drivers/media/platform/renesas/rcar-fcp.c

Source file repositories/reference/linux-study-clean/drivers/media/platform/renesas/rcar-fcp.c

File Facts

System
Linux kernel
Corpus path
drivers/media/platform/renesas/rcar-fcp.c
Extension
.c
Size
5111 bytes
Lines
217
Domain
Driver Families
Bucket
drivers/media
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 rcar_fcp_device {
	struct list_head list;
	struct device *dev;
	void __iomem *base;
};

static LIST_HEAD(fcp_devices);
static DEFINE_MUTEX(fcp_lock);

static inline void rcar_fcp_write(struct rcar_fcp_device *fcp, u32 reg, u32 val)
{
	iowrite32(val, fcp->base + reg);
}

/* -----------------------------------------------------------------------------
 * Public API
 */

/**
 * rcar_fcp_get - Find and acquire a reference to an FCP instance
 * @np: Device node of the FCP instance
 *
 * Search the list of registered FCP instances for the instance corresponding to
 * the given device node.
 *
 * Return a pointer to the FCP instance, or an ERR_PTR if the instance can't be
 * found.
 */
struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
{
	struct rcar_fcp_device *fcp;

	mutex_lock(&fcp_lock);

	list_for_each_entry(fcp, &fcp_devices, list) {
		if (fcp->dev->of_node != np)
			continue;

		get_device(fcp->dev);
		goto done;
	}

	fcp = ERR_PTR(-EPROBE_DEFER);

done:
	mutex_unlock(&fcp_lock);
	return fcp;
}
EXPORT_SYMBOL_GPL(rcar_fcp_get);

/**
 * rcar_fcp_put - Release a reference to an FCP instance
 * @fcp: The FCP instance
 *
 * Release the FCP instance acquired by a call to rcar_fcp_get().
 */
void rcar_fcp_put(struct rcar_fcp_device *fcp)
{
	if (fcp)
		put_device(fcp->dev);
}
EXPORT_SYMBOL_GPL(rcar_fcp_put);

struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp)
{
	return fcp->dev;
}
EXPORT_SYMBOL_GPL(rcar_fcp_get_device);

/**
 * rcar_fcp_enable - Enable an FCP
 * @fcp: The FCP instance
 *
 * Before any memory access through an FCP is performed by a module, the FCP
 * must be enabled by a call to this function. The enable calls are reference
 * counted, each successful call must be followed by one rcar_fcp_disable()
 * call when no more memory transfer can occur through the FCP.
 *
 * Return 0 on success or a negative error code if an error occurs. The enable
 * reference count isn't increased when this function returns an error.
 */
int rcar_fcp_enable(struct rcar_fcp_device *fcp)
{
	if (!fcp)
		return 0;

	return pm_runtime_resume_and_get(fcp->dev);
}
EXPORT_SYMBOL_GPL(rcar_fcp_enable);

Annotation

Implementation Notes