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3,052 Views
Registered: ‎10-15-2010

Handle ack of LWIP with hard DMA on PPC440

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Hi,

 

I would like to have some advises about method to handle LWIP communication with Hard DMA.

 

Environement :

- I'm using a virtex5 FX with a PPC440

- Hard DMA with descriptors and interrupt are setup

- Hard TEMAC is used to communicate with LAN

- Local link protocol is used to link sub VHDL module with the PPC

 

Design :

- Purpose is to receive data from the LWIP payload and send them to VHDL sub module by Llink

- Then VHDL sub module send back data that are writen on the DDR2 (also by Llink protocol)

- Finally the TEMAC read data on the DDR2 to send them on the LAN using the LWIP stack

- Actually i'm able to receive data from the LAN, then send them to VHDL sub module, then get data back from VHDL sub module and write them into the DDR2.

 

Problems :

- Everytime a DMA interrupt happen (every 1 writen packet), i get the data and send them on the TCP by the command "TCP_write()". Problem is that sometime acknowledge is to long so the TCP_buffer become full.

 

Questions :

- Can someone advise me on the way to handle acknowledge, read data from buffer descriptor and so please. I need a solution to read written data on the DDR2 and put them on the TCP/IP at the same time DMA is working by writing new data on the DDR2.

 

Thank you so much for your help.

David

 

 

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3,817 Views
Registered: ‎10-15-2010

please nobody can help !!

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3,818 Views
Registered: ‎10-15-2010

please nobody can help !!

View solution in original post

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