drivers/char/hw_random/ingenic-rng.c

Source file repositories/reference/linux-study-clean/drivers/char/hw_random/ingenic-rng.c

File Facts

System
Linux kernel
Corpus path
drivers/char/hw_random/ingenic-rng.c
Extension
.c
Size
3724 bytes
Lines
148
Domain
Driver Families
Bucket
drivers/char
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct ingenic_rng {
	enum ingenic_rng_version version;

	void __iomem *base;
	struct hwrng rng;
};

static int ingenic_rng_init(struct hwrng *rng)
{
	struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);

	writel(ERNG_ENABLE, priv->base + RNG_REG_ERNG_OFFSET);

	return 0;
}

static void ingenic_rng_cleanup(struct hwrng *rng)
{
	struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);

	writel(0, priv->base + RNG_REG_ERNG_OFFSET);
}

static int ingenic_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
{
	struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng);
	u32 *data = buf;
	u32 status;
	int ret;

	if (priv->version >= ID_X1000) {
		ret = readl_poll_timeout(priv->base + RNG_REG_ERNG_OFFSET, status,
					 status & ERNG_READY, 10, 1000);
		if (ret == -ETIMEDOUT) {
			pr_err("%s: Wait for RNG data ready timeout\n", __func__);
			return ret;
		}
	} else {
		/*
		 * A delay is required so that the current RNG data is not bit shifted
		 * version of previous RNG data which could happen if random data is
		 * read continuously from this device.
		 */
		udelay(20);
	}

	*data = readl(priv->base + RNG_REG_RNG_OFFSET);

	return 4;
}

static int ingenic_rng_probe(struct platform_device *pdev)
{
	struct ingenic_rng *priv;
	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)) {
		pr_err("%s: Failed to map RNG registers\n", __func__);
		return PTR_ERR(priv->base);
	}

	priv->version = (enum ingenic_rng_version)(uintptr_t)of_device_get_match_data(&pdev->dev);

	priv->rng.name = pdev->name;
	priv->rng.init = ingenic_rng_init;
	priv->rng.cleanup = ingenic_rng_cleanup;
	priv->rng.read = ingenic_rng_read;

	ret = hwrng_register(&priv->rng);
	if (ret) {
		dev_err(&pdev->dev, "Failed to register hwrng\n");
		return ret;
	}

	platform_set_drvdata(pdev, priv);

	dev_info(&pdev->dev, "Ingenic RNG driver registered\n");
	return 0;
}

static void ingenic_rng_remove(struct platform_device *pdev)
{
	struct ingenic_rng *priv = platform_get_drvdata(pdev);

	hwrng_unregister(&priv->rng);

Annotation

Implementation Notes