Thanks for the reply. Actually I am working on Kontron board. I think my question is not related to any chipset. Can we use LPC DMA on io mapped devices. In my experimenting board Embedded Controlled is getting access via LPC io port to PCH. For this can i use LPC DMA on this.
You are probably right that the answer is independent of chipset. However the reason I ask is that Intel provides some dedicated resources for compenents designated as "embedded". So if you are using an embedded chipset, I can point you to that support resource.
Here's the info on the support resource I mentioned.
The Intel® e-Help desk is staffed by Intel representatives who support select Intel embedded platforms including Intel® Atom™, 2nd Generation Core™ and
associated chipsets. Since you are using a Kontron board, chances are high that the chipset is one that Intel classifies as embedded.
To access e-Help, you need to be a Privileged member of the Intel® Embedded Community. If you are not already a Privileged member, you can request an upgrade to your community account here:
In addition to access to e-Help, Prvileged members may also access the confidential content within the Intel® Embedded Design Center, such as design documents, specifications, and training materials.
OK, so with all that said, I have some feedback from my Intel friends that IO DMA may be a feature that is enabled or disabled at the board level design. It is therefore suggested that you check with Kontron about that specific board. One way or another you might want to do that since it can take up to 10 business days to process your Privileged membership request.
Are you attempting to use the 8237 DMA engine on the CPU? This may be important , some embedded chipsets don't even support the 8237 and if they do they have limited DMA REQ and ACK lines for LPC devices. Also the 8237 engine is designed to connect one I/O register to memory. If you device absolutely requires to you to write to the device using and Index port , data port pair then you are not going to be able to use DMA. If you can set the IO Address then perhaps you could DMA to the DATA register. The I/O device would need to generate a DMA request too, you can't just DMA to any device without that device having essential handshaking for DMA operation.
From your limited description, I don't think you can do what you want to do.
Thanks for information. One more my dought is whether DMA device will have the address or not. I know that we can communicate the DMA device through DMA channel number. Shall we need to configure the reading address of device and system physical address for DMA in DMA controller registers?
Questions?
