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Forum Post: RE: DMTIMER PROBLEM

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[quote user="LIANG WANG102707"]

I have do print inside omap_dmtimer_stop(),it show that

l = __omap_dm_timer_read(timer, OMAP_TIMER_CTRL_REG, posted);

this sentence lead to fail

[/quote]

Looking inside the read function, it looks like if Write Posted mode is used, then the software synchronisation inside the dmtimer driver checks if there is a pending write access to the register and waits for it, but for some reason this ends up in a endless loop. I can't be 100% sure, but this is the only explanation I have from reading the source code:

[quote]    if (posted)
        while (__raw_readl(timer->pend) & (reg >> WPSHIFT))
            cpu_relax();[/quote]

Please try to print the value of timer->pend and reg>>WPSHIFT inside this while loop. This is inside the __omap_dm_timer_read() function.

More information about the DMTIMER Write Posted mode can be read inside the AM335x TRM, section 20.1.3.10.1.

Best regards,
Miroslav


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