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
More information about the Linuxppc-embedded
mailing list