From: joe joe <joe.tijerina@qi...> - 2011-07-08 01:38:17
I'm trying to read a SDMA register, DMA4_REVISION at physical address 0x4805
6000, from my application written in C. I'm using mmap() to map this
physical address to virtual address but I get the following error when I try
to read the register.
Unhandled fault: external abort on non-linefetch (0x1018) at 0x40021000
I know my mmap() implementation is right because I can read a GPMC register,
GPMC_REVISION at physical address 0x6E00 0000, and I can read from it no
BTW, I also tried using devmem2 utility and I got the same error. I also
googled around about this error and came up with possible cause, something
about the DMA module clocks not being enabled, and that I would have to
enable the module clock to read one of its registers. I don't know if that
is my problem, because I'm able to read this register from my kernel space
DMA driver with ioremap(). Anybody have a clue how I can solve my issue.
I was just trying to read the DMA status registers from my application to
prevent from having to make an ioctl() call to do the same thing.
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