Custom AXI DMA Driver

Hi All,
I am currently trying to write my own Simple AXI DMA driver so I may use AXI DMA under linux. In my driver I allocate buffers, map them to user space, etc. However in order to control the AXI DMA I need to use the request_mem_region, and ioremap to be able to set the control registers. This is where my problem is, whenever I try to request_mem_region it fails because that region is already mapped.
here is the /proc/iomem output
40400000 - 4040ffff /amba_pl/dma@40400000
how may I unmap this region so that I may grab it with my own driver?

Thank you.

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0 Former Member over 9 years ago

You shouldn't work with AXI DMA directly.
I mean Xilinx provide AXI DMA driver for Linux, when it loads it detects and add DMA channels for you and all you have to do is to use Linux DMA API to reserve and use channels in your own driver.

Google it. Specifically dma_request_channel(), dma_cap_set(), xilinx_dma_config structure.
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0 Former Member over 9 years ago

You shouldn't work with AXI DMA directly.
I mean Xilinx provide AXI DMA driver for Linux, when it loads it detects and add DMA channels for you and all you have to do is to use Linux DMA API to reserve and use channels in your own driver.

Google it. Specifically dma_request_channel(), dma_cap_set(), xilinx_dma_config structure.
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