From: Saravana Kannan <saravanak@google.com>
To: Rob Herring <robh@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Kevin Hilman <khilman@kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Len Brown <len.brown@intel.com>, Len Brown <lenb@kernel.org>,
Pavel Machek <pavel@ucw.cz>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Marc Zyngier <maz@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
linux-clk <linux-clk@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Android Kernel Team <kernel-team@android.com>
Subject: Re: [PATCH v4 4/8] of: property: Add fw_devlink support for optional properties
Date: Tue, 9 Feb 2021 13:54:52 -0800 [thread overview]
Message-ID: <CAGETcx_gHRd9UYHvSsHX_=NFF+HEJkamJp3JcpojuJob_a8_DA@mail.gmail.com> (raw)
In-Reply-To: <20210209213320.GA219007@robh.at.kernel.org>
On Tue, Feb 9, 2021 at 1:33 PM Rob Herring <robh@kernel.org> wrote:
>
> On Fri, Feb 05, 2021 at 02:26:40PM -0800, Saravana Kannan wrote:
> > Not all DT bindings are mandatory bindings. Add support for optional DT
> > bindings and mark iommus, iommu-map, dmas as optional DT bindings.
>
> I don't think we can say these are optional or not. It's got to be a
> driver decision somehow.
Right, so maybe the word "optional" isn't a good name for it. I can
change that if you want.
The point being, fw_devlink can't block the probe of this driver based
on iommu property. We let the driver decide if it wants to
-EPROBE_DEFER or not or however it wants to handle this.
> For example, if IOMMU is optional, what happens with this sequence:
>
> driver probes without IOMMU
> driver calls dma_map_?()
> IOMMU driver probes
> h/w accesses DMA buffer --> BOOM!
Right. But how is this really related to fw_devlink? AFAICT, this is
an issue even today. If the driver needs the IOMMU, then it needs to
make sure the IOMMU has probed? What am I missing?
-Saravana
next prev parent reply other threads:[~2021-02-09 23:55 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210205222651eucas1p28ef87073dea33c1c5224c14aa203bec5@eucas1p2.samsung.com>
2021-02-05 22:26 ` [PATCH v4 0/8] Make fw_devlink=on more forgiving Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 1/8] driver core: fw_devlink: Detect supplier devices that will never be added Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 2/8] of: property: Don't add links to absent suppliers Saravana Kannan
2021-02-09 21:25 ` Rob Herring
2021-02-05 22:26 ` [PATCH v4 3/8] driver core: Add fw_devlink.strict kernel param Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 4/8] of: property: Add fw_devlink support for optional properties Saravana Kannan
2021-02-09 21:33 ` Rob Herring
2021-02-09 21:54 ` Saravana Kannan [this message]
2021-02-10 8:25 ` Geert Uytterhoeven
2021-02-10 8:25 ` Geert Uytterhoeven
2021-02-05 22:26 ` [PATCH v4 5/8] driver core: fw_devlink: Handle suppliers that don't use driver core Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 6/8] irqdomain: Mark fwnodes when their irqdomain is added/removed Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 7/8] PM: domains: Mark fwnodes when their powerdomain " Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 8/8] clk: Mark fwnodes when their clock provider " Saravana Kannan
2021-02-08 15:38 ` Rob Herring
2021-02-08 23:34 ` Saravana Kannan
2021-02-10 11:44 ` [PATCH] clk: Mark fwnodes when their clock provider is added Tudor Ambarus
2021-02-10 11:44 ` Tudor Ambarus
2021-02-11 13:00 ` Greg KH
2021-02-13 0:37 ` Stephen Boyd
[not found] ` <CGME20210325133159eucas1p297b769beb681743fb32d362a86cc6e3e@eucas1p2.samsung.com>
2021-03-25 13:31 ` Marek Szyprowski
2021-03-25 15:47 ` Geert Uytterhoeven
2021-03-25 18:25 ` Nicolas Saenz Julienne
2021-03-26 18:13 ` Stephen Boyd
2021-03-26 18:29 ` Geert Uytterhoeven
[not found] ` <161705310317.3012082.15148238105608149214@swboyd.mtv.corp.google.com>
2021-03-29 23:28 ` Saravana Kannan
[not found] ` <161706920822.3012082.10047587064612237296@swboyd.mtv.corp.google.com>
2021-03-30 6:58 ` Geert Uytterhoeven
[not found] ` <161715734080.2260335.881350237641202575@swboyd.mtv.corp.google.com>
2021-03-31 7:05 ` Geert Uytterhoeven
[not found] ` <161721871083.2260335.2392646934517115770@swboyd.mtv.corp.google.com>
2021-04-05 11:04 ` Nicolas Saenz Julienne
2021-04-21 3:26 ` Guenter Roeck
2021-04-21 7:00 ` Saravana Kannan
2021-02-10 18:07 ` kernel test robot
2021-02-10 19:46 ` Tudor.Ambarus
2021-02-10 19:13 ` Saravana Kannan
2021-03-30 15:42 ` Guenter Roeck
2021-03-30 16:26 ` Saravana Kannan
[not found] ` <161317679292.1254594.15797939257637374295@swboyd.mtv.corp.google.com>
2021-02-14 21:15 ` [PATCH v4 8/8] clk: Mark fwnodes when their clock provider is added/removed Saravana Kannan
2021-02-06 2:45 ` [PATCH v4 0/8] Make fw_devlink=on more forgiving Saravana Kannan
2021-02-06 19:41 ` Geert Uytterhoeven
2021-02-06 20:47 ` Saravana Kannan
2021-02-08 8:40 ` Marek Szyprowski
2021-02-08 23:57 ` Saravana Kannan
2021-02-10 8:19 ` Tudor.Ambarus
2021-02-10 8:54 ` Saravana Kannan
2021-02-10 10:02 ` Tudor.Ambarus
2021-02-10 19:14 ` Saravana Kannan
2021-02-11 13:00 ` Geert Uytterhoeven
2021-02-11 13:05 ` Geert Uytterhoeven
2021-02-12 2:59 ` Saravana Kannan
2021-02-12 8:14 ` Geert Uytterhoeven
2021-02-12 20:57 ` Saravana Kannan
2021-02-15 12:38 ` Geert Uytterhoeven
2021-02-15 21:26 ` Saravana Kannan
2021-02-16 8:05 ` Geert Uytterhoeven
2021-02-16 18:48 ` Saravana Kannan
2021-02-16 20:31 ` Geert Uytterhoeven
2021-02-17 23:57 ` Saravana Kannan
2021-02-25 9:21 ` Geert Uytterhoeven
2021-02-15 15:16 ` Geert Uytterhoeven
2021-02-15 21:57 ` Saravana Kannan
2021-02-16 12:58 ` Geert Uytterhoeven
2021-02-15 11:19 ` Geert Uytterhoeven
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