如何添加内核驱动修改makefile

参考《linux设备驱动开发详解》

在./drivers目录下新增为ARM体系结构编写test驱动程序，树形结构为：

|-- test

|-- cpu

| `-- cpu.c

|-- test.c

|-- test_client.c

|-- test_ioctl.c

|-- test_proc.c

`-- test_queue.c

1、修改需要使用test驱动的目录下的Kconfig

在 arch/arm/Kconfig 增加下面内容

source "drivers/test/Kconfig"

2、修改test父目录下的Makefile

在./drivers/Makefile 增加下面内容

obj-$(CONFIG_TEST) +=test/

3、新增test目录下的Kconfig

##########################

# TEST driver configurations

##########################

menu "TEST Driver"

comment "TEST Driver"

config CONFIG_TEST

bool "TEST support"

config CONFIG_TEST_USER

tristate "TEST usr-space interface"

depend on CONFIG_TEST

endmenu

4、在test目录下新增Makefile

#drivers/test/Makefile

#

# Makefile for the TEST

#

obj-$(CONFIG_TEST) += test.o test_queue.o test_client.o

obj-$(CONFIG_TEST_USER) += test_ioctl.o

obj-$(CONFIG_PROC_FS) += test_proc.o

obj-$(CONFIG_TEST_CPU) += cpu/

5、在cpu子目录下新增Makefile

# Makefile for the TEST CPU

#

obj-$(CONFIG_TEST_CPU) += cpu.o

至此Konfig和Makefile 修改完成

Documentation/kbuild/makefiles.txt

=== 3 The kbuild files

Most Makefiles within the kernel are kbuild Makefiles that use the

kbuild infrastructure. This chapter introduces the syntax used in the

kbuild makefiles.

The preferred name for the kbuild files are 'Makefile' but 'Kbuild' can

be used and if both a 'Makefile' and a 'Kbuild' file exists, then the 'Kbuild'

file will be used.

Section 3.1 "Goal definitions" is a quick intro, further chapters provide

more details, with real examples.

--- 3.1 Goal definitions

Goal definitions are the main part (heart) of the kbuild Makefile.

These lines define the files to be built, any special compilation

options, and any subdirectories to be entered recursively.

The most simple kbuild makefile contains one line:

Example:

obj-y += foo.o

This tells kbuild that there is one object in that directory, named

foo.o. foo.o will be built from foo.c or foo.S.

If foo.o shall be built as a module, the variable obj-m is used.

Therefore the following pattern is often used:

Example:

obj-$(CONFIG_FOO) += foo.o

$(CONFIG_FOO) uates to either y (for built-in) or m (for module).

If CONFIG_FOO is neither y nor m, then the file will not be compiled

nor linked.

--- 3.2 Built-in object goals - obj-y

The kbuild Makefile specifies object files for vmlinux

in the $(obj-y) lists. These lists depend on the kernel

configuration.

Kbuild compiles all the $(obj-y) files. It then calls

"$(LD) -r" to merge these files into one
built-in.o file.

built-in.o is later linked into vmlinux by the parent Makefile.

The order of files in $(obj-y) is significant. Duplicates in

the lists are allowed: the first instance will be linked into

built-in.o and succeeding instances will be ignored.

Link order is significant, because certain functions

(module_init() / __initcall) will be called during boot in the

order they appear. So keep in mind that changing the link

order may e.g. change the order in which your SCSI

controllers are detected, and thus your disks are renumbered.

--- 3.3 Loadable module goals - obj-m

$(obj-m) specify object files which are built as loadable

kernel modules.

A module may be built from one source file or several source

files. In the case of one source file, the kbuild makefile

simply adds the file to $(obj-m).

Example:

#drivers/isdn/i4l/Makefile

obj-$(CONFIG_ISDN_PPP_BSDCOMP) += isdn_bsdcomp.o

Note: In this example $(CONFIG_ISDN_PPP_BSDCOMP) uates to 'm'

If a kernel module is built from several source files, you specify

that you want to build a module in the same way as above.

Kbuild needs to know which the parts that you want to build your

module from, so you have to tell it by setting an

$(<module_name>-objs) variable.

Example:

#drivers/isdn/i4l/Makefile

obj-$(CONFIG_ISDN) += isdn.o

isdn-objs := isdn_net_lib.o isdn_v110.o isdn_common.o

In this example, the module name will be isdn.o. Kbuild will

compile the objects listed in $(isdn-objs) and then run

"$(LD) -r" on the list of these files to generate isdn.o.

Kbuild recognises objects used for composite objects by the suffix

-objs, and the suffix -y. This allows the Makefiles to use

the value of a CONFIG_ symbol to determine if an object is part

of a composite object.

Example:

#fs/ext2/Makefile

obj-$(CONFIG_EXT2_FS) += ext2.o

ext2-y := balloc.o bitmap.o

ext2-$(CONFIG_EXT2_FS_XATTR) += xattr.o

In this example, xattr.o is only part of the composite object

ext2.o if $(CONFIG_EXT2_FS_XATTR) uates to 'y'.

Note: Of course, when you are building objects into the kernel,

the syntax above will also work. So, if you have CONFIG_EXT2_FS=y,

kbuild will build an ext2.o file for you out of the individual

parts and then link this into built-in.o, as you would expect.