linux arch 相关一些分析记录

/*

 * Set of macros to define architecture features.  This is built into

 * a table by the linker.

 */

#define MACHINE_START(_type,_name) \

static const struct machine_desc __mach_desc_##_type \

 __used \

 __attribute__((__section__(".arch.info.init"))) = { \

.nr = MACH_TYPE_##_type, \

.name = _name,

#define MACHINE_END \

};

[arch/arm/mach-mx35/mx35_3stack.c]

/*

 * The following uses standard kernel macros define in arch.h in order to

 * initialize __mach_desc_MX35_3DS data structure.

 */

/* *INDENT-OFF* */

MACHINE_START(MX35_3DS, "Freescale MX35 3-Stack Board")

/* Maintainer: Freescale Semiconductor, Inc. */

.phys_io = AIPS1_BASE_ADDR,

.io_pg_offst = ((AIPS1_BASE_ADDR_VIRT) >> 18) & 0xfffc,

.boot_params = PHYS_OFFSET + 0x100,

.fixup = fixup_mxc_board,

.map_io = mxc_map_io,

.init_irq = mxc_init_irq,

.init_machine = mxc_board_init,

.timer = &mxc_timer,

MACHINE_END

通过[include/linux/autoconf.h]

#define CONFIG_MACH_MX35_3DS 1

确定

#ifdef CONFIG_MACH_MX35_3DS

# ifdef machine_arch_type

#  undef machine_arch_type

#  define machine_arch_type __machine_arch_type

# else

#  define machine_arch_type MACH_TYPE_MX35_3DS

# endif

# define machine_is_mx35_3ds() (machine_arch_type == MACH_TYPE_MX35_3DS)

#else

# define machine_is_mx35_3ds() (0)

#endif

查找machine type流程:

setup_arch(&command_line);

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setup_machine(machine_arch_type);  //machine_arch_type 在autoconf.h定义

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lookup_machine_type   //[arch/arm/kernel/setup.c]

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/*

 * This provides a C-API version of the above function.

 */

ENTRY(lookup_machine_type)

stmfd sp!, {r4 - r6, lr}

mov r1, r0

bl __lookup_machine_type

mov r0, r5

ldmfd sp!, {r4 - r6, pc}

//[arch/arm/kernel/head-common.S]