I'm running Buildroot Linux in core 0 of an SC573. I would like a thread to wait for an event to be signaled by one of the SHARC cores. I've been using MCAPI, but it's staggeringly inefficient, not to mention buggy, so I'm looking for a simpler, faster alternative. One thing that might work would be to take an unused GPIO line, pulse it from the SHARC core, and have a Linux thread wait for an edge interrupt using the GPIO sysfs interface. But I'm wondering if there's a way to do it without actually involving a particular external hardware line. I'd like Linux to be able to open some pseudo-file, wait on it with read() or poll(), and then trigger it with some simple efficient operation in the SHARC. Is there a preferred way to do this, or am I stuck with MCAPI?