summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/omapdrm/tcm-sita.c
blob: d7f7bc9f061af0a989ebe7924bd624dea4266786 (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
/*
 * SImple Tiler Allocator (SiTA): 2D and 1D allocation(reservation) algorithm
 *
 * Authors: Ravi Ramachandra <r.ramachandra@ti.com>,
 *          Lajos Molnar <molnar@ti.com>
 *          Andy Gross <andy.gross@ti.com>
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This package is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/bitmap.h>
#include <linux/slab.h>
#include "tcm.h"

static unsigned long mask[8];
/*
 * pos		position in bitmap
 * w		width in slots
 * h		height in slots
 * map		ptr to bitmap
 * stride		slots in a row
 */
static void free_slots(unsigned long pos, u16 w, u16 h,
		unsigned long *map, u16 stride)
{
	int i;

	for (i = 0; i < h; i++, pos += stride)
		bitmap_clear(map, pos, w);
}

/*
 * w		width in slots
 * pos		ptr to position
 * map		ptr to bitmap
 * num_bits	number of bits in bitmap
 */
static int r2l_b2t_1d(u16 w, unsigned long *pos, unsigned long *map,
		size_t num_bits)
{
	unsigned long search_count = 0;
	unsigned long bit;
	bool area_found = false;

	*pos = num_bits - w;

	while (search_count < num_bits) {
		bit = find_next_bit(map, num_bits, *pos);

		if (bit - *pos >= w) {
			/* found a long enough free area */
			bitmap_set(map, *pos, w);
			area_found = true;
			break;
		}

		search_count = num_bits - bit + w;
		*pos = bit - w;
	}

	return (area_found) ? 0 : -ENOMEM;
}

/*
 * w = width in slots
 * h = height in slots
 * a = align in slots	(mask, 2^n-1, 0 is unaligned)
 * offset = offset in bytes from 4KiB
 * pos = position in bitmap for buffer
 * map = bitmap ptr
 * num_bits = size of bitmap
 * stride = bits in one row of container
 */
static int l2r_t2b(u16 w, u16 h, u16 a, s16 offset,
		unsigned long *pos, unsigned long slot_bytes,
		unsigned long *map, size_t num_bits, size_t slot_stride)
{
	int i;
	unsigned long index;
	bool area_free;
	unsigned long slots_per_band = PAGE_SIZE / slot_bytes;
	unsigned long bit_offset = (offset > 0) ? offset / slot_bytes : 0;
	unsigned long curr_bit = bit_offset;

	/* reset alignment to 1 if we are matching a specific offset */
	/* adjust alignment - 1 to get to the format expected in bitmaps */
	a = (offset > 0) ? 0 : a - 1;

	/* FIXME Return error if slots_per_band > stride */

	while (curr_bit < num_bits) {
		*pos = bitmap_find_next_zero_area(map, num_bits, curr_bit, w,
				a);

		/* skip forward if we are not at right offset */
		if (bit_offset > 0 && (*pos % slots_per_band != bit_offset)) {
			curr_bit = ALIGN(*pos, slots_per_band) + bit_offset;
			continue;
		}

		/* skip forward to next row if we overlap end of row */
		if ((*pos % slot_stride) + w > slot_stride) {
			curr_bit = ALIGN(*pos, slot_stride) + bit_offset;
			continue;
		}

		/* TODO: Handle overlapping 4K boundaries */

		/* break out of look if we will go past end of container */
		if ((*pos + slot_stride * h) > num_bits)
			break;

		/* generate mask that represents out matching pattern */
		bitmap_clear(mask, 0, slot_stride);
		bitmap_set(mask, (*pos % BITS_PER_LONG), w);

		/* assume the area is free until we find an overlap */
		area_free = true;

		/* check subsequent rows to see if complete area is free */
		for (i = 1; i < h; i++) {
			index = *pos / BITS_PER_LONG + i * 8;
			if (bitmap_intersects(&map[index], mask,
				(*pos % BITS_PER_LONG) + w)) {
				area_free = false;
				break;
			}
		}

		if (area_free)
			break;

		/* go forward past this match */
		if (bit_offset > 0)
			curr_bit = ALIGN(*pos, slots_per_band) + bit_offset;
		else
			curr_bit = *pos + a + 1;
	}

	if (area_free) {
		/* set area as in-use. iterate over rows */
		for (i = 0, index = *pos; i < h; i++, index += slot_stride)
			bitmap_set(map, index, w);
	}

	return (area_free) ? 0 : -ENOMEM;
}

static s32 sita_reserve_1d(struct tcm *tcm, u32 num_slots,
			   struct tcm_area *area)
{
	unsigned long pos;
	int ret;

	spin_lock(&(tcm->lock));
	ret = r2l_b2t_1d(num_slots, &pos, tcm->bitmap, tcm->map_size);
	if (!ret) {
		area->p0.x = pos % tcm->width;
		area->p0.y = pos / tcm->width;
		area->p1.x = (pos + num_slots - 1) % tcm->width;
		area->p1.y = (pos + num_slots - 1) / tcm->width;
	}
	spin_unlock(&(tcm->lock));

	return ret;
}

static s32 sita_reserve_2d(struct tcm *tcm, u16 h, u16 w, u16 align,
				s16 offset, u16 slot_bytes,
				struct tcm_area *area)
{
	unsigned long pos;
	int ret;

	spin_lock(&(tcm->lock));
	ret = l2r_t2b(w, h, align, offset, &pos, slot_bytes, tcm->bitmap,
			tcm->map_size, tcm->width);

	if (!ret) {
		area->p0.x = pos % tcm->width;
		area->p0.y = pos / tcm->width;
		area->p1.x = area->p0.x + w - 1;
		area->p1.y = area->p0.y + h - 1;
	}
	spin_unlock(&(tcm->lock));

	return ret;
}

static void sita_deinit(struct tcm *tcm)
{
	kfree(tcm);
}

static s32 sita_free(struct tcm *tcm, struct tcm_area *area)
{
	unsigned long pos;
	u16 w, h;

	pos = area->p0.x + area->p0.y * tcm->width;
	if (area->is2d) {
		w = area->p1.x - area->p0.x + 1;
		h = area->p1.y - area->p0.y + 1;
	} else {
		w = area->p1.x + area->p1.y * tcm->width - pos + 1;
		h = 1;
	}

	spin_lock(&(tcm->lock));
	free_slots(pos, w, h, tcm->bitmap, tcm->width);
	spin_unlock(&(tcm->lock));
	return 0;
}

struct tcm *sita_init(u16 width, u16 height)
{
	struct tcm *tcm;
	size_t map_size = BITS_TO_LONGS(width*height) * sizeof(unsigned long);

	if (width == 0 || height == 0)
		return NULL;

	tcm = kzalloc(sizeof(*tcm) + map_size, GFP_KERNEL);
	if (!tcm)
		goto error;

	/* Updating the pointers to SiTA implementation APIs */
	tcm->height = height;
	tcm->width = width;
	tcm->reserve_2d = sita_reserve_2d;
	tcm->reserve_1d = sita_reserve_1d;
	tcm->free = sita_free;
	tcm->deinit = sita_deinit;

	spin_lock_init(&tcm->lock);
	tcm->bitmap = (unsigned long *)(tcm + 1);
	bitmap_clear(tcm->bitmap, 0, width*height);

	tcm->map_size = width*height;

	return tcm;

error:
	kfree(tcm);
	return NULL;
}