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SubjectRe: isa_read/write not available on ppc - solution suggestions ??
On Tue, May 01, 2001 at 02:19:33PM -0700, Linus Torvalds wrote:
> On Tue, 1 May 2001, Russell King wrote:
> > Talking around this issue, is there any chance of getting the
> > official use of the first parameter to ioremap documented in
> > Documentation/IO-mapping.txt please? There appears to be
> > confusion as to whether it is:
> >
> > a) PCI bus address
> > b) CPU untranslated address
> It's neither.
> It's a cookie that you can do arithmetic off and pass on to the
> readx/writex, and nothing more. You cannot make any assumptions at all
> about what it means.
> In particular, you can _not_ assume that it is a PCI bus address ("WHICH
> bus?") and you can absolutely not assume that it is a CPU address (many
> CPU's do not "memory map" PCI at all).

In which case, can we change the following in IO-mapping.txt please?

* remap framebuffer PCI memory area at 0xFC000000,
* size 1MB, so that we can access it: We can directly
* access only the 640k-1MB area, so anything else
* has to be remapped.
char * baseptr = ioremap(0xFC000000, 1024*1024);

since its not true? (since 0xfc000000 is a cookie).

Russell King ( The developer of ARM Linux

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