UBOOT timer设置（基于S3C2440）

UBOOT TIMER设置（基于mini2440）

1. 相关代码

代码路径：cpu\arm920t\s3c24x0\timer.c

函数：

int timer_init(void)

{

struct s3c24x0_timers *timers = s3c24x0_get_base_timers();

ulong tmr;

 

/* use PWM Timer 4 because it has no output */

/* prescaler for Timer 4 is 16 */

writel(0x0f00, &timers->TCFG0);

if (timer_load_val == 0) {

/*

 * for 10 ms clock period @ PCLK with 4 bit divider = 1/2

 * (default) and prescaler = 16. Should be 10390

 * @33.25MHz and 15625 @ 50 MHz

 */

timer_load_val = get_PCLK() / (2 * 16 * 100);

timer_clk = get_PCLK() / (2 * 16);

}

/* load value for 10 ms timeout */

lastdec = timer_load_val;

writel(timer_load_val, &timers->TCNTB4);

/* auto load, manual update of Timer 4 */

tmr = (readl(&timers->TCON) & ~0x0700000) | 0x0600000;

writel(tmr, &timers->TCON);

/* auto load, start Timer 4 */

tmr = (tmr & ~0x0700000) | 0x0500000;

writel(tmr, &timers->TCON);

timestamp = 0;

 

return (0);

}

 

函数被调用的地方：

代码路径\lib_arm\board.c

函数指针数组：

init_fnc_t *init_sequence[] = {

#if defined(CONFIG_ARCH_CPU_INIT)

arch_cpu_init, /* basic arch cpu dependent setup */

#endif

board_init, /* basic board dependent setup */

#if defined(CONFIG_USE_IRQ)

interrupt_init, /* set up exceptions */

#endif

timer_init, /* initialize timer */

#ifdef CONFIG_FSL_ESDHC

get_clocks,

#endif

env_init, /* initialize environment */

init_baudrate, /* initialze baudrate settings */

serial_init, /* serial communications setup */

console_init_f, /* stage 1 init of console */

display_banner, /* say that we are here */

#if defined(CONFIG_DISPLAY_CPUINFO)

print_cpuinfo, /* display cpu info (and speed) */

#endif

#if defined(CONFIG_DISPLAY_BOARDINFO)

checkboard, /* display board info */

#endif

#if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C)

init_func_i2c,

#endif

dram_init, /* configure available RAM banks */

#if defined(CONFIG_CMD_PCI) || defined (CONFIG_PCI)

arm_pci_init,

#endif

display_dram_config,

NULL,

};

 

调用函数：void start_armboot (void)

代码：

for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {

if ((*init_fnc_ptr)() != 0) {

hang ();

}

}