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 this new driver over previous one are: 1. All local interrupts are registered as per-CPU interrupts 2. The RISC-V timer driver can register timer interrupt handler using kernel irq subsystem without relying on arch/riscv to explicitly call it's interrupt handler 3. The KVM RISC-V can use this driver to implement interrupt handler for per-HART guest external interrupt defined by the RISC-V H-Extension 4. In future, we can develop drivers for devices with per-HART interrupts without changing arch code or this driver (example, CLINT timer driver for RISC-V M-mode kernel) With this patchset, output of "cat /proc/interrupts" looks as follows: CPU0 CPU1 CPU2 CPU3 2: 379 0 0 0 SiFive PLIC 10 ttyS0 3: 591 0 0 0 SiFive PLIC 8 virtio0 5: 5079 10821 8435 12984 RISC-V INTC 5 riscv-timer IPI0: 2045 2537 891 870 Rescheduling interrupts IPI1: 9 269 91 168 Function call interrupts IPI2: 0 0 0 0 CPU stop interrupts The patchset is based up Linux-5.7-rc6 and can be found at riscv_intc_v5 branch of: https://github.com/avpatel/linux.git This series is tested on: 1. QEMU RV64 virt machine using Linux RISC-V S-mode 2. QEMU RV32 virt machine using Linux RISC-V S-mode 3. QEMU RV64 virt machine using Linux RISC-V M-mode (i.e. NoMMU) Changes since v4: - Rebased to Linux-5.7-rc6 and multi-PLIC improvement patches - Added separate patch to force select RISCV_INTC for CONFIG_RISCV - Fixed the driver for Linux RISC-V NoMMU Changes since v3: - Rebased to Linux-5.6-rc5 and Atish's PLIC patches - Added separate patch to rename and move plic_find_hart_id() to arch directory - Use riscv_of_parent_hartid() in riscv_intc_init() instead of atomic counter Changes since v2: - Dropped PATCH2 since it was merged long-time back - Rebased series from Linux-4.19-rc2 to Linux-5.6-rc2 Changes since v1: - Removed changes related to puggable IPI triggering - Separate patch for self-contained IPI handling routine - Removed patch for GENERIC_IRQ kconfig options - Added patch to remove do_IRQ() function - Rebased upon Atish's SMP patches Anup Patel (6): RISC-V: self-contained IPI handling routine RISC-V: Rename and move plic_find_hart_id() to arch directory irqchip: RISC-V per-HART local interrupt controller driver clocksource/drivers/timer-riscv: Use per-CPU timer interrupt RISC-V: Remove do_IRQ() function RISC-V: Force select RISCV_INTC for CONFIG_RISCV arch/riscv/Kconfig | 2 + arch/riscv/include/asm/irq.h | 5 - arch/riscv/include/asm/processor.h | 1 + arch/riscv/include/asm/smp.h | 3 + arch/riscv/kernel/cpu.c | 16 +++ arch/riscv/kernel/entry.S | 4 +- arch/riscv/kernel/irq.c | 33 +----- arch/riscv/kernel/smp.c | 11 +- arch/riscv/kernel/traps.c | 2 - drivers/clocksource/timer-riscv.c | 30 ++++- drivers/irqchip/Kconfig | 13 +++ drivers/irqchip/Makefile | 1 + drivers/irqchip/irq-riscv-intc.c | 150 +++++++++++++++++++++++++ drivers/irqchip/irq-sifive-plic.c | 52 +++++---- include/linux/cpuhotplug.h | 1 + include/linux/irqchip/irq-riscv-intc.h | 20 ++++ 16 files changed, 280 insertions(+), 64 deletions(-) create mode 100644 drivers/irqchip/irq-riscv-intc.c create mode 100644 include/linux/irqchip/irq-riscv-intc.h -- 2.25.1