Re: [PATCH V12 00/10] irqchip: Add LoongArch-related irqchip drivers

From: Marc Zyngier
Date: Sat Jun 18 2022 - 06:39:17 EST

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On Wed, 15 Jun 2022 07:07:20 +0100,
Jianmin Lv <lvjianmin@xxxxxxxxxxx> wrote:
>
> LoongArch is a new RISC ISA, which is a bit like MIPS or RISC-V.
> LoongArch includes a reduced 32-bit version (LA32R), a standard 32-bit
> version (LA32S) and a 64-bit version (LA64). LoongArch use ACPI as its
> boot protocol LoongArch-specific interrupt controllers (similar to APIC)
> are already added in the ACPI Specification 6.5(which may be published in
> early June this year and the board is reviewing the draft).
>
> Currently, LoongArch based processors (e.g. Loongson-3A5000) can only
> work together with LS7A chipsets. The irq chips in LoongArch computers
> include CPUINTC (CPU Core Interrupt Controller), LIOINTC (Legacy I/O
> Interrupt Controller), EIOINTC (Extended I/O Interrupt Controller),
> HTVECINTC (Hyper-Transport Vector Interrupt Controller), PCH-PIC (Main
> Interrupt Controller in LS7A chipset), PCH-LPC (LPC Interrupt Controller
> in LS7A chipset) and PCH-MSI (MSI Interrupt Controller).
>
> CPUINTC is a per-core controller (in CPU), LIOINTC/EIOINTC/HTVECINTC are
> per-package controllers (in CPU), while PCH-PIC/PCH-LPC/PCH-MSI are all
> controllers out of CPU (i.e., in chipsets). These controllers (in other
> words, irqchips) are linked in a hierarchy, and there are two models of
> hierarchy (legacy model and extended model).
>
> Legacy IRQ model:
>
> In this model, the IPI (Inter-Processor Interrupt) and CPU Local Timer
> interrupt go to CPUINTC directly, CPU UARTS interrupts go to LIOINTC,
> while all other devices interrupts go to PCH-PIC/PCH-LPC/PCH-MSI and
> gathered by HTVECINTC, and then go to LIOINTC, and then CPUINTC.
>
> +---------------------------------------------+
> | |
> | +-----+ +---------+ +-------+ |
> | | IPI | --> | CPUINTC | <-- | Timer | |
> | +-----+ +---------+ +-------+ |
> | ^ |
> | | |
> | +---------+ +-------+ |
> | | LIOINTC | <-- | UARTs | |
> | +---------+ +-------+ |
> | ^ |
> | | |
> | +-----------+ |
> | | HTVECINTC | |
> | +-----------+ |
> | ^ ^ |
> | | | |
> | +---------+ +---------+ |
> | | PCH-PIC | | PCH-MSI | |
> | +---------+ +---------+ |
> | ^ ^ ^ |
> | | | | |
> | +---------+ +---------+ +---------+ |
> | | PCH-LPC | | Devices | | Devices | |
> | +---------+ +---------+ +---------+ |
> | ^ |
> | | |
> | +---------+ |
> | | Devices | |
> | +---------+ |
> | |
> | |
> +---------------------------------------------+
>
> Extended IRQ model:
>
> In this model, the IPI (Inter-Processor Interrupt) and CPU Local Timer
> interrupt go to CPUINTC directly, CPU UARTS interrupts go to LIOINTC,
> while all other devices interrupts go to PCH-PIC/PCH-LPC/PCH-MSI and
> gathered by EIOINTC, and then go to to CPUINTC directly.
>
> +--------------------------------------------------------+
> | |
> | +-----+ +---------+ +-------+ |
> | | IPI | --> | CPUINTC | <-- | Timer | |
> | +-----+ +---------+ +-------+ |
> | ^ ^ |
> | | | |
> | +---------+ +---------+ +-------+ |
> | | EIOINTC | | LIOINTC | <-- | UARTs | |
> | +---------+ +---------+ +-------+ |
> | ^ ^ |
> | | | |
> | +---------+ +---------+ |
> | | PCH-PIC | | PCH-MSI | |
> | +---------+ +---------+ |
> | ^ ^ ^ |
> | | | | |
> | +---------+ +---------+ +---------+ |
> | | PCH-LPC | | Devices | | Devices | |
> | +---------+ +---------+ +---------+ |
> | ^ |
> | | |
> | +---------+ |
> | | Devices | |
> | +---------+ |
> | |
> | |
> +--------------------------------------------------------+
>
> The hierarchy model is constructed by parsing irq contronler structures
> in MADT. Some controllers((e.g. LIOINTC, HTVECINTC, EIOINTC and PCH-LPC)
> are hardcodingly connected to their parents, so their irqdomins are
> separately routed to their parents in a fixed way. Some controllers
> (e.g. PCH-PIC and PCH-MSI) could be routed to different parents for different
> CPU. The firmware will config EIOINTC for the newer CPU and config HTVECINTC
> for old CPU in MADT. By this way, PCH-PIC and PCH-MSI irqdomain can only be
> routed one parent irqdomin: HTVECINTC or EIOINTC.
>
>
> Example of irqchip topology in a system with two chipsets:
>
> +------------------------------------------------------------+
> | |
> | +------------------+ |
> | | CPUINTC | |
> | +------------------+ |
> | ^ ^ |
> | | | |
> | +----------+ +----------+ |
> | | EIOINTC 0| | EIOINTC 1| |
> | +----------+ +----------+ |
> | ^ ^ ^ ^ |
> | | | | | |
> | +----------+ +----------+ +----------+ +----------+ |
> | | PCH-PIC 0| | PCH-MSI 0| | PCH-PIC 1| | PCH-MSI 1| |
> | +----------+ +----------+ +----------+ +----------+ |
> | |
> | |
> +------------------------------------------------------------+
>
> For systems with two chipsets, there are tow group(consists of EIOINTC, PCH-PIC and PCH-MSI) irqdomains,
> and each group has same node id. So we defined a structure to mantain the relation of node and it's parent irqdomain.
>
> struct acpi_vector_group {
> int node;
> struct irq_domain *parent;
> };
>
> The initialization and use of acpi_vector_group array are following:
>
> 1 Entry of struct acpi_vector_group array initialization:
>
> By parsing MCFG, the node id（from bit44-47 of Base Address）of each pci segment is extracted. And from MADT, we have the node id of each EIOINTC.
>
> entrys[pci segment].node = node id of pci segment
> entrys[pci segment].parent = EIOINTC irqdomain(node id of EIOINTC == node id of pci segment)
>
> 2 Get parent irqdomain for PCH-PIC:
>
> From MADT, we have the node id of each PCH-PIC(from bit44-47 of Base Address).
> if (node of entry i == node of PCH-PIC)
> return entrys[i].parent;
>
> entrys[pci segment].node = node id of pci segment
> entrys[pci segment].parent = EIOINTC irqdomain(node id of EIOINTC == node id of pci segment)
>
> 3 Get parent irqdomain for PCH-MSI of pci segment:
>
> return entrys[pci segment].parent;
>
> 4 How to select a correct irqdomain to map irq for a device?
> For devices using legacy irq behind PCH-PIC, GSI is used to select correct PCH-PIC irqdomain.
> For devices using msi irq behind PCH-MSI, the pci segmen of the device is used to select correct PCH-MSI irqdomain.
>
> V1 -> V2:
> 1, Remove queued patches;
> 2, Move common logic of DT/ACPI probing to common functions;
> 3, Split .suspend()/.resume() functions to separate patches.
>
> V2 -> V3:
> 1, Fix a bug for loongson-pch-pic probe;
> 2, Some minor improvements for LPC controller.
>
> V3 -> V4:
> 1, Rework the CPU interrupt controller driver;
> 2, Some minor improvements for other controllers.
>
> V4 -> V5:
> 1, Add a description of LoonArch's IRQ model;
> 2, Support multiple EIOINTCs in one system;
> 3, Some minor improvements for other controllers.
>
> V5 -> V6:
> 1, Attach a fwnode to CPUINTC irq domain;
> 2, Use raw spinlock instead of generic spinlock;
> 3, Improve the method of restoring EIOINTC state;
> 4, Update documentation, comments and commit messages.
>
> V6 -> V7:
> 1, Fix build warnings reported by kernel test robot.
>
> V7 -> V8:
> 1, Add arguments sanity checking for irqchip init functions;
> 2, Support Loongson-3C5000 (One NUMA Node includes 4 EIOINTC Node).
>
> V8 -> V9:
> 1, Rebase on 5.17-rc5;
> 2, Update cover letter;
> 3, Some small improvements.
>
> V9 -> V10:
> 1, Rebase on 5.17-rc6;
> 2, Fix build warnings reported by kernel test robot.
>
> V10 -> V11:
> 1, Rebase on 5.18-rc4;
> 2, Fix irq affinity setting for EIOINTC;
> 3, Fix hwirq allocation failure for EIOINTC.
>
> V11 -> RFC:
> 1, Refactored the way to build irqchip hierarchy topology.
>
> RFC -> RFC V2:
> 1, Move all IO-interrupt related code to driver/irqchip from arch directory.
> 2. Add description for an example of two chipsets system.
>
> RFC V2 -> RFC V3:
> 1, Add support for multiple GSI domains
> 2, Use ACPI_GENERIC_GSI for GSI handling
> 3, Drop suspend-resume stuff
> 4, Export fwnode handles instead of irq domain handles
>
> RFC V3 -> V12:
> 1, Address patch attributions of the patch series
>
> Huacai Chen (7):
> irqchip: Add LoongArch CPU interrupt controller support
> irqchip/loongson-pch-pic: Add ACPI init support
> irqchip/loongson-pch-msi: Add ACPI init support
> irqchip/loongson-htvec: Add ACPI init support
> irqchip/loongson-liointc: Add ACPI init support
> irqchip: Add Loongson Extended I/O interrupt controller support
> irqchip: Add Loongson PCH LPC controller support
>
> Jianmin Lv (2):
> genirq/generic_chip: export irq_unmap_generic_chip
> irqchip: create library file for LoongArch irqchip driver
>
> Marc Zyngier (1):
> APCI: irq: Add support for multiple GSI domains
>
> drivers/acpi/bus.c | 3 +
> drivers/acpi/irq.c | 40 ++--
> drivers/irqchip/Kconfig | 28 +++
> drivers/irqchip/Makefile | 3 +
> drivers/irqchip/irq-gic-v3.c | 18 +-
> drivers/irqchip/irq-gic.c | 18 +-
> drivers/irqchip/irq-loongarch-cpu.c | 134 +++++++++++
> drivers/irqchip/irq-loongarch-pic-common.c | 122 ++++++++++
> drivers/irqchip/irq-loongarch-pic-common.h | 39 ++++
> drivers/irqchip/irq-loongson-eiointc.c | 347 +++++++++++++++++++++++++++++
> drivers/irqchip/irq-loongson-htvec.c | 119 +++++++---
> drivers/irqchip/irq-loongson-liointc.c | 225 ++++++++++++-------
> drivers/irqchip/irq-loongson-pch-lpc.c | 202 +++++++++++++++++
> drivers/irqchip/irq-loongson-pch-msi.c | 138 ++++++++----
> drivers/irqchip/irq-loongson-pch-pic.c | 171 +++++++++++---
> include/linux/acpi.h | 3 +-
> include/linux/cpuhotplug.h | 1 +
> include/linux/irq.h | 1 +
> kernel/irq/generic-chip.c | 2 +-
> 19 files changed, 1402 insertions(+), 212 deletions(-)
> create mode 100644 drivers/irqchip/irq-loongarch-cpu.c
> create mode 100644 drivers/irqchip/irq-loongarch-pic-common.c
> create mode 100644 drivers/irqchip/irq-loongarch-pic-common.h
> create mode 100644 drivers/irqchip/irq-loongson-eiointc.c
> create mode 100644 drivers/irqchip/irq-loongson-pch-lpc.c

One thing I don't see here is the removal of the irq code that
currently lives in arch/loongarch/kernel/acpi.c. It really should be
removed as part of this series with the patch that enables the common
ACPI irq code for this architecture.

Thanks,

M.

--
Without deviation from the norm, progress is not possible.

Next message: Pavel Machek: "Re: [PATCH 5.17 000/772] 5.17.14-rc1 review"
Previous message: Marc Zyngier: "Re: [PATCH V12 01/10] APCI: irq: Add support for multiple GSI domains"
Next in thread: Jianmin Lv: "Re: [PATCH V12 00/10] irqchip: Add LoongArch-related irqchip drivers"
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