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 
17 int 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 
25 void 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 
34 int 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 
55 int 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 = cpu_to_le32(dma_iv);
136 	cet->t_iv = cpu_to_le32(dma_iv);
137 
138 	cet->t_dst[0].addr = cpu_to_le32(dma_dst);
139 	cet->t_dst[0].len = cpu_to_le32(todo / 4);
140 	ce->chanlist[flow].timeout = 2000;
141 
142 	err = sun8i_ce_run_task(ce, 3, "PRNG");
143 	mutex_unlock(&ce->rnglock);
144 
145 	pm_runtime_put(ce->dev);
146 
147 err_pm:
148 	dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
149 err_dst:
150 	dma_unmap_single(ce->dev, dma_iv, ctx->slen, DMA_TO_DEVICE);
151 
152 	if (!err) {
153 		memcpy(dst, d, dlen);
154 		memcpy(ctx->seed, d + dlen, ctx->slen);
155 	}
156 err_iv:
157 	kfree_sensitive(d);
158 err_mem:
159 	return err;
160 }
161