diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/char/hw_random/ingenic-trng.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/drivers/char/hw_random/ingenic-trng.c b/drivers/char/hw_random/ingenic-trng.c new file mode 100644 index 000000000..0eb80f786 --- /dev/null +++ b/drivers/char/hw_random/ingenic-trng.c @@ -0,0 +1,165 @@ +// 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"); |