Messages in this thread |  | | Date | Tue, 1 May 2001 22:31:54 +0100 | From | Russell King <> | Subject | Re: 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 (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |