Re: [lwip-devel] [task #7244] Add sys_arch_ticks/jiffies in sys_arch

[address@hidden]

Paul, please don't post such questions to the bugtracker but to the 
lwip-devel list instead (I've put you on CC, in case you haven't 
subscribed the list).

Paul Preuß wrote:
> Follow-up Comment #9, task #7244 (project lwip):
>
> I want to port lwIP to a LPC1768. The stack has to run without operating
> system. I know that I have to write a new ethernetif.c therefore, but what is
> about the sys_arch. Is there something to do too? Beacause I read, that in
> this case no semaphores etc. are needed.
The sys_arch is rather an os_arch and you don't need it at all for pure 
NO_SYS=1 ports. For such ports, you only need cc.h, which declares some 
typedefs and defines.

In previous versions, you had to call the various timer functions 
yourself (at the appropriate intervals). However, from 1.4.0(rc1) on, 
there's a function sys_check_timeouts(), which you can call in your main 
loop. This function takes care of all the timer functions getting called.
> Is there a documentation, what I have
> to do to port the lwIP stack.
Apart from the documentation files in the 'doc' directory, I think 
there's some documentation about that on the wiki 
(http://lwip.wikia.com/). But reading existing ports might also help you 
a lot.
> And yet another question. When I try to compile the project (I took the
> STM32-F107 implementation as a basic) everything is fine. But while linking
> the files, the sys_now() produces a linker error. And I have seen, that is
> just declared but never defined. Is this a systick or something that I have to
> implement by myself?
Yep, you have to implement this yourself (returning the current time in 
milliseconds, as the comment in sys.h says). Seems like the fact that 
this implementation is up to the port seems to be missing :-)
However, you should only need if when using NO_SYS==0?

Simon