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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Sat, 25 Sep 2021 21:34:09 +0200
Message-ID: <CAK8P3a0p0YwsiG8NgZGPxGp=GwTLXfEO=D=CY3TtmYwiDSuaXg@mail.gmail.com>
Subject: Re: [PATCH 5/6] MIPS: implement architecture dependent 'pci_remap_iospace()'
To:     Sergio Paracuellos <sergio.paracuellos@gmail.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Rob Herring <robh@kernel.org>,
        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>
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On Sat, Sep 25, 2021 at 8:10 PM Sergio Paracuellos
<sergio.paracuellos@gmail.com> wrote:
> > It might be good to check that res->start is zero here, otherwise
> > the io_port_base would be off. That could happen if you ever have more
> > than one bridge.
>
> Do you mean something like the following?

Yes, exactly.

> int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
> {
>     unsigned long vaddr;
>     size_t size;
>
>     if (res->start != 0) {
>          // Should I WARN_ONCE or just show an error/warning message??
>          WARN_ONCE(1, "resource start must be zero\n");
>          return -ENODEV;
>    }

I don't care if it's WARN(), WARN_ONCE() or pr_warn(). If we ever see the
message, the system is not working and the person who caused the problem
will figure it out.

        Arnd