Re: [PATCH v3 0/8] Add support for LS7A LPC IRQ for MIPS Loongson systems

Re: [PATCH v3 0/8] Add support for LS7A LPC IRQ for MIPS Loongson systems

[Icenowy Zheng]

在 2026-03-18三的 21:57 +0800，Huacai Chen写道：
> Hi, Icenowy,
> 
> On Sun, Mar 15, 2026 at 12:28 AM Icenowy Zheng
> <zhengxingda@iscas.ac.cn> wrote:
> > 
> > This patchset tries to add support for Loongson 7A1000 PCH's LPC
> > interrupt controller to MIPS-based Loongson systems.
> > 
> > LPC, from software's perspective of view, is just ISA, so the
> > interrupts
> > should be handled as legacy ones occupying the lowest 0-15 IRQ
> > numbers.
> > Despite the current PCH LPC driver for ACPI-based LoongArch
> > Loongson
> > machines handled it, the setup is fragile and depends on its
> > specific
> > setup sequence (allocating the LPC IRQs first, and then allocate
> > the
> > parent IRQ at PCH PIC). The refactor of extracting parent IRQ
> > allocation
> > breaks this fragile sequence, so the first two commits is created
> > to
> > address this issue (by reserving ISA interrupts from the dynamic
> > allocation space).
> > 
> > Then the remaining commits are just adding OF(DT) based
> > initialization
> > of PCH LPC interrupt controller, like what happened on PCH PIC.
> > 
> > Tested on a Haier Boyue G51 system with legacy i8042 keyboard/mouse
> > as
> > integrated ones.
> > 
> > Changes in v3:
> > - Override arch_dynirq_lower_bound() in MIPS Loongson64 / LoongArch
> >   instead of modifying the global version of function.
> > - Added Rob's R-b to the binding patch.
> > 
> > Changes in v2:
> > - Rebased on top of `irq-drivers-2026-02-09` tag.
> > - Compatible changed to `loongson,ls7a-lpc` .
> > - Merged the patch for conditionally build of ACPI code to the
> > patch
> >   introducing OF code.
> > - Sorted function variable definitions.
> > - Reworded some commit messages as Thomas Glexiner suggests.
> > - Added __init to the LPC irqchip OF initialization code to prevent
> >   section mismatch.
> > 
> > Icenowy Zheng (8):
> >   MIPS: loongson64: Override arch_dynirq_lower_bound to reserve LPC
> > IRQs
> >   LoongArch: Override arch_dynirq_lower_bound to reserve LPC IRQs
> Use upper case for the first word, which means....

I'm going to change this for your preference, but please note that
there's no requirement of using upper case for `summary phrase` in the
Documentation/process/submitting-patches.rst document.

The examples in that document even include both examples with first
words being either upper case and lower case, which indicates both
should be acceptable:

```
Here are some good example Subjects::

    Subject: [PATCH 2/5] ext2: improve scalability of bitmap searching
    Subject: [PATCH v2 01/27] x86: fix eflags tracking
    Subject: [PATCH v2] sub/sys: Condensed patch summary
    Subject: [PATCH v2 M/N] sub/sys: Condensed patch summary
```

Thanks,
Icenowy

> 
> >   dt-bindings: interrupt-controller: add LS7A PCH LPC
> s/add/Add/g
> 
> >   irqchip/loongson-pch-lpc: extract non-ACPI-related code from ACPI
> > init
> s/extract/Extract/g
> 
> >   irqchip/loongson-pch-lpc: add OF init code
> s/add/Add/g
> 
> >   irqchip/loongson-pch-lpc: enable building on MIPS Loongson64
> s/enable/Enable/g
> 
> >   MIPS: Loongson64: dts: sort nodes
> s/sort/Sort/g
> 
> >   MIPS: Loongson64: dts: add node for LS7A PCH LPC
> s/add/Add/g
> 
> In addition, I think the last two patches should be in another series
> because they won't go to the irqchip tree.
> 
> Huacai
> 
> > 
> >  .../loongson,pch-lpc.yaml                     | 52 +++++++++++
> >  arch/loongarch/kernel/irq.c                   |  6 ++
> >  arch/mips/boot/dts/loongson/ls7a-pch.dtsi     | 17 +++-
> >  arch/mips/loongson64/init.c                   |  6 ++
> >  drivers/irqchip/Kconfig                       |  1 -
> >  drivers/irqchip/irq-loongson-pch-lpc.c        | 87 ++++++++++++++-
> > ----
> >  6 files changed, 144 insertions(+), 25 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/interrupt-
> > controller/loongson,pch-lpc.yaml
> > 
> > --
> > 2.52.0
> > 

Re: [PATCH v3 0/8] Add support for LS7A LPC IRQ for MIPS Loongson systems

[Icenowy Zheng]

在 2026-03-20五的 10:16 +0100，Thomas Gleixner写道：
> On Wed, Mar 18 2026 at 21:57, Huacai Chen wrote:
> > >   MIPS: Loongson64: dts: sort nodes
> > s/sort/Sort/g
> > 
> > >   MIPS: Loongson64: dts: add node for LS7A PCH LPC
> > s/add/Add/g
> > 
> > In addition, I think the last two patches should be in another
> > series
> > because they won't go to the irqchip tree.
> 
> Correct.

To be honest, I don't know whether the first two patches should go to
the irqchip tree either; but the irqchip driver refactor depends on
these two patches.

Thanks,
Icenowy

Re: [PATCH v3 0/8] Add support for LS7A LPC IRQ for MIPS Loongson systems

[Thomas Gleixner]

On Sat, Mar 21 2026 at 16:59, Icenowy Zheng wrote:
> 在 2026-03-18三的 21:57 +0800，Huacai Chen写道：
> I'm going to change this for your preference, but please note that
> there's no requirement of using upper case for `summary phrase` in the
> Documentation/process/submitting-patches.rst document.

Interrupt chip code is maintained in the tip tree and that tree has a
supplementary document, which explicitely requests this:

  https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#patch-subject