From: Jim Quinlan <jim2101024@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Brian Norris <computersforpeace@gmail.com>,
Russell King <rmk+kernel@armlinux.org.uk>,
Robin Murphy <robin.murphy@arm.com>,
Jonas Gorski <jonas.gorski@gmail.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
Linux-MIPS <linux-mips@linux-mips.org>,
linux-pci <linux-pci@vger.kernel.org>,
Kevin Cernekee <cernekee@gmail.com>,
Ralf Baechle <ralf@linux-mips.org>,
bcm-kernel-feedback-list <bcm-kernel-feedback-list@broadcom.com>,
Gregory Fong <gregory.0xf0@gmail.com>,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 4/8] PCI: brcmstb: Add dma-range mapping for inbound traffic
Date: Fri, 26 Jan 2018 12:46:44 -0500 [thread overview]
Message-ID: <CANCKTBszKRp7gYKE=S3fA0=MoOVFFkO6PgmR476t3HAJ9US2gg@mail.gmail.com> (raw)
In-Reply-To: <20180126075343.GB2356@lst.de>
On Fri, Jan 26, 2018 at 2:53 AM, Christoph Hellwig <hch@lst.de> wrote:
> On Wed, Jan 24, 2018 at 12:04:58PM -0800, Florian Fainelli wrote:
>> This looks nicer than the current shape, but this still requires to
>> register a PCI fixup to override phys_to_dma() and dma_to_phys(), and it
>> would appear that you have dodged my question about how this is supposed
>> to fit with an entirely modular PCIe root complex driver? Are you
>> suggesting that we split the module into a built-in part and a modular part?
>
> I don't think entirely modular PCI root bridges should be a focal point
> for the design. If we happen to support them by other design choices:
> fine, but they should not be a priority.
I disagree. If there is one common thing our customers request it is
the ability to remove (or control the insmod of after boot) the pcie
RC driver. I didn't add this in as a "nice-to-have".
>
> That being said if we have core dma mapping or PCIe code that has
> a list of offsets and the root complex only populates them it should
> work just fine.
I'm looking at arch/arm/include/asm/dma-mapping.h. In addition to
overriding dma_to_phsy() and phys_to_dma(), it looks like I may have
to define __arch_pfn_to_dma(), __arch_dma_to_pfn(),
__arch_dma_to_virt(), __arch_virt_to_dma(). Do you agree or is this
not necessary? If it is, this seems more intrusive than our
pcie-brcmstb-dma.c solution which doesn't require tentacles into
major include files and Kconfigs.
Another issue is that our function wrappers -- depending upon whether
we are dealing with a pci device or not -- will have to possibly call
the actual ARM and ARM64 definitions of these functions, which have
been of course #ifdef'd out. This means that our code must contain
identical copies of these functions' code and that the code must
somehow be kept in sync. Do you see a solution to this?
Jim
next prev parent reply other threads:[~2018-01-26 17:46 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-15 23:28 [PATCH v4 0/8] PCI: brcmstb: Add Broadcom Settopbox PCIe support Jim Quinlan
2018-01-15 23:28 ` [PATCH v4 1/8] SOC: brcmstb: add memory API Jim Quinlan
2018-03-09 15:07 ` James Hogan
2018-01-15 23:28 ` [PATCH v4 2/8] dt-bindings: pci: Add DT docs for Brcmstb PCIe device Jim Quinlan
2018-01-19 19:20 ` Rob Herring
2018-01-15 23:28 ` [PATCH v4 3/8] PCI: brcmstb: Add Broadcom STB PCIe host controller driver Jim Quinlan
2018-01-15 23:28 ` [PATCH v4 4/8] PCI: brcmstb: Add dma-range mapping for inbound traffic Jim Quinlan
2018-01-18 2:15 ` Rob Herring
2018-01-18 7:31 ` Christoph Hellwig
2018-01-18 15:09 ` Florian Fainelli
2018-01-18 15:23 ` Christoph Hellwig
2018-01-19 19:47 ` Florian Fainelli
2018-01-23 13:20 ` Christoph Hellwig
2018-01-24 20:04 ` Florian Fainelli
2018-01-26 7:53 ` Christoph Hellwig
2018-01-26 17:46 ` Jim Quinlan [this message]
2018-02-12 13:39 ` Jim Quinlan
2018-01-15 23:28 ` [PATCH v4 5/8] PCI/MSI: Enable PCI_MSI_IRQ_DOMAIN support for MIPS Jim Quinlan
2018-01-15 23:28 ` [PATCH v4 6/8] PCI: brcmstb: Add MSI capability Jim Quinlan
2018-01-15 23:28 ` [PATCH v4 7/8] MIPS: BMIPS: Add PCI bindings for 7425, 7435 Jim Quinlan
2018-03-09 14:44 ` James Hogan
2018-01-15 23:28 ` [PATCH v4 8/8] MIPS: BMIPS: Enable PCI Jim Quinlan
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