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Re: Help getting IP30/Octane fixed?

To: Johannes Dickgreber <>
Subject: Re: Help getting IP30/Octane fixed?
From: Kumba <>
Date: Sun, 10 May 2009 14:57:07 -0400
Cc: Linux MIPS List <>
In-reply-to: <>
Original-recipient: rfc822;
References: <> <>
User-agent: Thunderbird (Windows/20090302)
Johannes Dickgreber wrote:

This is whats wrong with SMP: from file include/asm/mach-ip30/heart.h

#define HEART_IMR(x)            ((volatile ulong *)0x900000000ff10000 + (8 * 

I schould be

#define HEART_IMR(x)            ((volatile ulong *)0x900000000ff10000 + (x))

or it schould be

#define HEART_IMR(x)            ((volatile ulong *) (0x900000000ff10000 + (8 * 

The IRQ MASK Register for the different CPUs are side by side.
In your version the factor 8 is used twice. First explicit inside the braces
and second, because of the pointer to ulong implicit done by the
I checked it by dissambling the code and my smp-kernel is working if i start
only with one cpu. With 2 cpus the smp-kernel is booting, but the init process
hangs then.

I'll have to test this when I get a new SMP module in. Found a cheap R10K (yuck) on eBay for real cheap that'll suffice. My R12000-300MHz refused to post at all (LED didn't even change to red, but the PROM would process NMI resets, oddly enough).

Ricardo (ricmm on IRC) explained it as this:

<ricmm> the baseline problem is that the secondary CPU's ipi irq is not triggering, the first one works <ricmm> and smp_call_function() is calling an init function on both CPUs with a wait_for_completion flag set <ricmm> but the second CPU will never run the function as the irq is not happening, therefore the flag will remain set
<ricmm> and smp_call_function() will spin waiting for the completion

the revert is not needed anymore, because of code in arch/mips/pci/ops-bridge.c
look for the function emulate_ioc3_cfg

Awesome, that's great to know!

i have done some more work on the older patches and have a working kernel.
if someone wants this patch, i can send it.

I'll take a look at it and see if I can integrate it into what I already have. Do you have it broken out into separate changes for the IOC3 metadriver and for the core IP30 code?


Joshua Kinard

"The past tempts us, the present confuses us, the future frightens us. And our lives slip away, moment by moment, lost in that vast, terrible in-between."

--Emperor Turhan, Centauri Republic

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