marvell/linux/drivers/soc/asr/geu/asr-rng-optee.c

// SPDX-License-Identifier: GPL-2.0
/*
 * linux/drivers/char/hw_random/asr-rng.c - Random Number Generator driver
 *
 * Copyright (C) 2023 ASR Micro Limited
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/clk.h>
#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/fs.h>
#ifdef CONFIG_TEE
#include <linux/tee_drv.h>
#endif

#include "asr-rng-optee.h"
#include "asr-geu-optee.h"

static struct teec_uuid pta_rng_uuid = ASR_RNG_ACCESS_UUID;

static int asr_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
{
	int ret = 0;
	size_t readsize;
	size_t size = max < 4096 ? max : 4096;

	(void)wait;

	ret = asrgeu_optee_acquire_ta_buff(&pta_rng_uuid, ASR_RNG_GET_DATA,
		data, size, &readsize);

	if (!ret)
		return readsize;

	return 0;
}

int asr_geu_rng_register(struct asr_geu_dev *geu_dd)
{
	int err = 0;
	struct device *dev = geu_dd->dev;
	struct asr_geu_rng *hwrng;

	hwrng = devm_kzalloc(dev, sizeof(*hwrng), GFP_KERNEL);
	if (!hwrng)
		return -ENOMEM;

	geu_dd->asr_rng = hwrng;

	hwrng->rng.name = "asr";
	hwrng->rng.read = asr_rng_read;
	hwrng->rng.quality = 1000;

	err = hwrng_register(&hwrng->rng);
	if (err) {
		dev_err(dev, "failed to register asr_rng!\n");
		return err;
	}

	return 0;
}

int asr_geu_rng_unregister(struct asr_geu_dev *geu_dd)
{
	struct device *dev = geu_dd->dev;
	struct asr_geu_rng *hwrng = geu_dd->asr_rng;

	hwrng_unregister(&hwrng->rng);

	devm_kfree(dev, hwrng);

	return 0;
}

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Yu Zhang <yuzhang@asrmicro.com>");
MODULE_DESCRIPTION("ASR H/W RNG driver with optee-os");