[ECOS] Driver with 2 EMAC

[ECOS] Driver with 2 EMAC

[mkhoyila]

Gentlemen,

Thanks for the help. Any of you have any reference on how to write a
driver to handle  2 EMACs. I am interested in setting up the structures
mostly. Any sample code is appreciated. Thanks.

Michael


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[ECOS] RE eCos : XXXX_RECV with zero copy

[mkhoyila]

Thanks Gary for your help on 2 EMAC. I have it working with 2EMACs.

I do have another question regarding XXXX_RECV function to implement
zero-copy. On the XXXX_SEND, I can avoid copying from scatter-gather list
to my DMA buffers since my hardware allows SOP (Start Of Packet) and EOP.

I also want to avoid copying in XXXX_RECV from DMA buffers to
Scatter-Gather list. Is there a way to acheive this? Meaning that I could
pass address/Length of my Receive DMA address to eCos where received data
is?

Thanks again.

MHK



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[ECOS] XXXX_RECV multiple packet receipt

[mkhoyila]

Gentlemen,

In some cases when a single receive interrupt happens, I get multiple
packets sitting in my Receive Buffers (multiple rxBuffers filled, each
buffer corresponds to one received packet). Is it possible to receive
these packets with a single call to eth_drv_dsr() which eventually
XXXX-Recv will be called?

I would like to take advantage of having multiple buffers and receiving
all at the same time for performance reasons.

I would appreciate your response to my earlier email regarding zero-copy
in XXXX_Recv function as well. Thank you.

Michael



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Re: [ECOS] XXXX_RECV multiple packet receipt

[Gary Thomas]

On Fri, 2005-09-02 at 15:23 -0700, mkhoyila@uci.edu wrote:
> Gentlemen,
> 
> In some cases when a single receive interrupt happens, I get multiple
> packets sitting in my Receive Buffers (multiple rxBuffers filled, each
> buffer corresponds to one received packet). Is it possible to receive
> these packets with a single call to eth_drv_dsr() which eventually
> XXXX-Recv will be called?
> 
> I would like to take advantage of having multiple buffers and receiving
> all at the same time for performance reasons.
> 

Yes, this works just fine.  In your DSR handler, simply call 
eth_drv_recv() for every packet that you have buffered up.

> I would appreciate your response to my earlier email regarding zero-copy
> in XXXX_Recv function as well. Thank you.

This is a much harder problem and, sadly, with the current upper
layer design, there is no way to accomplish it at this time.  It
would require a fairly significant restructuring of the middle
layer (eth_drv) which sits between the stacks and the hardware
drivers.

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------


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