irqchip: Add RISC-V advanced PLIC driver

The RISC-V advanced interrupt architecture (AIA) specification defines
a new interrupt controller for managing wired interrupts on a RISC-V
platform. This new interrupt controller is referred to as advanced
platform-level interrupt controller (APLIC) which can forward wired
interrupts to CPUs (or HARTs) as local interrupts OR as message
signaled interrupts.
(For more details refer https://github.com/riscv/riscv-aia)

This patch adds an irqchip driver for RISC-V APLIC found on RISC-V
platforms.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>

drivers/irqchip/Kconfig

@@ -544,6 +544,12 @@ config SIFIVE_PLIC
 	select IRQ_DOMAIN_HIERARCHY
 	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
+config RISCV_APLIC
+	bool
+	depends on RISCV
+	select IRQ_DOMAIN_HIERARCHY
+	select GENERIC_MSI_IRQ
+
 config RISCV_IMSIC
 	bool
 	depends on RISCV

drivers/irqchip/Makefile

@@ -95,6 +95,7 @@ obj-$(CONFIG_QCOM_MPM)			+= irq-qcom-mpm.o
 obj-$(CONFIG_CSKY_MPINTC)		+= irq-csky-mpintc.o
 obj-$(CONFIG_CSKY_APB_INTC)		+= irq-csky-apb-intc.o
 obj-$(CONFIG_RISCV_INTC)		+= irq-riscv-intc.o
+obj-$(CONFIG_RISCV_APLIC)		+= irq-riscv-aplic.o
 obj-$(CONFIG_RISCV_IMSIC)		+= irq-riscv-imsic.o
 obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
 obj-$(CONFIG_IMX_IRQSTEER)		+= irq-imx-irqsteer.o