Messages in this thread |  | | Date | Mon, 9 Sep 2002 13:29:42 -0400 (EDT) | From | "Richard B. Johnson" <> | Subject | RE: Calculating kernel logical address .. |
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On Mon, 9 Sep 2002, Imran Badr wrote:
> > So, what you gurus suggest me to do? How can I get physical address of a > user buffer (which was originally mmap'ed() from a kmalloc() allocation) and > which would also be protable across multiple platforms? > > Thanks. > Imran.
I think there is a virt_to_bus() macro and its inverse. The 'bus' address is what you need to give to bus-masters that do DMA. This is different than virt_to_phys(), which happens to be the same on some platforms but would not be the same on those, like PPC (Motorola), which have separate address spaces for different things (RAM, I/O, etc).
Isn't this what you want?
Cheers, Dick Johnson Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips). The US military has given us many words, FUBAR, SNAFU, now ENRON. Yes, top management were graduates of West Point and Annapolis.
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