From: Greg KH <gregkh@linuxfoundation.org>
To: Benjamin GAIGNARD <benjamin.gaignard@st.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Grant Likely <grant.likely@arm.com>,
"robh@kernel.org" <robh@kernel.org>,
Loic PALLARDY <loic.pallardy@st.com>,
"arnd@arndb.de" <arnd@arndb.de>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"system-dt@lists.openampproject.org"
<system-dt@lists.openampproject.org>,
"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"lkml@metux.net" <lkml@metux.net>,
"linux-imx@nxp.com" <linux-imx@nxp.com>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
"sudeep.holla@arm.com" <sudeep.holla@arm.com>,
"fabio.estevam@nxp.com" <fabio.estevam@nxp.com>,
"stefano.stabellini@xilinx.com" <stefano.stabellini@xilinx.com>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 2/7] bus: Introduce firewall controller framework
Date: Sun, 16 Feb 2020 08:21:11 +0100 [thread overview]
Message-ID: <20200216072111.GA14598@kroah.com> (raw)
In-Reply-To: <409eb745-aab2-86a7-bd3a-9e8e05bed057@st.com>
On Sat, Feb 15, 2020 at 12:41:07PM +0000, Benjamin GAIGNARD wrote:
>
> On 2/14/20 10:40 PM, Greg KH wrote:
> > On Fri, Feb 14, 2020 at 05:05:07PM +0100, Linus Walleij wrote:
> >> On Fri, Jan 31, 2020 at 10:06 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >>
> >>> Why do people want to abuse the platform bus so much? If a device is on
> >>> a bus that can have such a controller, then it is on a real bus, use it!
> >> I'm not saying it is a good thing, but the reason why it is (ab)used so
> >> much can be found in:
> >> drivers/of/platform.c
> >>
> >> TL;DR: struct platform_device is the Device McDeviceFace and
> >> platform bus the Bus McBusFace used by the device tree parser since
> >> it is slightly to completely unaware of what devices it is actually
> >> spawning.
> > <snip>
> >
> > Yeah, great explaination, and I understand. DT stuff really is ok to be
> > on a platform bus, as that's what almost all of them are.
> >
> > But, when you try to start messing around with things like this
> > "firewall" says it is doing, it's then obvious that this really isn't a
> > DT like thing, but rather you do have a bus involved with a controller
> > so that should be used instead.
>
> Ok but how put in place a new bus while keeping the devices on platform
> bus to avoid changing all the drivers ?
You don't, you put them all on your real bus, as that is what you now
have.
> > Or just filter away the DT stuff so that the kernel never even sees
> > those devices, which might just be simplest :)
>
> yes but we lost the possibility to change the firewall configuration at
> run time. I do expect to be able to describe in the DT firewall configuration
> and to use them at run time. That could allow, for example, to handover
> a HW block to the coprocessor when the main core is going to be suspended
> to save power.
Then use a real bus :)
thanks,
greg k-h
next prev parent reply other threads:[~2020-02-16 12:20 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 15:37 [PATCH v2 0/7] Introduce bus firewall controller framework Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 1/7] dt-bindings: bus: Add firewall bindings Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 2/7] bus: Introduce firewall controller framework Benjamin Gaignard
2020-01-28 15:52 ` Greg KH
2020-01-28 16:41 ` Benjamin GAIGNARD
2020-01-28 16:57 ` Greg KH
2020-01-28 20:29 ` Benjamin GAIGNARD
2020-01-29 5:49 ` Greg KH
2020-01-29 9:42 ` Linus Walleij
2020-01-29 9:52 ` Greg KH
2020-01-29 11:17 ` Mark Brown
2020-01-31 8:37 ` Benjamin GAIGNARD
2020-01-31 9:06 ` Greg KH
2020-02-14 16:05 ` Linus Walleij
2020-02-14 21:40 ` Greg KH
2020-02-15 12:41 ` Benjamin GAIGNARD
2020-02-16 7:21 ` Greg KH [this message]
2020-01-28 15:38 ` [PATCH v2 3/7] base: Add calls to firewall controller Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 4/7] dt-bindings: bus: Add STM32 ETZPC " Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 5/7] bus: firewall: Add driver for STM32 ETZPC controller Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 6/7] ARM: dts: stm32: Add firewall node for stm32mp157 SoC Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 7/7] ARM: dts: stm32: enable firewall controller node on stm32mp157c-ed1 Benjamin Gaignard
2020-01-28 16:36 ` [PATCH v2 0/7] Introduce bus firewall controller framework Sudeep Holla
2020-01-28 16:46 ` Benjamin GAIGNARD
2020-01-28 17:17 ` Sudeep Holla
2020-01-28 20:06 ` Benjamin GAIGNARD
2020-01-28 22:06 ` Robin Murphy
2020-01-29 13:40 ` Benjamin GAIGNARD
2020-01-31 18:25 ` Robin Murphy
2020-02-03 13:16 ` Benjamin GAIGNARD
2020-01-31 20:51 ` Florian Fainelli
2020-02-03 13:41 ` Benjamin GAIGNARD
2020-01-31 20:48 ` Florian Fainelli
2020-02-02 12:23 ` Mark Brown
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