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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2020 Michael Walle <michael@walle.cc>
*
* Driver for Freescale Cryptographic Accelerator and Assurance
* Module (CAAM) hardware random number generator.
*/
#include <asm/cache.h>
#include <common.h>
#include <cpu_func.h>
#include <dm.h>
#include <rng.h>
#include <linux/kernel.h>
#include "desc_constr.h"
#include "jobdesc.h"
#include "jr.h"
#define CAAM_RNG_MAX_FIFO_STORE_SIZE 16
#define CAAM_RNG_DESC_LEN (3 * CAAM_CMD_SZ + CAAM_PTR_SZ)
struct caam_rng_priv {
u32 desc[CAAM_RNG_DESC_LEN / 4];
u8 data[CAAM_RNG_MAX_FIFO_STORE_SIZE] __aligned(ARCH_DMA_MINALIGN);
};
static int caam_rng_read_one(struct caam_rng_priv *priv)
{
int size = ALIGN(CAAM_RNG_MAX_FIFO_STORE_SIZE, ARCH_DMA_MINALIGN);
int ret;
ret = run_descriptor_jr(priv->desc);
if (ret < 0)
return -EIO;
invalidate_dcache_range((unsigned long)priv->data,
(unsigned long)priv->data + size);
return 0;
}
static int caam_rng_read(struct udevice *dev, void *data, size_t len)
{
struct caam_rng_priv *priv = dev_get_priv(dev);
u8 *buffer = data;
size_t size;
int ret;
while (len) {
ret = caam_rng_read_one(priv);
if (ret)
return ret;
size = min(len, (size_t)CAAM_RNG_MAX_FIFO_STORE_SIZE);
memcpy(buffer, priv->data, size);
buffer += size;
len -= size;
}
return 0;
}
static int caam_rng_probe(struct udevice *dev)
{
struct caam_rng_priv *priv = dev_get_priv(dev);
ulong size = ALIGN(CAAM_RNG_DESC_LEN, ARCH_DMA_MINALIGN);
inline_cnstr_jobdesc_rng(priv->desc, priv->data,
CAAM_RNG_MAX_FIFO_STORE_SIZE);
flush_dcache_range((unsigned long)priv->desc,
(unsigned long)priv->desc + size);
return 0;
}
static const struct dm_rng_ops caam_rng_ops = {
.read = caam_rng_read,
};
U_BOOT_DRIVER(caam_rng) = {
.name = "caam-rng",
.id = UCLASS_RNG,
.ops = &caam_rng_ops,
.probe = caam_rng_probe,
.priv_auto = sizeof(struct caam_rng_priv),
.flags = DM_FLAG_ALLOC_PRIV_DMA,
};
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