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
next prev parent 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
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