1// SPDX-License-Identifier: GPL-2.0
2/*
3 * sl3516-ce-rng.c - hardware cryptographic offloader for SL3516 SoC.
4 *
5 * Copyright (C) 2021 Corentin Labbe <clabbe@baylibre.com>
6 *
7 * This file handle the RNG found in the SL3516 crypto engine
8 */
9#include "sl3516-ce.h"
10#include <linux/pm_runtime.h>
11#include <linux/hw_random.h>
12
13static int sl3516_ce_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
14{
15	struct sl3516_ce_dev *ce;
16	u32 *data = buf;
17	size_t read = 0;
18	int err;
19
20	ce = container_of(rng, struct sl3516_ce_dev, trng);
21
22#ifdef CONFIG_CRYPTO_DEV_SL3516_DEBUG
23	ce->hwrng_stat_req++;
24	ce->hwrng_stat_bytes += max;
25#endif
26
27	err = pm_runtime_get_sync(ce->dev);
28	if (err < 0) {
29		pm_runtime_put_noidle(ce->dev);
30		return err;
31	}
32
33	while (read < max) {
34		*data = readl(ce->base + IPSEC_RAND_NUM_REG);
35		data++;
36		read += 4;
37	}
38
39	pm_runtime_put(ce->dev);
40
41	return read;
42}
43
44int sl3516_ce_rng_register(struct sl3516_ce_dev *ce)
45{
46	int ret;
47
48	ce->trng.name = "SL3516 Crypto Engine RNG";
49	ce->trng.read = sl3516_ce_rng_read;
50	ce->trng.quality = 700;
51
52	ret = hwrng_register(&ce->trng);
53	if (ret)
54		dev_err(ce->dev, "Fail to register the RNG\n");
55	return ret;
56}
57
58void sl3516_ce_rng_unregister(struct sl3516_ce_dev *ce)
59{
60	hwrng_unregister(&ce->trng);
61}
62