On Mon, Mar 07, 2016 at 03:00:50PM -0500, Kenneth Adam Miller wrote: > I have a driver that manages three sets of identical data structures that > differ only in address values. Currently, I pray that the device file to which > I have callbacks mapped for the driver gets called sequentially, because there > are pairs of mmap's that need to be made. I know that this isn't the most ideal > way to do it, so I'm searching for a better way rather than to swap out the > values on each method call. > > There are several things I am aware of but for each one I have questions: > 1) there are kernel module parameters > If I use kernel module parameters, I need to be able to insert the kernel > module three times in order to have each one have a distinct set of global > memory and mapped callbacks to distinct files. Can that be done? Second, I will > need to compile the driver statically later. How can I pass those parameters > that would otherwise be on the command line in statically? Never use kernel module parameters for a driver, nor for any other kernel module you create. They are global and don't work for device-specific issues. > 2) I can compile the driver in three times with a compile time flag. This is > the simplest and easiest, but it requires some buildroot and makefile foo that > I think is a dirty hack. It's also never accepted, don't do that. > 3) I could have the init function create three separate files, since it is on > init that I discover what my values are. But then I have to also associate > identical functions that reference global variables in the kernel object. > Duplicating the code would be worse that compiling the same code three times > with a kernel parameter, even though that would help me solve my distinct > globals problem. So how could I parameterisze a char device with data specific > to the instance? open() gives you the hook to do so, please just do that. There's a whole kernel tree full of examples of how to do this, take a look at existing code please. thanks, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
