[RFC,v2,00/21] RISC-V: ACPI: Add external interrupt controller support

This series adds support for the below ECR approved by ASWG.
1) MADT - https://drive.google.com/file/d/1oMGPyOD58JaPgMl1pKasT-VKsIKia7zR/view?usp=sharing

The series primarily enables irqchip drivers for RISC-V ACPI based
platforms.

In addition, PCI ACPI related functions are migrated from arm64 to
common file so that we don't need to duplicate them for RISC-V.

On RISC-V platforms, apart from root irqchips which provide local
interrupts and IPI, all other interrupt controllers are probed late
during boot. Hence, the drivers for the devices connected to these
interrupt controllers which are probed late, should also support
deferred probe. While ACPI platform devices/drivers seem to support
deferred probe since they use acpi_irq_get(), the PNP devices and the
PCI INTx expect GSIs are registered early. So, patches are required
to enable few essential drivers to support deferred probe. To minimize
the impact, a new CONFIG option is introduced which can be enabled only
by the architecture like RISC-V which supports deferred irqchip probe.

This series is based on Anup's AIA v11 series. Since Anup's AIA v11 is
not merged yet and first time introducing deferred probe, this series is
still kept as RFC. Looking forward for the feedback!

Changes since RFC v1:
	1) Abandoned swnode approach as per Marc's feedback.
	2) To cope up with AIA series changes which changed irqchip driver
	   probe from core_initcall() to platform_driver, added patches
	   to support deferred probing.
	3) Rebased on top of Anup's AIA v11 and added tags.

To test the series,

1) Qemu should be built using the riscv_acpi_b2_v4 branch at
https://github.com/vlsunil/qemu.git

2) EDK2 should be built using the instructions at:
https://github.com/tianocore/edk2/blob/master/OvmfPkg/RiscVVirt/README.md

3) Build Linux using this series on top of Anup's AIA v11 series.

Run Qemu:
qemu-system-riscv64 \
 -M virt,pflash0=pflash0,pflash1=pflash1,aia=aplic-imsic \
 -m 2G -smp 8 \
 -serial mon:stdio \
 -device virtio-gpu-pci -full-screen \
 -device qemu-xhci \
 -device usb-kbd \
 -blockdev node-name=pflash0,driver=file,read-only=on,filename=RISCV_VIRT_CODE.fd \
 -blockdev node-name=pflash1,driver=file,filename=RISCV_VIRT_VARS.fd \
 -netdev user,id=net0 -device virtio-net-pci,netdev=net0 \
 -kernel arch/riscv/boot/Image \
 -initrd rootfs.cpio \
 -append "root=/dev/ram ro console=ttyS0 rootwait earlycon=uart8250,mmio,0x10000000"

To boot with APLIC only, use aia=aplic.
To boot with PLIC, remove aia= option.

This series is also available in acpi_b2_v2_riscv_aia_v11 branch at
https://github.com/vlsunil/linux.git

Based-on: 20231023172800.315343-1-apatel@ventanamicro.com
(https://lore.kernel.org/lkml/20231023172800.315343-1-apatel@ventanamicro.com/)

Sunil V L (21):
  arm64: PCI: Migrate ACPI related functions to pci-acpi.c
  RISC-V: ACPI: Implement PCI related functionality
  ACPI: Kconfig: Introduce new option to support deferred GSI probe
  ACPI: irq: Add support for deferred probe in acpi_register_gsi()
  pnp.h: Return -EPROBE_DEFER for disabled IRQ resource in pnp_irq()
  RISC-V: Kconfig: Select deferred GSI probe for ACPI systems
  serial: 8250_pnp: Add support for deferred probe
  ACPI: pci_irq: Avoid warning for deferred probe in
    acpi_pci_irq_enable()
  ACPI: scan.c: Add weak arch specific function to reorder the IRQCHIP
    probe
  ACPI: RISC-V: Implement arch function to reorder irqchip probe entries
  PCI: MSI: Add helper function to set system wide MSI support
  PCI: pci-acpi.c: Return correct value from pcibios_alloc_irq()
  irqchip: riscv-intc: Add ACPI support for AIA
  irqchip: riscv-imsic: Add ACPI support
  irqchip: riscv-aplic: Add ACPI support
  irqchip: irq-sifive-plic: Add ACPI support
  ACPI: bus: Add RINTC IRQ model for RISC-V
  irqchip: riscv-intc: Set ACPI irqmodel
  ACPI: bus: Add acpi_riscv_init function
  ACPI: RISC-V: Create APLIC platform device
  ACPI: RISC-V: Create PLIC platform device

 arch/arm64/kernel/pci.c                    | 191 ---------------------
 arch/riscv/Kconfig                         |   3 +
 arch/riscv/include/asm/irq.h               |  31 ++++
 arch/riscv/kernel/acpi.c                   |  31 ++--
 drivers/acpi/Kconfig                       |   3 +
 drivers/acpi/bus.c                         |   4 +
 drivers/acpi/irq.c                         |  12 +-
 drivers/acpi/pci_irq.c                     |   7 +-
 drivers/acpi/riscv/Makefile                |   2 +-
 drivers/acpi/riscv/init.c                  |  15 ++
 drivers/acpi/riscv/init.h                  |   6 +
 drivers/acpi/riscv/irq.c                   | 120 +++++++++++++
 drivers/acpi/scan.c                        |   3 +
 drivers/irqchip/irq-riscv-aplic-direct.c   |  22 ++-
 drivers/irqchip/irq-riscv-aplic-main.c     | 105 ++++++++---
 drivers/irqchip/irq-riscv-aplic-main.h     |   1 +
 drivers/irqchip/irq-riscv-aplic-msi.c      |  10 +-
 drivers/irqchip/irq-riscv-imsic-early.c    |  52 +++++-
 drivers/irqchip/irq-riscv-imsic-platform.c |  51 ++++--
 drivers/irqchip/irq-riscv-imsic-state.c    | 128 +++++++-------
 drivers/irqchip/irq-riscv-imsic-state.h    |   2 +-
 drivers/irqchip/irq-riscv-intc.c           | 114 +++++++++++-
 drivers/irqchip/irq-sifive-plic.c          | 113 ++++++++++--
 drivers/pci/msi/msi.c                      |   5 +
 drivers/pci/pci-acpi.c                     | 182 ++++++++++++++++++++
 drivers/pci/pci.h                          |   2 +
 drivers/tty/serial/8250/8250_pnp.c         |  18 +-
 include/linux/acpi.h                       |   9 +
 include/linux/irqchip/riscv-imsic.h        |  10 ++
 include/linux/pnp.h                        |  10 +-
 30 files changed, 906 insertions(+), 356 deletions(-)
 create mode 100644 drivers/acpi/riscv/init.c
 create mode 100644 drivers/acpi/riscv/init.h
 create mode 100644 drivers/acpi/riscv/irq.c