1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * sun8i-ce-trng.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 TRNG
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 <linux/hw_random.h>
16 /*
17 * Note that according to the algorithm ID, 2 versions of the TRNG exists,
18 * The first present in H3/H5/R40/A64 and the second present in H6.
19 * This file adds support for both, but only the second is working
20 * reliabily according to rngtest.
21 **/
22
sun8i_ce_trng_read(struct hwrng * rng,void * data,size_t max,bool wait)23 static int sun8i_ce_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
24 {
25 struct sun8i_ce_dev *ce;
26 dma_addr_t dma_dst;
27 int err = 0;
28 int flow = 3;
29 unsigned int todo;
30 struct sun8i_ce_flow *chan;
31 struct ce_task *cet;
32 u32 common;
33 void *d;
34
35 ce = container_of(rng, struct sun8i_ce_dev, trng);
36
37 /* round the data length to a multiple of 32*/
38 todo = max + 32;
39 todo -= todo % 32;
40
41 d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
42 if (!d)
43 return -ENOMEM;
44
45 #ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
46 ce->hwrng_stat_req++;
47 ce->hwrng_stat_bytes += todo;
48 #endif
49
50 dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
51 if (dma_mapping_error(ce->dev, dma_dst)) {
52 dev_err(ce->dev, "Cannot DMA MAP DST\n");
53 err = -EFAULT;
54 goto err_dst;
55 }
56
57 err = pm_runtime_resume_and_get(ce->dev);
58 if (err < 0)
59 goto err_pm;
60
61 mutex_lock(&ce->rnglock);
62 chan = &ce->chanlist[flow];
63
64 cet = &chan->tl[0];
65 memset(cet, 0, sizeof(struct ce_task));
66
67 cet->t_id = cpu_to_le32(flow);
68 common = ce->variant->trng | CE_COMM_INT;
69 cet->t_common_ctl = cpu_to_le32(common);
70
71 /* recent CE (H6) need length in bytes, in word otherwise */
72 if (ce->variant->trng_t_dlen_in_bytes)
73 cet->t_dlen = cpu_to_le32(todo);
74 else
75 cet->t_dlen = cpu_to_le32(todo / 4);
76
77 cet->t_sym_ctl = 0;
78 cet->t_asym_ctl = 0;
79
80 cet->t_dst[0].addr = cpu_to_le32(dma_dst);
81 cet->t_dst[0].len = cpu_to_le32(todo / 4);
82 ce->chanlist[flow].timeout = todo;
83
84 err = sun8i_ce_run_task(ce, 3, "TRNG");
85 mutex_unlock(&ce->rnglock);
86
87 pm_runtime_put(ce->dev);
88
89 err_pm:
90 dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
91
92 if (!err) {
93 memcpy(data, d, max);
94 err = max;
95 }
96 err_dst:
97 kfree_sensitive(d);
98 return err;
99 }
100
sun8i_ce_hwrng_register(struct sun8i_ce_dev * ce)101 int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce)
102 {
103 int ret;
104
105 if (ce->variant->trng == CE_ID_NOTSUPP) {
106 dev_info(ce->dev, "TRNG not supported\n");
107 return 0;
108 }
109 ce->trng.name = "sun8i Crypto Engine TRNG";
110 ce->trng.read = sun8i_ce_trng_read;
111
112 ret = hwrng_register(&ce->trng);
113 if (ret)
114 dev_err(ce->dev, "Fail to register the TRNG\n");
115 return ret;
116 }
117
sun8i_ce_hwrng_unregister(struct sun8i_ce_dev * ce)118 void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce)
119 {
120 if (ce->variant->trng == CE_ID_NOTSUPP)
121 return;
122 hwrng_unregister(&ce->trng);
123 }
124