// SPDX-License-Identifier: GPL-2.0
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/*
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* sun8i-ce-trng.c - hardware cryptographic offloader for
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* Allwinner H3/A64/H5/H2+/H6/R40 SoC
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*
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* Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
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*
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* This file handle the TRNG
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*
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* You could find a link for the datasheet in Documentation/arm/sunxi.rst
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*/
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#include "sun8i-ce.h"
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#include <linux/dma-mapping.h>
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#include <linux/pm_runtime.h>
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#include <linux/hw_random.h>
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/*
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* Note that according to the algorithm ID, 2 versions of the TRNG exists,
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* The first present in H3/H5/R40/A64 and the second present in H6.
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* This file adds support for both, but only the second is working
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* reliabily according to rngtest.
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**/
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static int sun8i_ce_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
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{
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struct sun8i_ce_dev *ce;
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dma_addr_t dma_dst;
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int err = 0;
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int flow = 3;
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unsigned int todo;
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struct sun8i_ce_flow *chan;
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struct ce_task *cet;
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u32 common;
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void *d;
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ce = container_of(rng, struct sun8i_ce_dev, trng);
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/* round the data length to a multiple of 32*/
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todo = max + 32;
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todo -= todo % 32;
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d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
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if (!d)
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return -ENOMEM;
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#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
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ce->hwrng_stat_req++;
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ce->hwrng_stat_bytes += todo;
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#endif
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dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
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if (dma_mapping_error(ce->dev, dma_dst)) {
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dev_err(ce->dev, "Cannot DMA MAP DST\n");
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err = -EFAULT;
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goto err_dst;
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}
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err = pm_runtime_get_sync(ce->dev);
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if (err < 0) {
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pm_runtime_put_noidle(ce->dev);
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goto err_pm;
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}
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mutex_lock(&ce->rnglock);
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chan = &ce->chanlist[flow];
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cet = &chan->tl[0];
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memset(cet, 0, sizeof(struct ce_task));
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cet->t_id = cpu_to_le32(flow);
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common = ce->variant->trng | CE_COMM_INT;
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cet->t_common_ctl = cpu_to_le32(common);
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/* recent CE (H6) need length in bytes, in word otherwise */
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if (ce->variant->trng_t_dlen_in_bytes)
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cet->t_dlen = cpu_to_le32(todo);
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else
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cet->t_dlen = cpu_to_le32(todo / 4);
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cet->t_sym_ctl = 0;
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cet->t_asym_ctl = 0;
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cet->t_dst[0].addr = cpu_to_le32(dma_dst);
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cet->t_dst[0].len = cpu_to_le32(todo / 4);
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ce->chanlist[flow].timeout = todo;
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err = sun8i_ce_run_task(ce, 3, "TRNG");
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mutex_unlock(&ce->rnglock);
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pm_runtime_put(ce->dev);
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err_pm:
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dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
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if (!err) {
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memcpy(data, d, max);
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err = max;
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}
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memzero_explicit(d, todo);
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err_dst:
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kfree(d);
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return err;
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}
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int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce)
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{
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int ret;
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if (ce->variant->trng == CE_ID_NOTSUPP) {
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dev_info(ce->dev, "TRNG not supported\n");
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return 0;
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}
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ce->trng.name = "sun8i Crypto Engine TRNG";
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ce->trng.read = sun8i_ce_trng_read;
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ce->trng.quality = 1000;
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ret = hwrng_register(&ce->trng);
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if (ret)
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dev_err(ce->dev, "Fail to register the TRNG\n");
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return ret;
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}
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void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce)
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{
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if (ce->variant->trng == CE_ID_NOTSUPP)
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return;
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hwrng_unregister(&ce->trng);
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}
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