DMA with powerspan II -Fpga card

I had posted earlier my issues with Fpga card.

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The AMIRIX fpga card uses powerspan II pci bus switch fro Tundra. The powerpc inside teh fpga has linux running..I have some data in my PLB master/slave module which has to be transferred to the host pc. So I was suggested to llok into DMA transfer part. I went through the powerspan II manual . It doesnt provide the details of data cycle for the DMA . i.e it only says to write the DMA configuration registers with the source address , destination address... and then raisethe go signal. Now my problem is that the source address needs to be the on-board RAM address. I dont want to use the onboard RAM.I dont want to use the powerpc either. I wanted to write a module in vhdl to do the confguration adn the forward the data to the bridge. I dont know whether this is possible. I

I dont have experience in this field. How can I do a transfer of data from my master/slave module to the host computer? Is there a way ? Thanks, Nitesh

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Nitesh
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Nitesh

Because all the addresses on the PCI bus are set by a mixture of card requirements and software allocation during PCI configuration you will need software/driver to read the allocation and give the relevant details to your card for the DMA transfer.

John Adair Enterpoint Ltd. - Home of Raggedstone1. The Low Cost Spartan-3 PCI Development Board.

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John Adair

I have started with the driver on the host side but the thing is I am still not cear about some things. I have access to the config registers from the host side. I also can initiate a data transfer from the host side and read data from the on-board RAM. I also have an option of configuring from the Processor bus side( interfaced with fpga). but I dont know how to give data to the pci bridge. i.e how to initiate a transfer from inside the fpga without using the on-board RAM or powerpc in the tranfer.The user manual says only how to configure i.e give the start address( source address in the ram ) , size of data and the destination address. It doesnt tell how to go about if i have to send data without using the RAM, the timing diagrams. Thanks, Nitesh

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Nitesh

I am working on drivers n the host side. I wasnt clear about few things. I can configure the bridge from the fpga side over the processor bus. In the manual its not stated as to how to do the data transfer without using the on-board RAM. It only specifies how to configure the bridge for the DMA transfer (with initiation fromthe fpga side ) i.e to specify the start address on the on-board ram , destination address and the size. How do I go about tranferring the data without using the on-board external RAM. Is it possible? Thanks, Nitesh

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Nitesh

Nitesh

As I thing Brian said you need to look at the chip specification. Usually you will find a register/s location at a particular offset/s from the BAR base address for these kind of DMA transfers but I don't have a lot recent PLX experience to expand on that.

John Adair Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan3 Development Board.

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John Adair

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