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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Ingenic True Random Number Generator driver
- * Copyright (c) 2019 漆鹏振 (Qi Pengzhen) <[email protected]>
- * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <[email protected]>
- */
- #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) <[email protected]>");
- MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <[email protected]>");
- MODULE_DESCRIPTION("Ingenic True Random Number Generator driver");
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