summaryrefslogtreecommitdiffstats
path: root/drivers/crypto/stm32/stm32_crc32.c
blob: 090582baecfe87ee0486b32a9e992281020e4dcf (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
/*
 * Copyright (C) STMicroelectronics SA 2017
 * Author: Fabien Dessenne <fabien.dessenne@st.com>
 * License terms:  GNU General Public License (GPL), version 2
 */

#include <linux/bitrev.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <crypto/internal/hash.h>

#include <asm/unaligned.h>

#define DRIVER_NAME             "stm32-crc32"
#define CHKSUM_DIGEST_SIZE      4
#define CHKSUM_BLOCK_SIZE       1

/* Registers */
#define CRC_DR                  0x00000000
#define CRC_CR                  0x00000008
#define CRC_INIT                0x00000010
#define CRC_POL                 0x00000014

/* Registers values */
#define CRC_CR_RESET            BIT(0)
#define CRC_CR_REVERSE          (BIT(7) | BIT(6) | BIT(5))
#define CRC_INIT_DEFAULT        0xFFFFFFFF

/* Polynomial reversed */
#define POLY_CRC32              0xEDB88320
#define POLY_CRC32C             0x82F63B78

struct stm32_crc {
	struct list_head list;
	struct device    *dev;
	void __iomem     *regs;
	struct clk       *clk;
	u8               pending_data[sizeof(u32)];
	size_t           nb_pending_bytes;
};

struct stm32_crc_list {
	struct list_head dev_list;
	spinlock_t       lock; /* protect dev_list */
};

static struct stm32_crc_list crc_list = {
	.dev_list = LIST_HEAD_INIT(crc_list.dev_list),
	.lock     = __SPIN_LOCK_UNLOCKED(crc_list.lock),
};

struct stm32_crc_ctx {
	u32 key;
	u32 poly;
};

struct stm32_crc_desc_ctx {
	u32    partial; /* crc32c: partial in first 4 bytes of that struct */
	struct stm32_crc *crc;
};

static int stm32_crc32_cra_init(struct crypto_tfm *tfm)
{
	struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm);

	mctx->key = CRC_INIT_DEFAULT;
	mctx->poly = POLY_CRC32;
	return 0;
}

static int stm32_crc32c_cra_init(struct crypto_tfm *tfm)
{
	struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm);

	mctx->key = CRC_INIT_DEFAULT;
	mctx->poly = POLY_CRC32C;
	return 0;
}

static int stm32_crc_setkey(struct crypto_shash *tfm, const u8 *key,
			    unsigned int keylen)
{
	struct stm32_crc_ctx *mctx = crypto_shash_ctx(tfm);

	if (keylen != sizeof(u32)) {
		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
		return -EINVAL;
	}

	mctx->key = get_unaligned_le32(key);
	return 0;
}

static int stm32_crc_init(struct shash_desc *desc)
{
	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
	struct stm32_crc *crc;

	spin_lock_bh(&crc_list.lock);
	list_for_each_entry(crc, &crc_list.dev_list, list) {
		ctx->crc = crc;
		break;
	}
	spin_unlock_bh(&crc_list.lock);

	/* Reset, set key, poly and configure in bit reverse mode */
	writel_relaxed(bitrev32(mctx->key), ctx->crc->regs + CRC_INIT);
	writel_relaxed(bitrev32(mctx->poly), ctx->crc->regs + CRC_POL);
	writel_relaxed(CRC_CR_RESET | CRC_CR_REVERSE, ctx->crc->regs + CRC_CR);

	/* Store partial result */
	ctx->partial = readl_relaxed(ctx->crc->regs + CRC_DR);
	ctx->crc->nb_pending_bytes = 0;

	return 0;
}

static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
			    unsigned int length)
{
	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
	struct stm32_crc *crc = ctx->crc;
	u32 *d32;
	unsigned int i;

	if (unlikely(crc->nb_pending_bytes)) {
		while (crc->nb_pending_bytes != sizeof(u32) && length) {
			/* Fill in pending data */
			crc->pending_data[crc->nb_pending_bytes++] = *(d8++);
			length--;
		}

		if (crc->nb_pending_bytes == sizeof(u32)) {
			/* Process completed pending data */
			writel_relaxed(*(u32 *)crc->pending_data,
				       crc->regs + CRC_DR);
			crc->nb_pending_bytes = 0;
		}
	}

	d32 = (u32 *)d8;
	for (i = 0; i < length >> 2; i++)
		/* Process 32 bits data */
		writel_relaxed(*(d32++), crc->regs + CRC_DR);

	/* Store partial result */
	ctx->partial = readl_relaxed(crc->regs + CRC_DR);

	/* Check for pending data (non 32 bits) */
	length &= 3;
	if (likely(!length))
		return 0;

	if ((crc->nb_pending_bytes + length) >= sizeof(u32)) {
		/* Shall not happen */
		dev_err(crc->dev, "Pending data overflow\n");
		return -EINVAL;
	}

	d8 = (const u8 *)d32;
	for (i = 0; i < length; i++)
		/* Store pending data */
		crc->pending_data[crc->nb_pending_bytes++] = *(d8++);

	return 0;
}

static int stm32_crc_final(struct shash_desc *desc, u8 *out)
{
	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);

	/* Send computed CRC */
	put_unaligned_le32(mctx->poly == POLY_CRC32C ?
			   ~ctx->partial : ctx->partial, out);

	return 0;
}

static int stm32_crc_finup(struct shash_desc *desc, const u8 *data,
			   unsigned int length, u8 *out)
{
	return stm32_crc_update(desc, data, length) ?:
	       stm32_crc_final(desc, out);
}

static int stm32_crc_digest(struct shash_desc *desc, const u8 *data,
			    unsigned int length, u8 *out)
{
	return stm32_crc_init(desc) ?: stm32_crc_finup(desc, data, length, out);
}

static struct shash_alg algs[] = {
	/* CRC-32 */
	{
		.setkey         = stm32_crc_setkey,
		.init           = stm32_crc_init,
		.update         = stm32_crc_update,
		.final          = stm32_crc_final,
		.finup          = stm32_crc_finup,
		.digest         = stm32_crc_digest,
		.descsize       = sizeof(struct stm32_crc_desc_ctx),
		.digestsize     = CHKSUM_DIGEST_SIZE,
		.base           = {
			.cra_name               = "crc32",
			.cra_driver_name        = DRIVER_NAME,
			.cra_priority           = 200,
			.cra_blocksize          = CHKSUM_BLOCK_SIZE,
			.cra_alignmask          = 3,
			.cra_ctxsize            = sizeof(struct stm32_crc_ctx),
			.cra_module             = THIS_MODULE,
			.cra_init               = stm32_crc32_cra_init,
		}
	},
	/* CRC-32Castagnoli */
	{
		.setkey         = stm32_crc_setkey,
		.init           = stm32_crc_init,
		.update         = stm32_crc_update,
		.final          = stm32_crc_final,
		.finup          = stm32_crc_finup,
		.digest         = stm32_crc_digest,
		.descsize       = sizeof(struct stm32_crc_desc_ctx),
		.digestsize     = CHKSUM_DIGEST_SIZE,
		.base           = {
			.cra_name               = "crc32c",
			.cra_driver_name        = DRIVER_NAME,
			.cra_priority           = 200,
			.cra_blocksize          = CHKSUM_BLOCK_SIZE,
			.cra_alignmask          = 3,
			.cra_ctxsize            = sizeof(struct stm32_crc_ctx),
			.cra_module             = THIS_MODULE,
			.cra_init               = stm32_crc32c_cra_init,
		}
	}
};

static int stm32_crc_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct stm32_crc *crc;
	struct resource *res;
	int ret;

	crc = devm_kzalloc(dev, sizeof(*crc), GFP_KERNEL);
	if (!crc)
		return -ENOMEM;

	crc->dev = dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	crc->regs = devm_ioremap_resource(dev, res);
	if (IS_ERR(crc->regs)) {
		dev_err(dev, "Cannot map CRC IO\n");
		return PTR_ERR(crc->regs);
	}

	crc->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(crc->clk)) {
		dev_err(dev, "Could not get clock\n");
		return PTR_ERR(crc->clk);
	}

	ret = clk_prepare_enable(crc->clk);
	if (ret) {
		dev_err(crc->dev, "Failed to enable clock\n");
		return ret;
	}

	platform_set_drvdata(pdev, crc);

	spin_lock(&crc_list.lock);
	list_add(&crc->list, &crc_list.dev_list);
	spin_unlock(&crc_list.lock);

	ret = crypto_register_shashes(algs, ARRAY_SIZE(algs));
	if (ret) {
		dev_err(dev, "Failed to register\n");
		clk_disable_unprepare(crc->clk);
		return ret;
	}

	dev_info(dev, "Initialized\n");

	return 0;
}

static int stm32_crc_remove(struct platform_device *pdev)
{
	struct stm32_crc *crc = platform_get_drvdata(pdev);

	spin_lock(&crc_list.lock);
	list_del(&crc->list);
	spin_unlock(&crc_list.lock);

	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));

	clk_disable_unprepare(crc->clk);

	return 0;
}

static const struct of_device_id stm32_dt_ids[] = {
	{ .compatible = "st,stm32f7-crc", },
	{},
};
MODULE_DEVICE_TABLE(of, stm32_dt_ids);

static struct platform_driver stm32_crc_driver = {
	.probe  = stm32_crc_probe,
	.remove = stm32_crc_remove,
	.driver = {
		.name           = DRIVER_NAME,
		.of_match_table = stm32_dt_ids,
	},
};

module_platform_driver(stm32_crc_driver);

MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
MODULE_DESCRIPTION("STMicrolectronics STM32 CRC32 hardware driver");
MODULE_LICENSE("GPL");