Messages in this thread | | | From | "Randall Hyde" <> | Subject | mmap to Access PCI space? | Date | Thu, 23 Oct 2003 20:36:12 -0700 |
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Hi All, I need to access a couple of SATA chips from a user-mode program (yep, running as root). I know for a fact that my chip resides at address 0xfc300000 (/proc/iomem and /proc/ide/siimage tells me this). Can I do a mmap like the following to access the registers on ths chip?
fdDevMem = open( "/dev/mem", O_RDWR ); ptr = mmap ( NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, fdDevMem, 0xfc300000 );
When I try this, I get a valid pointer back, but it doesn't seem to be mapped to my si3112 chip register bank.
I've also used code like the following: ptr = mmap ( 0xfc300000, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0 );
Same story. If I use MAP_FIXED and/or MAP_PRIVATE, the mmap call fails.
What am I doing wrong here? Thanks, Randy Hyde
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