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b51dbe90 FD |
1 | /* |
2 | * Copyright (C) STMicroelectronics SA 2017 | |
3 | * Author: Fabien Dessenne <fabien.dessenne@st.com> | |
4 | * License terms: GNU General Public License (GPL), version 2 | |
5 | */ | |
6 | ||
7 | #include <linux/bitrev.h> | |
8 | #include <linux/clk.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/platform_device.h> | |
11 | ||
12 | #include <crypto/internal/hash.h> | |
13 | ||
14 | #include <asm/unaligned.h> | |
15 | ||
16 | #define DRIVER_NAME "stm32-crc32" | |
17 | #define CHKSUM_DIGEST_SIZE 4 | |
18 | #define CHKSUM_BLOCK_SIZE 1 | |
19 | ||
20 | /* Registers */ | |
21 | #define CRC_DR 0x00000000 | |
22 | #define CRC_CR 0x00000008 | |
23 | #define CRC_INIT 0x00000010 | |
24 | #define CRC_POL 0x00000014 | |
25 | ||
26 | /* Registers values */ | |
27 | #define CRC_CR_RESET BIT(0) | |
28 | #define CRC_CR_REVERSE (BIT(7) | BIT(6) | BIT(5)) | |
29 | #define CRC_INIT_DEFAULT 0xFFFFFFFF | |
30 | ||
31 | /* Polynomial reversed */ | |
32 | #define POLY_CRC32 0xEDB88320 | |
33 | #define POLY_CRC32C 0x82F63B78 | |
34 | ||
35 | struct stm32_crc { | |
36 | struct list_head list; | |
37 | struct device *dev; | |
38 | void __iomem *regs; | |
39 | struct clk *clk; | |
40 | u8 pending_data[sizeof(u32)]; | |
41 | size_t nb_pending_bytes; | |
42 | }; | |
43 | ||
44 | struct stm32_crc_list { | |
45 | struct list_head dev_list; | |
46 | spinlock_t lock; /* protect dev_list */ | |
47 | }; | |
48 | ||
49 | static struct stm32_crc_list crc_list = { | |
50 | .dev_list = LIST_HEAD_INIT(crc_list.dev_list), | |
51 | .lock = __SPIN_LOCK_UNLOCKED(crc_list.lock), | |
52 | }; | |
53 | ||
54 | struct stm32_crc_ctx { | |
55 | u32 key; | |
56 | u32 poly; | |
57 | }; | |
58 | ||
59 | struct stm32_crc_desc_ctx { | |
60 | u32 partial; /* crc32c: partial in first 4 bytes of that struct */ | |
61 | struct stm32_crc *crc; | |
62 | }; | |
63 | ||
64 | static int stm32_crc32_cra_init(struct crypto_tfm *tfm) | |
65 | { | |
66 | struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm); | |
67 | ||
68 | mctx->key = CRC_INIT_DEFAULT; | |
69 | mctx->poly = POLY_CRC32; | |
70 | return 0; | |
71 | } | |
72 | ||
73 | static int stm32_crc32c_cra_init(struct crypto_tfm *tfm) | |
74 | { | |
75 | struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm); | |
76 | ||
77 | mctx->key = CRC_INIT_DEFAULT; | |
78 | mctx->poly = POLY_CRC32C; | |
79 | return 0; | |
80 | } | |
81 | ||
82 | static int stm32_crc_setkey(struct crypto_shash *tfm, const u8 *key, | |
83 | unsigned int keylen) | |
84 | { | |
85 | struct stm32_crc_ctx *mctx = crypto_shash_ctx(tfm); | |
86 | ||
87 | if (keylen != sizeof(u32)) { | |
88 | crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
89 | return -EINVAL; | |
90 | } | |
91 | ||
92 | mctx->key = get_unaligned_le32(key); | |
93 | return 0; | |
94 | } | |
95 | ||
96 | static int stm32_crc_init(struct shash_desc *desc) | |
97 | { | |
98 | struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc); | |
99 | struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm); | |
100 | struct stm32_crc *crc; | |
101 | ||
102 | spin_lock_bh(&crc_list.lock); | |
103 | list_for_each_entry(crc, &crc_list.dev_list, list) { | |
104 | ctx->crc = crc; | |
105 | break; | |
106 | } | |
107 | spin_unlock_bh(&crc_list.lock); | |
108 | ||
109 | /* Reset, set key, poly and configure in bit reverse mode */ | |
110 | writel(bitrev32(mctx->key), ctx->crc->regs + CRC_INIT); | |
111 | writel(bitrev32(mctx->poly), ctx->crc->regs + CRC_POL); | |
112 | writel(CRC_CR_RESET | CRC_CR_REVERSE, ctx->crc->regs + CRC_CR); | |
113 | ||
114 | /* Store partial result */ | |
115 | ctx->partial = readl(ctx->crc->regs + CRC_DR); | |
116 | ctx->crc->nb_pending_bytes = 0; | |
117 | ||
118 | return 0; | |
119 | } | |
120 | ||
121 | static int stm32_crc_update(struct shash_desc *desc, const u8 *d8, | |
122 | unsigned int length) | |
123 | { | |
124 | struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc); | |
125 | struct stm32_crc *crc = ctx->crc; | |
126 | u32 *d32; | |
127 | unsigned int i; | |
128 | ||
129 | if (unlikely(crc->nb_pending_bytes)) { | |
130 | while (crc->nb_pending_bytes != sizeof(u32) && length) { | |
131 | /* Fill in pending data */ | |
132 | crc->pending_data[crc->nb_pending_bytes++] = *(d8++); | |
133 | length--; | |
134 | } | |
135 | ||
136 | if (crc->nb_pending_bytes == sizeof(u32)) { | |
137 | /* Process completed pending data */ | |
138 | writel(*(u32 *)crc->pending_data, crc->regs + CRC_DR); | |
139 | crc->nb_pending_bytes = 0; | |
140 | } | |
141 | } | |
142 | ||
143 | d32 = (u32 *)d8; | |
144 | for (i = 0; i < length >> 2; i++) | |
145 | /* Process 32 bits data */ | |
146 | writel(*(d32++), crc->regs + CRC_DR); | |
147 | ||
148 | /* Store partial result */ | |
149 | ctx->partial = readl(crc->regs + CRC_DR); | |
150 | ||
151 | /* Check for pending data (non 32 bits) */ | |
152 | length &= 3; | |
153 | if (likely(!length)) | |
154 | return 0; | |
155 | ||
156 | if ((crc->nb_pending_bytes + length) >= sizeof(u32)) { | |
157 | /* Shall not happen */ | |
158 | dev_err(crc->dev, "Pending data overflow\n"); | |
159 | return -EINVAL; | |
160 | } | |
161 | ||
162 | d8 = (const u8 *)d32; | |
163 | for (i = 0; i < length; i++) | |
164 | /* Store pending data */ | |
165 | crc->pending_data[crc->nb_pending_bytes++] = *(d8++); | |
166 | ||
167 | return 0; | |
168 | } | |
169 | ||
170 | static int stm32_crc_final(struct shash_desc *desc, u8 *out) | |
171 | { | |
172 | struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc); | |
173 | struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm); | |
174 | ||
175 | /* Send computed CRC */ | |
176 | put_unaligned_le32(mctx->poly == POLY_CRC32C ? | |
177 | ~ctx->partial : ctx->partial, out); | |
178 | ||
179 | return 0; | |
180 | } | |
181 | ||
182 | static int stm32_crc_finup(struct shash_desc *desc, const u8 *data, | |
183 | unsigned int length, u8 *out) | |
184 | { | |
185 | return stm32_crc_update(desc, data, length) ?: | |
186 | stm32_crc_final(desc, out); | |
187 | } | |
188 | ||
189 | static int stm32_crc_digest(struct shash_desc *desc, const u8 *data, | |
190 | unsigned int length, u8 *out) | |
191 | { | |
192 | return stm32_crc_init(desc) ?: stm32_crc_finup(desc, data, length, out); | |
193 | } | |
194 | ||
195 | static struct shash_alg algs[] = { | |
196 | /* CRC-32 */ | |
197 | { | |
198 | .setkey = stm32_crc_setkey, | |
199 | .init = stm32_crc_init, | |
200 | .update = stm32_crc_update, | |
201 | .final = stm32_crc_final, | |
202 | .finup = stm32_crc_finup, | |
203 | .digest = stm32_crc_digest, | |
204 | .descsize = sizeof(struct stm32_crc_desc_ctx), | |
205 | .digestsize = CHKSUM_DIGEST_SIZE, | |
206 | .base = { | |
207 | .cra_name = "crc32", | |
208 | .cra_driver_name = DRIVER_NAME, | |
209 | .cra_priority = 200, | |
210 | .cra_blocksize = CHKSUM_BLOCK_SIZE, | |
211 | .cra_alignmask = 3, | |
212 | .cra_ctxsize = sizeof(struct stm32_crc_ctx), | |
213 | .cra_module = THIS_MODULE, | |
214 | .cra_init = stm32_crc32_cra_init, | |
215 | } | |
216 | }, | |
217 | /* CRC-32Castagnoli */ | |
218 | { | |
219 | .setkey = stm32_crc_setkey, | |
220 | .init = stm32_crc_init, | |
221 | .update = stm32_crc_update, | |
222 | .final = stm32_crc_final, | |
223 | .finup = stm32_crc_finup, | |
224 | .digest = stm32_crc_digest, | |
225 | .descsize = sizeof(struct stm32_crc_desc_ctx), | |
226 | .digestsize = CHKSUM_DIGEST_SIZE, | |
227 | .base = { | |
228 | .cra_name = "crc32c", | |
229 | .cra_driver_name = DRIVER_NAME, | |
230 | .cra_priority = 200, | |
231 | .cra_blocksize = CHKSUM_BLOCK_SIZE, | |
232 | .cra_alignmask = 3, | |
233 | .cra_ctxsize = sizeof(struct stm32_crc_ctx), | |
234 | .cra_module = THIS_MODULE, | |
235 | .cra_init = stm32_crc32c_cra_init, | |
236 | } | |
237 | } | |
238 | }; | |
239 | ||
240 | static int stm32_crc_probe(struct platform_device *pdev) | |
241 | { | |
242 | struct device *dev = &pdev->dev; | |
243 | struct stm32_crc *crc; | |
244 | struct resource *res; | |
245 | int ret; | |
246 | ||
247 | crc = devm_kzalloc(dev, sizeof(*crc), GFP_KERNEL); | |
248 | if (!crc) | |
249 | return -ENOMEM; | |
250 | ||
251 | crc->dev = dev; | |
252 | ||
253 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
254 | crc->regs = devm_ioremap_resource(dev, res); | |
255 | if (IS_ERR(crc->regs)) { | |
256 | dev_err(dev, "Cannot map CRC IO\n"); | |
257 | return PTR_ERR(crc->regs); | |
258 | } | |
259 | ||
260 | crc->clk = devm_clk_get(dev, NULL); | |
261 | if (IS_ERR(crc->clk)) { | |
262 | dev_err(dev, "Could not get clock\n"); | |
263 | return PTR_ERR(crc->clk); | |
264 | } | |
265 | ||
266 | ret = clk_prepare_enable(crc->clk); | |
267 | if (ret) { | |
268 | dev_err(crc->dev, "Failed to enable clock\n"); | |
269 | return ret; | |
270 | } | |
271 | ||
272 | platform_set_drvdata(pdev, crc); | |
273 | ||
274 | spin_lock(&crc_list.lock); | |
275 | list_add(&crc->list, &crc_list.dev_list); | |
276 | spin_unlock(&crc_list.lock); | |
277 | ||
278 | ret = crypto_register_shashes(algs, ARRAY_SIZE(algs)); | |
279 | if (ret) { | |
280 | dev_err(dev, "Failed to register\n"); | |
281 | clk_disable_unprepare(crc->clk); | |
282 | return ret; | |
283 | } | |
284 | ||
285 | dev_info(dev, "Initialized\n"); | |
286 | ||
287 | return 0; | |
288 | } | |
289 | ||
290 | static int stm32_crc_remove(struct platform_device *pdev) | |
291 | { | |
292 | struct stm32_crc *crc = platform_get_drvdata(pdev); | |
293 | ||
294 | spin_lock(&crc_list.lock); | |
295 | list_del(&crc->list); | |
296 | spin_unlock(&crc_list.lock); | |
297 | ||
298 | crypto_unregister_shash(algs); | |
299 | ||
300 | clk_disable_unprepare(crc->clk); | |
301 | ||
302 | return 0; | |
303 | } | |
304 | ||
305 | static const struct of_device_id stm32_dt_ids[] = { | |
306 | { .compatible = "st,stm32f7-crc", }, | |
307 | {}, | |
308 | }; | |
929562b1 | 309 | MODULE_DEVICE_TABLE(of, stm32_dt_ids); |
b51dbe90 FD |
310 | |
311 | static struct platform_driver stm32_crc_driver = { | |
312 | .probe = stm32_crc_probe, | |
313 | .remove = stm32_crc_remove, | |
314 | .driver = { | |
315 | .name = DRIVER_NAME, | |
316 | .of_match_table = stm32_dt_ids, | |
317 | }, | |
318 | }; | |
319 | ||
320 | module_platform_driver(stm32_crc_driver); | |
321 | ||
322 | MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>"); | |
323 | MODULE_DESCRIPTION("STMicrolectronics STM32 CRC32 hardware driver"); | |
324 | MODULE_LICENSE("GPL"); |