Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-only
/*
 * PIC32 RNG driver
 *
 * Joshua Henderson <joshua.henderson@microchip.com>
 * Copyright (C) 2016 Microchip Technology Inc.  All rights reserved.
 */
 
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/err.h>
#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
 
#define RNGCON		0x04
#define  TRNGEN		BIT(8)
#define  PRNGEN		BIT(9)
#define  PRNGCONT	BIT(10)
#define  TRNGMOD	BIT(11)
#define  SEEDLOAD	BIT(12)
#define RNGPOLY1	0x08
#define RNGPOLY2	0x0C
#define RNGNUMGEN1	0x10
#define RNGNUMGEN2	0x14
#define RNGSEED1	0x18
#define RNGSEED2	0x1C
#define RNGRCNT		0x20
#define  RCNT_MASK	0x7F
 
struct pic32_rng {
<------>void __iomem	*base;
<------>struct hwrng	rng;
<------>struct clk	*clk;
};
 
/*
 * The TRNG can generate up to 24Mbps. This is a timeout that should be safe
 * enough given the instructions in the loop and that the TRNG may not always
 * be at maximum rate.
 */
#define RNG_TIMEOUT 500
 
static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max,
<------><------><------>  bool wait)
{
<------>struct pic32_rng *priv = container_of(rng, struct pic32_rng, rng);
<------>u64 *data = buf;
<------>u32 t;
<------>unsigned int timeout = RNG_TIMEOUT;
 
<------>do {
<------><------>t = readl(priv->base + RNGRCNT) & RCNT_MASK;
<------><------>if (t == 64) {
<------><------><------>/* TRNG value comes through the seed registers */
<------><------><------>*data = ((u64)readl(priv->base + RNGSEED2) << 32) +
<------><------><------><------>readl(priv->base + RNGSEED1);
<------><------><------>return 8;
<------><------>}
<------>} while (wait && --timeout);
 
<------>return -EIO;
}
 
static int pic32_rng_probe(struct platform_device *pdev)
{
<------>struct pic32_rng *priv;
<------>u32 v;
<------>int ret;
 
<------>priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
<------>if (!priv)
<------><------>return -ENOMEM;
 
<------>priv->base = devm_platform_ioremap_resource(pdev, 0);
<------>if (IS_ERR(priv->base))
<------><------>return PTR_ERR(priv->base);
 
<------>priv->clk = devm_clk_get(&pdev->dev, NULL);
<------>if (IS_ERR(priv->clk))
<------><------>return PTR_ERR(priv->clk);
 
<------>ret = clk_prepare_enable(priv->clk);
<------>if (ret)
<------><------>return ret;
 
<------>/* enable TRNG in enhanced mode */
<------>v = TRNGEN | TRNGMOD;
<------>writel(v, priv->base + RNGCON);
 
<------>priv->rng.name = pdev->name;
<------>priv->rng.read = pic32_rng_read;
 
<------>ret = hwrng_register(&priv->rng);
<------>if (ret)
<------><------>goto err_register;
 
<------>platform_set_drvdata(pdev, priv);
 
<------>return 0;
 
err_register:
<------>clk_disable_unprepare(priv->clk);
<------>return ret;
}
 
static int pic32_rng_remove(struct platform_device *pdev)
{
<------>struct pic32_rng *rng = platform_get_drvdata(pdev);
 
<------>hwrng_unregister(&rng->rng);
<------>writel(0, rng->base + RNGCON);
<------>clk_disable_unprepare(rng->clk);
<------>return 0;
}
 
static const struct of_device_id pic32_rng_of_match[] __maybe_unused = {
<------>{ .compatible	= "microchip,pic32mzda-rng", },
<------>{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pic32_rng_of_match);
 
static struct platform_driver pic32_rng_driver = {
<------>.probe		= pic32_rng_probe,
<------>.remove		= pic32_rng_remove,
<------>.driver		= {
<------><------>.name	= "pic32-rng",
<------><------>.of_match_table = of_match_ptr(pic32_rng_of_match),
<------>},
};
 
module_platform_driver(pic32_rng_driver);
 
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Joshua Henderson <joshua.henderson@microchip.com>");
MODULE_DESCRIPTION("Microchip PIC32 RNG Driver");