(page) + offset;
	WARN_ON(size == 0);

	if (!check_addr("map_single", dev, bus, size))
		return bad_dma_address;

	dma_sync(dma_addr_to_virt(bus), size, dir);

	return bus;
}

static void hexagon_sync_single_for_cpu(struct device *dev,
					dma_addr_t dma_handle, size_t size,
					enum dma_data_direction dir)
{
	dma_sync(dma_addr_to_virt(dma_handle), size, dir);
}

static void hexagon_sync_single_for_device(struct device *dev,
					dma_addr_t dma_handle, size_t size,
					enum dma_data_direction dir)
{
	dma_sync(dma_addr_to_virt(dma_handle), size, dir);
}

struct dma_map_ops hexagon_dma_ops = {
	.alloc_coherent	= hexagon_dma_alloc_coherent,
	.free_coherent	= hexagon_free_coherent,
	.map_sg		= hexagon_map_sg,
	.map_page	= hexagon_map_page,
	.sync_single_for_cpu = hexagon_sync_single_for_cpu,
	.sync_single_for_device = hexagon_sync_single_for_device,
	.is_phys	= 1,
};

void __init hexagon_dma_init(void)
{
	if (dma_ops)
		return;

	dma_ops = &hexagon_dma_ops;
}