David Miller wrote:
From: Daniel Hellstrom <daniel@xxxxxxxxxxx>
Date: Thu, 03 Feb 2011 09:50:05 +0100
David Miller wrote:
Ok, this looks mostly fine to me.
Once we have the sun4m/sun4d versions written I can think about
applying this.
We might want to abstract out the common code of the dispatch and
service stuff you have for LEON, otherwise we'll have 3 copies of
that code that sets and clears the mask state.
Perhaps something using BTFIXUP or similar.
I was thinking so too, BTFIXUPs for CPU model specific "IPI
operations" to avoid the switch-statement in the arch_ functions.
Exactly.
I have made new IPI patches that uses BTFIXUPs as we discussed above.
From another discussion we had:
David Miller wrote:
I think we can make this work on sun4m/sun4c/sun4d, which have several
software interrupt vectors available.
sun4m has 15 soft interrupts, in the sun4m_irq_percpu->{pending,clear,set}
registers, these live sequentially starting at bit 16, as per the definition
of the SUN4M_SOFT_INT() macro.
The only catch is that we'll need to peek at the ->pending register(s) to
determine if we have a hardware or software interrupt pending at a given
PIL level (or both).
I have made an implementation for sun4m which I think will work, I added
code to the IRQ traphandler to check for the IPIs as you suggested above
and clearing the pending register. The previous sun4m code had some IPI
checks already which I beleive was old unused code that was never
called, so I removed that.. Do you have any ideas what was going on in
the old code (smp_reschedule_irq)? Please see patch and commit message.
I don't have the sun4d-SMP hardware so it would be great if someone
could test the patches?
I'm not sure how the software interrupt triggering works on sun4c, but that
doesn't matter since we only need this on SMP.
I skip sun4c in this patch.
The sun4d code has a sun4d_send_ipi() interface from which the necessary
code can be constructed.
I started making a sun4d patch however I don't know the hardware enough
to make a guess. My problem is that I think I can generate an IPI but
don't know how to ACK them, detect them, which IRQs to use etc. Is there
a way to distinguish between soft and hard IRQs on sun4d? If I had a
piece of document about sun4d it could be possible, but guessing from
looking at unimplemented code... I hope someone else can take over here,
probably it is very similar to the sun4m implementation.
Also, this time I added some IPI IRQ statistics to the genirq
arch_show_interrupts() function, I hope that it may help someone trying
to implement IPIs on sun4d.
After booting on a LEON4 dualcore board:
# cat /proc/interrupts
CPU0 CPU1
2: 2808 0 leon-edge timer
3: 2809 2741 leon-per-cpu ticker
5: 198 0 leon-edge apbuart
13: 0 0 leon-pcilvl GRPCI2_JUMP
20: 0 0 grpci2-pcilvl GRPCI2_ERR
RES: 29 6 IPI rescheduling interrupts
CAL: 35 32 IPI function call interrupts
NMI: 1 1 Non-maskable interrupts
Daniel
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