linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Benjamin Gaignard <benjamin.gaignard@linaro.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>,
	Alexandre Torgue <alexandre.torgue@st.com>,
	linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-stm32@st-md-mailman.stormreply.com,
	Benjamin GAIGNARD <benjamin.gaignard@st.com>
Subject: Re: [PATCH 2/3] pinctrl: stm32: protect configuration registers with a hwspinlock
Date: Tue, 20 Nov 2018 09:38:30 +0100	[thread overview]
Message-ID: <CA+M3ks6nnj69KJay=nGS=RP2jEkPa0wibfVkwYN9-CSq=fHowg@mail.gmail.com> (raw)
In-Reply-To: <CACRpkdZD5EurbTRyUg7AWRZqVQ-6rmUQDUmVVCFU3r0Y1bwnVg@mail.gmail.com>

Le lun. 19 nov. 2018 à 13:20, Linus Walleij <linus.walleij@linaro.org> a écrit :
>
> On Tue, Nov 13, 2018 at 10:51 AM Benjamin Gaignard
> <benjamin.gaignard@linaro.org> wrote:
>
> > If a hwspinlock if defined in device tree use it to protect
> > configuration registers.
> >
> > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
>
> Patch applied with Alex' ACK.

Thanks

>
> Out of curiosity: what is it protecting against?
> I would guess simultaneous access from another CPU
> but the commit doesn't say.
>
> Simultaneous access from two CPUs makes it extra important
> that all register access is read-modify-write, so I'd have a second
> check over the code to make sure this is the case.

Yes it is to protect configuration registers from being used at the same by
cortexA and cortexM.

>
> Yours,
> Linus Walleij

  reply	other threads:[~2018-11-20  8:40 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-13  9:51 [PATCH 0/3] make pin-controller use hwspinlock Benjamin Gaignard
2018-11-13  9:51 ` [PATCH 1/3] dt-bindings: pinctrl: stm32: Document hwlocks properties Benjamin Gaignard
2018-11-19 12:16   ` Linus Walleij
2018-11-13  9:51 ` [PATCH 2/3] pinctrl: stm32: protect configuration registers with a hwspinlock Benjamin Gaignard
2018-11-13 10:40   ` Alexandre Torgue
2018-11-19 12:20   ` Linus Walleij
2018-11-20  8:38     ` Benjamin Gaignard [this message]
2018-11-13  9:51 ` [PATCH 3/3] ARM: dts: stm32: Add hwlock for pinctrl Benjamin Gaignard
2018-11-13  9:58   ` Alexandre Torgue

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='CA+M3ks6nnj69KJay=nGS=RP2jEkPa0wibfVkwYN9-CSq=fHowg@mail.gmail.com' \
    --to=benjamin.gaignard@linaro.org \
    --cc=alexandre.torgue@st.com \
    --cc=benjamin.gaignard@st.com \
    --cc=devicetree@vger.kernel.org \
    --cc=linus.walleij@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-gpio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-stm32@st-md-mailman.stormreply.com \
    --cc=robh+dt@kernel.org \
    --subject='Re: [PATCH 2/3] pinctrl: stm32: protect configuration registers with a hwspinlock' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).