On Thu, May 28, 2020 at 12:17 AM Palmer Dabbelt <pal...@dabbelt.com> wrote: > > On Thu, 21 May 2020 06:32:55 PDT (-0700), Anup Patel wrote: > > 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 > > So I read through this a bit, and while I haven't gone through every line of > code I'm somewhat inclined toward taking it. > > During the original RISC-V port submission we went back and forth between > having this first-level interrupt controller in arch/riscv/ vs > drivers/irqchip/. The original deciding factor was that the ISA mandated the > interrupt controller, but as that's proving to be less and less the case every > day (with the CLIC and M-mode Linux) it certainly seem sane to move all our > interrupt controller drivers out of arch/riscv/. > > This is certainly a step in the right direction, and it handles some of the > more glaring issues (iscv_timer_interrupt and lacking IRQs for the CLINT). I > think we should just go ahead and merge it, even though there might be some > more refactoring to do when we eventually end up with another interrupt > controller. > > I think it's best if this all goes in through a single tree, as it seems more > work than it's worth to split it up. I'm happy to take it through my tree if > that's OK with the irqchip folks?
A small heads up... Marc has queued a few PLIC improvement patches for Linux-next. (https://patchwork.kernel.org/cover/11555051/) This series (particularly PATCH3) is based upon above mentioned PLIC patches. Apart from above, I don't see any potential merge conflicts. Regards, Anup