[RFC PATCH 0/5] New RISC-V Local Interrupt Controller Driver

From: Anup Patel
Date: Tue Sep 04 2018 - 08:45:44 EST


This patchset provides a new RISC-V Local Interrupt Controller Driver
for managing per-CPU local interrupts. The overall approach is inspired
from the way per-CPU local interrupts are handled by Linux ARM64 and
ARM GICv3 driver.

Few advantages of having this new driver are as follows:
1. It registers all local interrupts as per-CPU interrupts
2. We can develop drivers for devices with per-CPU local interrupts
without changing arch code or this driver
3. It allows local interrupt controller DT node under each CPU DT node
as well as single system-wide DT node for local interrupt controller.

With this patchset, output of "cat /proc/interrupts" looks as follows:
CPU0 CPU1 CPU2 CPU3
5: 995 1012 997 1015 RISC-V INTC 5 Edge riscv_timer
8: 23 6 10 7 SiFive PLIC 8 Edge virtio0
10: 9 10 5 4 SiFive PLIC 10 Edge ttyS0

The patchset is based up Linux-4.19-rc2 and can be found at
riscv_intc_v1 branch of:
https://github.com/avpatel/linux.git

Anup Patel (5):
RISC-V: Make IPI triggering flexible
RISC-V: No need to pass scause as arg to do_IRQ()
RISC-V: Select useful GENERIC_IRQ kconfig options
irqchip: RISC-V Local Interrupt Controller Driver
clocksource: riscv_timer: Make timer interrupt as a per-CPU interrupt

arch/riscv/Kconfig | 4 +
arch/riscv/include/asm/irq.h | 16 ++-
arch/riscv/include/asm/smp.h | 10 ++
arch/riscv/kernel/entry.S | 1 -
arch/riscv/kernel/irq.c | 45 +--------
arch/riscv/kernel/smp.c | 23 ++++-
drivers/clocksource/riscv_timer.c | 76 ++++++++++++---
drivers/irqchip/Kconfig | 15 ++-
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-riscv-intc.c | 156 ++++++++++++++++++++++++++++++
drivers/irqchip/irq-sifive-plic.c | 21 +++-
include/linux/cpuhotplug.h | 1 +
12 files changed, 301 insertions(+), 68 deletions(-)
create mode 100644 drivers/irqchip/irq-riscv-intc.c

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2.17.1