[PATCH v2 00/21] irqchip: gic: killing gic_arch_extn and co, slowly
santosh shilimkar
santosh.shilimkar at oracle.com
Wed Jan 7 10:45:58 PST 2015
Marc,
On 1/7/2015 9:42 AM, Marc Zyngier wrote:
> The gic_arch_extn hack that a number of platform use has been nagging
> me for too long. It is only there for the benefit of a few platform,
> and yet it impacts all GIC users. Moreover, it gives people the wrong
> idea ("let's use it to put some new custom hack in there"...).
>
> But now that stacked irq domains have landed in -next, the time has
> come for gic_arch_extn to meet the Big Bit Bucket.
>
> This patch series takes several steps towards the elimination of
> gic_arch_extn:
>
> - moves Tegra's legacy interrupt controller support to
> drivers/irqchip, implementing a stacked domain on top of the
> standard GIC.
>
> - OMAP, imx6 and exynos are also converted to stacked domains, but
> their implementation is left in place (the code is far too
> intricately mixed with other details of the platform for me to even
> try to move it). Some OMAP variants get a special treatment as we
> also kill the crossbar horror (more on that below).
>
> - shmobile, ux500 and zynq are only slightly modified.
>
> - The GIC itself is cleaned up, and some other bits and bobs are
> adjusted for a good measure.
>
> About the TI crossbar:
>
> - The allocation of interrupts in this domain is fairly similar to
> what we do for MSI (see the GICv2m driver), and stacked domains have
> proved to be a fitting solution.
>
> - The current description in DT is currently entierely inaccurate, and
> as we already broke it for the OMAP WUGEN block, we might as well do
> it again for the TI crossbar.
>
> - The way crossbar, WUGEN and GIC interract is quite complex (this is
> effectively a stack of three interrupt controllers with interesting
> exceptions and braindead routing), and stacked domains are the right
> abstraction for that.
>
> - Other platforms (Freescale Vybrid) are starting to come up with the
> same type of things, and it'd be good to avoid them following the
> same broken model.
>
> - It removes a few lines from the code base so it can't completely be
> a bad idea!
>
> So this patch series does exactly that: make the crossbar a stacked
> interrupt controller that only takes care of setting up the routing,
> fix the DTs to represent the actual HW, and remove a bit of the
> craziness from the GIC code.
>
> It is worth realizing that:
>
> - I haven't been able to test this as much as I would have wanted to
> (it's only been tested on tegra2 and omap5).
>
> - I've created DT bindings when needed, updated existing ones, but I
> haven't created a binding for platforms that already used an
> undocumented one (imx6, I'm looking at you).
>
> - I've relaxed quite a bit of the locking in the GIC code. I believe
> this is safe, but someone else should give it a long hard look.
>
> - This actively *breaks* existing setups. Once you boot a new kernel
> with an old DT, suspend/resume *will* be broken. Old kernels on a
> new DT won't even boot! You've been warned. This really outline the
> necessity of actually describing the HW in device trees...
>
> As for the patches, they are on top of 3.19-rc3.
>
> I've pushed the code to:
> git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git irq/die-gic-arch-extn-die-die-die
>
> Comments welcome,
>
> M.
>
> Marc Zyngier (21):
> ARM: tegra: irq: nuke leftovers from non-DT support
> irqchip: tegra: add DT-based support for legacy interrupt controller
> ARM: tegra: skip gic_arch_extn setup if DT has a LIC node
> ARM: tegra: update DTs to expose legacy interrupt controller
> DT: tegra: add binding for the legacy interrupt controller
> ARM: tegra: remove old LIC support
> genirq: Add irqchip_set_wake_parent
> irqchip: crossbar: convert dra7 crossbar to stacked domains
> DT: update ti,irq-crossbar binding
> irqchip: GIC: get rid of routable domain
> DT: arm,gic: kill arm,routable-irqs
> ARM: omap: convert wakeupgen to stacked domains
> DT: omap4/5: add binding for the wake-up generator
> ARM: imx6: convert GPC to stacked domains
> ARM: exynos4/5: convert pmu wakeup to stacked domains
> DT: exynos: update PMU binding
> irqchip: gic: add an entry point to set up irqchip flags
> ARM: shmobile: remove use of gic_arch_extn.irq_set_wake
> ARM: ux500: switch from gic_arch_extn to gic_set_irqchip_flags
> ARM: zynq: switch from gic_arch_extn to gic_set_irqchip_flags
> irqchip: gic: Drop support for gic_arch_extn
>
Thanks a lot for killing those gic_arch_extn and cross-bar with
newly added stacked domains. It cleans up the GIC code for better.
Feel free to add my ack if you need one.
Acked-by: Santosh Shilimkar <ssantosh at kernel.org>
Regards,
Snatosh
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