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Then how to use Qsys to connect to large memory chip (DDR II)?
If I assign large Bar size covering the whole address of DDR II, computer will not boot.
What to do to make large memory chip to work with PCIe?
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You need to use slight-of-hand and indirection :)
You need to think of the memory map of your board as being independent/separate to the memory map of your x86 host. If you want to move results between your Qsys memory map and your x86 host memory, then you use DMA. The DMA controller needs to be able to see both PCIe addresses and Qsys addresses to be efficient.
If you use the x86 host to directly read and write to your Qsys system, it will not be very efficient (low data rate). Typically you use (slow) x86 transactions to setup the DMA controller, and then let it perform efficient transfers.
Cheers,
Dave
Honored Contributor
