problem with accessing memory mapped area

Mark Chambers markc at
Sat Feb 12 00:27:47 EST 2005

> In addition, in the address range 0x30000000-0x300000FF, I have a CPLD
> mapped.
> Now, I wish to access the registers of this CPLD. For this, I create a
> module and insert it into the kernel. Now, in my 'init_module' function, I
> map the address range 0x30000000-0x300000FF to cpld_mem:
> But when I execute this program on the target, it crashes after displaying
> "Writing to CPLD". Sometimes it says 'Bus error' and some other times I
> a 'Kernel panic' message and the system reboots.

If you are getting 'bus error' it sounds like the memory controller is not
up [correctly] for this address.  Do you know if the bootloader is
the CPLD chip select correctly?

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