Orange Pi5 kernel

/*
 * Copyright (c) 2011 Peter Korsgaard <jacmet@sunsite.dk>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */
 
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/hw_random.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
 
#define TRNG_CR		0x00
#define TRNG_MR		0x04
#define TRNG_ISR	0x1c
#define TRNG_ODATA	0x50
 
#define TRNG_KEY	0x524e4700 /* RNG */
 
#define TRNG_HALFR	BIT(0) /* generate RN every 168 cycles */
 
struct atmel_trng_data {
<------>bool has_half_rate;
};
 
struct atmel_trng {
<------>struct clk *clk;
<------>void __iomem *base;
<------>struct hwrng rng;
};
 
static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max,
<------><------><------>   bool wait)
{
<------>struct atmel_trng *trng = container_of(rng, struct atmel_trng, rng);
<------>u32 *data = buf;
 
<------>/* data ready? */
<------>if (readl(trng->base + TRNG_ISR) & 1) {
<------><------>*data = readl(trng->base + TRNG_ODATA);
<------><------>/*
<------><------>  ensure data ready is only set again AFTER the next data
<------><------>  word is ready in case it got set between checking ISR
<------><------>  and reading ODATA, so we don't risk re-reading the
<------><------>  same word
<------><------>*/
<------><------>readl(trng->base + TRNG_ISR);
<------><------>return 4;
<------>} else
<------><------>return 0;
}
 
static void atmel_trng_enable(struct atmel_trng *trng)
{
<------>writel(TRNG_KEY | 1, trng->base + TRNG_CR);
}
 
static void atmel_trng_disable(struct atmel_trng *trng)
{
<------>writel(TRNG_KEY, trng->base + TRNG_CR);
}
 
static int atmel_trng_probe(struct platform_device *pdev)
{
<------>struct atmel_trng *trng;
<------>const struct atmel_trng_data *data;
<------>int ret;
 
<------>trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
<------>if (!trng)
<------><------>return -ENOMEM;
 
<------>trng->base = devm_platform_ioremap_resource(pdev, 0);
<------>if (IS_ERR(trng->base))
<------><------>return PTR_ERR(trng->base);
 
<------>trng->clk = devm_clk_get(&pdev->dev, NULL);
<------>if (IS_ERR(trng->clk))
<------><------>return PTR_ERR(trng->clk);
<------>data = of_device_get_match_data(&pdev->dev);
<------>if (!data)
<------><------>return -ENODEV;
 
<------>if (data->has_half_rate) {
<------><------>unsigned long rate = clk_get_rate(trng->clk);
 
<------><------>/* if peripheral clk is above 100MHz, set HALFR */
<------><------>if (rate > 100000000)
<------><------><------>writel(TRNG_HALFR, trng->base + TRNG_MR);
<------>}
 
<------>ret = clk_prepare_enable(trng->clk);
<------>if (ret)
<------><------>return ret;
 
<------>atmel_trng_enable(trng);
<------>trng->rng.name = pdev->name;
<------>trng->rng.read = atmel_trng_read;
 
<------>ret = devm_hwrng_register(&pdev->dev, &trng->rng);
<------>if (ret)
<------><------>goto err_register;
 
<------>platform_set_drvdata(pdev, trng);
 
<------>return 0;
 
err_register:
<------>clk_disable_unprepare(trng->clk);
<------>atmel_trng_disable(trng);
<------>return ret;
}
 
static int atmel_trng_remove(struct platform_device *pdev)
{
<------>struct atmel_trng *trng = platform_get_drvdata(pdev);
 
 
<------>atmel_trng_disable(trng);
<------>clk_disable_unprepare(trng->clk);
 
<------>return 0;
}
 
#ifdef CONFIG_PM
static int atmel_trng_suspend(struct device *dev)
{
<------>struct atmel_trng *trng = dev_get_drvdata(dev);
 
<------>atmel_trng_disable(trng);
<------>clk_disable_unprepare(trng->clk);
 
<------>return 0;
}
 
static int atmel_trng_resume(struct device *dev)
{
<------>struct atmel_trng *trng = dev_get_drvdata(dev);
<------>int ret;
 
<------>ret = clk_prepare_enable(trng->clk);
<------>if (ret)
<------><------>return ret;
 
<------>atmel_trng_enable(trng);
 
<------>return 0;
}
 
static const struct dev_pm_ops atmel_trng_pm_ops = {
<------>.suspend	= atmel_trng_suspend,
<------>.resume		= atmel_trng_resume,
};
#endif /* CONFIG_PM */
 
static const struct atmel_trng_data at91sam9g45_config = {
<------>.has_half_rate = false,
};
 
static const struct atmel_trng_data sam9x60_config = {
<------>.has_half_rate = true,
};
 
static const struct of_device_id atmel_trng_dt_ids[] = {
<------>{
<------><------>.compatible = "atmel,at91sam9g45-trng",
<------><------>.data = &at91sam9g45_config,
<------>}, {
<------><------>.compatible = "microchip,sam9x60-trng",
<------><------>.data = &sam9x60_config,
<------>}, {
<------><------>/* sentinel */
<------>}
};
MODULE_DEVICE_TABLE(of, atmel_trng_dt_ids);
 
static struct platform_driver atmel_trng_driver = {
<------>.probe		= atmel_trng_probe,
<------>.remove		= atmel_trng_remove,
<------>.driver		= {
<------><------>.name	= "atmel-trng",
#ifdef CONFIG_PM
<------><------>.pm	= &atmel_trng_pm_ops,
#endif /* CONFIG_PM */
<------><------>.of_match_table = atmel_trng_dt_ids,
<------>},
};
 
module_platform_driver(atmel_trng_driver);
 
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
MODULE_DESCRIPTION("Atmel true random number generator driver");