[v3,0/4] New RISC-V Local Interrupt Controller Driver

Message

Anup Patel Feb. 19, 2020, 5:15 p.m. UTC

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       
  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-5.6-rc2 and can be found at riscv_intc_v3
branch of: https://github.com/avpatel/linux.git

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 (4):
  RISC-V: self-contained IPI handling routine
  irqchip: RISC-V Per-HART Local Interrupt Controller Driver
  clocksource: timer-riscv: Make timer interrupt as a per-CPU interrupt
  RISC-V: Remove do_IRQ() function

 arch/riscv/Kconfig                |   1 +
 arch/riscv/include/asm/irq.h      |   5 --
 arch/riscv/include/asm/smp.h      |   3 +
 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 |  79 ++++++++++++------
 drivers/irqchip/Kconfig           |  13 +++
 drivers/irqchip/Makefile          |   1 +
 drivers/irqchip/irq-riscv-intc.c  | 131 ++++++++++++++++++++++++++++++
 drivers/irqchip/irq-sifive-plic.c |  39 ++++++++-
 include/linux/cpuhotplug.h        |   2 +
 13 files changed, 252 insertions(+), 72 deletions(-)
 create mode 100644 drivers/irqchip/irq-riscv-intc.c