diff options
Diffstat (limited to 'drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c')
| -rw-r--r-- | drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c new file mode 100644 index 000000000..dd677e9ed --- /dev/null +++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * sun8i-ss-prng.c - hardware cryptographic offloader for + * Allwinner A80/A83T SoC + * + * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com> + * + * This file handle the PRNG found in the SS + * + * You could find a link for the datasheet in Documentation/arm/sunxi.rst + */ +#include "sun8i-ss.h" +#include <linux/dma-mapping.h> +#include <linux/pm_runtime.h> +#include <crypto/internal/rng.h> + +int sun8i_ss_prng_seed(struct crypto_rng *tfm, const u8 *seed, + unsigned int slen) +{ + struct sun8i_ss_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm); + + if (ctx->seed && ctx->slen != slen) { + kfree_sensitive(ctx->seed); + ctx->slen = 0; + ctx->seed = NULL; + } + if (!ctx->seed) + ctx->seed = kmalloc(slen, GFP_KERNEL | GFP_DMA); + if (!ctx->seed) + return -ENOMEM; + + memcpy(ctx->seed, seed, slen); + ctx->slen = slen; + + return 0; +} + +int sun8i_ss_prng_init(struct crypto_tfm *tfm) +{ + struct sun8i_ss_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm); + + memset(ctx, 0, sizeof(struct sun8i_ss_rng_tfm_ctx)); + return 0; +} + +void sun8i_ss_prng_exit(struct crypto_tfm *tfm) +{ + struct sun8i_ss_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm); + + kfree_sensitive(ctx->seed); + ctx->seed = NULL; + ctx->slen = 0; +} + +int sun8i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src, + unsigned int slen, u8 *dst, unsigned int dlen) +{ + struct sun8i_ss_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm); + struct rng_alg *alg = crypto_rng_alg(tfm); + struct sun8i_ss_alg_template *algt; + struct sun8i_ss_dev *ss; + dma_addr_t dma_iv, dma_dst; + unsigned int todo; + int err = 0; + int flow; + void *d; + u32 v; + + algt = container_of(alg, struct sun8i_ss_alg_template, alg.rng); + ss = algt->ss; + + if (ctx->slen == 0) { + dev_err(ss->dev, "The PRNG is not seeded\n"); + return -EINVAL; + } + + /* The SS does not give an updated seed, so we need to get a new one. + * So we will ask for an extra PRNG_SEED_SIZE data. + * We want dlen + seedsize rounded up to a multiple of PRNG_DATA_SIZE + */ + todo = dlen + PRNG_SEED_SIZE + PRNG_DATA_SIZE; + todo -= todo % PRNG_DATA_SIZE; + + d = kzalloc(todo, GFP_KERNEL | GFP_DMA); + if (!d) + return -ENOMEM; + + flow = sun8i_ss_get_engine_number(ss); + +#ifdef CONFIG_CRYPTO_DEV_SUN8I_SS_DEBUG + algt->stat_req++; + algt->stat_bytes += todo; +#endif + + v = SS_ALG_PRNG | SS_PRNG_CONTINUE | SS_START; + if (flow) + v |= SS_FLOW1; + else + v |= SS_FLOW0; + + dma_iv = dma_map_single(ss->dev, ctx->seed, ctx->slen, DMA_TO_DEVICE); + if (dma_mapping_error(ss->dev, dma_iv)) { + dev_err(ss->dev, "Cannot DMA MAP IV\n"); + err = -EFAULT; + goto err_free; + } + + dma_dst = dma_map_single(ss->dev, d, todo, DMA_FROM_DEVICE); + if (dma_mapping_error(ss->dev, dma_dst)) { + dev_err(ss->dev, "Cannot DMA MAP DST\n"); + err = -EFAULT; + goto err_iv; + } + + err = pm_runtime_resume_and_get(ss->dev); + if (err < 0) + goto err_pm; + err = 0; + + mutex_lock(&ss->mlock); + writel(dma_iv, ss->base + SS_IV_ADR_REG); + /* the PRNG act badly (failing rngtest) without SS_KEY_ADR_REG set */ + writel(dma_iv, ss->base + SS_KEY_ADR_REG); + writel(dma_dst, ss->base + SS_DST_ADR_REG); + writel(todo / 4, ss->base + SS_LEN_ADR_REG); + + reinit_completion(&ss->flows[flow].complete); + ss->flows[flow].status = 0; + /* Be sure all data is written before enabling the task */ + wmb(); + + writel(v, ss->base + SS_CTL_REG); + + wait_for_completion_interruptible_timeout(&ss->flows[flow].complete, + msecs_to_jiffies(todo)); + if (ss->flows[flow].status == 0) { + dev_err(ss->dev, "DMA timeout for PRNG (size=%u)\n", todo); + err = -EFAULT; + } + /* Since cipher and hash use the linux/cryptoengine and that we have + * a cryptoengine per flow, we are sure that they will issue only one + * request per flow. + * Since the cryptoengine wait for completion before submitting a new + * one, the mlock could be left just after the final writel. + * But cryptoengine cannot handle crypto_rng, so we need to be sure + * nothing will use our flow. + * The easiest way is to grab mlock until the hardware end our requests. + * We could have used a per flow lock, but this would increase + * complexity. + * The drawback is that no request could be handled for the other flow. + */ + mutex_unlock(&ss->mlock); + + pm_runtime_put(ss->dev); + +err_pm: + dma_unmap_single(ss->dev, dma_dst, todo, DMA_FROM_DEVICE); +err_iv: + dma_unmap_single(ss->dev, dma_iv, ctx->slen, DMA_TO_DEVICE); + + if (!err) { + memcpy(dst, d, dlen); + /* Update seed */ + memcpy(ctx->seed, d + dlen, ctx->slen); + } +err_free: + kfree_sensitive(d); + + return err; +} |