Hi Philipp, On Thu, May 10, 2012 at 02:52:11PM +0200, Philipp Ittershagen wrote: > (resend, forgot CC) > > Hi Andre! > > On Thu, May 10, 2012 at 11:09:07AM +0200, Andre Haupt wrote: > > Hi folks, > > > > Its been a while since i last did some kernel related stuff, > > so please bear with me if this sounds strange to your ears. > > > > What i want to achieve: > > I want to implement a hardware trigger that a user space process > > can react on. > > > > I need a driver that blocks a process/thread until a sepcific > > hardware interrupt occurs. The process should call a kernel > > interface and then should get blocked until another > > process/thread calls another kernel interface to stop waiting > > for the irq or an interrupt actually occurs. > > > > What i have: > > Back in the days i wrote a little character driver which implemented > > 2 ioctl commands. One command (IOCTL_TRIGGER_WAIT_IRQ) put the > > calling process to sleep using wait_evemt_interruptible() and > > the other command (IOCTL_TRIGGER_STOP_WAIT_IRQ) woke a processes > > again by calling wake_up_interruptible(). > > > > Now ioctls are frowned upon and i do not want to mess with > > majors and minors anymore either. > > > > Do you have any hints to the right approach for such a driver? > > Should i use some sysfs interface? If yes, which? Or does > > such a driver already exist? Can it be one completely in > > user space? > > Why don't you use open(), write(), read() etc. to do the job? > > Tasks which should block can then do > > echo wait > /dev/yourdevname > > and another process can cancel the waiting by doing > > echo cancel > /dev/yourdevname Or better, reading the device file blocks and returns the trigger status (none, triggered, aborted) and writing to the device file wakes up the sleeping processes. So cat /dev/mydevice would block until an interrupt occurs or someone does an echo foo > /dev/mydevice. I vagely remember having done that in the first place. I cant remember why i went with the ioctl stuff back then, though. cheers, Andre _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
