drivers/usb/host/xhci-ext-caps.h

Source file repositories/reference/linux-study-clean/drivers/usb/host/xhci-ext-caps.h

File Facts

System
Linux kernel
Corpus path
drivers/usb/host/xhci-ext-caps.h
Extension
.h
Size
5239 bytes
Lines
158
Domain
Driver Families
Bucket
drivers/usb
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 xhci_protocol_caps {
	u32	revision;
	u32	name_string;
	u32	port_info;
};

#define	XHCI_EXT_PORT_MAJOR(x)	(((x) >> 24) & 0xff)
#define	XHCI_EXT_PORT_MINOR(x)	(((x) >> 16) & 0xff)
#define	XHCI_EXT_PORT_PSIC(x)	(((x) >> 28) & 0x0f)
#define	XHCI_EXT_PORT_OFF(x)	((x) & 0xff)
#define	XHCI_EXT_PORT_COUNT(x)	(((x) >> 8) & 0xff)

#define	XHCI_EXT_PORT_PSIV(x)	(((x) >> 0) & 0x0f)
#define	XHCI_EXT_PORT_PSIE(x)	(((x) >> 4) & 0x03)
#define	XHCI_EXT_PORT_PLT(x)	(((x) >> 6) & 0x03)
#define	XHCI_EXT_PORT_PFD(x)	(((x) >> 8) & 0x01)
#define	XHCI_EXT_PORT_LP(x)	(((x) >> 14) & 0x03)
#define	XHCI_EXT_PORT_PSIM(x)	(((x) >> 16) & 0xffff)

#include <linux/io.h>

/**
 * Find the offset of the extended capabilities with capability ID id.
 *
 * @base	PCI MMIO registers base address.
 * @start	address at which to start looking, (0 or HCC_PARAMS to start at
 *		beginning of list)
 * @id		Extended capability ID to search for, or 0 for the next
 *		capability
 *
 * Returns the offset of the next matching extended capability structure.
 * Some capabilities can occur several times, e.g., the XHCI_EXT_CAPS_PROTOCOL,
 * and this provides a way to find them all.
 */

static inline int xhci_find_next_ext_cap(void __iomem *base, u32 start, int id)
{
	u32 val;
	u32 next;
	u32 offset;

	offset = start;
	if (!start || start == XHCI_HCC_PARAMS_OFFSET) {
		val = readl(base + XHCI_HCC_PARAMS_OFFSET);
		if (val == ~0)
			return 0;
		offset = XHCI_HCC_EXT_CAPS(val) << 2;
		if (!offset)
			return 0;
	}
	do {
		val = readl(base + offset);
		if (val == ~0)
			return 0;
		if (offset != start && (id == 0 || XHCI_EXT_CAPS_ID(val) == id))
			return offset;

		next = XHCI_EXT_CAPS_NEXT(val);
		offset += next << 2;
	} while (next);

	return 0;
}

Annotation

Implementation Notes