linux-kernel - Re: [PATCH v7 4/8] PCI: endpoint: Add support to handle multiple base for mapping outbound memory

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Date:   Thu, 9 Apr 2020 11:12:45 +0100
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Bjorn Helgaas <helgaas@...nel.org>,
        Kishon Vijay Abraham I <kishon@...com>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Andrew Murray <amurray@...goodpenguin.co.uk>,
        Marek Vasut <marek.vasut+renesas@...il.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Tom Joseph <tjoseph@...ence.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        linux-pci <linux-pci@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>,
        LAK <linux-arm-kernel@...ts.infradead.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>
Subject: Re: [PATCH v7 4/8] PCI: endpoint: Add support to handle multiple base
 for mapping outbound memory

Hi Bjorn,

Thank you for the review.

On Thu, Apr 9, 2020 at 12:46 AM Bjorn Helgaas <helgaas@...nel.org> wrote:
>
> On Wed, Apr 08, 2020 at 04:37:56PM +0100, Lad Prabhakar wrote:
> > R-Car PCIe controller has support to map multiple memory regions for
> > mapping the outbound memory in local system also the controller limits
> > single allocation for each region (that is, once a chunk is used from the
> > region it cannot be used to allocate a new one). This features inspires to
> > add support for handling multiple memory bases in endpoint framework.
> >
> > With this patch pci_epc_mem_init() initializes address space for endpoint
> > controller which support single window and whereas __pci_epc_mem_init()
> > now accepts pointer to multiple windows supported by endpoint controller.
>
> Adding a double underscore prefix usually indicates an internal
> function that skips some checking.
>
> It doesn't seem like quite the right thing for this external interface
> that adds functionality.  Maybe the name could include something like
> "multi"?
>
Agreed. how about pci_epc_mem_multi_init() ?

> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> This needs an ack from Kishon, of course.
>
Yes waiting for Kishon to review it.

> This patch seems like it does several things that could possibly be
> split into separate patches?
>
>   - Change pci_epc_mem_init() interface to add page_size argument (the
>     only one that touches cadence & rockchip; it would be nice if this
>     were a tiny patch)
>
Can be done.

>   - Add struct pci_epc_mem_window
>
>   - Add a pci_epc_multi_mem_init() or similar, implement
>     pci_epc_mem_init() in terms of it (as you already do)
>
The above two needs to be single patch. Is that OK with you ?

Cheers,
--Prabhakar