A few questions in embedded linux

[Roland Dreier]

>>>>> "Khai" == Khai Trinh <kqtrinh at yahoo.com> writes:

    Khai> Regarding to my question 1 below. After I check and use high
    Khai> mem, and CMDLINE="mem=60M", recompile my kernel, static link
    Khai> my driver using the 4M reserved RAM space, I got this
    Khai> message

    Khai> kernel: __ioremap(): phys addr 3c00000 is RAM lr c000a57c

Look at arch/ppc/mm/pgtable.c, where that message is being printed.
The kernel thinks that the address 3c00000 (which is 60 MB) is below
high_memory, which is where it thinks the top of memory is.

The most likely explanation is that you are doing something wrong when
you pass "mem=60M" to the kernel.

Have your driver print out virt_to_phys(high_memory) and check that
the kernel really thinks it only has 60 MB of memory.

 - Roland

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