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Altera_Forum
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15 years ago

Chaining DMA Scatter-Gather mode problems (SG-DMA)

Hey guys, I got some problems in the Chaining DMA (CDMA) SG-DMA mode. Based on the source code of the Altera PCI-E DEMO program, I am using WinDriver to develop the application. When tran...
Altera_Forum's avatar
Altera_Forum
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15 years ago

In the process of chaining dma, the smallest data dma_read & dma_write support in a TLP-unit is 4(DW). but actually, we find the data-playload of each TLP is not multiple of the 4(dw) sometimes, it will make mismatch of data in dma read then write .

Ask: What shouled I do to make sure the data-length is multiple of 4 in DT(Descriptor -table), and also with the data-length of each TLP?