1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * sun8i-ss-prng.c - hardware cryptographic offloader for
4 * Allwinner A80/A83T SoC
5 *
6 * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
7 *
8 * This file handle the PRNG found in the SS
9 *
10 * You could find a link for the datasheet in Documentation/arm/sunxi.rst
11 */
12 #include "sun8i-ss.h"
13 #include <linux/dma-mapping.h>
14 #include <linux/pm_runtime.h>
15 #include <crypto/internal/rng.h>
16
sun8i_ss_prng_seed(struct crypto_rng * tfm,const u8 * seed,unsigned int slen)17 int sun8i_ss_prng_seed(struct crypto_rng *tfm, const u8 *seed,
18 unsigned int slen)
19 {
20 struct sun8i_ss_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
21
22 if (ctx->seed && ctx->slen != slen) {
23 memzero_explicit(ctx->seed, ctx->slen);
24 kfree(ctx->seed);
25 ctx->slen = 0;
26 ctx->seed = NULL;
27 }
28 if (!ctx->seed)
29 ctx->seed = kmalloc(slen, GFP_KERNEL | GFP_DMA);
30 if (!ctx->seed)
31 return -ENOMEM;
32
33 memcpy(ctx->seed, seed, slen);
34 ctx->slen = slen;
35
36 return 0;
37 }
38
sun8i_ss_prng_init(struct crypto_tfm * tfm)39 int sun8i_ss_prng_init(struct crypto_tfm *tfm)
40 {
41 struct sun8i_ss_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
42
43 memset(ctx, 0, sizeof(struct sun8i_ss_rng_tfm_ctx));
44 return 0;
45 }
46
sun8i_ss_prng_exit(struct crypto_tfm * tfm)47 void sun8i_ss_prng_exit(struct crypto_tfm *tfm)
48 {
49 struct sun8i_ss_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
50
51 memzero_explicit(ctx->seed, ctx->slen);
52 kfree(ctx->seed);
53 ctx->seed = NULL;
54 ctx->slen = 0;
55 }
56
sun8i_ss_prng_generate(struct crypto_rng * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int dlen)57 int sun8i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
58 unsigned int slen, u8 *dst, unsigned int dlen)
59 {
60 struct sun8i_ss_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
61 struct rng_alg *alg = crypto_rng_alg(tfm);
62 struct sun8i_ss_alg_template *algt;
63 struct sun8i_ss_dev *ss;
64 dma_addr_t dma_iv, dma_dst;
65 unsigned int todo;
66 int err = 0;
67 int flow;
68 void *d;
69 u32 v;
70
71 algt = container_of(alg, struct sun8i_ss_alg_template, alg.rng);
72 ss = algt->ss;
73
74 if (ctx->slen == 0) {
75 dev_err(ss->dev, "The PRNG is not seeded\n");
76 return -EINVAL;
77 }
78
79 /* The SS does not give an updated seed, so we need to get a new one.
80 * So we will ask for an extra PRNG_SEED_SIZE data.
81 * We want dlen + seedsize rounded up to a multiple of PRNG_DATA_SIZE
82 */
83 todo = dlen + PRNG_SEED_SIZE + PRNG_DATA_SIZE;
84 todo -= todo % PRNG_DATA_SIZE;
85
86 d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
87 if (!d)
88 return -ENOMEM;
89
90 flow = sun8i_ss_get_engine_number(ss);
91
92 #ifdef CONFIG_CRYPTO_DEV_SUN8I_SS_DEBUG
93 algt->stat_req++;
94 algt->stat_bytes += todo;
95 #endif
96
97 v = SS_ALG_PRNG | SS_PRNG_CONTINUE | SS_START;
98 if (flow)
99 v |= SS_FLOW1;
100 else
101 v |= SS_FLOW0;
102
103 dma_iv = dma_map_single(ss->dev, ctx->seed, ctx->slen, DMA_TO_DEVICE);
104 if (dma_mapping_error(ss->dev, dma_iv)) {
105 dev_err(ss->dev, "Cannot DMA MAP IV\n");
106 err = -EFAULT;
107 goto err_free;
108 }
109
110 dma_dst = dma_map_single(ss->dev, d, todo, DMA_FROM_DEVICE);
111 if (dma_mapping_error(ss->dev, dma_dst)) {
112 dev_err(ss->dev, "Cannot DMA MAP DST\n");
113 err = -EFAULT;
114 goto err_iv;
115 }
116
117 err = pm_runtime_get_sync(ss->dev);
118 if (err < 0) {
119 pm_runtime_put_noidle(ss->dev);
120 goto err_pm;
121 }
122 err = 0;
123
124 mutex_lock(&ss->mlock);
125 writel(dma_iv, ss->base + SS_IV_ADR_REG);
126 /* the PRNG act badly (failing rngtest) without SS_KEY_ADR_REG set */
127 writel(dma_iv, ss->base + SS_KEY_ADR_REG);
128 writel(dma_dst, ss->base + SS_DST_ADR_REG);
129 writel(todo / 4, ss->base + SS_LEN_ADR_REG);
130
131 reinit_completion(&ss->flows[flow].complete);
132 ss->flows[flow].status = 0;
133 /* Be sure all data is written before enabling the task */
134 wmb();
135
136 writel(v, ss->base + SS_CTL_REG);
137
138 wait_for_completion_interruptible_timeout(&ss->flows[flow].complete,
139 msecs_to_jiffies(todo));
140 if (ss->flows[flow].status == 0) {
141 dev_err(ss->dev, "DMA timeout for PRNG (size=%u)\n", todo);
142 err = -EFAULT;
143 }
144 /* Since cipher and hash use the linux/cryptoengine and that we have
145 * a cryptoengine per flow, we are sure that they will issue only one
146 * request per flow.
147 * Since the cryptoengine wait for completion before submitting a new
148 * one, the mlock could be left just after the final writel.
149 * But cryptoengine cannot handle crypto_rng, so we need to be sure
150 * nothing will use our flow.
151 * The easiest way is to grab mlock until the hardware end our requests.
152 * We could have used a per flow lock, but this would increase
153 * complexity.
154 * The drawback is that no request could be handled for the other flow.
155 */
156 mutex_unlock(&ss->mlock);
157
158 pm_runtime_put(ss->dev);
159
160 err_pm:
161 dma_unmap_single(ss->dev, dma_dst, todo, DMA_FROM_DEVICE);
162 err_iv:
163 dma_unmap_single(ss->dev, dma_iv, ctx->slen, DMA_TO_DEVICE);
164
165 if (!err) {
166 memcpy(dst, d, dlen);
167 /* Update seed */
168 memcpy(ctx->seed, d + dlen, ctx->slen);
169 }
170 memzero_explicit(d, todo);
171 err_free:
172 kfree(d);
173
174 return err;
175 }
176