Subject: Re: MPC8250 + PCMCIA + airo_cs card + IO Port mapping problem?

From: Dan Malek <[email-masked]>
Date: Thu, 22 May 2003 00:33:51 -0400

Jim Rowe wrote:

>>>From what I can see - and please correct me if I'm wrong, the way that
> Linux translates the Port IO to the memory mapped IO is through the outb
> and outw macros, which add an offset of _IO_BASE. How do I determine the
> correct value of _IO_BASE?

The value of _IO_BASE depends upon how you configure and map the host PCI
bridge on the 8250.

> ... I looked in m8260_setup.c and found

The 8260 doesn't have a PCI bridge, so these mappings aren't appropriate
for your board.  The 0xf0000000 is needed to get to the IMMR space, but
those accesses don't (shouldn't) be using in/out macros.  The 0xe0000000
space is generally used for flash prom, external devices, local sdram
and so on.

There are a variety of configuration options for the PCI bridge and all of
the other I/O in your system and the mapping using either BATs or page
tables.  It depends upon the address ranges of all of the I/O in your
system and their physical space allocation.

	-- Dan

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