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

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Message-ID: <aX8jjqxrl2ccN1lA@pie>
Date: Sun, 1 Feb 2026 09:57:34 +0000
From: Yao Zi <me@...ao.cc>
To: Icenowy Zheng <zhengxingda@...as.ac.cn>,
	Thomas Gleixner <tglx@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	Huacai Chen <chenhuacai@...nel.org>,
	Jiaxun Yang <jiaxun.yang@...goat.com>
Cc: linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-mips@...r.kernel.org
Subject: Re: [PATCH 0/8] Add support for LS7A LPC IRQ for MIPS Loongson
 systems

On Sat, Jan 31, 2026 at 05:45:39PM +0800, Icenowy Zheng wrote:
> This patchset tries to add support for Loongson 7A1000 PCH's LPC IRQ
> controller to MIPS-based Loongson systems.
> 
> LPC, from software's perspective of view, is just ISA, so the IRQs
> 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 commit is created to address
> for this issue (by reserving ISA IRQs from the dynamic IRQ allocation
> space).
> 
> Then the remaining commits are just adding OF(DT) based initialization
> of PCH LPC IRQ controller, like what happened on PCH PIC.
> 
> Tested on a Haier Boyue G51 system with legacy i8042 keyboard/mouse as
> integrated ones. I don't own a LoongArch-based device with LPC
> peripherals, so test on LoongArch machines are welcomed.

Tested on TongFang L860-T2 system, which is LoongArch-based and exposes
keyboard and mouse as i8042, too. Nothing breaks with this series,

$ cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3
  1:        606          0          0          0  PCH LPC   1  i8042
 12:        645          0          0          0  PCH LPC  12  i8042
 20:      16393      14853      15443      17386  CPUINTC  12  IPI
 21:       4515       4154       3756       3701  CPUINTC  11  timer
 22:          0          0          0          0  PCH PIC   1  acpi
 28:          0          0          0          0  PCH PIC   7  loongson-alarm
 29:          0          0          0          0  PCH PIC   8  ls2x-i2c, ls2x-i2c, ls2x-i2c, ls2x-i2c, ls2x-i2c, ls2x-i2c
 37:          0          0          0          0 PCH-PCI-MSI-0000:00:09.0   0  PCIe bwctrl
 39:          0          0          0          0 PCH-PCI-MSI-0000:00:0a.0   0  PCIe bwctrl
 41:          0          0          0          0 PCH-PCI-MSI-0000:00:0b.0   0  PCIe bwctrl
 43:          0          0          0          0 PCH-PCI-MSI-0000:00:0c.0   0  PCIe bwctrl
 45:          0          0          0          0 PCH-PCI-MSI-0000:00:0d.0   0  PCIe bwctrl
 47:          0          0          0          0 PCH-PCI-MSI-0000:00:11.0   0  PCIe bwctrl
 49:          0          0          0          0 PCH-PCI-MSI-0000:00:13.0   0  PCIe bwctrl
 50:          0          0          0          0  PCH PIC  21  ahci[0000:00:08.0]
 51:         14          0          0          0 PCH-PCI-MSIX-0000:06:00.0   0  nvme0q0
 52:          0          0          0          0  PCH PIC  22  ahci[0000:00:08.1]
 53:          0          0          0          0  PCH PIC  23  ahci[0000:00:08.2]
 54:          0          0          0          0 PCH-PCI-MSI-0000:04:00.0   0  ahci[0000:04:00.0]
 55:        952          0          0          0 PCH-PCI-MSIX-0000:06:00.0   1  nvme0q1
 56:          0       1590          0          0 PCH-PCI-MSIX-0000:06:00.0   2  nvme0q2
 57:          0          0        916          0 PCH-PCI-MSIX-0000:06:00.0   3  nvme0q3
 58:          0          0          0       3836 PCH-PCI-MSIX-0000:06:00.0   4  nvme0q4
 61:       2649          0          0          0 PCH-PCI-MSI-0000:07:00.0   0  amdgpu
 62:       2561          0          0          0 PCH-PCI-MSI-0000:01:00.0   0  iwlwifi
IPI0:        350        507        573        311 LoongArch  1  Rescheduling interrupts
IPI1:      16044      14345      14870      17074 LoongArch  2  Function call interrupts
IPI2:          0          0          0          0 LoongArch  3  IRQ work interrupts
IPI3:          0          0          0          0 LoongArch  4  Clear vector interrupts
ERR:         12

Tested-by: Yao Zi <me@...ao.cc>

Thanks for your work!

Regards,
Yao Zi