sun8i-ce-prng.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * sun8i-ce-prng.c - hardware cryptographic offloader for
  4 * Allwinner H3/A64/H5/H2+/H6/R40 SoC
  5 *
  6 * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
  7 *
  8 * This file handle the PRNG
  9 *
 10 * You could find a link for the datasheet in Documentation/arch/arm/sunxi.rst
 11 */
 12#include "sun8i-ce.h"
 13#include <linux/dma-mapping.h>
 14#include <linux/pm_runtime.h>
 15#include <crypto/internal/rng.h>
 16
 17int sun8i_ce_prng_init(struct crypto_tfm *tfm)
 18{
 19	struct sun8i_ce_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
 20
 21	memset(ctx, 0, sizeof(struct sun8i_ce_rng_tfm_ctx));
 22	return 0;
 23}
 24
 25void sun8i_ce_prng_exit(struct crypto_tfm *tfm)
 26{
 27	struct sun8i_ce_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
 28
 29	kfree_sensitive(ctx->seed);
 30	ctx->seed = NULL;
 31	ctx->slen = 0;
 32}
 33
 34int sun8i_ce_prng_seed(struct crypto_rng *tfm, const u8 *seed,
 35		       unsigned int slen)
 36{
 37	struct sun8i_ce_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
 38
 39	if (ctx->seed && ctx->slen != slen) {
 40		kfree_sensitive(ctx->seed);
 41		ctx->slen = 0;
 42		ctx->seed = NULL;
 43	}
 44	if (!ctx->seed)
 45		ctx->seed = kmalloc(slen, GFP_KERNEL | GFP_DMA);
 46	if (!ctx->seed)
 47		return -ENOMEM;
 48
 49	memcpy(ctx->seed, seed, slen);
 50	ctx->slen = slen;
 51
 52	return 0;
 53}
 54
 55int sun8i_ce_prng_generate(struct crypto_rng *tfm, const u8 *src,
 56			   unsigned int slen, u8 *dst, unsigned int dlen)
 57{
 58	struct sun8i_ce_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
 59	struct rng_alg *alg = crypto_rng_alg(tfm);
 60	struct sun8i_ce_alg_template *algt;
 61	struct sun8i_ce_dev *ce;
 62	dma_addr_t dma_iv, dma_dst;
 63	int err = 0;
 64	int flow = 3;
 65	unsigned int todo;
 66	struct sun8i_ce_flow *chan;
 67	struct ce_task *cet;
 68	u32 common, sym;
 69	void *d;
 70
 71	algt = container_of(alg, struct sun8i_ce_alg_template, alg.rng);
 72	ce = algt->ce;
 73
 74	if (ctx->slen == 0) {
 75		dev_err(ce->dev, "not seeded\n");
 76		return -EINVAL;
 77	}
 78
 79	/* we want dlen + seedsize rounded up to a multiple of PRNG_DATA_SIZE */
 80	todo = dlen + ctx->slen + PRNG_DATA_SIZE * 2;
 81	todo -= todo % PRNG_DATA_SIZE;
 82
 83	d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
 84	if (!d) {
 85		err = -ENOMEM;
 86		goto err_mem;
 87	}
 88
 89	dev_dbg(ce->dev, "%s PRNG slen=%u dlen=%u todo=%u multi=%u\n", __func__,
 90		slen, dlen, todo, todo / PRNG_DATA_SIZE);
 91
 92#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
 93	algt->stat_req++;
 94	algt->stat_bytes += todo;
 95#endif
 96
 97	dma_iv = dma_map_single(ce->dev, ctx->seed, ctx->slen, DMA_TO_DEVICE);
 98	if (dma_mapping_error(ce->dev, dma_iv)) {
 99		dev_err(ce->dev, "Cannot DMA MAP IV\n");
100		err = -EFAULT;
101		goto err_iv;
102	}
103
104	dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
105	if (dma_mapping_error(ce->dev, dma_dst)) {
106		dev_err(ce->dev, "Cannot DMA MAP DST\n");
107		err = -EFAULT;
108		goto err_dst;
109	}
110
111	err = pm_runtime_resume_and_get(ce->dev);
112	if (err < 0)
113		goto err_pm;
114
115	mutex_lock(&ce->rnglock);
116	chan = &ce->chanlist[flow];
117
118	cet = &chan->tl[0];
119	memset(cet, 0, sizeof(struct ce_task));
120
121	cet->t_id = cpu_to_le32(flow);
122	common = ce->variant->prng | CE_COMM_INT;
123	cet->t_common_ctl = cpu_to_le32(common);
124
125	/* recent CE (H6) need length in bytes, in word otherwise */
126	if (ce->variant->prng_t_dlen_in_bytes)
127		cet->t_dlen = cpu_to_le32(todo);
128	else
129		cet->t_dlen = cpu_to_le32(todo / 4);
130
131	sym = PRNG_LD;
132	cet->t_sym_ctl = cpu_to_le32(sym);
133	cet->t_asym_ctl = 0;
134
135	cet->t_key = desc_addr_val_le32(ce, dma_iv);
136	cet->t_iv = desc_addr_val_le32(ce, dma_iv);
137
138	cet->t_dst[0].addr = desc_addr_val_le32(ce, dma_dst);
139	cet->t_dst[0].len = cpu_to_le32(todo / 4);
140
141	err = sun8i_ce_run_task(ce, 3, "PRNG");
142	mutex_unlock(&ce->rnglock);
143
144	pm_runtime_put(ce->dev);
145
146err_pm:
147	dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
148err_dst:
149	dma_unmap_single(ce->dev, dma_iv, ctx->slen, DMA_TO_DEVICE);
150
151	if (!err) {
152		memcpy(dst, d, dlen);
153		memcpy(ctx->seed, d + dlen, ctx->slen);
154	}
155err_iv:
156	kfree_sensitive(d);
157err_mem:
158	return err;
159}