drivers/reset/starfive/reset-starfive-jh71x0.c

Source file repositories/reference/linux-study-clean/drivers/reset/starfive/reset-starfive-jh71x0.c

File Facts

System
Linux kernel
Corpus path
drivers/reset/starfive/reset-starfive-jh71x0.c
Extension
.c
Size
3425 bytes
Lines
135
Domain
Driver Families
Bucket
drivers/reset
Inferred role
Driver Families: exported/initcall integration point
Status
integration 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 jh71x0_reset {
	struct reset_controller_dev rcdev;
	/* protect registers against concurrent read-modify-write */
	spinlock_t lock;
	void __iomem *assert;
	void __iomem *status;
	const u32 *asserted;
};

static inline struct jh71x0_reset *
jh71x0_reset_from(struct reset_controller_dev *rcdev)
{
	return container_of(rcdev, struct jh71x0_reset, rcdev);
}

static int jh71x0_reset_update(struct reset_controller_dev *rcdev,
			       unsigned long id, bool assert)
{
	struct jh71x0_reset *data = jh71x0_reset_from(rcdev);
	unsigned long offset = id / 32;
	u32 mask = BIT(id % 32);
	void __iomem *reg_assert = data->assert + offset * sizeof(u32);
	void __iomem *reg_status = data->status + offset * sizeof(u32);
	u32 done = data->asserted ? data->asserted[offset] & mask : 0;
	u32 value;
	unsigned long flags;
	int ret;

	if (!assert)
		done ^= mask;

	spin_lock_irqsave(&data->lock, flags);

	value = readl(reg_assert);
	if (assert)
		value |= mask;
	else
		value &= ~mask;
	writel(value, reg_assert);

	/* if the associated clock is gated, deasserting might otherwise hang forever */
	ret = readl_poll_timeout_atomic(reg_status, value, (value & mask) == done, 0, 1000);

	spin_unlock_irqrestore(&data->lock, flags);
	return ret;
}

static int jh71x0_reset_assert(struct reset_controller_dev *rcdev,
			       unsigned long id)
{
	return jh71x0_reset_update(rcdev, id, true);
}

static int jh71x0_reset_deassert(struct reset_controller_dev *rcdev,
				 unsigned long id)
{
	return jh71x0_reset_update(rcdev, id, false);
}

static int jh71x0_reset_reset(struct reset_controller_dev *rcdev,
			      unsigned long id)
{
	int ret;

	ret = jh71x0_reset_assert(rcdev, id);
	if (ret)
		return ret;

	return jh71x0_reset_deassert(rcdev, id);
}

static int jh71x0_reset_status(struct reset_controller_dev *rcdev,
			       unsigned long id)
{
	struct jh71x0_reset *data = jh71x0_reset_from(rcdev);
	unsigned long offset = id / 32;
	u32 mask = BIT(id % 32);
	void __iomem *reg_status = data->status + offset * sizeof(u32);
	u32 value = readl(reg_status);

	if (!data->asserted)
		return !(value & mask);

	return !((value ^ data->asserted[offset]) & mask);
}

static const struct reset_control_ops jh71x0_reset_ops = {
	.assert		= jh71x0_reset_assert,
	.deassert	= jh71x0_reset_deassert,
	.reset		= jh71x0_reset_reset,

Annotation

Implementation Notes