Re: TLB and CSSBAR problems with MPC8540 and BDI2000

["Matthew S. McClintock" <mattsm@arlut.utexas.edu>]

Now it does not freeze at that code, but it freezes later right after it
jumps to the code in ram. If I look at where u-boot should be in memory
I see the following:

0ffdc000 : c09566a0 45fd08eb c89576d5 01fd28eb  ..f.E.....v...(.
0ffdc010 : c0fb66d7 45fd08eb c8fb76a0 05fd28eb  ..f.E.....v...(.
0ffdc020 : c89566d5 45fd08eb c8fb66d5 45fd08eb  ..f.E.....f.E...
0ffdc030 : c0db66a0 45fd08eb c89576d5 41fd28eb  ..f.E.....v.A.(.
0ffdc040 : c8fb66d7 45fd08eb c0fb66a0 45fd08eb  ..f.E.....f.E...
0ffdc050 : c89566d5 45fd08eb c0fb66d5 45fd08eb  ..f.E.....f.E...
0ffdc060 : c8fb66a0 45fd08eb c89576d5 45fd28eb  ..f.E.....v.E.(.
0ffdc070 : c0fb76d7 45fd28eb c8fb76a0 45fd28eb  ..v.E.(...v.E.(.
0ffdc080 : c09566d5 45fd08eb c8fb66d5 45fd08eb  ..f.E.....f.E...
...
...

Something went wrong =) Any ideas?

Matthew

On Wed, 2004-01-28 at 10:10, Kumar Gala wrote:
> Matthew,
>
> Can you try something out.  I wondering if its the tlbre/tlbwe that's
> causing problems or the MMU flash invalidate. (i'm guessing the 2nd.
>
> Can you try adding this code back in and see what happens.  It looks to
> me that the #ifdef is to generous to start with.  The invalidation of
> the MMU is not really part of the work around.
>
> #if defined(CONFIG_MPC85xx_REV1)
> 	lis	r2,0x1000
> 	mtspr	MAS0,r2
> 	tlbre
> 	tlbwe
> 	isync
> #if 0
> 	li      r2, 0x001e
> 	mtspr   MMUCSR0, r2
> 	isync
> #endif
> #endif
>
> - kumar
>
> On Jan 28, 2004, at 9:57 AM, Matthew S. McClintock wrote:
>
> >
> > On Wed, 2004-01-14 at 11:19, Milliorn Gary-rxcr80 wrote:
> >
> >>>
> >>> Yep.  I have one now.  Make sure your u-boot image also has a TLB1
> >>> entry for your "default" CCSRBAR.  Further, make sure your BDI init
> >>> section doesn't move the CCSRBAR from the default value assumed by
> >>> your u-boot image.  I had the latter correct, just didn't realize
> >>> that a "TLB1 flash invalidate" command to the MMUCSR0 doesn't seem
> >>> to honor the 'invalidate protect' in the TLB entry.  Everything
> >>> works fine when you get all of the ducks in a row :-)
> >>
> >>   The TLB1 issue is due to the MPC85x0 errata "CPU4"; there's a s/w
> >> workaround.  It's nice if BDI fixes it for you, but seems like it
> >> would
> >> not be necessary.
> >>
> >
> > 	So I have noticed some things, maybe someone here can explain this.
> > When If configure everything with my bdi2000 and attempt to boot u-boot
> > my CPU will crash (COP freeze) when I get to the code that implements
> > the software workaround that was mentioned above.
> >
> > 	However if I do not configure anything with the bdi2000, and boot
> > u-boot, it will load just fine. I have even removed the code that
> > causes
> > the crash in u-boot, recompiled u-boot and with those changes u-boot
> > will not crash the CPU. But, that same u-boot image will not boot if I
> > do not have the bdi2000 attached.
> >
> > 	So I guess the question is, what could be configured that would cause
> > this CPU to crash when the code for the errata was executed?
> >
> > Here is the code for the workaround:
> >
> > /* invalidate MMU L1/L2 */
> > /* Note: before invalidate MMU L1/L2, we read TLB1 Entry 0 and then
> >  * write it back immediately to fixup a bug(Errata CPU4)  for this
> > initial
> >  * TLB1 entry 0,otherwise the TLB1 entry 0 will be invalidated.
> >  */
> > #if defined(CONFIG_MPC85xx_REV1)
> > 	lis	r2,0x1000
> > 	mtspr	MAS0,r2
> > 	tlbre
> > 	tlbwe
> > 	isync
> > 	li      r2, 0x001e
> > 	mtspr   MMUCSR0, r2
> > 	isync
> > #endif
> >
> > --
> > Matthew S. McClintock <mattsm@arlut.utexas.edu>
> >
> >
>
>
--
Matthew S. McClintock <mattsm@arlut.utexas.edu>


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