From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>,
Liviu Dudau <Liviu.Dudau@arm.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Andy Lutomirski <luto@amacapital.net>,
linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
Wenrui Li <wenrui.li@rock-chips.com>,
Gabriele Paoloni <gabriele.paoloni@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Shawn Lin <shawn.lin@rock-chips.com>,
Will Deacon <will.deacon@arm.com>,
Michal Simek <michal.simek@xilinx.com>,
Thierry Reding <thierry.reding@gmail.com>,
Tanmay Inamdar <tinamdar@apm.com>,
linux-arch@vger.kernel.org,
Pratyush Anand <pratyush.anand@gmail.com>,
Russell King <linux@armlinux.org.uk>,
Jon Mason <jonmason@broadcom.com>,
Murali Karicheri <m-karicheri2@ti.com>,
Arnd Bergmann <arnd@arndb.de>,
Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>,
Ray Jui <rjui@broadcom.com>, John Garry <john.garry@huawei.com>,
Joao Pinto <Joao.Pinto@synopsys.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Mingkai Hu <mingkai.hu@freescale.com>,
Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
Jingoo Han <jingoohan1@gmail.com>,
linux-kernel@vger.kernel.org,
Stanimir Varbanov <svarbanov@mm-sol.com>,
Minghuan Lian <minghuan.Lian@freescale.com>,
Zhou Wang <wangzhou1@hisilicon.com>,
Roy Zang <tie-fei.zang@freescale.com>
Subject: Re: [PATCH 02/20] PCI: fix pci_remap_iospace() remap attribute
Date: Mon, 20 Mar 2017 16:26:27 +0000 [thread overview]
Message-ID: <20170320162627.GE7632@red-moon> (raw)
In-Reply-To: <20170320160636.GB24572@bhelgaas-glaptop.roam.corp.google.com>
On Mon, Mar 20, 2017 at 11:06:36AM -0500, Bjorn Helgaas wrote:
[...]
> > > > @@ -3375,7 +3375,7 @@ int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
> > > > return -EINVAL;
> > > >
> > > > return ioremap_page_range(vaddr, vaddr + resource_size(res), phys_addr,
> > > > - pgprot_device(PAGE_KERNEL));
> > > > + pgprot_noncached(PAGE_KERNEL));
> > >
> > > ...
> > > I do find this puzzling because I naively expected pgprot_noncached()
> > > to match up with ioremap_nocache(), and apparently it doesn't.
> > >
> > > For example, ARM64 ioremap_nocache() uses PROT_DEVICE_nGnRE, which
> > > doesn't match the MT_DEVICE_nGnRnE in pgprot_noncached().
> > >
> > > The point of these patches is to use non-posted mappings. Apparently
> > > you can do that with pgprot_noncached() here, but ioremap_nocache()
> > > isn't enough for the config space mappings?
> >
> > This is for iospace it seems, so the other patch I think was for
> > config space.
>
> I understand that 02/20 is for PCI I/O port space and 03/20 is for PCI
> config space. I'm confused because I thought we wanted the same
> non-posted mapping for both, but looks like they're different.
>
> Patch 02/20 uses ioremap_page_range(..., pgprot_noncached(PAGE_KERNEL))
> to map PCI I/O port space:
>
> #define pgprot_noncached(prot) \
> __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRnE) | PTE_PXN | PTE_UXN)
>
> Patch 03/20 uses ioremap_nocache() to map PCI config space:
>
> #define ioremap_nocache(addr, size) __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE))
>
> So the I/O port mapping uses MT_DEVICE_nGnRnE, while the config space
> mapping uses PROT_DEVICE_nGnRE, which looks different.
On ARM64 (PATCH 4) and ARM (PATCH 5) we override pci_remap_cfgspace()
with implementations that provide non-posted writes bus attributes,
PATCH 3 is just there to provide a "safe" (well, I need input on that)
fall-back.
Thanks,
Lorenzo
next prev parent reply other threads:[~2017-03-20 16:36 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-27 15:14 [PATCH 00/20] PCI: fix config and I/O Address space memory mappings Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 01/20] PCI: remove __weak tag from pci_remap_iospace() Lorenzo Pieralisi
2017-03-01 16:15 ` Arnd Bergmann
2017-02-27 15:14 ` [PATCH 02/20] PCI: fix pci_remap_iospace() remap attribute Lorenzo Pieralisi
2017-03-16 21:48 ` Bjorn Helgaas
2017-03-17 0:33 ` Luis R. Rodriguez
2017-03-17 10:43 ` Liviu Dudau
2017-03-17 16:26 ` Luis R. Rodriguez
2017-03-20 16:19 ` Lorenzo Pieralisi
2017-03-20 16:06 ` Bjorn Helgaas
2017-03-20 16:26 ` Lorenzo Pieralisi [this message]
2017-03-20 16:38 ` Bjorn Helgaas
2017-02-27 15:14 ` [PATCH 03/20] asm-generic/io.h: add PCI config space remap interface Lorenzo Pieralisi
2017-03-16 21:12 ` Bjorn Helgaas
2017-03-17 0:08 ` Luis R. Rodriguez
2017-03-20 10:22 ` John Garry
2017-03-20 16:27 ` Bjorn Helgaas
2017-03-20 18:45 ` Lorenzo Pieralisi
2017-03-22 15:04 ` Lorenzo Pieralisi
2017-03-22 15:15 ` Arnd Bergmann
2017-03-22 16:29 ` Bjorn Helgaas
2017-02-27 15:14 ` [PATCH 04/20] ARM64: implement pci_remap_cfgspace() interface Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 05/20] ARM: " Lorenzo Pieralisi
2017-03-20 16:43 ` Russell King - ARM Linux
2017-03-21 15:26 ` Lorenzo Pieralisi
2017-03-21 16:53 ` Russell King - ARM Linux
2017-02-27 15:14 ` [PATCH 06/20] PCI: ECAM: use pci_remap_cfgspace() to map config region Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 07/20] PCI: implement Devres interface to map PCI config space Lorenzo Pieralisi
2017-02-28 10:43 ` Lorenzo Pieralisi
2017-03-01 23:54 ` Andy Shevchenko
2017-03-02 12:05 ` Lorenzo Pieralisi
2017-03-02 12:50 ` Andy Shevchenko
2017-03-02 19:24 ` Tejun Heo
2017-03-02 20:08 ` Thierry Reding
2017-02-27 15:14 ` [PATCH 08/20] PCI: xilinx: update PCI config space remap function Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 09/20] PCI: xilinx-nwl: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 10/20] PCI: spear13xx: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 11/20] PCI: rockchip: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 12/20] PCI: qcom: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 13/20] PCI: iproc-platform: " Lorenzo Pieralisi
2017-02-27 21:21 ` Ray Jui
2017-02-28 10:54 ` Lorenzo Pieralisi
2017-02-28 17:42 ` Ray Jui
2017-02-27 15:14 ` [PATCH 14/20] PCI: hisi: " Lorenzo Pieralisi
2017-03-02 10:56 ` Gabriele Paoloni
2017-03-02 11:49 ` Lorenzo Pieralisi
2017-03-02 11:53 ` Gabriele Paoloni
2017-02-27 15:14 ` [PATCH 15/20] PCI: designware: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 16/20] PCI: armada8k: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 17/20] PCI: xgene: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 18/20] PCI: tegra: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 19/20] PCI: layerscape: " Lorenzo Pieralisi
2017-02-27 15:14 ` [PATCH 20/20] PCI: keystone-dw: " Lorenzo Pieralisi
2017-03-01 16:18 ` [PATCH 00/20] PCI: fix config and I/O Address space memory mappings Arnd Bergmann
2017-03-02 18:00 ` Lorenzo Pieralisi
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