drivers/crypto/fsl/rng.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2020 Michael Walle <michael@walle.cc>
   4  *
   5  * Driver for Freescale Cryptographic Accelerator and Assurance
   6  * Module (CAAM) hardware random number generator.
   7  */
   8
   9 #include <asm/cache.h>
  10 #include <common.h>
  11 #include <cpu_func.h>
  12 #include <dm.h>
  13 #include <rng.h>
  14 #include <linux/kernel.h>
  15 #include "desc_constr.h"
  16 #include "jobdesc.h"
  17 #include "jr.h"
  18
  19 #define CAAM_RNG_MAX_FIFO_STORE_SIZE 16
  20 #define CAAM_RNG_DESC_LEN (3 * CAAM_CMD_SZ + CAAM_PTR_SZ)
  21
  22 struct caam_rng_priv {
  23         u32 desc[CAAM_RNG_DESC_LEN / 4];
  24         u8 data[CAAM_RNG_MAX_FIFO_STORE_SIZE] __aligned(ARCH_DMA_MINALIGN);
  25 };
  26
  27 static int caam_rng_read_one(struct caam_rng_priv *priv)
  28 {
  29         int size = ALIGN(CAAM_RNG_MAX_FIFO_STORE_SIZE, ARCH_DMA_MINALIGN);
  30         int ret;
  31
  32         ret = run_descriptor_jr(priv->desc);
  33         if (ret < 0)
  34                 return -EIO;
  35
  36         invalidate_dcache_range((unsigned long)priv->data,
  37                                 (unsigned long)priv->data + size);
  38
  39         return 0;
  40 }
  41
  42 static int caam_rng_read(struct udevice *dev, void *data, size_t len)
  43 {
  44         struct caam_rng_priv *priv = dev_get_priv(dev);
  45         u8 *buffer = data;
  46         size_t size;
  47         int ret;
  48
  49         while (len) {
  50                 ret = caam_rng_read_one(priv);
  51                 if (ret)
  52                         return ret;
  53
  54                 size = min(len, (size_t)CAAM_RNG_MAX_FIFO_STORE_SIZE);
  55
  56                 memcpy(buffer, priv->data, size);
  57                 buffer += size;
  58                 len -= size;
  59         }
  60
  61         return 0;
  62 }
  63
  64 static int caam_rng_probe(struct udevice *dev)
  65 {
  66         struct caam_rng_priv *priv = dev_get_priv(dev);
  67         ulong size = ALIGN(CAAM_RNG_DESC_LEN, ARCH_DMA_MINALIGN);
  68
  69         inline_cnstr_jobdesc_rng(priv->desc, priv->data,
  70                                  CAAM_RNG_MAX_FIFO_STORE_SIZE);
  71         flush_dcache_range((unsigned long)priv->desc,
  72                            (unsigned long)priv->desc + size);
  73
  74         return 0;
  75 }
  76
  77 static const struct dm_rng_ops caam_rng_ops = {
  78         .read = caam_rng_read,
  79 };
  80
  81 U_BOOT_DRIVER(caam_rng) = {
  82         .name = "caam-rng",
  83         .id = UCLASS_RNG,
  84         .ops = &caam_rng_ops,
  85         .probe = caam_rng_probe,
  86         .priv_auto_alloc_size = sizeof(struct caam_rng_priv),
  87         .flags = DM_FLAG_ALLOC_PRIV_DMA,
  88 };