BSP_install_rtems_irq_handler API

[Thomas Doerfler]

Hi Till,

moving to the new API (at least for PowerPC) is encouraged, 
because the old exception handling code has some bad links 
between libbsp and libcpu code/preprocessor statements. 

I am currently moving the helas403 BSP and PPC403/405 CPU code 
to the new exception handling, and I really have a split 
opinion on the new API. I think that some part are really 
nice, like to "irq_on" and "irq_off" functions in the drivers, 
but you are right, not passing the vector numbers to the irq 
function is really one design flaw among others (IMHO):

*IRQ/exception related numbers are generously mixed into one 
enumeration, this makes things hard to distinguish

*at least for PPC there seems to be no standard way to 
provide a new exception handler without giving it its own 
assembler entry/exit code, although the default handler 
code could easily be modified to support this

*part of the related files is placed in libcpu, another part 
in libbsp, without clear definitions which parts are 
architecture specific, which are microcontroller specific 
and which are really board specific. (maybe a hirarchy 
lib/libbsp/<arch>/shared/<controllerchip>/xxx would help 
there)

Maybe your mail might start a discussion how to improve 
structure, but it will take some time (and testing) to reorder 
things once more. I also don't think that changing the API 
every year is a good idea... My idea would be to discuss ideas 
how to improve things and then, when a consensus is there  
rework them.

Bye,
	Thomas.


> Hi all.
> 
> I realize that more and more BSPs are migrating to the
> new interrupt management API. Has the design
> of this new API (which IMHO is rather clumsy) ever
> been thoroughly discussed?
> 
> I believe that it is a major design flaw not to pass
> the ISR any information (user pointer or at least the
> vector number). Without ugly hacks, it is impossible
> for a driver to support multiple instances of a device
> or for BSPs to support interrupt sharing.
> 
> What was the reason for making ISRs
> 
> typedef void (*rtems_irq_hdl)           (void);
> 
> and is there still a chance to change this API??
> 
> Regards
> 
> -- Till.




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