IRQ controllers and timers are the two types of device the kernel requires before being able to use the device driver model.
ACPI so far lacks a proper probing infrastructure similar to the one we have with DT, where we're able to declare IRQ chips and clocksources inside the driver code, and let the core code pick it up and call us back on a match. This leads to all kind of really ugly hacks all over the arm64 code and even in the ACPI layer.
It turns out that providing such a probing infrastructure is rather easy, and provides a much deserved cleanup in both the arch code, the GIC driver, and the architected timer driver.
I'm sure there is some more code to be deleted, and one can only wonder why this wasn't done before the arm64 code was initially merged (the diffstat says it all...).
Patches are against v4.2, and a branch is available at
git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git acpi/device-probing
Marc Zyngier (5): acpi: Add basic device probing infrastructure irqchip/acpi: Add probing infrastructure for ACPI-based irqchips irqchip/gic: Convert the GIC driver to ACPI probing clocksource/acpi: Add probing infrastructure for ACPI-based clocksources clocksource/arm_arch_timer: Convert to ACPI probing
arch/arm64/include/asm/acpi.h | 1 - arch/arm64/include/asm/irq.h | 13 ------- arch/arm64/kernel/acpi.c | 25 ------------- arch/arm64/kernel/time.c | 6 ---- drivers/acpi/scan.c | 41 +++++++++++++++++++++ drivers/clocksource/arm_arch_timer.c | 10 +----- drivers/clocksource/clksrc-of.c | 4 +++ drivers/irqchip/irq-gic.c | 69 ++++++++++++++++++------------------ drivers/irqchip/irqchip.c | 5 ++- include/asm-generic/vmlinux.lds.h | 11 ++++++ include/linux/acpi.h | 56 +++++++++++++++++++++++++++++ include/linux/acpi_irq.h | 10 ------ include/linux/clocksource.h | 6 ---- include/linux/irqchip.h | 16 +++++++++ include/linux/irqchip/arm-gic-acpi.h | 31 ---------------- 15 files changed, 166 insertions(+), 138 deletions(-) delete mode 100644 include/linux/acpi_irq.h delete mode 100644 include/linux/irqchip/arm-gic-acpi.h