PCI DMA support on the MPC8250
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===== Original Message From Allen Curtis <[email protected]> =====
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But the DMA transfers are working and are 5 time faster. You must only
program
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them. It is just 5 registers to configure. You buffers in RAM must be allocated with
consistent_allocto avoid caching on them and you must always write physical addresses in the DMAregisters( use virt_to_phys). Note For PCI addressesvirt_to_physdoesn't work well. You must take the addresses from the "remap" function code. I did it and it works very well.Do you have a patch for you DMA support?
No, but I will make one for the physical address lookup code, the small changes to support DMA in the kernel (access of EUMBAR base address) and the snippet of my code that I use in my driver.
It will be against a 2.4.17 Kernel( sorry )
Note : I have A generic DMA driver but it has a big setup time of 25000 cycles making it interesting (better than memcpy) only for blocks larger than 2KBytes.
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