[PATCH v3 00/11] Linux RISC-V AIA Support

Anup Patel
2023-05-08T14:29:15Z

The RISC-V AIA specification is now frozen as-per the RISC-V international
process. The latest frozen specifcation can be found at:
https://github.com/riscv/riscv-aia/releases/download/1.0-RC1/riscv-interrupts-1.0-RC1.pdf

At a high-level, the AIA specification adds three things:
1) AIA CSRs
- Improved local interrupt support
2) Incoming Message Signaled Interrupt Controller (IMSIC)
- Per-HART MSI controller
- Support MSI virtualization
- Support IPI along with virtualization
3) Advanced Platform-Level Interrupt Controller (APLIC)
- Wired interrupt controller
- In MSI-mode, converts wired interrupt into MSIs (i.e. MSI generator)
- In Direct-mode, injects external interrupts directly into HARTs

For an overview of the AIA specification, refer the recent AIA virtualization
talk at KVM Forum 2022:
https://static.sched.com/hosted_files/kvmforum2022/a1/AIA_Virtualization_in_KVM_RISCV_final.pdf
https://www.youtube.com/watch?v=r071dL8Z0yo

The PATCH3 of this series conflicts with the "irqchip/riscv-intc: Add ACPI
support" patch of the "Add basic ACPI support for RISC-V" series.
(Refer, https://lore.kernel.org/linux-riscv/20230508115237.216337-1-sunilvl@ventanamicro.com/)

To test this series, use QEMU v7.2 (or higher) and OpenSBI v1.2 (or higher).

These patches can also be found in the riscv_aia_v3 branch at:
https://github.com/avpatel/linux.git

Changes since v2:
- Rebased on Linux-6.4-rc1
- Addressed Rob's comments on DT bindings patches 4 and 8.
- Addessed Marc's comments on IMSIC driver PATCH5
- Replaced use of OF apis in APLIC and IMSIC drivers with FWNODE apis
this makes both drivers easily portable for ACPI support. This also
removes unnecessary indirection from the APLIC and IMSIC drivers.
- PATCH1 is a new patch for portability with ACPI support
- PATCH2 is a new patch to fix probing in APLIC drivers for APLIC-only systems.
- PATCH7 is a new patch which addresses the IOMMU DMA domain issues pointed
out by SiFive

Changes since v1:
- Rebased on Linux-6.2-rc2
- Addressed comments on IMSIC DT bindings for PATCH4
- Use raw_spin_lock_irqsave() on ids_lock for PATCH5
- Improved MMIO alignment checks in PATCH5 to allow MMIO regions
with holes.
- Addressed comments on APLIC DT bindings for PATCH6
- Fixed warning splat in aplic_msi_write_msg() caused by
zeroed MSI message in PATCH7
- Dropped DT property riscv,slow-ipi instead will have module
parameter in future.

Anup Patel (11):
RISC-V: Add riscv_fw_parent_hartid() function
of/irq: Set FWNODE_FLAG_BEST_EFFORT for the interrupt controller DT
nodes
irqchip/riscv-intc: Add support for RISC-V AIA
dt-bindings: interrupt-controller: Add RISC-V incoming MSI controller
irqchip: Add RISC-V incoming MSI controller driver
irqchip/riscv-imsic: Add support for PCI MSI irqdomain
irqchip/riscv-imsic: Improve IOMMU DMA support
dt-bindings: interrupt-controller: Add RISC-V advanced PLIC
irqchip: Add RISC-V advanced PLIC driver
RISC-V: Select APLIC and IMSIC drivers
MAINTAINERS: Add entry for RISC-V AIA drivers

.../interrupt-controller/riscv,aplic.yaml | 162 +++
.../interrupt-controller/riscv,imsics.yaml | 172 +++
MAINTAINERS | 12 +
arch/riscv/Kconfig | 2 +
arch/riscv/include/asm/processor.h | 3 +
arch/riscv/kernel/cpu.c | 12 +
drivers/iommu/dma-iommu.c | 38 +
drivers/irqchip/Kconfig | 20 +-
drivers/irqchip/Makefile | 2 +
drivers/irqchip/irq-riscv-aplic.c | 750 ++++++++++++
drivers/irqchip/irq-riscv-imsic.c | 1080 +++++++++++++++++
drivers/irqchip/irq-riscv-intc.c | 36 +-
drivers/of/irq.c | 10 +
include/linux/iommu.h | 6 +
include/linux/irqchip/riscv-aplic.h | 119 ++
include/linux/irqchip/riscv-imsic.h | 86 ++
16 files changed, 2503 insertions(+), 7 deletions(-)
create mode 100644 Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml
create mode 100644 Documentation/devicetree/bindings/interrupt-controller/riscv,imsics.yaml
create mode 100644 drivers/irqchip/irq-riscv-aplic.c
create mode 100644 drivers/irqchip/irq-riscv-imsic.c
create mode 100644 include/linux/irqchip/riscv-aplic.h
create mode 100644 include/linux/irqchip/riscv-imsic.h

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2.34.1