drivers/crypto/gemini/sl3516-ce-rng.c

   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 }