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1// SPDX-License-Identifier: GPL-2.02/*3 * sun8i-ce-trng.c - hardware cryptographic offloader for4 * Allwinner H3/A64/H5/H2+/H6/R40 SoC5 *6 * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>7 *8 * This file handle the TRNG9 *10 * You could find a link for the datasheet in Documentation/arch/arm/sunxi.rst11 */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 working20 * 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_DEBUG46 ce->hwrng_stat_req++;47 ce->hwrng_stat_bytes += todo;48#endif49 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_resume_and_get(ce->dev);58 if (err < 0)59 goto err_pm;60 61 mutex_lock(&ce->rnglock);62 chan = &ce->chanlist[flow];63 64 cet = &chan->tl[0];65 memset(cet, 0, sizeof(struct ce_task));66 67 cet->t_id = cpu_to_le32(flow);68 common = ce->variant->trng | CE_COMM_INT;69 cet->t_common_ctl = cpu_to_le32(common);70 71 /* recent CE (H6) need length in bytes, in word otherwise */72 if (ce->variant->trng_t_dlen_in_bytes)73 cet->t_dlen = cpu_to_le32(todo);74 else75 cet->t_dlen = cpu_to_le32(todo / 4);76 77 cet->t_sym_ctl = 0;78 cet->t_asym_ctl = 0;79 80 cet->t_dst[0].addr = desc_addr_val_le32(ce, dma_dst);81 cet->t_dst[0].len = cpu_to_le32(todo / 4);82 ce->chanlist[flow].timeout = todo;83 84 err = sun8i_ce_run_task(ce, 3, "TRNG");85 mutex_unlock(&ce->rnglock);86 87 pm_runtime_put(ce->dev);88 89err_pm:90 dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);91 92 if (!err) {93 memcpy(data, d, max);94 err = max;95 }96err_dst:97 kfree_sensitive(d);98 return err;99}100 101int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce)102{103 int ret;104 105 if (ce->variant->trng == CE_ID_NOTSUPP) {106 dev_info(ce->dev, "TRNG not supported\n");107 return 0;108 }109 ce->trng.name = "sun8i Crypto Engine TRNG";110 ce->trng.read = sun8i_ce_trng_read;111 112 ret = hwrng_register(&ce->trng);113 if (ret)114 dev_err(ce->dev, "Fail to register the TRNG\n");115 return ret;116}117 118void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce)119{120 if (ce->variant->trng == CE_ID_NOTSUPP)121 return;122 hwrng_unregister(&ce->trng);123}124