crypto/gemini/sl3516-ce-rng.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * sl3516-ce-rng.c - hardware cryptographic offloader for SL3516 SoC.
0004  *
0005  * Copyright (C) 2021 Corentin Labbe <clabbe@baylibre.com>
0006  *
0007  * This file handle the RNG found in the SL3516 crypto engine
0008  */
0009 #include "sl3516-ce.h"
0010 #include <linux/pm_runtime.h>
0011 #include <linux/hw_random.h>
0012
0013 static int sl3516_ce_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
0014 {
0015     struct sl3516_ce_dev *ce;
0016     u32 *data = buf;
0017     size_t read = 0;
0018     int err;
0019
0020     ce = container_of(rng, struct sl3516_ce_dev, trng);
0021
0022 #ifdef CONFIG_CRYPTO_DEV_SL3516_DEBUG
0023     ce->hwrng_stat_req++;
0024     ce->hwrng_stat_bytes += max;
0025 #endif
0026
0027     err = pm_runtime_get_sync(ce->dev);
0028     if (err < 0) {
0029         pm_runtime_put_noidle(ce->dev);
0030         return err;
0031     }
0032
0033     while (read < max) {
0034         *data = readl(ce->base + IPSEC_RAND_NUM_REG);
0035         data++;
0036         read += 4;
0037     }
0038
0039     pm_runtime_put(ce->dev);
0040
0041     return read;
0042 }
0043
0044 int sl3516_ce_rng_register(struct sl3516_ce_dev *ce)
0045 {
0046     int ret;
0047
0048     ce->trng.name = "SL3516 Crypto Engine RNG";
0049     ce->trng.read = sl3516_ce_rng_read;
0050     ce->trng.quality = 700;
0051
0052     ret = hwrng_register(&ce->trng);
0053     if (ret)
0054         dev_err(ce->dev, "Fail to register the RNG\n");
0055     return ret;
0056 }
0057
0058 void sl3516_ce_rng_unregister(struct sl3516_ce_dev *ce)
0059 {
0060     hwrng_unregister(&ce->trng);
0061 }