This may not strictly be MicroBlaze specific, but maybe there's someone dealing with uClinux that has come across a techique applicable to my issue:
We have a SystemAce CardFlash with a single FAT partition. Our custom board gives an interrupt when the AC power begins to fail, allowing us at least 20ms of time before on-board power begins to go away. I'm trying to find a reliable way to flush anything that might be in uClinux's buffers to the CardFlash when we get that interrupt.
I believe sync() does what we want, but I'm having issues getting there fast enough. We catch the power fail interrupt just fine. Then we throw a signal that gets caught by a handler in our application. Our application priority has been set so we catch the signal reliably quickly in the handler, and so far we're running less than 1ms into our available time.
But it seems like the call to sync() does not return reliably in the time available, even if we know there is nothing pending to write to the CardFlash.
I don't know if I've chosen a silly way of doing this, or if there is some other side-effect or function of sync() that might be taking the time.
Any and all thoughts appreciated.
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