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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 16 Dec 2021 13:55:06 +0100
Message-ID: <CAK8P3a3R67D+0KLrTncr+SiHg79itRkxbG9caDo6YsHKzRwwkA@mail.gmail.com>
Subject: Re: [PATCH v3 5/6] MIPS: implement architecture-specific 'pci_remap_iospace()'
To:     Xi Ruoyao <xry111@mengyan1223.wang>
Cc:     Sergio Paracuellos <sergio.paracuellos@gmail.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Rob Herring <robh@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Liviu Dudau <Liviu.Dudau@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        gregkh <gregkh@linuxfoundation.org>,
        "open list:BROADCOM NVRAM DRIVER" <linux-mips@vger.kernel.org>,
        linux-pci <linux-pci@vger.kernel.org>,
        linux-staging@lists.linux.dev, NeilBrown <neil@brown.name>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>
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On Thu, Dec 16, 2021 at 12:44 PM Xi Ruoyao <xry111@mengyan1223.wang> wrote:
>
> On Sat, 2021-09-25 at 22:32 +0200, Sergio Paracuellos wrote:
> > To make PCI IO work we need to properly virtually map IO cpu physical address
> > and set this virtual address as the address of the first PCI IO port which
> > is set using function 'set_io_port_base()'.
> >
> > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
>
> Hi,
>
> the change is causing a WARNING on loongson64g-4core-ls7a:
>
> [    0.105781] loongson-pci 1a000000.pci:       IO 0x0018020000..0x001803ffff ->
>  0x0000020000
> [    0.105792] loongson-pci 1a000000.pci:      MEM 0x0040000000..0x007fffffff ->
>  0x0040000000
> [    0.105801] ------------[ cut here ]------------
> [    0.105804] WARNING: CPU: 0 PID: 1 at arch/mips/pci/pci-generic.c:55 pci_remap_iospace+0x80/0x88
> [    0.105815] resource start address is not zero
>
> I'm not sure how to fix this one.

It looks like this machine has two I/O spaces, one for ISA at 0x18000000/0x00000
and one for PCI at 0x18020000/0x20000, but the implementation assumes there
is only one. If you want to use pci_remap_iospace() on this platform,
it needs to
be extended to allow more than one such space.

       Arnd