Accessing peripheral bus devices on 460GT

vb vb at vsbe.com
Thu Aug 7 12:52:53 EST 2008


I am trying to bring up a 2.6.25 based system on a 460GT platform. I
am using the OF tree cloned off canyonblands.dts, and I am not sure if
something is missing in the tree, or in the kernel, or I am doing
something stupid.

The problem is that I don't seem to be able to access any peripheral
device activated by cs1, 2, 3 (I have not tried touching the NOR flash
(cs0) just yet). If I don't touch any peripherals the system can
netbboot or diskboot all the way to the linux prompt.

But unfortunately, the damn peripherals have to be touched :-)

I do invoke ioremap_nocache(<phys addr>, <addr range size>), and it
returns a virtual address. The thing is that as soon as I try
accessing the device off this pointer an exception is thrown. From
u-boot  I can access the <phys addr>..+<addr range size> space no
problem.

 I see that the dts file mentions that u-boot is supposed to supply
the "ranges" property in the /plb/opb/ebc section; examining the
u-boot code for different amcc platforms shows that only the NOR flash
size is supplied there.

I guess the real question is how do I gain access to the EBC mapped
hardware configured by u-boot?

can someone please shed any light on this,

thanks a lot in advance,

Vadim


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