Vijay Padiyar wrote: >I am running Linux 2.6.10 on an MPC8260 target. We have an I2C controller >that is part of our application code. In VxWorks, we could address the >MPC8260 I2C memory registers directly from application space and so this was >not a problem.
The I2C abstraction layer of Linux is very good, and user-land support quite comfortable. Why bother port/develop a new driver? Besides, interrupt handling in user-space can be troublesome.. >Can you suggest some kind of a "synchronization" function which I can call >from *user space* which will ensure that all values written to mmaped memory >locations from user space are actually flushed to their physical locations? >I think this might be a potential problem with my code. Please have a look at Denx's FAQ for accessing memory bus: http://www.denx.de/twiki/bin/view/PPCEmbedded/DeviceDrivers#Section_Acce ssingPeripheralsFromUserSpace or shorter: http://tinyurl.com/6c7th Depending on the O_SYNC flag passed to open, the mmap'ed memory will be accessed through non guarded cache or not. See linux/drivers/char/mem.c. The ppc instruction "eieio" deals with I/O ordering. Regards, -- Stephane
