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