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@xxxxxxxxxx>
Regards,
Snatosh
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