LXR linux/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * sun8i-ce-trng.c - hardware cryptographic offloader for
   4 * Allwinner H3/A64/H5/H2+/H6/R40 SoC
   5 *
   6 * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
   7 *
   8 * This file handle the TRNG
   9 *
  10 * You could find a link for the datasheet in Documentation/arm/sunxi.rst
  11 */
  12#include "sun8i-ce.h"
  13#include <linux/dma-mapping.h>
  14#include <linux/pm_runtime.h>
  15#include <linux/hw_random.h>
  16/*
  17 * Note that according to the algorithm ID, 2 versions of the TRNG exists,
  18 * The first present in H3/H5/R40/A64 and the second present in H6.
  19 * This file adds support for both, but only the second is working
  20 * reliabily according to rngtest.
  21 **/
  22
  23static int sun8i_ce_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
  24{
  25        struct sun8i_ce_dev *ce;
  26        dma_addr_t dma_dst;
  27        int err = 0;
  28        int flow = 3;
  29        unsigned int todo;
  30        struct sun8i_ce_flow *chan;
  31        struct ce_task *cet;
  32        u32 common;
  33        void *d;
  34
  35        ce = container_of(rng, struct sun8i_ce_dev, trng);
  36
  37        /* round the data length to a multiple of 32*/
  38        todo = max + 32;
  39        todo -= todo % 32;
  40
  41        d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
  42        if (!d)
  43                return -ENOMEM;
  44
  45#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
  46        ce->hwrng_stat_req++;
  47        ce->hwrng_stat_bytes += todo;
  48#endif
  49
  50        dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
  51        if (dma_mapping_error(ce->dev, dma_dst)) {
  52                dev_err(ce->dev, "Cannot DMA MAP DST\n");
  53                err = -EFAULT;
  54                goto err_dst;
  55        }
  56
  57        err = pm_runtime_get_sync(ce->dev);
  58        if (err < 0) {
  59                pm_runtime_put_noidle(ce->dev);
  60                goto err_pm;
  61        }
  62
  63        mutex_lock(&ce->rnglock);
  64        chan = &ce->chanlist[flow];
  65
  66        cet = &chan->tl[0];
  67        memset(cet, 0, sizeof(struct ce_task));
  68
  69        cet->t_id = cpu_to_le32(flow);
  70        common = ce->variant->trng | CE_COMM_INT;
  71        cet->t_common_ctl = cpu_to_le32(common);
  72
  73        /* recent CE (H6) need length in bytes, in word otherwise */
  74        if (ce->variant->trng_t_dlen_in_bytes)
  75                cet->t_dlen = cpu_to_le32(todo);
  76        else
  77                cet->t_dlen = cpu_to_le32(todo / 4);
  78
  79        cet->t_sym_ctl = 0;
  80        cet->t_asym_ctl = 0;
  81
  82        cet->t_dst[0].addr = cpu_to_le32(dma_dst);
  83        cet->t_dst[0].len = cpu_to_le32(todo / 4);
  84        ce->chanlist[flow].timeout = todo;
  85
  86        err = sun8i_ce_run_task(ce, 3, "TRNG");
  87        mutex_unlock(&ce->rnglock);
  88
  89        pm_runtime_put(ce->dev);
  90
  91err_pm:
  92        dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
  93
  94        if (!err) {
  95                memcpy(data, d, max);
  96                err = max;
  97        }
  98err_dst:
  99        kfree_sensitive(d);
 100        return err;
 101}
 102
 103int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce)
 104{
 105        int ret;
 106
 107        if (ce->variant->trng == CE_ID_NOTSUPP) {
 108                dev_info(ce->dev, "TRNG not supported\n");
 109                return 0;
 110        }
 111        ce->trng.name = "sun8i Crypto Engine TRNG";
 112        ce->trng.read = sun8i_ce_trng_read;
 113        ce->trng.quality = 1000;
 114
 115        ret = hwrng_register(&ce->trng);
 116        if (ret)
 117                dev_err(ce->dev, "Fail to register the TRNG\n");
 118        return ret;
 119}
 120
 121void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce)
 122{
 123        if (ce->variant->trng == CE_ID_NOTSUPP)
 124                return;
 125        hwrng_unregister(&ce->trng);
 126}
 127