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