1 // SPDX-License-Identifier: GPL-2.0
3 * sun8i-ss-prng.c - hardware cryptographic offloader for
4 * Allwinner A80/A83T SoC
6 * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
8 * This file handle the PRNG found in the SS
10 * You could find a link for the datasheet in Documentation/arm/sunxi.rst
13 #include <linux/dma-mapping.h>
14 #include <linux/pm_runtime.h>
15 #include <crypto/internal/rng.h>
17 int sun8i_ss_prng_seed(struct crypto_rng *tfm, const u8 *seed,
20 struct sun8i_ss_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
22 if (ctx->seed && ctx->slen != slen) {
23 memzero_explicit(ctx->seed, ctx->slen);
29 ctx->seed = kmalloc(slen, GFP_KERNEL | GFP_DMA);
33 memcpy(ctx->seed, seed, slen);
39 int sun8i_ss_prng_init(struct crypto_tfm *tfm)
41 struct sun8i_ss_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
43 memset(ctx, 0, sizeof(struct sun8i_ss_rng_tfm_ctx));
47 void sun8i_ss_prng_exit(struct crypto_tfm *tfm)
49 struct sun8i_ss_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
51 memzero_explicit(ctx->seed, ctx->slen);
57 int sun8i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
58 unsigned int slen, u8 *dst, unsigned int dlen)
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;
71 algt = container_of(alg, struct sun8i_ss_alg_template, alg.rng);
75 dev_err(ss->dev, "The PRNG is not seeded\n");
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
83 todo = dlen + PRNG_SEED_SIZE + PRNG_DATA_SIZE;
84 todo -= todo % PRNG_DATA_SIZE;
86 d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
90 flow = sun8i_ss_get_engine_number(ss);
92 #ifdef CONFIG_CRYPTO_DEV_SUN8I_SS_DEBUG
94 algt->stat_bytes += todo;
97 v = SS_ALG_PRNG | SS_PRNG_CONTINUE | SS_START;
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");
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");
117 err = pm_runtime_get_sync(ss->dev);
119 pm_runtime_put_noidle(ss->dev);
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);
131 reinit_completion(&ss->flows[flow].complete);
132 ss->flows[flow].status = 0;
133 /* Be sure all data is written before enabling the task */
136 writel(v, ss->base + SS_CTL_REG);
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);
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
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
154 * The drawback is that no request could be handled for the other flow.
156 mutex_unlock(&ss->mlock);
158 pm_runtime_put(ss->dev);
161 dma_unmap_single(ss->dev, dma_dst, todo, DMA_FROM_DEVICE);
163 dma_unmap_single(ss->dev, dma_iv, ctx->slen, DMA_TO_DEVICE);
166 memcpy(dst, d, dlen);
168 memcpy(ctx->seed, d + dlen, ctx->slen);
170 memzero_explicit(d, todo);