| 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 | |
| 13 | static 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(dev: ce->dev); |
| 28 | if (err < 0) { |
| 29 | pm_runtime_put_noidle(dev: ce->dev); |
| 30 | return err; |
| 31 | } |
| 32 | |
| 33 | while (read < max) { |
| 34 | *data = readl(addr: ce->base + IPSEC_RAND_NUM_REG); |
| 35 | data++; |
| 36 | read += 4; |
| 37 | } |
| 38 | |
| 39 | pm_runtime_put(dev: ce->dev); |
| 40 | |
| 41 | return read; |
| 42 | } |
| 43 | |
| 44 | int 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(rng: &ce->trng); |
| 53 | if (ret) |
| 54 | dev_err(ce->dev, "Fail to register the RNG\n"); |
| 55 | return ret; |
| 56 | } |
| 57 | |
| 58 | void sl3516_ce_rng_unregister(struct sl3516_ce_dev *ce) |
| 59 | { |
| 60 | hwrng_unregister(rng: &ce->trng); |
| 61 | } |
| 62 |