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SubjectAccessing high PCI memory
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<DIV><FONT face=Arial size=2>I am trying to read from and write to the I/O
memory, in which a PCI board is mapped. As I could read in this mailing list, I
used the function vremap (I am using Linux 2.0.36) to get the virtual address
associated with the high PCI memory address, and then, I used the functions
readb and writeb. Unfortunately, it seems not to work :</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2>When I try to get the data page back from pte
(using pgd_offset, pmd_offset, pte_offset and pte_page), I obtain something like
0xF000F000, while the address I wanted to vremap was 0xFEA00000.</FONT></DIV>
<DIV><FONT face=Arial size=2>Furthermore, I noticed that the result of pgd_val
was always 0.</FONT></DIV>
<DIV><FONT color=#000000 face=Arial size=2>(I control the fact that the
read-access or the write-access doesn't work by observing some signals on the
board).</FONT></DIV>
<DIV><FONT color=#000000 face=Arial size=2></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2>Where is the mistake?</FONT></DIV>
<DIV><FONT face=Arial size=2>Thank you for your help</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2>Nathalie Barat</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2>PS : please CC to me
(nbarat@kaptech.com)</FONT></DIV></BODY></HTML>
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