summaryrefslogtreecommitdiffstats
path: root/drivers/base/regmap/regcache-lzo.c
blob: 6f77d7319fc6dd35182fecefcaa56a4650fed65f (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
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
/*
 * Register cache access API - LZO caching support
 *
 * Copyright 2011 Wolfson Microelectronics plc
 *
 * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
 *
 * This program 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.
 */

#include <linux/device.h>
#include <linux/lzo.h>
#include <linux/slab.h>

#include "internal.h"

static int regcache_lzo_exit(struct regmap *map);

struct regcache_lzo_ctx {
	void *wmem;
	void *dst;
	const void *src;
	size_t src_len;
	size_t dst_len;
	size_t decompressed_size;
	unsigned long *sync_bmp;
	int sync_bmp_nbits;
};

#define LZO_BLOCK_NUM 8
static int regcache_lzo_block_count(struct regmap *map)
{
	return LZO_BLOCK_NUM;
}

static int regcache_lzo_prepare(struct regcache_lzo_ctx *lzo_ctx)
{
	lzo_ctx->wmem = kmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
	if (!lzo_ctx->wmem)
		return -ENOMEM;
	return 0;
}

static int regcache_lzo_compress(struct regcache_lzo_ctx *lzo_ctx)
{
	size_t compress_size;
	int ret;

	ret = lzo1x_1_compress(lzo_ctx->src, lzo_ctx->src_len,
			       lzo_ctx->dst, &compress_size, lzo_ctx->wmem);
	if (ret != LZO_E_OK || compress_size > lzo_ctx->dst_len)
		return -EINVAL;
	lzo_ctx->dst_len = compress_size;
	return 0;
}

static int regcache_lzo_decompress(struct regcache_lzo_ctx *lzo_ctx)
{
	size_t dst_len;
	int ret;

	dst_len = lzo_ctx->dst_len;
	ret = lzo1x_decompress_safe(lzo_ctx->src, lzo_ctx->src_len,
				    lzo_ctx->dst, &dst_len);
	if (ret != LZO_E_OK || dst_len != lzo_ctx->dst_len)
		return -EINVAL;
	return 0;
}

static int regcache_lzo_compress_cache_block(struct regmap *map,
		struct regcache_lzo_ctx *lzo_ctx)
{
	int ret;

	lzo_ctx->dst_len = lzo1x_worst_compress(PAGE_SIZE);
	lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
	if (!lzo_ctx->dst) {
		lzo_ctx->dst_len = 0;
		return -ENOMEM;
	}

	ret = regcache_lzo_compress(lzo_ctx);
	if (ret < 0)
		return ret;
	return 0;
}

static int regcache_lzo_decompress_cache_block(struct regmap *map,
		struct regcache_lzo_ctx *lzo_ctx)
{
	int ret;

	lzo_ctx->dst_len = lzo_ctx->decompressed_size;
	lzo_ctx->dst = kmalloc(lzo_ctx->dst_len, GFP_KERNEL);
	if (!lzo_ctx->dst) {
		lzo_ctx->dst_len = 0;
		return -ENOMEM;
	}

	ret = regcache_lzo_decompress(lzo_ctx);
	if (ret < 0)
		return ret;
	return 0;
}

static inline int regcache_lzo_get_blkindex(struct regmap *map,
					    unsigned int reg)
{
	return ((reg / map->reg_stride) * map->cache_word_size) /
		DIV_ROUND_UP(map->cache_size_raw,
			     regcache_lzo_block_count(map));
}

static inline int regcache_lzo_get_blkpos(struct regmap *map,
					  unsigned int reg)
{
	return (reg / map->reg_stride) %
		    (DIV_ROUND_UP(map->cache_size_raw,
				  regcache_lzo_block_count(map)) /
		     map->cache_word_size);
}

static inline int regcache_lzo_get_blksize(struct regmap *map)
{
	return DIV_ROUND_UP(map->cache_size_raw,
			    regcache_lzo_block_count(map));
}

static int regcache_lzo_init(struct regmap *map)
{
	struct regcache_lzo_ctx **lzo_blocks;
	size_t bmp_size;
	int ret, i, blksize, blkcount;
	const char *p, *end;
	unsigned long *sync_bmp;

	ret = 0;

	blkcount = regcache_lzo_block_count(map);
	map->cache = kcalloc(blkcount, sizeof(*lzo_blocks),
			     GFP_KERNEL);
	if (!map->cache)
		return -ENOMEM;
	lzo_blocks = map->cache;

	/*
	 * allocate a bitmap to be used when syncing the cache with
	 * the hardware.  Each time a register is modified, the corresponding
	 * bit is set in the bitmap, so we know that we have to sync
	 * that register.
	 */
	bmp_size = map->num_reg_defaults_raw;
	sync_bmp = kmalloc_array(BITS_TO_LONGS(bmp_size), sizeof(long),
				 GFP_KERNEL);
	if (!sync_bmp) {
		ret = -ENOMEM;
		goto err;
	}
	bitmap_zero(sync_bmp, bmp_size);

	/* allocate the lzo blocks and initialize them */
	for (i = 0; i < blkcount; i++) {
		lzo_blocks[i] = kzalloc(sizeof **lzo_blocks,
					GFP_KERNEL);
		if (!lzo_blocks[i]) {
			kfree(sync_bmp);
			ret = -ENOMEM;
			goto err;
		}
		lzo_blocks[i]->sync_bmp = sync_bmp;
		lzo_blocks[i]->sync_bmp_nbits = bmp_size;
		/* alloc the working space for the compressed block */
		ret = regcache_lzo_prepare(lzo_blocks[i]);
		if (ret < 0)
			goto err;
	}

	blksize = regcache_lzo_get_blksize(map);
	p = map->reg_defaults_raw;
	end = map->reg_defaults_raw + map->cache_size_raw;
	/* compress the register map and fill the lzo blocks */
	for (i = 0; i < blkcount; i++, p += blksize) {
		lzo_blocks[i]->src = p;
		if (p + blksize > end)
			lzo_blocks[i]->src_len = end - p;
		else
			lzo_blocks[i]->src_len = blksize;
		ret = regcache_lzo_compress_cache_block(map,
						       lzo_blocks[i]);
		if (ret < 0)
			goto err;
		lzo_blocks[i]->decompressed_size =
			lzo_blocks[i]->src_len;
	}

	return 0;
err:
	regcache_lzo_exit(map);
	return ret;
}

static int regcache_lzo_exit(struct regmap *map)
{
	struct regcache_lzo_ctx **lzo_blocks;
	int i, blkcount;

	lzo_blocks = map->cache;
	if (!lzo_blocks)
		return 0;

	blkcount = regcache_lzo_block_count(map);
	/*
	 * the pointer to the bitmap used for syncing the cache
	 * is shared amongst all lzo_blocks.  Ensure it is freed
	 * only once.
	 */
	if (lzo_blocks[0])
		kfree(lzo_blocks[0]->sync_bmp);
	for (i = 0; i < blkcount; i++) {
		if (lzo_blocks[i]) {
			kfree(lzo_blocks[i]->wmem);
			kfree(lzo_blocks[i]->dst);
		}
		/* each lzo_block is a pointer returned by kmalloc or NULL */
		kfree(lzo_blocks[i]);
	}
	kfree(lzo_blocks);
	map->cache = NULL;
	return 0;
}

static int regcache_lzo_read(struct regmap *map,
			     unsigned int reg, unsigned int *value)
{
	struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
	int ret, blkindex, blkpos;
	size_t blksize, tmp_dst_len;
	void *tmp_dst;

	/* index of the compressed lzo block */
	blkindex = regcache_lzo_get_blkindex(map, reg);
	/* register index within the decompressed block */
	blkpos = regcache_lzo_get_blkpos(map, reg);
	/* size of the compressed block */
	blksize = regcache_lzo_get_blksize(map);
	lzo_blocks = map->cache;
	lzo_block = lzo_blocks[blkindex];

	/* save the pointer and length of the compressed block */
	tmp_dst = lzo_block->dst;
	tmp_dst_len = lzo_block->dst_len;

	/* prepare the source to be the compressed block */
	lzo_block->src = lzo_block->dst;
	lzo_block->src_len = lzo_block->dst_len;

	/* decompress the block */
	ret = regcache_lzo_decompress_cache_block(map, lzo_block);
	if (ret >= 0)
		/* fetch the value from the cache */
		*value = regcache_get_val(map, lzo_block->dst, blkpos);

	kfree(lzo_block->dst);
	/* restore the pointer and length of the compressed block */
	lzo_block->dst = tmp_dst;
	lzo_block->dst_len = tmp_dst_len;

	return ret;
}

static int regcache_lzo_write(struct regmap *map,
			      unsigned int reg, unsigned int value)
{
	struct regcache_lzo_ctx *lzo_block, **lzo_blocks;
	int ret, blkindex, blkpos;
	size_t blksize, tmp_dst_len;
	void *tmp_dst;

	/* index of the compressed lzo block */
	blkindex = regcache_lzo_get_blkindex(map, reg);
	/* register index within the decompressed block */
	blkpos = regcache_lzo_get_blkpos(map, reg);
	/* size of the compressed block */
	blksize = regcache_lzo_get_blksize(map);
	lzo_blocks = map->cache;
	lzo_block = lzo_blocks[blkindex];

	/* save the pointer and length of the compressed block */
	tmp_dst = lzo_block->dst;
	tmp_dst_len = lzo_block->dst_len;

	/* prepare the source to be the compressed block */
	lzo_block->src = lzo_block->dst;
	lzo_block->src_len = lzo_block->dst_len;

	/* decompress the block */
	ret = regcache_lzo_decompress_cache_block(map, lzo_block);
	if (ret < 0) {
		kfree(lzo_block->dst);
		goto out;
	}

	/* write the new value to the cache */
	if (regcache_set_val(map, lzo_block->dst, blkpos, value)) {
		kfree(lzo_block->dst);
		goto out;
	}

	/* prepare the source to be the decompressed block */
	lzo_block->src = lzo_block->dst;
	lzo_block->src_len = lzo_block->dst_len;

	/* compress the block */
	ret = regcache_lzo_compress_cache_block(map, lzo_block);
	if (ret < 0) {
		kfree(lzo_block->dst);
		kfree(lzo_block->src);
		goto out;
	}

	/* set the bit so we know we have to sync this register */
	set_bit(reg / map->reg_stride, lzo_block->sync_bmp);
	kfree(tmp_dst);
	kfree(lzo_block->src);
	return 0;
out:
	lzo_block->dst = tmp_dst;
	lzo_block->dst_len = tmp_dst_len;
	return ret;
}

static int regcache_lzo_sync(struct regmap *map, unsigned int min,
			     unsigned int max)
{
	struct regcache_lzo_ctx **lzo_blocks;
	unsigned int val;
	int i;
	int ret;

	lzo_blocks = map->cache;
	i = min;
	for_each_set_bit_from(i, lzo_blocks[0]->sync_bmp,
			      lzo_blocks[0]->sync_bmp_nbits) {
		if (i > max)
			continue;

		ret = regcache_read(map, i, &val);
		if (ret)
			return ret;

		/* Is this the hardware default?  If so skip. */
		ret = regcache_lookup_reg(map, i);
		if (ret > 0 && val == map->reg_defaults[ret].def)
			continue;

		map->cache_bypass = true;
		ret = _regmap_write(map, i, val);
		map->cache_bypass = false;
		if (ret)
			return ret;
		dev_dbg(map->dev, "Synced register %#x, value %#x\n",
			i, val);
	}

	return 0;
}

struct regcache_ops regcache_lzo_ops = {
	.type = REGCACHE_COMPRESSED,
	.name = "lzo",
	.init = regcache_lzo_init,
	.exit = regcache_lzo_exit,
	.read = regcache_lzo_read,
	.write = regcache_lzo_write,
	.sync = regcache_lzo_sync
};