[coreboot] Dump GPIO I/O Registers

joe at smittys.pointclark.net joe at smittys.pointclark.net
Tue Feb 19 10:59:47 CET 2008

Quoting Peter Stuge <peter at stuge.se>:

> On Mon, Feb 18, 2008 at 07:45:55PM -0500, joe at smittys.pointclark.net wrote:
>> > Once you have the base address, you can read the GPIO control
>> > registers from /dev/port, with the seek equal to the base address.
>> How?? This is the part I am looking for, this would be the golden
>> ticket:-)
> Oh! This can be fairly simple.
> dd if=/dev/ioport bs=1 skip=$[0xbasehere] count=asmanyasyouwant | xxd
OK, so lets clarify?

GPIOBASE?GPIO Base Address (LPC I/F?D31:F0)
31:16 Reserved
15:6 Base Address ? R/W. Provides the 64 bytes of I/O space for GPIO.
5:1 Reserved
0 Resource Indicator ? RO. Hardwired to 1; indicates I/O space.

1. My value is 0x00000501. So if only bits 15:6 are the base address  
this would make my base address 0x14 correct? This value would become  

2. Would I put 64 in "asmanyasyouwant" to dump the whole 64 bytes of  
I/O space?

3. What is the pipe xxd for?

Thanks again for the help:-)

Thanks - Joe

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