From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Rob Herring <robh@kernel.org>
Cc: Heiko Stuebner <heiko@sntech.de>,
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"open list:MEDIA DRIVERS FOR RENESAS - FCP"
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Ley Foon Tan <lftan@altera.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v3 19/25] PCI: of: Add inbound resource parsing to helpers
Date: Thu, 31 Oct 2019 10:09:36 +0000 [thread overview]
Message-ID: <20191031100936.GB22203@e121166-lin.cambridge.arm.com> (raw)
In-Reply-To: <CAL_Jsq+9U3E7hQsg0yqJqMJrcZ2n4UfK_es+5-4qg=VCSHiL5g@mail.gmail.com>
On Wed, Oct 30, 2019 at 05:18:25PM -0500, Rob Herring wrote:
> On Wed, Oct 30, 2019 at 9:56 AM Lorenzo Pieralisi
> <lorenzo.pieralisi@arm.com> wrote:
> >
> > On Wed, Oct 30, 2019 at 12:49:59PM +0000, Robin Murphy wrote:
> > > On 30/10/2019 11:48, Lorenzo Pieralisi wrote:
> > > > [+Cc Robin]
> > > >
> > > > On Wed, Oct 30, 2019 at 12:14:54PM +0530, Srinath Mannam wrote:
> > > > > Hi Lorenzo,
> > > > >
> > > > > Thanks for the details.
> > > > > Based on Robin's comment in the old patch, I thought dma_ranges list
> > > > > will be in sorted order.
> > > > > https://lore.kernel.org/lkml/741a4210-251c-9c00-d4a7-bc7ebf8cd57b@arm.com/
> > > > >
> > > > > Now, another patch is required to sort the list before reserving in
> > > > > iova_reserve_pci_windows() function.
> > > > >
> > > > > Regards,
> > > > > Srinath.
> > > >
> > > > Don't top-post please.
> > > >
> > > > https://en.wikipedia.org/wiki/Posting_style#Top-posting
> > > >
> > > > Yes, the dma_ranges list must be sorted somehow I reckon
> > > > iova_reserve_pci_windows() is where it should be done (since that's
> > > > where the requirement is) or it can be done in
> > > > devm_of_pci_get_host_bridge_resources().
> > > >
> > > > Thoughts ?
> > >
> > > Right, strictly it's only iova_reserve_pci_windows() that needs the list
> > > sorted, it just worked out that maintaining the list in sorted order by
> > > construction took a fair bit less code than explicitly sorting it. In terms
> > > of preserving that behaviour in a slightly more generalised fashion I
> > > suppose we could add something like:
> > >
> > > void pci_add_resource_offset_sorted(struct list_head *resources,
> > > struct resource *res,
> > > resource_size_t offset)
> > > {
> > > struct resource_entry *entry;
> > >
> > > resource_list_for_each_entry(entry, resources)
> > > if (entry->res.start > res.start)
> > > break;
> > >
> > > pci_add_resource_offset(&entry->node, res, offset);
> > > }
> > >
> > > but if you'd rather add a specific resource_list_sort() or even just
> > > open-code it in iommu-dma, I don't have any real preference. The "least code
> > > necessary" approach definitely made sense when individual drivers were
> > > expected to build their own lists, but once it gets generalised then having
> > > a sensible and robust API becomes a more important consideration.
> >
> > I think that open coding it in iommu-dma is fine, @RobH would you be
> > able to add this to the series please ? I think it should be added to
> > prevent any regressions, we can't rely on dma-ranges entries order in DT
> > files.
>
> I don't think it's good to be modifying the list as a side effect of
> calling iova_reserve_pci_windows() and making a copy of it wouldn't be
> great either. So I'm just going to keep it sorted in
> devm_of_pci_get_host_bridge_resources().
Yes I thought about that - that's the most reasonable approach I think.
Thanks,
Lorenzo
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next prev parent reply other threads:[~2019-10-31 10:09 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-28 16:32 [PATCH v3 00/25] PCI host resource consolidation Rob Herring
2019-10-28 16:32 ` [PATCH v3 01/25] resource: Add a resource_list_first_type helper Rob Herring
2019-10-28 16:32 ` [PATCH v3 02/25] PCI: Export pci_parse_request_of_pci_ranges() Rob Herring
2019-10-28 16:32 ` [PATCH v3 03/25] PCI: aardvark: Use pci_parse_request_of_pci_ranges() Rob Herring
2019-10-28 16:32 ` [PATCH v3 04/25] PCI: altera: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 05/25] PCI: dwc: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 06/25] PCI: faraday: " Rob Herring
2019-11-03 19:12 ` Linus Walleij
2019-10-28 16:32 ` [PATCH v3 07/25] PCI: iproc: " Rob Herring
2019-10-29 15:58 ` Srinath Mannam
2019-10-29 17:09 ` Florian Fainelli
2019-10-28 16:32 ` [PATCH v3 08/25] PCI: mediatek: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 09/25] PCI: mobiveil: " Rob Herring
2019-10-29 9:00 ` Z.q. Hou
2019-10-28 16:32 ` [PATCH v3 10/25] PCI: rockchip: " Rob Herring
2019-12-05 17:56 ` Enric Balletbo Serra
2019-12-06 13:52 ` Lorenzo Pieralisi
2019-12-06 14:09 ` Lorenzo Pieralisi
2019-12-06 14:59 ` Enric Balletbo Serra
2019-10-28 16:32 ` [PATCH v3 11/25] PCI: rockchip: Drop storing driver private outbound resource data Rob Herring
2019-12-06 15:36 ` Lorenzo Pieralisi
2019-12-10 17:33 ` Enric Balletbo Serra
2019-12-11 9:39 ` Enric Balletbo Serra
2019-10-28 16:32 ` [PATCH v3 12/25] PCI: v3-semi: Use pci_parse_request_of_pci_ranges() Rob Herring
2019-10-28 16:32 ` [PATCH v3 13/25] PCI: xgene: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 14/25] PCI: xilinx: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 15/25] PCI: xilinx-nwl: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 16/25] PCI: versatile: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 17/25] PCI: versatile: Remove usage of PHYS_OFFSET Rob Herring
2019-10-28 16:32 ` [PATCH v3 18/25] PCI: versatile: Enable COMPILE_TEST Rob Herring
2019-10-28 16:32 ` [PATCH v3 19/25] PCI: of: Add inbound resource parsing to helpers Rob Herring
2019-10-29 11:07 ` Lorenzo Pieralisi
2019-10-29 15:56 ` Srinath Mannam
2019-10-29 17:34 ` Lorenzo Pieralisi
2019-10-30 6:44 ` Srinath Mannam
2019-10-30 11:48 ` Lorenzo Pieralisi
2019-10-30 12:49 ` Robin Murphy
2019-10-30 14:56 ` Lorenzo Pieralisi
2019-10-30 22:18 ` Rob Herring
2019-10-31 10:09 ` Lorenzo Pieralisi [this message]
2019-10-29 22:12 ` Bjorn Helgaas
2019-10-28 16:32 ` [PATCH v3 20/25] PCI: ftpci100: Use inbound resources for setup Rob Herring
2019-10-28 16:32 ` [PATCH v3 21/25] PCI: v3-semi: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 22/25] PCI: xgene: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 23/25] PCI: iproc: " Rob Herring
2019-10-29 15:59 ` Srinath Mannam
2019-10-28 16:32 ` [PATCH v3 24/25] PCI: rcar: " Rob Herring
2019-10-28 16:32 ` [PATCH v3 25/25] PCI: Make devm_of_pci_get_host_bridge_resources() static Rob Herring
2019-10-31 10:57 ` [PATCH v3 00/25] PCI host resource consolidation Lorenzo Pieralisi
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