* Additional data/instruction BATs not initialized for MPC8280?
@ 2005-01-25 17:49 annamaya
2005-01-25 19:10 ` Eugene Surovegin
0 siblings, 1 reply; 3+ messages in thread
From: annamaya @ 2005-01-25 17:49 UTC (permalink / raw)
To: linuxppc-embedded
I have read in the specs for the MPC8280 that it has a
G2_LE core which has 4 additional data and instruction
BATs. However, I dont see these BATS being cleared
early in the kernel. I only see that the first 4 pairs
are cleared using the mtspr instructions. But my
kernel comes up just fine and everything seems to work
OK. Dont we need to clear the other set of I/DBATS?
What happens when we dont do this? Thanks in advance.
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Additional data/instruction BATs not initialized for MPC8280?
2005-01-25 17:49 Additional data/instruction BATs not initialized for MPC8280? annamaya
@ 2005-01-25 19:10 ` Eugene Surovegin
2005-01-25 19:40 ` annamaya
0 siblings, 1 reply; 3+ messages in thread
From: Eugene Surovegin @ 2005-01-25 19:10 UTC (permalink / raw)
To: annamaya; +Cc: linuxppc-embedded
On Tue, Jan 25, 2005 at 09:49:13AM -0800, annamaya wrote:
> I have read in the specs for the MPC8280 that it has a
> G2_LE core which has 4 additional data and instruction
> BATs. However, I dont see these BATS being cleared
> early in the kernel. I only see that the first 4 pairs
> are cleared using the mtspr instructions. But my
> kernel comes up just fine and everything seems to work
> OK. Dont we need to clear the other set of I/DBATS?
> What happens when we dont do this? Thanks in advance.
Additional BATs in G2_LE core must be explicitly enabled in HID2 (HBE
bit), until then they "don't exist" :).
--
Eugene
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Additional data/instruction BATs not initialized for MPC8280?
2005-01-25 19:10 ` Eugene Surovegin
@ 2005-01-25 19:40 ` annamaya
0 siblings, 0 replies; 3+ messages in thread
From: annamaya @ 2005-01-25 19:40 UTC (permalink / raw)
To: Eugene Surovegin; +Cc: linuxppc-embedded
Doh! So that's how we get away with it.
--- Eugene Surovegin <ebs@ebshome.net> wrote:
> On Tue, Jan 25, 2005 at 09:49:13AM -0800, annamaya
> wrote:
> > I have read in the specs for the MPC8280 that it
> has a
> > G2_LE core which has 4 additional data and
> instruction
> > BATs. However, I dont see these BATS being cleared
> > early in the kernel. I only see that the first 4
> pairs
> > are cleared using the mtspr instructions. But my
> > kernel comes up just fine and everything seems to
> work
> > OK. Dont we need to clear the other set of
> I/DBATS?
> > What happens when we dont do this? Thanks in
> advance.
>
> Additional BATs in G2_LE core must be explicitly
> enabled in HID2 (HBE
> bit), until then they "don't exist" :).
>
> --
> Eugene
>
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2005-01-25 17:49 Additional data/instruction BATs not initialized for MPC8280? annamaya
2005-01-25 19:10 ` Eugene Surovegin
2005-01-25 19:40 ` annamaya
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