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e24f7c9e YK |
1 | /* |
2 | * caam - Freescale FSL CAAM support for hw_random | |
3 | * | |
4 | * Copyright 2011 Freescale Semiconductor, Inc. | |
5 | * | |
6 | * Based on caamalg.c crypto API driver. | |
7 | * | |
8 | * relationship between job descriptors to shared descriptors: | |
9 | * | |
10 | * --------------- -------------- | |
11 | * | JobDesc #0 |-------------------->| ShareDesc | | |
12 | * | *(buffer 0) | |------------->| (generate) | | |
13 | * --------------- | | (move) | | |
14 | * | | (store) | | |
15 | * --------------- | -------------- | |
16 | * | JobDesc #1 |------| | |
17 | * | *(buffer 1) | | |
18 | * --------------- | |
19 | * | |
20 | * A job desc looks like this: | |
21 | * | |
22 | * --------------------- | |
23 | * | Header | | |
24 | * | ShareDesc Pointer | | |
25 | * | SEQ_OUT_PTR | | |
26 | * | (output buffer) | | |
27 | * --------------------- | |
28 | * | |
29 | * The SharedDesc never changes, and each job descriptor points to one of two | |
30 | * buffers for each device, from which the data will be copied into the | |
31 | * requested destination | |
32 | */ | |
33 | ||
34 | #include <linux/hw_random.h> | |
35 | #include <linux/completion.h> | |
36 | #include <linux/atomic.h> | |
37 | ||
38 | #include "compat.h" | |
39 | ||
40 | #include "regs.h" | |
41 | #include "intern.h" | |
42 | #include "desc_constr.h" | |
43 | #include "jr.h" | |
44 | #include "error.h" | |
45 | ||
46 | /* | |
47 | * Maximum buffer size: maximum number of random, cache-aligned bytes that | |
48 | * will be generated and moved to seq out ptr (extlen not allowed) | |
49 | */ | |
50 | #define RN_BUF_SIZE (0xffff / L1_CACHE_BYTES * \ | |
51 | L1_CACHE_BYTES) | |
52 | ||
53 | /* length of descriptors */ | |
54 | #define DESC_JOB_O_LEN (CAAM_CMD_SZ * 2 + CAAM_PTR_SZ * 2) | |
4842234f | 55 | #define DESC_RNG_LEN (4 * CAAM_CMD_SZ) |
e24f7c9e YK |
56 | |
57 | /* Buffer, its dma address and lock */ | |
58 | struct buf_data { | |
412c98c1 | 59 | u8 buf[RN_BUF_SIZE] ____cacheline_aligned; |
e24f7c9e YK |
60 | dma_addr_t addr; |
61 | struct completion filled; | |
62 | u32 hw_desc[DESC_JOB_O_LEN]; | |
63 | #define BUF_NOT_EMPTY 0 | |
64 | #define BUF_EMPTY 1 | |
65 | #define BUF_PENDING 2 /* Empty, but with job pending --don't submit another */ | |
66 | atomic_t empty; | |
67 | }; | |
68 | ||
69 | /* rng per-device context */ | |
70 | struct caam_rng_ctx { | |
71 | struct device *jrdev; | |
72 | dma_addr_t sh_desc_dma; | |
73 | u32 sh_desc[DESC_RNG_LEN]; | |
74 | unsigned int cur_buf_idx; | |
75 | int current_buf; | |
76 | struct buf_data bufs[2]; | |
77 | }; | |
78 | ||
6e4e603a | 79 | static struct caam_rng_ctx *rng_ctx; |
e24f7c9e YK |
80 | |
81 | static inline void rng_unmap_buf(struct device *jrdev, struct buf_data *bd) | |
82 | { | |
83 | if (bd->addr) | |
84 | dma_unmap_single(jrdev, bd->addr, RN_BUF_SIZE, | |
85 | DMA_FROM_DEVICE); | |
86 | } | |
87 | ||
88 | static inline void rng_unmap_ctx(struct caam_rng_ctx *ctx) | |
89 | { | |
90 | struct device *jrdev = ctx->jrdev; | |
91 | ||
92 | if (ctx->sh_desc_dma) | |
4842234f YJ |
93 | dma_unmap_single(jrdev, ctx->sh_desc_dma, |
94 | desc_bytes(ctx->sh_desc), DMA_TO_DEVICE); | |
e24f7c9e YK |
95 | rng_unmap_buf(jrdev, &ctx->bufs[0]); |
96 | rng_unmap_buf(jrdev, &ctx->bufs[1]); | |
97 | } | |
98 | ||
99 | static void rng_done(struct device *jrdev, u32 *desc, u32 err, void *context) | |
100 | { | |
101 | struct buf_data *bd; | |
102 | ||
103 | bd = (struct buf_data *)((char *)desc - | |
104 | offsetof(struct buf_data, hw_desc)); | |
105 | ||
fa9659cd MV |
106 | if (err) |
107 | caam_jr_strstatus(jrdev, err); | |
e24f7c9e YK |
108 | |
109 | atomic_set(&bd->empty, BUF_NOT_EMPTY); | |
110 | complete(&bd->filled); | |
e7472422 VM |
111 | |
112 | /* Buffer refilled, invalidate cache */ | |
113 | dma_sync_single_for_cpu(jrdev, bd->addr, RN_BUF_SIZE, DMA_FROM_DEVICE); | |
114 | ||
e24f7c9e YK |
115 | #ifdef DEBUG |
116 | print_hex_dump(KERN_ERR, "rng refreshed buf@: ", | |
117 | DUMP_PREFIX_ADDRESS, 16, 4, bd->buf, RN_BUF_SIZE, 1); | |
118 | #endif | |
119 | } | |
120 | ||
121 | static inline int submit_job(struct caam_rng_ctx *ctx, int to_current) | |
122 | { | |
123 | struct buf_data *bd = &ctx->bufs[!(to_current ^ ctx->current_buf)]; | |
124 | struct device *jrdev = ctx->jrdev; | |
125 | u32 *desc = bd->hw_desc; | |
126 | int err; | |
127 | ||
128 | dev_dbg(jrdev, "submitting job %d\n", !(to_current ^ ctx->current_buf)); | |
129 | init_completion(&bd->filled); | |
130 | err = caam_jr_enqueue(jrdev, desc, rng_done, ctx); | |
131 | if (err) | |
132 | complete(&bd->filled); /* don't wait on failed job*/ | |
133 | else | |
134 | atomic_inc(&bd->empty); /* note if pending */ | |
135 | ||
136 | return err; | |
137 | } | |
138 | ||
139 | static int caam_read(struct hwrng *rng, void *data, size_t max, bool wait) | |
140 | { | |
6e4e603a | 141 | struct caam_rng_ctx *ctx = rng_ctx; |
e24f7c9e YK |
142 | struct buf_data *bd = &ctx->bufs[ctx->current_buf]; |
143 | int next_buf_idx, copied_idx; | |
144 | int err; | |
145 | ||
146 | if (atomic_read(&bd->empty)) { | |
147 | /* try to submit job if there wasn't one */ | |
148 | if (atomic_read(&bd->empty) == BUF_EMPTY) { | |
149 | err = submit_job(ctx, 1); | |
150 | /* if can't submit job, can't even wait */ | |
151 | if (err) | |
152 | return 0; | |
153 | } | |
154 | /* no immediate data, so exit if not waiting */ | |
155 | if (!wait) | |
156 | return 0; | |
157 | ||
158 | /* waiting for pending job */ | |
159 | if (atomic_read(&bd->empty)) | |
160 | wait_for_completion(&bd->filled); | |
161 | } | |
162 | ||
163 | next_buf_idx = ctx->cur_buf_idx + max; | |
164 | dev_dbg(ctx->jrdev, "%s: start reading at buffer %d, idx %d\n", | |
165 | __func__, ctx->current_buf, ctx->cur_buf_idx); | |
166 | ||
167 | /* if enough data in current buffer */ | |
168 | if (next_buf_idx < RN_BUF_SIZE) { | |
169 | memcpy(data, bd->buf + ctx->cur_buf_idx, max); | |
170 | ctx->cur_buf_idx = next_buf_idx; | |
171 | return max; | |
172 | } | |
173 | ||
174 | /* else, copy what's left... */ | |
175 | copied_idx = RN_BUF_SIZE - ctx->cur_buf_idx; | |
176 | memcpy(data, bd->buf + ctx->cur_buf_idx, copied_idx); | |
177 | ctx->cur_buf_idx = 0; | |
178 | atomic_set(&bd->empty, BUF_EMPTY); | |
179 | ||
180 | /* ...refill... */ | |
181 | submit_job(ctx, 1); | |
182 | ||
183 | /* and use next buffer */ | |
184 | ctx->current_buf = !ctx->current_buf; | |
185 | dev_dbg(ctx->jrdev, "switched to buffer %d\n", ctx->current_buf); | |
186 | ||
187 | /* since there already is some data read, don't wait */ | |
188 | return copied_idx + caam_read(rng, data + copied_idx, | |
189 | max - copied_idx, false); | |
190 | } | |
191 | ||
ce572085 | 192 | static inline int rng_create_sh_desc(struct caam_rng_ctx *ctx) |
e24f7c9e YK |
193 | { |
194 | struct device *jrdev = ctx->jrdev; | |
195 | u32 *desc = ctx->sh_desc; | |
196 | ||
61bb86bb | 197 | init_sh_desc(desc, HDR_SHARE_SERIAL); |
e24f7c9e YK |
198 | |
199 | /* Propagate errors from shared to job descriptor */ | |
200 | append_cmd(desc, SET_OK_NO_PROP_ERRORS | CMD_LOAD); | |
201 | ||
202 | /* Generate random bytes */ | |
203 | append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG); | |
204 | ||
205 | /* Store bytes */ | |
206 | append_seq_fifo_store(desc, RN_BUF_SIZE, FIFOST_TYPE_RNGSTORE); | |
207 | ||
208 | ctx->sh_desc_dma = dma_map_single(jrdev, desc, desc_bytes(desc), | |
209 | DMA_TO_DEVICE); | |
ce572085 HG |
210 | if (dma_mapping_error(jrdev, ctx->sh_desc_dma)) { |
211 | dev_err(jrdev, "unable to map shared descriptor\n"); | |
212 | return -ENOMEM; | |
213 | } | |
e24f7c9e YK |
214 | #ifdef DEBUG |
215 | print_hex_dump(KERN_ERR, "rng shdesc@: ", DUMP_PREFIX_ADDRESS, 16, 4, | |
216 | desc, desc_bytes(desc), 1); | |
217 | #endif | |
ce572085 | 218 | return 0; |
e24f7c9e YK |
219 | } |
220 | ||
ce572085 | 221 | static inline int rng_create_job_desc(struct caam_rng_ctx *ctx, int buf_id) |
e24f7c9e YK |
222 | { |
223 | struct device *jrdev = ctx->jrdev; | |
224 | struct buf_data *bd = &ctx->bufs[buf_id]; | |
225 | u32 *desc = bd->hw_desc; | |
226 | int sh_len = desc_len(ctx->sh_desc); | |
227 | ||
228 | init_job_desc_shared(desc, ctx->sh_desc_dma, sh_len, HDR_SHARE_DEFER | | |
229 | HDR_REVERSE); | |
230 | ||
231 | bd->addr = dma_map_single(jrdev, bd->buf, RN_BUF_SIZE, DMA_FROM_DEVICE); | |
ce572085 HG |
232 | if (dma_mapping_error(jrdev, bd->addr)) { |
233 | dev_err(jrdev, "unable to map dst\n"); | |
234 | return -ENOMEM; | |
235 | } | |
e24f7c9e YK |
236 | |
237 | append_seq_out_ptr_intlen(desc, bd->addr, RN_BUF_SIZE, 0); | |
238 | #ifdef DEBUG | |
239 | print_hex_dump(KERN_ERR, "rng job desc@: ", DUMP_PREFIX_ADDRESS, 16, 4, | |
240 | desc, desc_bytes(desc), 1); | |
241 | #endif | |
ce572085 | 242 | return 0; |
e24f7c9e YK |
243 | } |
244 | ||
245 | static void caam_cleanup(struct hwrng *rng) | |
246 | { | |
247 | int i; | |
248 | struct buf_data *bd; | |
249 | ||
250 | for (i = 0; i < 2; i++) { | |
6e4e603a | 251 | bd = &rng_ctx->bufs[i]; |
e24f7c9e YK |
252 | if (atomic_read(&bd->empty) == BUF_PENDING) |
253 | wait_for_completion(&bd->filled); | |
254 | } | |
255 | ||
6e4e603a | 256 | rng_unmap_ctx(rng_ctx); |
e24f7c9e YK |
257 | } |
258 | ||
ce572085 | 259 | static int caam_init_buf(struct caam_rng_ctx *ctx, int buf_id) |
e24f7c9e YK |
260 | { |
261 | struct buf_data *bd = &ctx->bufs[buf_id]; | |
ce572085 HG |
262 | int err; |
263 | ||
264 | err = rng_create_job_desc(ctx, buf_id); | |
265 | if (err) | |
266 | return err; | |
e24f7c9e | 267 | |
e24f7c9e YK |
268 | atomic_set(&bd->empty, BUF_EMPTY); |
269 | submit_job(ctx, buf_id == ctx->current_buf); | |
270 | wait_for_completion(&bd->filled); | |
ce572085 HG |
271 | |
272 | return 0; | |
e24f7c9e YK |
273 | } |
274 | ||
ce572085 | 275 | static int caam_init_rng(struct caam_rng_ctx *ctx, struct device *jrdev) |
e24f7c9e | 276 | { |
ce572085 HG |
277 | int err; |
278 | ||
e24f7c9e | 279 | ctx->jrdev = jrdev; |
ce572085 HG |
280 | |
281 | err = rng_create_sh_desc(ctx); | |
282 | if (err) | |
283 | return err; | |
284 | ||
e24f7c9e YK |
285 | ctx->current_buf = 0; |
286 | ctx->cur_buf_idx = 0; | |
ce572085 HG |
287 | |
288 | err = caam_init_buf(ctx, 0); | |
289 | if (err) | |
290 | return err; | |
291 | ||
292 | err = caam_init_buf(ctx, 1); | |
293 | if (err) | |
294 | return err; | |
295 | ||
296 | return 0; | |
e24f7c9e YK |
297 | } |
298 | ||
299 | static struct hwrng caam_rng = { | |
300 | .name = "rng-caam", | |
301 | .cleanup = caam_cleanup, | |
302 | .read = caam_read, | |
303 | }; | |
304 | ||
305 | static void __exit caam_rng_exit(void) | |
306 | { | |
6e4e603a | 307 | caam_jr_free(rng_ctx->jrdev); |
e24f7c9e | 308 | hwrng_unregister(&caam_rng); |
6e4e603a | 309 | kfree(rng_ctx); |
e24f7c9e YK |
310 | } |
311 | ||
312 | static int __init caam_rng_init(void) | |
313 | { | |
cfc6f11b | 314 | struct device *dev; |
35af6403 RG |
315 | struct device_node *dev_node; |
316 | struct platform_device *pdev; | |
317 | struct device *ctrldev; | |
bf83490e | 318 | struct caam_drv_private *priv; |
ce572085 | 319 | int err; |
35af6403 RG |
320 | |
321 | dev_node = of_find_compatible_node(NULL, NULL, "fsl,sec-v4.0"); | |
322 | if (!dev_node) { | |
323 | dev_node = of_find_compatible_node(NULL, NULL, "fsl,sec4.0"); | |
324 | if (!dev_node) | |
325 | return -ENODEV; | |
326 | } | |
327 | ||
328 | pdev = of_find_device_by_node(dev_node); | |
329 | if (!pdev) { | |
330 | of_node_put(dev_node); | |
331 | return -ENODEV; | |
332 | } | |
333 | ||
334 | ctrldev = &pdev->dev; | |
335 | priv = dev_get_drvdata(ctrldev); | |
336 | of_node_put(dev_node); | |
337 | ||
338 | /* | |
339 | * If priv is NULL, it's probably because the caam driver wasn't | |
340 | * properly initialized (e.g. RNG4 init failed). Thus, bail out here. | |
341 | */ | |
342 | if (!priv) | |
343 | return -ENODEV; | |
e24f7c9e | 344 | |
bf83490e VM |
345 | /* Check for an instantiated RNG before registration */ |
346 | if (!(rd_reg32(&priv->ctrl->perfmon.cha_num_ls) & CHA_ID_LS_RNG_MASK)) | |
347 | return -ENODEV; | |
348 | ||
cfc6f11b RG |
349 | dev = caam_jr_alloc(); |
350 | if (IS_ERR(dev)) { | |
351 | pr_err("Job Ring Device allocation for transform failed\n"); | |
352 | return PTR_ERR(dev); | |
353 | } | |
9c4f9733 | 354 | rng_ctx = kmalloc(sizeof(*rng_ctx), GFP_DMA); |
ac8ad307 FE |
355 | if (!rng_ctx) { |
356 | err = -ENOMEM; | |
357 | goto free_caam_alloc; | |
358 | } | |
ce572085 HG |
359 | err = caam_init_rng(rng_ctx, dev); |
360 | if (err) | |
ac8ad307 | 361 | goto free_rng_ctx; |
e24f7c9e | 362 | |
cfc6f11b | 363 | dev_info(dev, "registering rng-caam\n"); |
e24f7c9e | 364 | return hwrng_register(&caam_rng); |
ac8ad307 FE |
365 | |
366 | free_rng_ctx: | |
367 | kfree(rng_ctx); | |
368 | free_caam_alloc: | |
369 | caam_jr_free(dev); | |
370 | return err; | |
e24f7c9e YK |
371 | } |
372 | ||
373 | module_init(caam_rng_init); | |
374 | module_exit(caam_rng_exit); | |
375 | ||
376 | MODULE_LICENSE("GPL"); | |
377 | MODULE_DESCRIPTION("FSL CAAM support for hw_random API"); | |
378 | MODULE_AUTHOR("Freescale Semiconductor - NMG"); |