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Diffstat (limited to 'drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c')
-rw-r--r--drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c177
1 files changed, 177 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 0000000000..a923cfc655
--- /dev/null
+++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c
@@ -0,0 +1,177 @@
+// 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/arch/arm/sunxi.rst
+ */
+#include "sun8i-ss.h"
+#include <linux/dma-mapping.h>
+#include <linux/kernel.h>
+#include <linux/mm.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);
+ 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;
+ unsigned int todo_with_padding;
+ 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;
+
+ todo_with_padding = ALIGN(todo, dma_get_cache_alignment());
+ if (todo_with_padding < todo || todo < dlen)
+ return -EOVERFLOW;
+
+ d = kzalloc(todo_with_padding, GFP_KERNEL);
+ 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;
+}