I implemented the entry point in my driver and from user-land with the pointer returned from mmap() I can access my SRAM. Unfortunately, every time I try to write I have an "EMT trap". Actually, sometimes I have this error also reading...
Have you got any idea about this misbehave? Luigi -----Messaggio originale----- Da: Stefano Babic [mailto:[email protected]] Inviato: martedì 5 ottobre 2010 16.58 A: Luigi Rizzi Cc: [email protected] Oggetto: Re: [ELDK] Userland memory access Luigi Rizzi wrote: > Hello, > > I connected an external SRAM to my TQM885D module. In the driver I'm > writing, with the virtual address returned by ioremap(), I can access > the memory locations with readb/writeb functions and also with direct > access. > > It's possible to map this kernel virtual space also in a user land > process? Of course. You need to implement the mmap entry point in your driver, as the framebuffer drivers are usual to do. Your application in user space needs only to call mmap() after opening your driver and use the returned pointer to access your SRAM. See more info with "man mmap". You find a lot of examples in kernel how to write the mmap entry point. Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: [email protected] ===================================================================== _______________________________________________ eldk mailing list [email protected] http://lists.denx.de/mailman/listinfo/eldk
