All of lore.kernel.org
 help / color / mirror / Atom feed
From: Greg KH <gregkh@linuxfoundation.org>
To: Benjamin GAIGNARD <benjamin.gaignard@st.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
	Loic PALLARDY <loic.pallardy@st.com>,
	"arnd@arndb.de" <arnd@arndb.de>,
	"robh@kernel.org" <robh@kernel.org>,
	"shawnguo@kernel.org" <shawnguo@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Grant Likely <grant.likely@arm.com>,
	"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>,
	"system-dt@lists.openampproject.org"
	<system-dt@lists.openampproject.org>,
	"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
	"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

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
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

  reply	other threads:[~2020-02-16 12:20 UTC|newest]

Thread overview: 68+ 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 15:37 ` Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 1/7] dt-bindings: bus: Add firewall bindings Benjamin Gaignard
2020-01-28 15:38   ` Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 2/7] bus: Introduce firewall controller framework Benjamin Gaignard
2020-01-28 15:38   ` Benjamin Gaignard
2020-01-28 15:52   ` Greg KH
2020-01-28 15:52     ` Greg KH
2020-01-28 16:41     ` Benjamin GAIGNARD
2020-01-28 16:41       ` Benjamin GAIGNARD
2020-01-28 16:57       ` Greg KH
2020-01-28 16:57         ` Greg KH
2020-01-28 20:29         ` Benjamin GAIGNARD
2020-01-28 20:29           ` Benjamin GAIGNARD
2020-01-29  5:49           ` Greg KH
2020-01-29  5:49             ` Greg KH
2020-01-29  9:42           ` Linus Walleij
2020-01-29  9:42             ` Linus Walleij
2020-01-29  9:52             ` Greg KH
2020-01-29  9:52               ` Greg KH
2020-01-29 11:17               ` Mark Brown
2020-01-29 11:17                 ` Mark Brown
2020-01-31  8:37                 ` Benjamin GAIGNARD
2020-01-31  8:37                   ` Benjamin GAIGNARD
2020-01-31  9:06                   ` Greg KH
2020-01-31  9:06                     ` Greg KH
2020-02-14 16:05                     ` Linus Walleij
2020-02-14 16:05                       ` Linus Walleij
2020-02-14 21:40                       ` Greg KH
2020-02-14 21:40                         ` Greg KH
2020-02-15 12:41                         ` Benjamin GAIGNARD
2020-02-15 12:41                           ` Benjamin GAIGNARD
2020-02-16  7:21                           ` Greg KH [this message]
2020-02-16  7:21                             ` Greg KH
2020-01-28 15:38 ` [PATCH v2 3/7] base: Add calls to firewall controller Benjamin Gaignard
2020-01-28 15:38   ` Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 4/7] dt-bindings: bus: Add STM32 ETZPC " Benjamin Gaignard
2020-01-28 15:38   ` 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   ` 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   ` 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 15:38   ` Benjamin Gaignard
2020-01-28 16:36 ` [PATCH v2 0/7] Introduce bus firewall controller framework Sudeep Holla
2020-01-28 16:36   ` Sudeep Holla
2020-01-28 16:46   ` Benjamin GAIGNARD
2020-01-28 16:46     ` Benjamin GAIGNARD
2020-01-28 17:17     ` Sudeep Holla
2020-01-28 17:17       ` Sudeep Holla
2020-01-28 20:06       ` Benjamin GAIGNARD
2020-01-28 20:06         ` Benjamin GAIGNARD
2020-01-28 22:06         ` Robin Murphy
2020-01-28 22:06           ` Robin Murphy
2020-01-29 13:40           ` Benjamin GAIGNARD
2020-01-29 13:40             ` Benjamin GAIGNARD
2020-01-31 18:25             ` Robin Murphy
2020-01-31 18:25               ` Robin Murphy
2020-02-03 13:16               ` Benjamin GAIGNARD
2020-02-03 13:16                 ` Benjamin GAIGNARD
2020-01-31 20:51             ` Florian Fainelli
2020-01-31 20:51               ` Florian Fainelli
2020-02-03 13:41               ` Benjamin GAIGNARD
2020-02-03 13:41                 ` Benjamin GAIGNARD
2020-01-31 20:48         ` Florian Fainelli
2020-01-31 20:48           ` Florian Fainelli
2020-02-02 12:23           ` Mark Brown
2020-02-02 12:23             ` Mark Brown

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200216072111.GA14598@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=arnd@arndb.de \
    --cc=benjamin.gaignard@st.com \
    --cc=devicetree@vger.kernel.org \
    --cc=fabio.estevam@nxp.com \
    --cc=grant.likely@arm.com \
    --cc=kernel@pengutronix.de \
    --cc=linus.walleij@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-imx@nxp.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lkml@metux.net \
    --cc=loic.pallardy@st.com \
    --cc=robh@kernel.org \
    --cc=s.hauer@pengutronix.de \
    --cc=sfr@canb.auug.org.au \
    --cc=shawnguo@kernel.org \
    --cc=stefano.stabellini@xilinx.com \
    --cc=sudeep.holla@arm.com \
    --cc=system-dt@lists.openampproject.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.