* Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> [150115 02:53]:
> On Wed, Jan 14, 2015 at 02:14:08PM -0800, Tony Lindgren wrote:
> > Hi all,
> >
> > Looks like the legacy IRQ numbers are now all wrong at least for omap4
> > since commit 9a1091ef0017 ("irqchip: gic: Support hierarchy irq domain.").
> >
> > Instead of this:
> >
> > # cat /proc/interrupts
> > CPU0 CPU1
> > 29: 1124 981 GIC 29 twd
> > 39: 0 0 GIC 39 TWL6030-PIH
> > 41: 0 0 GIC 41 l3-dbg-irq
> > 42: 0 0 GIC 42 l3-app-irq
> > 44: 0 0 GIC 44 DMA
> > 45: 7854 0 GIC 45 omap-dma-engine
> > 52: 0 0 GIC 52 gpmc
> > ...
> >
> >
> > We now have:
> >
> > # cat /proc/interrupts
> > CPU0 CPU1
> > 16: 343 0 GIC 69 gp_timer
> > 17: 1160 1017 GIC 29 twd
> > 18: 0 0 GIC 41 l3-dbg-irq
> > 19: 1 0 GIC 42 l3-app-irq
> > 22: 7850 0 GIC 45 omap-dma-engine
> > 44: 0 0 4a310000.gpio 18 DMA
> > 61: 2730 0 48055000.gpio 2 eth0
> > 223: 0 0 GIC 52 gpmc
> > ...
> >
> > So the DMA interrupt using the legacy mapping with something like
> > irq = 12 + OMAP44XX_IRQ_GIC_START now is wrong and unfortunately
> > at least omaps still have a bunch of the legacy interrupts still
> > around.
> >
> > And that naturally produces all kinds of strange errors like:
> >
> > WARNING: CPU: 0 PID: 1 at drivers/bus/omap_l3_noc.c:147 l3_interrupt_handler+0x214/0x340()
> > 44000000.ocp:L3 Custom Error: MASTER MPU TARGET L4CFG (Idle): Data Access in Supervisor mode during Functional access
> > ...
> > [<c05f21e4>] (__irq_svc) from [<c05f1974>] (_raw_spin_unlock_irqrestore+0x34/0x44)
> > [<c05f1974>] (_raw_spin_unlock_irqrestore) from [<c00914a8>] (__setup_irq+0x244/0x530)
> > [<c00914a8>] (__setup_irq) from [<c00917d4>] (setup_irq+0x40/0x8c)
> > [<c00917d4>] (setup_irq) from [<c0039c8c>] (omap_system_dma_probe+0x1d4/0x2b4)
> > [<c0039c8c>] (omap_system_dma_probe) from [<c03b2200>] (platform_drv_probe+0x44/0xa4)
> > ...
>
> I don't think we've proven a link there. While you're right that it
> causes the wrong interrupt to be claimed, I have two kernels here,
> both claim the same interrupt, one which is multi-platform and issues
> that strange warning, and one which targets only OMAP4 which doesn't.
>
> There's something else going on which causes the bus errors which we
> haven't found.
I think it gets triggered if you enable PREEMPT.
Regards,
Tony
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