Roy Jose(deleted)
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Virtual to physical adress problem for DMA
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Roy Jose(deleted)
02/13/2014 11:44 PM
post108796
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Virtual to physical adress problem for DMA
Hello All.
Working on porting SDIO driver on to QNX. I am using DMA for reading and writing data basically for DMA iam using 4
bytes for transfer meaning
i need to read an integer value using DMA by passing integer address for DMA.
How is this done.
I have an integer variable int value;
For DMA i get the physical address of this address value
mem_offset64(&vaue, NOFD, 1, &offset, 0)
This physical address is used for DMA. Problem i see is iam not able to get any value from the controller later using
mmap for 4 bytes allocation i got the adress same address was used for DMA which was successful.
Later i used volatile int value which also didn't give the right physical address for successful DMA.
Is there a way where i can get right physical address for address of value which will result in successful DMA.
Regards
Kaushik
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