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// SPDX-License-Identifier: GPL-2.0
/*
* Ingenic True Random Number Generator driver
* Copyright (c) 2019 漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>
* Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
*/
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
/* DTRNG register offsets */
#define TRNG_REG_CFG_OFFSET 0x00
#define TRNG_REG_RANDOMNUM_OFFSET 0x04
#define TRNG_REG_STATUS_OFFSET 0x08
/* bits within the CFG register */
#define CFG_RDY_CLR BIT(12)
#define CFG_INT_MASK BIT(11)
#define CFG_GEN_EN BIT(0)
/* bits within the STATUS register */
#define STATUS_RANDOM_RDY BIT(0)
struct ingenic_trng {
void __iomem *base;
struct clk *clk;
struct hwrng rng;
};
static int ingenic_trng_init(struct hwrng *rng)
{
struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
unsigned int ctrl;
ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
ctrl |= CFG_GEN_EN;
writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
return 0;
}
static void ingenic_trng_cleanup(struct hwrng *rng)
{
struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
unsigned int ctrl;
ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
ctrl &= ~CFG_GEN_EN;
writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
}
static int ingenic_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
{
struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
u32 *data = buf;
u32 status;
int ret;
ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status,
status & STATUS_RANDOM_RDY, 10, 1000);
if (ret == -ETIMEDOUT) {
pr_err("%s: Wait for DTRNG data ready timeout\n", __func__);
return ret;
}
*data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET);
return 4;
}
static int ingenic_trng_probe(struct platform_device *pdev)
{
struct ingenic_trng *trng;
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)) {
pr_err("%s: Failed to map DTRNG registers\n", __func__);
ret = PTR_ERR(trng->base);
return PTR_ERR(trng->base);
}
trng->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(trng->clk)) {
ret = PTR_ERR(trng->clk);
pr_crit("%s: Cannot get DTRNG clock\n", __func__);
return PTR_ERR(trng->clk);
}
ret = clk_prepare_enable(trng->clk);
if (ret) {
pr_crit("%s: Unable to enable DTRNG clock\n", __func__);
return ret;
}
trng->rng.name = pdev->name;
trng->rng.init = ingenic_trng_init;
trng->rng.cleanup = ingenic_trng_cleanup;
trng->rng.read = ingenic_trng_read;
ret = hwrng_register(&trng->rng);
if (ret) {
dev_err(&pdev->dev, "Failed to register hwrng\n");
goto err_unprepare_clk;
}
platform_set_drvdata(pdev, trng);
dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n");
return 0;
err_unprepare_clk:
clk_disable_unprepare(trng->clk);
return ret;
}
static int ingenic_trng_remove(struct platform_device *pdev)
{
struct ingenic_trng *trng = platform_get_drvdata(pdev);
unsigned int ctrl;
hwrng_unregister(&trng->rng);
ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
ctrl &= ~CFG_GEN_EN;
writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
clk_disable_unprepare(trng->clk);
return 0;
}
static const struct of_device_id ingenic_trng_of_match[] = {
{ .compatible = "ingenic,x1830-dtrng" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, ingenic_trng_of_match);
static struct platform_driver ingenic_trng_driver = {
.probe = ingenic_trng_probe,
.remove = ingenic_trng_remove,
.driver = {
.name = "ingenic-trng",
.of_match_table = ingenic_trng_of_match,
},
};
module_platform_driver(ingenic_trng_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>");
MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>");
MODULE_DESCRIPTION("Ingenic True Random Number Generator driver");
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