Re: question about writing to memory directly from user space in Linux
From: Stefan Nickl <hidden>
Date: 2005-03-24 07:44:14
From: Stefan Nickl <hidden>
Date: 2005-03-24 07:44:14
On Wed, 2005-03-23 at 09:10 -0800, Eugene Surovegin wrote:
On Wed, Mar 23, 2005 at 10:46:45AM +0100, Stefan Nickl wrote:quoted
On Wed, 2005-03-23 at 14:25 +0530, Vijay Padiyar wrote:quoted
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.Have a look at linux/include/asm-ppc/{io.h,system.h} and http://www.xml.com/ldd/chapter/book/ch08.html The eieio instruction doesn't need supervisor rights.eieio is a nop on 603e core.
Interesting, I was not aware of this. eieio is handled differently between MPC8245 and MPC8260. Anyways, it's a non-issue as IO memory should have the right WIMG bits set to take care of this, and modelling it with a in-kernel i2c bus as suggested on the list is soo much nicer. -- Stefan Nickl Kontron Modular Computers