Goddeeris Frederic wrote: > > So the key is that by address is above ioremap_base. That I initially got > away with not using ioremap is a coincidence? Right?
No, it's not a coincidence. I've written sufficiently about virtual space mapping on the embedded processors in the past and if you just search the mailing list archives you will find all of the answers. The short answer.....on some processors, like the 8xx, there is a common address space used by many device drivers and functions unique to this processor. The granularity of mapping required is very small, resulting in many overlapped maps if you constantly use ioremap() in all of these cases. For this processor, a common area is ioremap()'ed by the memory management early in the kernel initialization for all of these uses. The side effect of mapping this early is you get a 1:1 virtual to physical mapping because the kernel VM is not yet fully initialized. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/