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/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	memzero_explicit(ctx->seed, ctx->slen);
30	kfree(ctx->seed);
31	ctx->seed = NULL;
32	ctx->slen = 0;
33}
34
35int sun8i_ce_prng_seed(struct crypto_rng *tfm, const u8 *seed,
36		       unsigned int slen)
37{
38	struct sun8i_ce_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
39
40	if (ctx->seed && ctx->slen != slen) {
41		memzero_explicit(ctx->seed, ctx->slen);
42		kfree(ctx->seed);
43		ctx->slen = 0;
44		ctx->seed = NULL;
45	}
46	if (!ctx->seed)
47		ctx->seed = kmalloc(slen, GFP_KERNEL | GFP_DMA);
48	if (!ctx->seed)
49		return -ENOMEM;
50
51	memcpy(ctx->seed, seed, slen);
52	ctx->slen = slen;
53
54	return 0;
55}
56
57int sun8i_ce_prng_generate(struct crypto_rng *tfm, const u8 *src,
58			   unsigned int slen, u8 *dst, unsigned int dlen)
59{
60	struct sun8i_ce_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
61	struct rng_alg *alg = crypto_rng_alg(tfm);
62	struct sun8i_ce_alg_template *algt;
63	struct sun8i_ce_dev *ce;
64	dma_addr_t dma_iv, dma_dst;
65	int err = 0;
66	int flow = 3;
67	unsigned int todo;
68	struct sun8i_ce_flow *chan;
69	struct ce_task *cet;
70	u32 common, sym;
71	void *d;
72
73	algt = container_of(alg, struct sun8i_ce_alg_template, alg.rng);
74	ce = algt->ce;
75
76	if (ctx->slen == 0) {
77		dev_err(ce->dev, "not seeded\n");
78		return -EINVAL;
79	}
80
81	/* we want dlen + seedsize rounded up to a multiple of PRNG_DATA_SIZE */
82	todo = dlen + ctx->slen + PRNG_DATA_SIZE * 2;
83	todo -= todo % PRNG_DATA_SIZE;
84
85	d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
86	if (!d) {
87		err = -ENOMEM;
88		goto err_mem;
89	}
90
91	dev_dbg(ce->dev, "%s PRNG slen=%u dlen=%u todo=%u multi=%u\n", __func__,
92		slen, dlen, todo, todo / PRNG_DATA_SIZE);
93
94#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
95	algt->stat_req++;
96	algt->stat_bytes += todo;
97#endif
98
99	dma_iv = dma_map_single(ce->dev, ctx->seed, ctx->slen, DMA_TO_DEVICE);
100	if (dma_mapping_error(ce->dev, dma_iv)) {
101		dev_err(ce->dev, "Cannot DMA MAP IV\n");
102		err = -EFAULT;
103		goto err_iv;
104	}
105
106	dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
107	if (dma_mapping_error(ce->dev, dma_dst)) {
108		dev_err(ce->dev, "Cannot DMA MAP DST\n");
109		err = -EFAULT;
110		goto err_dst;
111	}
112
113	err = pm_runtime_get_sync(ce->dev);
114	if (err < 0) {
115		pm_runtime_put_noidle(ce->dev);
116		goto err_pm;
117	}
118
119	mutex_lock(&ce->rnglock);
120	chan = &ce->chanlist[flow];
121
122	cet = &chan->tl[0];
123	memset(cet, 0, sizeof(struct ce_task));
124
125	cet->t_id = cpu_to_le32(flow);
126	common = ce->variant->prng | CE_COMM_INT;
127	cet->t_common_ctl = cpu_to_le32(common);
128
129	/* recent CE (H6) need length in bytes, in word otherwise */
130	if (ce->variant->prng_t_dlen_in_bytes)
131		cet->t_dlen = cpu_to_le32(todo);
132	else
133		cet->t_dlen = cpu_to_le32(todo / 4);
134
135	sym = PRNG_LD;
136	cet->t_sym_ctl = cpu_to_le32(sym);
137	cet->t_asym_ctl = 0;
138
139	cet->t_key = cpu_to_le32(dma_iv);
140	cet->t_iv = cpu_to_le32(dma_iv);
141
142	cet->t_dst[0].addr = cpu_to_le32(dma_dst);
143	cet->t_dst[0].len = cpu_to_le32(todo / 4);
144	ce->chanlist[flow].timeout = 2000;
145
146	err = sun8i_ce_run_task(ce, 3, "PRNG");
147	mutex_unlock(&ce->rnglock);
148
149	pm_runtime_put(ce->dev);
150
151err_pm:
152	dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
153err_dst:
154	dma_unmap_single(ce->dev, dma_iv, ctx->slen, DMA_TO_DEVICE);
155
156	if (!err) {
157		memcpy(dst, d, dlen);
158		memcpy(ctx->seed, d + dlen, ctx->slen);
159	}
160	memzero_explicit(d, todo);
161err_iv:
162	kfree(d);
163err_mem:
164	return err;
165}
166