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