From: Bjorn Helgaas <helgaas@kernel.org>
To: David Laight <David.Laight@ACULAB.COM>
Cc: "'Krzysztof Wilczyński'" <kw@linux.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Heiko Stuebner" <heiko@sntech.de>,
"Shawn Lin" <shawn.lin@rock-chips.com>,
"Paul Mackerras" <paulus@samba.org>,
"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
"Jonathan Chocron" <jonnyc@amazon.com>,
"Toan Le" <toan@os.amperecomputing.com>,
"Will Deacon" <will@kernel.org>, "Rob Herring" <robh@kernel.org>,
"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
"Michal Simek" <michal.simek@xilinx.com>,
"linux-rockchip@lists.infradead.org"
<linux-rockchip@lists.infradead.org>,
"bcm-kernel-feedback-list@broadcom.com"
<bcm-kernel-feedback-list@broadcom.com>,
"Jonathan Derrick" <jonathan.derrick@intel.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"Ray Jui" <rjui@broadcom.com>,
"Florian Fainelli" <f.fainelli@gmail.com>,
"linux-rpi-kernel@lists.infradead.org"
<linux-rpi-kernel@lists.infradead.org>,
"Jonathan Cameron" <Jonathan.Cameron@huawei.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"Scott Branden" <sbranden@broadcom.com>,
"Zhou Wang" <wangzhou1@hisilicon.com>,
"Robert Richter" <rrichter@marvell.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"Nicolas Saenz Julienne" <nsaenzjulienne@suse.de>
Subject: Re: [PATCH v6 4/5] PCI: vmd: Update type of the __iomem pointers
Date: Mon, 30 Nov 2020 11:20:58 -0600 [thread overview]
Message-ID: <20201130172058.GA1088391@bjorn-Precision-5520> (raw)
In-Reply-To: <81f4ddc2f0524b4b80c8a0bfa2df57fe@AcuMS.aculab.com>
On Mon, Nov 30, 2020 at 09:06:56AM +0000, David Laight wrote:
> From: Krzysztof Wilczynski
> > Sent: 29 November 2020 23:08
> >
> > Use "void __iomem" instead "char __iomem" pointer type when working with
> > the accessor functions (with names like readb() or writel(), etc.) to
> > better match a given accessor function signature where commonly the
> > address pointing to an I/O memory region would be a "void __iomem"
> > pointer.
>
> ISTM that is heading in the wrong direction.
>
> I think (form the variable names etc) that these are pointers
> to specific registers.
>
> So what you ought to have is a type for that register block.
> Typically this is actually a structure - to give some type
> checking that the offsets are being used with the correct
> base address.
In this case, "cfgbar" is not really a pointer to a register; it's the
address of memory-mapped config space. The VMD hardware turns
accesses to that space into PCI config transactions on its secondary
side. xgene_pcie_get_cfg_base() and brcm_pcie_map_conf() are similar
situations and use "void *".
Bjorn
next prev parent reply other threads:[~2020-11-30 17:22 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-29 23:07 [PATCH v6 0/5] PCI: Unify ECAM constants in native PCI Express drivers Krzysztof Wilczyński
2020-11-29 23:07 ` [PATCH v6 1/5] " Krzysztof Wilczyński
2020-11-30 11:08 ` Lorenzo Pieralisi
2020-11-30 15:30 ` Krzysztof Wilczyński
2020-11-30 18:23 ` Derrick, Jonathan
2020-12-06 20:16 ` Krzysztof Wilczyński
2020-12-07 3:25 ` Florian Fainelli
2020-12-07 20:29 ` Jim Quinlan
2020-11-29 23:07 ` [PATCH v6 2/5] PCI: thunder-pem: Add constant for custom ".bus_shit" initialiser Krzysztof Wilczyński
2020-11-29 23:07 ` [PATCH v6 3/5] PCI: iproc: Convert to use the new ECAM constants Krzysztof Wilczyński
2020-11-29 23:07 ` [PATCH v6 4/5] PCI: vmd: Update type of the __iomem pointers Krzysztof Wilczyński
2020-11-30 9:06 ` David Laight
2020-11-30 17:20 ` Bjorn Helgaas [this message]
2020-11-30 18:19 ` Derrick, Jonathan
2020-11-29 23:07 ` [PATCH v6 5/5] PCI: xgene: Removed unused ".bus_shift" initialisers from pci-xgene.c Krzysztof Wilczyński
2020-12-01 15:34 ` [PATCH v6 0/5] PCI: Unify ECAM constants in native PCI Express drivers Lorenzo Pieralisi
2020-12-08 15:41 ` Michael Walle
2020-12-08 21:06 ` Bjorn Helgaas
2020-12-08 21:11 ` Michael Walle
2020-12-09 12:36 ` Bjorn Helgaas
2020-12-09 13:08 ` Michael Walle
2020-12-09 14:57 ` Bjorn Helgaas
2020-12-09 15:40 ` Michael Walle
2020-12-09 20:29 ` Vladimir Oltean
2020-12-09 20:59 ` Bjorn Helgaas
2020-12-09 21:20 ` Vladimir Oltean
2020-12-09 21:34 ` Bjorn Helgaas
2020-12-09 21:43 ` Vladimir Oltean
2020-12-09 22:05 ` Bjorn Helgaas
2020-12-10 17:38 ` Bjorn Helgaas
2020-12-10 19:58 ` Michael Walle
2020-12-08 16:07 ` Qian Cai
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