drivers/char/hw_random/mtk-rng.c

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

File Facts

System
Linux kernel
Corpus path
drivers/char/hw_random/mtk-rng.c
Extension
.c
Size
6611 bytes
Lines
289
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 mtk_rng {
	void __iomem *base;
	struct clk *clk;
	struct hwrng rng;
	struct device *dev;
	unsigned long flags;
};

static int mtk_rng_init(struct hwrng *rng)
{
	struct mtk_rng *priv = to_mtk_rng(rng);
	u32 val;
	int err;

	err = clk_prepare_enable(priv->clk);
	if (err)
		return err;

	val = readl(priv->base + RNG_CTRL);
	val |= RNG_EN;
	writel(val, priv->base + RNG_CTRL);

	return 0;
}

static void mtk_rng_cleanup(struct hwrng *rng)
{
	struct mtk_rng *priv = to_mtk_rng(rng);
	u32 val;

	val = readl(priv->base + RNG_CTRL);
	val &= ~RNG_EN;
	writel(val, priv->base + RNG_CTRL);

	clk_disable_unprepare(priv->clk);
}

static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait)
{
	struct mtk_rng *priv = to_mtk_rng(rng);
	int ready;

	ready = readl(priv->base + RNG_CTRL) & RNG_READY;
	if (!ready && wait)
		readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready,
					  ready & RNG_READY, USEC_POLL,
					  TIMEOUT_POLL);
	return !!(ready & RNG_READY);
}

static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
{
	struct mtk_rng *priv = to_mtk_rng(rng);
	int retval = 0;

	pm_runtime_get_sync(priv->dev);

	while (max >= sizeof(u32)) {
		if (!mtk_rng_wait_ready(rng, wait))
			break;

		*(u32 *)buf = readl(priv->base + RNG_DATA);
		retval += sizeof(u32);
		buf += sizeof(u32);
		max -= sizeof(u32);
	}

	pm_runtime_put_sync_autosuspend(priv->dev);

	return retval || !wait ? retval : -EIO;
}

static int mtk_rng_read_smc(struct hwrng *rng, void *buf, size_t max,
			    bool wait)
{
	struct arm_smccc_res res;
	int retval = 0;

	while (max >= sizeof(u32)) {
		arm_smccc_smc(MTK_SIP_KERNEL_GET_RND, 0, 0, 0, 0, 0, 0, 0,
			      &res);
		if (res.a0)
			break;

		*(u32 *)buf = res.a1;
		retval += sizeof(u32);
		buf += sizeof(u32);
		max -= sizeof(u32);
	}

Annotation

Implementation Notes