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From: Albert Herranz <albert_herranz@yahoo•es>
To: Segher Boessenkool <segher@kernel•crashing.org>
Cc: linuxppc-dev@lists•ozlabs.org
Subject: Re: [RFC PATCH v4 2/2] powerpc: gamecube/wii: early debugging using usbgecko
Date: Fri, 04 Dec 2009 17:54:05 +0100	[thread overview]
Message-ID: <4B193EAD.2040303@yahoo.es> (raw)
In-Reply-To: <364F1867-9601-44FD-B140-EAA0FCC2C237@kernel.crashing.org>

Segher Boessenkool wrote:
>> +#ifdef CONFIG_PPC_EARLY_DEBUG_USBGECKO
>> +setup_usbgecko_bat:
>> +    /* prepare a BAT for early io */
>> +#if defined(CONFIG_GAMECUBE)
>> +    lis    r8, 0x0c00
>> +#elif defined(CONFIG_WII)
>> +    lis    r8, 0x0d00
>> +#else
>> +#error Invalid platform for USB Gecko based early debugging.
>> +#endif
> 
> A kernel with both CONFIG_WII and CONFIG_GAMECUBE works fine
> on either, right?  If so, could you please switch the two #ifs?
> A dual-platform kernel will be used on a Wii much more likely
> than on a GC.
> 

Nope, a GameCube kernel currently doesn't work on a Wii and the same the other way around.

But I can make that particular check a runtime check.
The idea would be to enclose that snippet in GAMECUBE_COMMON and check the PVR. If it is a Gekko (a fixed value) then we have a GameCube, otherwise we assume a Wii.

>> +    /*
>> +     * The virtual address used must match the virtual address
>> +     * associated to the fixmap entry FIX_EARLY_DEBUG_BASE.
>> +     */
>> +    lis    r11, 0xfffe    /* top 128K */
>> +    ori    r8, r8, 0x002a    /* uncached, guarded ,rw */
>> +    ori    r11, r11, 0x3    /* 128K */
> 
> I think you should clear Vp since the BAT mapping can survive until
> after user space is started; it won't hurt to remove it either way.
> So 2 instead of 3.  And put the meaning in the comment :-)

This BAT is re-setup again on MMU_init, way before starting userspace.
But I'll make it Vs=1, Vp=0 here too :)

> 
> Looks fine otherwise.
> 

Thanks.

> 
> Segher
> 
> 

Cheers,
Albert

  reply	other threads:[~2009-12-04 16:54 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-03 20:34 [RFC PATCH v4 0/2] rework of usbgecko-based early debug Albert Herranz
2009-12-03 20:34 ` [RFC PATCH v4 1/2] powerpc: reserve fixmap entries for " Albert Herranz
2009-12-11 22:15   ` Benjamin Herrenschmidt
2009-12-03 20:35 ` [RFC PATCH v4 2/2] powerpc: gamecube/wii: early debugging using usbgecko Albert Herranz
2009-12-04 12:04   ` Segher Boessenkool
2009-12-04 16:54     ` Albert Herranz [this message]
2009-12-04 19:56       ` Segher Boessenkool
2009-12-11 22:16   ` Benjamin Herrenschmidt

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