aboutsummaryrefslogtreecommitdiff
path: root/drivers/crypto/caam/caamrng.c
blob: 77d048dfe5d061923a1e1422c00a525aa10c5908 (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
// SPDX-License-Identifier: GPL-2.0+
/*
 * caam - Freescale FSL CAAM support for hw_random
 *
 * Copyright 2011 Freescale Semiconductor, Inc.
 * Copyright 2018-2019 NXP
 *
 * Based on caamalg.c crypto API driver.
 *
 */

#include <linux/hw_random.h>
#include <linux/completion.h>
#include <linux/atomic.h>
#include <linux/kfifo.h>

#include "compat.h"

#include "regs.h"
#include "intern.h"
#include "desc_constr.h"
#include "jr.h"
#include "error.h"

#define CAAM_RNG_MAX_FIFO_STORE_SIZE	16

/*
 * Length of used descriptors, see caam_init_desc()
 */
#define CAAM_RNG_DESC_LEN (CAAM_CMD_SZ +				\
			   CAAM_CMD_SZ +				\
			   CAAM_CMD_SZ + CAAM_PTR_SZ_MAX)

/* rng per-device context */
struct caam_rng_ctx {
	struct hwrng rng;
	struct device *jrdev;
	struct device *ctrldev;
	void *desc_async;
	void *desc_sync;
	struct work_struct worker;
	struct kfifo fifo;
};

struct caam_rng_job_ctx {
	struct completion *done;
	int *err;
};

static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r)
{
	return (struct caam_rng_ctx *)r->priv;
}

static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err,
			  void *context)
{
	struct caam_rng_job_ctx *jctx = context;

	if (err)
		*jctx->err = caam_jr_strstatus(jrdev, err);

	complete(jctx->done);
}

static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma)
{
	init_job_desc(desc, 0);	/* + 1 cmd_sz */
	/* Generate random bytes: + 1 cmd_sz */
	append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG |
			 OP_ALG_PR_ON);
	/* Store bytes: + 1 cmd_sz + caam_ptr_sz  */
	append_fifo_store(desc, dst_dma,
			  CAAM_RNG_MAX_FIFO_STORE_SIZE, FIFOST_TYPE_RNGSTORE);

	print_hex_dump_debug("rng job desc@: ", DUMP_PREFIX_ADDRESS,
			     16, 4, desc, desc_bytes(desc), 1);

	return desc;
}

static int caam_rng_read_one(struct device *jrdev,
			     void *dst, int len,
			     void *desc,
			     struct completion *done)
{
	dma_addr_t dst_dma;
	int err, ret = 0;
	struct caam_rng_job_ctx jctx = {
		.done = done,
		.err  = &ret,
	};

	len = CAAM_RNG_MAX_FIFO_STORE_SIZE;

	dst_dma = dma_map_single(jrdev, dst, len, DMA_FROM_DEVICE);
	if (dma_mapping_error(jrdev, dst_dma)) {
		dev_err(jrdev, "unable to map destination memory\n");
		return -ENOMEM;
	}

	init_completion(done);
	err = caam_jr_enqueue(jrdev,
			      caam_init_desc(desc, dst_dma),
			      caam_rng_done, &jctx);
	if (err == -EINPROGRESS) {
		wait_for_completion(done);
		err = 0;
	}

	dma_unmap_single(jrdev, dst_dma, len, DMA_FROM_DEVICE);

	return err ?: (ret ?: len);
}

static void caam_rng_fill_async(struct caam_rng_ctx *ctx)
{
	struct scatterlist sg[1];
	struct completion done;
	int len, nents;

	sg_init_table(sg, ARRAY_SIZE(sg));
	nents = kfifo_dma_in_prepare(&ctx->fifo, sg, ARRAY_SIZE(sg),
				     CAAM_RNG_MAX_FIFO_STORE_SIZE);
	if (!nents)
		return;

	len = caam_rng_read_one(ctx->jrdev, sg_virt(&sg[0]),
				sg[0].length,
				ctx->desc_async,
				&done);
	if (len < 0)
		return;

	kfifo_dma_in_finish(&ctx->fifo, len);
}

static void caam_rng_worker(struct work_struct *work)
{
	struct caam_rng_ctx *ctx = container_of(work, struct caam_rng_ctx,
						worker);
	caam_rng_fill_async(ctx);
}

static int caam_read(struct hwrng *rng, void *dst, size_t max, bool wait)
{
	struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
	int out;

	if (wait) {
		struct completion done;

		return caam_rng_read_one(ctx->jrdev, dst, max,
					 ctx->desc_sync, &done);
	}

	out = kfifo_out(&ctx->fifo, dst, max);
	if (kfifo_is_empty(&ctx->fifo))
		schedule_work(&ctx->worker);

	return out;
}

static void caam_cleanup(struct hwrng *rng)
{
	struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);

	flush_work(&ctx->worker);
	caam_jr_free(ctx->jrdev);
	kfifo_free(&ctx->fifo);
}

static int caam_init(struct hwrng *rng)
{
	struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
	int err;

	ctx->desc_sync = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN,
				      GFP_DMA | GFP_KERNEL);
	if (!ctx->desc_sync)
		return -ENOMEM;

	ctx->desc_async = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN,
				       GFP_DMA | GFP_KERNEL);
	if (!ctx->desc_async)
		return -ENOMEM;

	if (kfifo_alloc(&ctx->fifo, CAAM_RNG_MAX_FIFO_STORE_SIZE,
			GFP_DMA | GFP_KERNEL))
		return -ENOMEM;

	INIT_WORK(&ctx->worker, caam_rng_worker);

	ctx->jrdev = caam_jr_alloc();
	err = PTR_ERR_OR_ZERO(ctx->jrdev);
	if (err) {
		kfifo_free(&ctx->fifo);
		pr_err("Job Ring Device allocation for transform failed\n");
		return err;
	}

	/*
	 * Fill async buffer to have early randomness data for
	 * hw_random
	 */
	caam_rng_fill_async(ctx);

	return 0;
}

int caam_rng_init(struct device *ctrldev);

void caam_rng_exit(struct device *ctrldev)
{
	devres_release_group(ctrldev, caam_rng_init);
}

int caam_rng_init(struct device *ctrldev)
{
	struct caam_rng_ctx *ctx;
	u32 rng_inst;
	struct caam_drv_private *priv = dev_get_drvdata(ctrldev);
	int ret;

	/* Check for an instantiated RNG before registration */
	if (priv->era < 10)
		rng_inst = (rd_reg32(&priv->ctrl->perfmon.cha_num_ls) &
			    CHA_ID_LS_RNG_MASK) >> CHA_ID_LS_RNG_SHIFT;
	else
		rng_inst = rd_reg32(&priv->ctrl->vreg.rng) & CHA_VER_NUM_MASK;

	if (!rng_inst)
		return 0;

	if (!devres_open_group(ctrldev, caam_rng_init, GFP_KERNEL))
		return -ENOMEM;

	ctx = devm_kzalloc(ctrldev, sizeof(*ctx), GFP_KERNEL);
	if (!ctx)
		return -ENOMEM;

	ctx->ctrldev = ctrldev;

	ctx->rng.name    = "rng-caam";
	ctx->rng.init    = caam_init;
	ctx->rng.cleanup = caam_cleanup;
	ctx->rng.read    = caam_read;
	ctx->rng.priv    = (unsigned long)ctx;
	ctx->rng.quality = 1024;

	dev_info(ctrldev, "registering rng-caam\n");

	ret = devm_hwrng_register(ctrldev, &ctx->rng);
	if (ret) {
		caam_rng_exit(ctrldev);
		return ret;
	}

	devres_close_group(ctrldev, caam_rng_init);
	return 0;
}