1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * sun8i-ce-trng.c - hardware cryptographic offloader for
4*4882a593Smuzhiyun * Allwinner H3/A64/H5/H2+/H6/R40 SoC
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * This file handle the TRNG
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * You could find a link for the datasheet in Documentation/arm/sunxi.rst
11*4882a593Smuzhiyun */
12*4882a593Smuzhiyun #include "sun8i-ce.h"
13*4882a593Smuzhiyun #include <linux/dma-mapping.h>
14*4882a593Smuzhiyun #include <linux/pm_runtime.h>
15*4882a593Smuzhiyun #include <linux/hw_random.h>
16*4882a593Smuzhiyun /*
17*4882a593Smuzhiyun * Note that according to the algorithm ID, 2 versions of the TRNG exists,
18*4882a593Smuzhiyun * The first present in H3/H5/R40/A64 and the second present in H6.
19*4882a593Smuzhiyun * This file adds support for both, but only the second is working
20*4882a593Smuzhiyun * reliabily according to rngtest.
21*4882a593Smuzhiyun **/
22*4882a593Smuzhiyun
sun8i_ce_trng_read(struct hwrng * rng,void * data,size_t max,bool wait)23*4882a593Smuzhiyun static int sun8i_ce_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
24*4882a593Smuzhiyun {
25*4882a593Smuzhiyun struct sun8i_ce_dev *ce;
26*4882a593Smuzhiyun dma_addr_t dma_dst;
27*4882a593Smuzhiyun int err = 0;
28*4882a593Smuzhiyun int flow = 3;
29*4882a593Smuzhiyun unsigned int todo;
30*4882a593Smuzhiyun struct sun8i_ce_flow *chan;
31*4882a593Smuzhiyun struct ce_task *cet;
32*4882a593Smuzhiyun u32 common;
33*4882a593Smuzhiyun void *d;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun ce = container_of(rng, struct sun8i_ce_dev, trng);
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun /* round the data length to a multiple of 32*/
38*4882a593Smuzhiyun todo = max + 32;
39*4882a593Smuzhiyun todo -= todo % 32;
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
42*4882a593Smuzhiyun if (!d)
43*4882a593Smuzhiyun return -ENOMEM;
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun #ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
46*4882a593Smuzhiyun ce->hwrng_stat_req++;
47*4882a593Smuzhiyun ce->hwrng_stat_bytes += todo;
48*4882a593Smuzhiyun #endif
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
51*4882a593Smuzhiyun if (dma_mapping_error(ce->dev, dma_dst)) {
52*4882a593Smuzhiyun dev_err(ce->dev, "Cannot DMA MAP DST\n");
53*4882a593Smuzhiyun err = -EFAULT;
54*4882a593Smuzhiyun goto err_dst;
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun err = pm_runtime_get_sync(ce->dev);
58*4882a593Smuzhiyun if (err < 0) {
59*4882a593Smuzhiyun pm_runtime_put_noidle(ce->dev);
60*4882a593Smuzhiyun goto err_pm;
61*4882a593Smuzhiyun }
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun mutex_lock(&ce->rnglock);
64*4882a593Smuzhiyun chan = &ce->chanlist[flow];
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun cet = &chan->tl[0];
67*4882a593Smuzhiyun memset(cet, 0, sizeof(struct ce_task));
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun cet->t_id = cpu_to_le32(flow);
70*4882a593Smuzhiyun common = ce->variant->trng | CE_COMM_INT;
71*4882a593Smuzhiyun cet->t_common_ctl = cpu_to_le32(common);
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun /* recent CE (H6) need length in bytes, in word otherwise */
74*4882a593Smuzhiyun if (ce->variant->trng_t_dlen_in_bytes)
75*4882a593Smuzhiyun cet->t_dlen = cpu_to_le32(todo);
76*4882a593Smuzhiyun else
77*4882a593Smuzhiyun cet->t_dlen = cpu_to_le32(todo / 4);
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun cet->t_sym_ctl = 0;
80*4882a593Smuzhiyun cet->t_asym_ctl = 0;
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun cet->t_dst[0].addr = cpu_to_le32(dma_dst);
83*4882a593Smuzhiyun cet->t_dst[0].len = cpu_to_le32(todo / 4);
84*4882a593Smuzhiyun ce->chanlist[flow].timeout = todo;
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun err = sun8i_ce_run_task(ce, 3, "TRNG");
87*4882a593Smuzhiyun mutex_unlock(&ce->rnglock);
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun pm_runtime_put(ce->dev);
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun err_pm:
92*4882a593Smuzhiyun dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun if (!err) {
95*4882a593Smuzhiyun memcpy(data, d, max);
96*4882a593Smuzhiyun err = max;
97*4882a593Smuzhiyun }
98*4882a593Smuzhiyun memzero_explicit(d, todo);
99*4882a593Smuzhiyun err_dst:
100*4882a593Smuzhiyun kfree(d);
101*4882a593Smuzhiyun return err;
102*4882a593Smuzhiyun }
103*4882a593Smuzhiyun
sun8i_ce_hwrng_register(struct sun8i_ce_dev * ce)104*4882a593Smuzhiyun int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce)
105*4882a593Smuzhiyun {
106*4882a593Smuzhiyun int ret;
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun if (ce->variant->trng == CE_ID_NOTSUPP) {
109*4882a593Smuzhiyun dev_info(ce->dev, "TRNG not supported\n");
110*4882a593Smuzhiyun return 0;
111*4882a593Smuzhiyun }
112*4882a593Smuzhiyun ce->trng.name = "sun8i Crypto Engine TRNG";
113*4882a593Smuzhiyun ce->trng.read = sun8i_ce_trng_read;
114*4882a593Smuzhiyun ce->trng.quality = 1000;
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun ret = hwrng_register(&ce->trng);
117*4882a593Smuzhiyun if (ret)
118*4882a593Smuzhiyun dev_err(ce->dev, "Fail to register the TRNG\n");
119*4882a593Smuzhiyun return ret;
120*4882a593Smuzhiyun }
121*4882a593Smuzhiyun
sun8i_ce_hwrng_unregister(struct sun8i_ce_dev * ce)122*4882a593Smuzhiyun void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce)
123*4882a593Smuzhiyun {
124*4882a593Smuzhiyun if (ce->variant->trng == CE_ID_NOTSUPP)
125*4882a593Smuzhiyun return;
126*4882a593Smuzhiyun hwrng_unregister(&ce->trng);
127*4882a593Smuzhiyun }
128