[uClinux-dev] init problems

[Michael Broughton]

Claude,

The 5282 cache has a bug, that does not mean it is broken.

Take a closer look at the device errata and the code you posted: you 
will see that the code implements the workaround described in the device 
errata.

I don't know what it causing your problem, but it may have to do with 
the config settings you chose. My suggestion is to double check that you 
are using the correct vendor/board (5282evb vs. 5282lite), then verify 
that the default settings are correct. Don't just assume that the 
defaults are correct. I know there are a lot of menu's but it shouldn't 
take more than ten minutes to check for any obvious problems.

If you are still stuck after doing this, just wait for someone with a 
powerful brain to reply.

Mike


Claude wrote:
> Hi again,
> With regard to my init problems, I think I have found the problem. What really 
> halts is the function __flush_cache_all() that is called by do_mmap(). In my 
> case (working with MCF5282) this is an inline function that implements some 
> assembly code, in particular the following one:
> static inline void __flush_cache_all(void)
> {
> 	...
> #if defined(CONFIG_M527x) || defined(CONFIG_M528x)
> 	__asm__ __volatile__ (
>         	"movel	#0x81400100, %%d0\n\t"
>         	"movec	%%d0, %%CACR\n\t"
> 		"nop\n\t"
> 		: : : "d0" );
> #endif /* CONFIG_M527x || CONFIG_M528x */
>
> 	...
> }
>
> As I can see, this code affects the MCF5282's CACHE module which, according to 
> Freescale's MCF5282 device errata, it does not work. I have revised the 
> initial start up code (i.e. head.S) and the macro CACHE_ENABLE is always 
> called. Thus, I have uClinux playing with a dangerous toy: the MCF5282's 
> cache.
>
> I know that the answer to my problem may be trivial: just disable CACHE. The 
> question is that I don't know whether there are other modules that may use 
> CACHE as __flush_cache_all() does. Although I could disable cache in the 
> start up code, functions as __flush_cache_all would activate it again.
>
>
>
> Could you help me?
>
> Thanks in advance
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