RE: [lwip-users] Ethernet Driver development guidelines (BlackfinBF536 BF537 integrated EMAC)

[Bill Auerbach]

> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden On Behalf
> Of Stephane Lesage
> Sent: Tuesday, March 18, 2008 2:21 PM
> To: Mailing list for lwIP users
> Subject: Re: [lwip-users] Ethernet Driver development guidelines
> (BlackfinBF536 BF537 integrated EMAC)
> 
> I'm now OK with packet buffer memory.
> 
> I know you don't use an OS.
> But how are you handling packet Output ? Are you waiting actual
> transmission in netif->link_output() ?

As far as output goes, I use the tcp_sent callbacks to send data until it is
sent.  If the data to send is dynamic, it is released.  If I need to send
more than once with a call to tcp_write, I build a linked list of outgoing
data.  When tcp_sent needs data and the current chunk is done, the next
section in the queue is sent.  This is much like the lwIP send queues, only
for me it's for the connection.  I guess I made a buffering socket.  It
never blocks and can queue a lot of data.  After 128MB, data from one source
(an outgoing continuous log) is truncated.  This queuing allows me to send a
HTML page and all of the images requested without blocking - all to be sent
in the background as tcp_sent needs.

Bill