Re: [Sm5xx-devel] SM501 framebuffer driver

[Bill Gatliff <bgat@billgatliff.com>]

Robert Whaley wrote:

> Bill Gatliff wrote:
>
>> Paul:
>>
>> Paul Mundt wrote:
>>
>>> Hi Bill, fancy seeing you in this thread ;-)
>>>  
>>>
>>
>> Heh, you need to talk to the guy at the door.  He'll let anyone in, 
>> I'm proof!  :)
>>
>>> We want the 8051 blob in userspace if anything, there's little 
>>> reason to
>>> tie this in to the module specifically, and it's handy to expose the
>>> interface for people that are specifically interested in loading in
>>> alternate code on the 8051.
>>>
>>> As far as including source for the 8051 code itself, that would be nice
>>> to have, but I doubt it's something the majority of users are going to
>>> care about. I've certainly never seen any.
>>>  
>>>
>>
>> I totally agree on all points.  But I hate blobs.  If the source code 
>> is around, I'd love to have it recorded somewhere even though we all 
>> know that Kbuild and most users won't know what to do with it.  Just 
>> In Case.
>>
>> Do we even know where this blob came from originally?
>>
>>> On that note, do you have a pointer to some of the various ALSA
>>> implementations that are floating around? I've only seen the OSS driver
>>> we had in CVS, and that provides a rather dysmal starting point..
>>>  
>>>
>>
>> Whaley sent me one just last week (hi Robert!).  Given that, I don't 
>> suppose he'd mind my forwarding the patch on.
>
>
> Not at all.  BTW: we use this (moderately buggy) compiler to compile 
> the 8051 code:
>
> http://sourceforge.net/project/showfiles.php?group_id=599
>
> Between the bugs in the compiler and the absence of documentation in 
> the SM501 manual about 8051 interrupts, etc.   It was pretty difficult 
> making this work.
>
> Don't try anything remotely like this with this compiler:
>
> u8 a, b;
> u32 c;
>
>    c |= a << b;
>
>

WTF?!    :)

And here I was thinking that SDCC was probably pretty good...


>+
>+/* There are 2 copies of shared because the shared SRAM is not safe if
>+ * the 8051 is reading/writing to a location while the CPU is
>+ * writing/reading the same location (according to the SM501 manual
>+ * and verified by tests).  So 2 redundant copies are maintained and
>+ * for the contents to be considered valid the same data must be
>+ * present in both copies.
>+ */
>  
>

Classic SM501.  "Here's a feature that works.... but it doesn't!"  :)


b.g.

-- 
Bill Gatliff
bgat@billgatliff.com


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