深入Device Tree--LINUX中用DT_MACHINE_START/MACHINE_START
本文上接 深入Device Tree。
关于驱动想说的话：以前总以为高而攀不到。花时间去积累了，总会进步的。
这个世界需要的是全力以赴，战胜他人先战胜子自己！！
LINUX中用DT_MACHINE_START/MACHINE_START定义的MACH，并给出定义的各个成员函数在初始化过程中被调用的时机
所以 如下的 DT_MACHINE_START,
可展开为 ： DT_MACHINE_START(MSM8974_DT, "Qualcomm MSM 8974 (Flattened Device Tree)")
.map_io = msm8974_map_io,
.init_irq = msm_dt_init_irq,
.init_machine = msm8974_init,
.handle_irq = gic_handle_irq,
.timer = &msm_dt_timer,
.dt_compat = msm8974_dt_match,
.reserve = msm_8974_reserve,
.init_very_early = msm8974_init_very_early,
.restart = msm_restart,
.smp = &msm8974_smp_ops,
MACHINE_END
static const struct machine_desc __mach_desc_MSM8974_DT{
__used
__attribute__((__section__(".arch.info.init"))) = {
.nr = ~0,
.name = "Qualcomm MSM 8974 (Flattened Device Tree)",
.map_io = msm8974_map_io,
.init_irq = msm_dt_init_irq,
.init_machine = msm8974_init,
.handle_irq = gic_handle_irq,
.timer = &msm_dt_timer,
.dt_compat = msm8974_dt_match,
.reserve = msm_8974_reserve,
.init_very_early = msm8974_init_very_early,
.restart = msm_restart,
.smp = &msm8974_smp_ops,
};
定义了"struct machine_desc"的类型变量，放在 section(".arch.info.init")，是内核初始化数据。
*******************************************************************************************
*** DT_MACHINE_START 宏展开
*******************************************************************************************
kernel\arch\arm\include\asm\mach\arch.h
/*
* 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 \
};
#define DT_MACHINE_START(_name, _namestr) \
static const struct machine_desc __mach_desc_##_name \
__used \
__attribute__((__section__(".arch.info.init"))) = { \
.nr = ~0, \
.name = _namestr,
#endif
machine_desc 的定义
struct machine_desc {
unsigned int nr; /* architecture number */
const char *name; /* architecture name */
unsigned long atag_offset; /* tagged list (relative) */
const char *const *dt_compat; /* array of device tree
* 'compatible' strings */
unsigned int nr_irqs; /* number of IRQs */
#ifdef CONFIG_ZONE_DMA
phys_addr_t dma_zone_size; /* size of DMA-able area */
#endif
unsigned int video_start; /* start of video RAM */
unsigned int video_end; /* end of video RAM */
unsigned char reserve_lp0 :1; /* never has lp0 */
unsigned char reserve_lp1 :1; /* never has lp1 */
unsigned char reserve_lp2 :1; /* never has lp2 */
enum reboot_mode reboot_mode; /* default restart mode */
unsigned l2c_aux_val; /* L2 cache aux value */
unsigned l2c_aux_mask; /* L2 cache aux mask */
void (*l2c_write_sec)(unsigned long, unsigned);
struct smp_operations *smp; /* SMP operations */
bool (*smp_init)(void);
void (*fixup)(struct tag *, char **);
void (*dt_fixup)(void);
void (*init_meminfo)(void);
void (*reserve)(void);/* reserve mem blocks */
void (*map_io)(void);/* IO mapping function */
void (*init_early)(void);
void (*init_irq)(void);
void (*init_time)(void);
void (*init_machine)(void);
void (*init_late)(void);
#ifdef CONFIG_MULTI_IRQ_HANDLER
void (*handle_irq)(struct pt_regs *);
#endif
void (*restart)(enum reboot_mode, const char *);
};