Doh! Thank you! This looks to be the problem, I've made some changes
to the code (calling mmap.read(4) rather than mmap.read_bye()) and
everything seems to be working.
On Tue, Oct 20, 2009 at 8:27 PM, Paul Walmsley <paul@xxxxxxxxx> wrote:
> On Tue, 20 Oct 2009, Brett Graham wrote:
>
>> --minimal python example--
>> open("/dev/mem", O_RDWR|O_SYNC|O_LARGEFILE) = 3
>> fstat64(3, {st_mode=S_IFCHR|0640, st_rdev=makedev(1, 1), ...}) = 0
>> dup(3) = 4
>> mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0x48088) = 0x40020000
>> --- SIGBUS (Bus error) @ 0 (0) ---
>> +++ killed by SIGBUS +++
>> Process 1633 detached
>
> Your script:
>
>>> m = mmap.mmap(f, mmap.PAGESIZE, mmap.MAP_SHARED, mmap.PROT_WRITE |
>>> mmap.PROT_READ, offset=addr & ~MAP_MASK)
>>> m.seek(addr & MAP_MASK)
>
> So the mmap() is working fine, based on the output above...
>
>>> c = m.read_byte()
>
> ... but the above line is going to fail. GPTIMER registers need 16-
> or 32-bit accesses[1].
>
>
> - Paul
>
> 1. OMAP34xx TRM 16.3.2:
>
> "CAUTION
> The GP timer registers are limited to 32-bit and 16-bit data accesses;
> 8-bit access is not allowed and can corrupt the register content."
>
>
>
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