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Altera_Forum
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17 years ago

Altera PCI Express Development Kit: Linux DMA Driver

Hi, I am a newbie to FPGA design and implementation. While installing the PCI express board on LINUX machine, I don't see Demo application driver for DMA read and write for LINUX (Manual talk...
Altera_Forum's avatar
Altera_Forum
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16 years ago

Hi Leon (and others),

I have been playing with your driver and tinkering with my own modifications. I have a questions - do we really need to have cache coherent memory for "DESCRIPTOR TABLE". I am trying to export descriptor table and bar at userspace. Have you tried mmap'ing a pci_alloc_consistent memory into User space.

For me mmap is successful (for Table descriptor) but my writes are not visible to me. I don't see any change in memory after writes ( e.g. after writing 0x0000FADE, it is not visible). I am able to do similar thing with kmalloc allocation. It seems that write is not working correctly.

Any help will be appreciated.

-VIneet

Thanks in advance