Dear Vinay, THX for You answer! On 21 Mar 2002 at 15:07, Vinay wrote: > Why do you need ioremap() as you are using request_region() . ioremap() must > be used when you are requesting for a memory region (request_mem_region) . > > can u explain u'r problem in detail . I'm implementing the real time clock handling routines for a ppc platform. This equipment has own RTC chip (not the one which is integrated to the CPU as the kernel sources expects). I need to get/set rtc time from the kernel, so I modified arch/ppc/kernel/m8xx_setup.c to use the proper IO ports for setting and getting data to and from the RTC chip (with readb and writeb). Also I had to create an RTC module which also modifies data stored in the RTC chip. So there are two possible way to communicate with the RTC: thru the kernel and thru the module. I wanted to create the kernel modification no to allow anyone else to touches the IO range of the RTC. That's why I wanted to use request_region() in the kernel. But when I do that the kernel is not able to boot up. Now I don't use the request_region() in the kernel, just in the loadable module, so I can see the result in /proc/ioports and no other modules can touch these io region, but there is a possibility to load an other module before mine which can modify the data stored in the RTC chip. Would it be possible to forbid other processes to reach a given IO range in the kernel? TIA && Good byte! -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
