drivers/net/ethernet/sfc/bitfield.h

Source file repositories/reference/linux-study-clean/drivers/net/ethernet/sfc/bitfield.h

File Facts

System
Linux kernel
Corpus path
drivers/net/ethernet/sfc/bitfield.h
Extension
.h
Size
23256 bytes
Lines
617
Domain
Driver Families
Bucket
drivers/net
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

#ifndef EFX_BITFIELD_H
#define EFX_BITFIELD_H

/*
 * Efx bitfield access
 *
 * Efx NICs make extensive use of bitfields up to 128 bits
 * wide.  Since there is no native 128-bit datatype on most systems,
 * and since 64-bit datatypes are inefficient on 32-bit systems and
 * vice versa, we wrap accesses in a way that uses the most efficient
 * datatype.
 *
 * The NICs are PCI devices and therefore little-endian.  Since most
 * of the quantities that we deal with are DMAed to/from host memory,
 * we define our datatypes (efx_oword_t, efx_qword_t and
 * efx_dword_t) to be little-endian.
 */

/* Lowest bit numbers and widths */
#define EFX_DUMMY_FIELD_LBN 0
#define EFX_DUMMY_FIELD_WIDTH 0
#define EFX_BYTE_0_LBN 0
#define EFX_BYTE_0_WIDTH 8
#define EFX_WORD_0_LBN 0
#define EFX_WORD_0_WIDTH 16
#define EFX_WORD_1_LBN 16
#define EFX_WORD_1_WIDTH 16
#define EFX_DWORD_0_LBN 0
#define EFX_DWORD_0_WIDTH 32
#define EFX_DWORD_1_LBN 32
#define EFX_DWORD_1_WIDTH 32
#define EFX_DWORD_2_LBN 64
#define EFX_DWORD_2_WIDTH 32
#define EFX_DWORD_3_LBN 96
#define EFX_DWORD_3_WIDTH 32
#define EFX_QWORD_0_LBN 0
#define EFX_QWORD_0_WIDTH 64

/* Specified attribute (e.g. LBN) of the specified field */
#define EFX_VAL(field, attribute) field ## _ ## attribute
/* Low bit number of the specified field */
#define EFX_LOW_BIT(field) EFX_VAL(field, LBN)
/* Bit width of the specified field */
#define EFX_WIDTH(field) EFX_VAL(field, WIDTH)
/* High bit number of the specified field */
#define EFX_HIGH_BIT(field) (EFX_LOW_BIT(field) + EFX_WIDTH(field) - 1)
/* Mask equal in width to the specified field.
 *
 * For example, a field with width 5 would have a mask of 0x1f.
 *
 * The maximum width mask that can be generated is 64 bits.
 */
#define EFX_MASK64(width)			\
	((width) == 64 ? ~((u64) 0) :		\
	 (((((u64) 1) << (width))) - 1))

/* Mask equal in width to the specified field.
 *
 * For example, a field with width 5 would have a mask of 0x1f.
 *
 * The maximum width mask that can be generated is 32 bits.  Use
 * EFX_MASK64 for higher width fields.
 */
#define EFX_MASK32(width)			\
	((width) == 32 ? ~((u32) 0) :		\
	 (((((u32) 1) << (width))) - 1))

/* A doubleword (i.e. 4 byte) datatype - little-endian in HW */
typedef union efx_dword {
	__le32 u32[1];
} efx_dword_t;

/* A quadword (i.e. 8 byte) datatype - little-endian in HW */
typedef union efx_qword {
	__le64 u64[1];
	__le32 u32[2];
	efx_dword_t dword[2];
} efx_qword_t;

/* An octword (eight-word, i.e. 16 byte) datatype - little-endian in HW */
typedef union efx_oword {
	__le64 u64[2];
	efx_qword_t qword[2];
	__le32 u32[4];
	efx_dword_t dword[4];
} efx_oword_t;

/* Format string and value expanders for printk */
#define EFX_DWORD_FMT "%08x"
#define EFX_QWORD_FMT "%08x:%08x"

Annotation

Implementation Notes