understanding an IO question

[Charles Krinke]

I have a board using an 8541 which is based on the mpc85xx_cds bsp. It
has one PCI device connected to the 8541, an ASIC we make that maps in
resources for its registers at 0x8400_0000 - 0x8400_0038.

The driver for our ASIC works in an 8241 design and I am trying to get
its register access working in the 8541 and need a little additional
understanding.

I can see in cat /proc/iomem where we have memory apparently allocated
for our registers, like this.

cat /proc/iomem
80000000-9fffffff : PCI1 host bridge
  84000000-84000038 : ichar
  88000000-8fffffff : ichar
e0003000-e00030ff : fsl-i2c.1
e0004500-e0004507 : serial

In our driver, I do an ioremap_nocache with 0x8400_0000 as an argument
to the ioremap and am returned a virtual address of the form
0xc905_8000. Unfortunately, I cannot seem to access my registers as they
all return zero when accessed with the iowrite32/ioread32 helper
functions.

A little further. We do use the Outbound Address Translation window
feature in the 8541 to get to our PCI device and I do set this up in
uboot and I can read and write registers on our ASIC from uboot. Its
just in the Linux driver that I seem to be having trouble.

So,... I am hoping someone could give me a couple of pointers on where
to look next for the missing piece of why I cannot access the registers
on our ASIC from Linux whereas things were working fine from uboot
before booting Linux.

Charles