// SPDX-License-Identifier: GPL-2.0
/*
 * sl3516-ce-rng.c - hardware cryptographic offloader for SL3516 SoC.
 *
 * Copyright (C) 2021 Corentin Labbe <clabbe@baylibre.com>
 *
 * This file handle the RNG found in the SL3516 crypto engine
 */
#include "sl3516-ce.h"
#include <linux/pm_runtime.h>
#include <linux/hw_random.h>

static int sl3516_ce_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
{
        struct sl3516_ce_dev *ce;
        u32 *data = buf;
        size_t read = 0;
        int err;

        ce = container_of(rng, struct sl3516_ce_dev, trng);

#ifdef CONFIG_CRYPTO_DEV_SL3516_DEBUG
        ce->hwrng_stat_req++;
        ce->hwrng_stat_bytes += max;
#endif

        err = pm_runtime_get_sync(ce->dev);
        if (err < 0) {
                pm_runtime_put_noidle(ce->dev);
                return err;
        }

        while (read < max) {
                *data = readl(ce->base + IPSEC_RAND_NUM_REG);
                data++;
                read += 4;
        }

        pm_runtime_put(ce->dev);

        return read;
}

int sl3516_ce_rng_register(struct sl3516_ce_dev *ce)
{
        int ret;

        ce->trng.name = "SL3516 Crypto Engine RNG";
        ce->trng.read = sl3516_ce_rng_read;
        ce->trng.quality = 700;

        ret = hwrng_register(&ce->trng);
        if (ret)
                dev_err(ce->dev, "Fail to register the RNG\n");
        return ret;
}

void sl3516_ce_rng_unregister(struct sl3516_ce_dev *ce)
{
        hwrng_unregister(&ce->trng);
}