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