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Message-Id: <201409200420.31433.arnd@arndb.de>
Date: Sat, 20 Sep 2014 04:20:31 +0200
From: Arnd Bergmann <arnd@...db.de>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Liviu Dudau <Liviu.Dudau@....com>,
Rob Herring <robh+dt@...nel.org>,
Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <Will.Deacon@....com>,
Russell King <linux@....linux.org.uk>,
"linux-pci" <linux-pci@...r.kernel.org>,
Linus Walleij <linus.walleij@...aro.org>,
Tanmay Inamdar <tinamdar@....com>,
Grant Likely <grant.likely@...retlab.ca>,
Sinan Kaya <okaya@...eaurora.org>,
Jingoo Han <jg1.han@...sung.com>,
Kukjin Kim <kgene.kim@...sung.com>,
Suravee Suthikulanit <suravee.suthikulpanit@....com>,
"linux-arch" <linux-arch@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Device Tree ML <devicetree@...r.kernel.org>,
LAKML <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v11 10/10] PCI: Introduce pci_remap_iospace() for remapping PCI I/O bus resources into CPU space
On Friday 19 September 2014, Bjorn Helgaas wrote:
> On Thu, Sep 18, 2014 at 02:30:25AM +0100, Liviu Dudau wrote:
> PCI_IOBASE is a virtual address. So PCI_IOBASE + res->start is also a
> virtual address (only for IORESOURCE_IO).
>
> Since res->start is normally a *physical* address, I think it would be less
> confusing to do something like this:
>
> vaddr = PCI_IOBASE + res->start;
> ioremap_page_range(vaddr, vaddr + resource_size(res), ...);
>
> so we have a hint that the first two ioremap_page_range() parameters are
> virtual addresses. It's also confusing that it uses "unsigned long" for
> the virtual addresses, when we usually use "void *". But that's out of
> scope for this patch.
Good idea. I think it will have to be (unsigned long)PCI_IOBASE above then,
since ioremap_page_range takes a 'unsigned long' virtual address and PCI_IOBASE
should really remain an __iomem pointer.
Arnd
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