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(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 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(&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(&ce->trng); 61 } 62