Maximum ioremap size for ppc arch?

Arnd Bergmann arnd at
Mon Dec 3 21:20:22 EST 2007

On Monday 03 December 2007, michael.firth at wrote:
> I'm trying to get am MPC834x system running that has 256MBytes of NOR
> flash connected.
> The physmap flash driver is failing to ioremap() that amount of space,
> while on a similar system with 128Mbytes of flash, there are no
> problems.
> Is this a known limitation of ioremap() on the ppc architecture, or
> specifically the MPC834x family, and is there any (hopefully easy) way
> to increase this limit?

The amount of ioremap space is very limited on 32bit systems in general,
since most people are more interested in having a large physical address
space without highmem. Look at the definition of VMALLOC_START and
VMALLOC_END if you want to change the settings on your system.

	Arnd <><

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