Linux Device Drivers, Second Edition

Quick Reference

The following symbols were introduced in this chapter.

#include <linux/types.h> , typedef u8; , typedef u16; , typedef u32; , typedef u64;

These types are guaranteed to be 8-, 16-, 32-, and 64-bit unsigned integer values. The equivalent signed types exist as well. In user space, you can refer to the types as __u8, __u16, and so forth.

#include <asm/page.h> , PAGE_SIZE , PAGE_SHIFT

These symbols define the number of bytes per page for the current architecture and the number of bits in the page offset (12 for 4-KB pages and 13 for 8-KB pages).

#include <asm/byteorder.h> , __LITTLE_ENDIAN , __BIG_ENDIAN

Only one of the two symbols is defined, depending on the architecture.

#include <asm/byteorder.h> , u32 __cpu_to_le32 (u32); , u32 __le32_to_cpu (u32); ,

Functions for converting between known byte orders and that of the processor. There are more than 60 such functions; see the various files in include/linux/byteorder/ for a full list and the ways in which they are defined.

#include <asm/unaligned.h> , get_unaligned(ptr); , put_unaligned(val, ptr);

Some architectures need to protect unaligned data access using these macros. The macros expand to normal pointer dereferencing for architectures that permit you to access unaligned data.

#include <linux/list.h> , list_add(struct list_head *new, struct list_head *head); , list_add_tail(struct list_head *new, struct list_head *head); , list_del(struct list_head *entry); , list_empty(struct list_head *head); , list_entry(entry, type, member); , list_splice(struct list_head *list, struct list_head *head);

Functions for manipulating circular, doubly linked lists.