irqchip/irq-mtk-cirq: Add support for System CIRQ on MT8192

On some SoCs the System CIRQ register layout is slightly different,
as there are more registers per function and in some cases other
differences later in the layout: this is seen on at least MT8192,
but it's also valid for some other "contemporary" SoCs both for
Chromebooks and for smartphones.

Add the new "v2" register layout and use it if the compatible
"mediatek,mt8192-cirq" is found.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221128092217.36552-5-angelogioacchino.delregno@collabora.com

irqchip/irq-mtk-cirq: Move register offsets to const array

In preparation to add support for new SoCs having a different
register layout, add an enumeration that documents register
offsets and move the definitions for the same to a u32 array;

Selecting the right register offsets array is done by adding an
of_device_id array containing all of the currently supported
compatible strings pointing to the "v1" offsets array (as data):
since no devicetree declares the `mediatek,mtk-cirq` compatible
without a SoC-specific one, it wasn't necessary to provide any
legacy fallback.

Every usage of the aforemementioned definitions was changed to
get a register address through a newly introduced `mtk_cirq_reg()`
accessor.

This change brings no functional changes.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221128092217.36552-4-angelogioacchino.delregno@collabora.com

irq: Fix typos in comments

Fix ~36 single-word typos in the IRQ, irqchip and irqdomain code comments.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

irqchip: Revert modular support for drivers using IRQCHIP_PLATFORM_DRIVER helperse

It has become obvious that switching a number of irqchip drivers
to being platform drivers without considering the platform was a
mistake. We have multiple reports of end-point drivers not
probing because the irqchip driver isn't there yet, breaking
the expectations of the users.

This patch reverts:

920ecb8c35cb ("irqchip/mtk-cirq: Convert to a platform driver")
f97dbf48ca43 ("irqchip/mtk-sysirq: Convert to a platform driver")
5be57099d445 ("irqchip/qcom-pdc: Switch to using IRQCHIP_PLATFORM_DRIVER helper macros")
95bf9305d2e3 ("irqchip/qcom-pdc: Allow QCOM_PDC to be loadable as a permanent module")

and leave QCOM PDC, MTK sysrq and cirq drivers as built-in, special purpose
drivers for the time being until we have worked out a better solution.

Reported-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reported-by: Frank Wunderlich <linux@fw-web.de>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/93debe6a0308b66d3f307af67ba7ec2c@kernel.org

irqchip/mtk-cirq: Convert to a platform driver

This driver can work as a platform driver. So covert it to a platform
driver.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Hanks Chen <hanks.chen@mediatek.com>
Link: https://lore.kernel.org/r/20200718000637.3632841-5-saravanak@google.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 655 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

irqchip: Add Mediatek mtk-cirq driver

In Mediatek SOCs, the CIRQ is a low power interrupt controller
designed to works outside MCUSYS which comprises with Cortex-Ax
cores,CCI and GIC.

The CIRQ controller is integrated in between MCUSYS( include
Cortex-Ax, CCI and GIC ) and interrupt sources as the second
level interrupt controller. The external interrupts which outside
MCUSYS will feed through CIRQ then bypass to GIC. CIRQ can monitors
all edge trigger interupts. When an edge interrupt is triggered,
CIRQ can record the status and generate a pulse signal to GIC when
flush command executed.

When system enters sleep mode, MCUSYS will be turned off to improve
power consumption, also GIC is power down. The edge trigger interrupts
will be lost in this scenario without CIRQ.

This commit provides the CIRQ irqchip implement.

Signed-off-by: Youlin Pei <youlin.pei@mediatek.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>