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Re: port uclinux on stm32f7?

Question asked by sheng yang on Apr 14, 2018
Latest reply on Apr 18, 2018 by sheng yang
Branched from an earlier discussion

I add earlyprintl support for stm32f767igt,and it seems success.i modified the start_kernel() function as below

extern void printascii(const char *);
asmlinkage __visible void __init start_kernel(void)
{
char *command_line;
char *after_dashes;
printascii("iysheng debug!!!!");

}

i get the console output

iysheng debug!!!![ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 4.4.0-uc0-g17edafa-dirty (shengyang@red.redzone) (gcc version 5.4.0 (GCC) ) #64 PREEMPT Sat Apr 14 20:21:44 CST 2018
[ 0.000000] CPU: ARMv7-M [411fc270] revision 0 (ARMv7M), cr=00000000
[ 0.000000] CPU: unknown data cache, unknown instruction cache
[ 0.000000] Machine model: STMicroelectronics STM32429i-EVAL board
[ 0.000000] bootconsole [earlycon0] enabled
[ 0.000000] debug: i.....

 

But when i debug  timer function,i add one line code in file uClinux/linux/drivers/clocksource/timer-stm32.c as

static irqreturn_t stm32_clock_event_handler(int irq, void *dev_id)
{
struct stm32_clock_event_ddata *data = dev_id;

writel_relaxed(0, data->base + TIM_SR);

data->evtdev.event_handler(&data->evtdev);
printk("iysheng *******\n");
return IRQ_HANDLED;
}

then i get nothing from console,i get confuzed,why could this happen,clk and timer will init after these code i add in start_kernl().So why that happed ,why could i get nothing from the console? 

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