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From: Fabien DESSENNE <fabien.dessenne@st.com>
To: Ohad Ben-Cohen <ohad@wizery.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre TORGUE <alexandre.torgue@st.com>,
	Jonathan Corbet <corbet@lwn.net>,
	"linux-remoteproc@vger.kernel.org"
	<linux-remoteproc@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-stm32@st-md-mailman.stormreply.com" 
	<linux-stm32@st-md-mailman.stormreply.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>
Cc: Benjamin GAIGNARD <benjamin.gaignard@st.com>,
	Fabien DESSENNE <fabien.dessenne@st.com>
Subject: Re: [PATCH v2 0/6] hwspinlock: allow sharing of hwspinlocks
Date: Mon, 13 May 2019 09:13:11 +0000	[thread overview]
Message-ID: <25aae4ca-0568-ccaf-0c47-4f5f4e2e8599@st.com> (raw)
In-Reply-To: <1556183843-28033-1-git-send-email-fabien.dessenne@st.com>

Hi


I Got Rob's Reviewed-by. Any further comments?


Fabien


On 25/04/2019 11:17 AM, Fabien Dessenne wrote:
> The current implementation does not allow two different devices to use
> a common hwspinlock. This patch set proposes to have, as an option, some
> hwspinlocks shared between several users.
>
> Below is an example that explain the need for this:
> 	exti: interrupt-controller@5000d000 {
> 		compatible = "st,stm32mp1-exti", "syscon";
> 		interrupt-controller;
> 		#interrupt-cells = <2>;
> 		reg = <0x5000d000 0x400>;
> 		hwlocks = <&hsem 1>;
> 	};
> The two drivers (stm32mp1-exti and syscon) refer to the same hwlock.
> With the current hwspinlock implementation, only the first driver succeeds
> in requesting (hwspin_lock_request_specific) the hwlock. The second request
> fails.
>
>
> The proposed approach does not modify the API, but extends the DT 'hwlocks'
> property with a second optional parameter (the first one identifies an
> hwlock) that specifies whether an hwlock is requested for exclusive usage
> (current behavior) or can be shared between several users.
> Examples:
> 	hwlocks = <&hsem 8>;	Ref to hwlock #8 for exclusive usage
> 	hwlocks = <&hsem 8 0>;	Ref to hwlock #8 for exclusive (0) usage
> 	hwlocks = <&hsem 8 1>;	Ref to hwlock #8 for shared (1) usage
>
> As a constraint, the #hwlock-cells value must be 1 or 2.
> In the current implementation, this can have theorically any value but:
> - all of the exisiting drivers use the same value : 1.
> - the framework supports only one value : 1 (see implementation of
>    of_hwspin_lock_simple_xlate())
> Hence, it shall not be a problem to restrict this value to 1 or 2 since
> it won't break any driver.
>
> Changes since v1:
> * Removed useless 'status = "okay"' from stm32mp157c.dtsi
>
> Fabien Dessenne (6):
>    dt-bindings: hwlock: add support of shared locks
>    hwspinlock: allow sharing of hwspinlocks
>    dt-bindings: hwlock: update STM32 #hwlock-cells value
>    ARM: dts: stm32: Add hwspinlock node for stm32mp157 SoC
>    ARM: dts: stm32: Add hwlock for irqchip on stm32mp157
>    ARM: dts: stm32: hwlocks for GPIO for stm32mp157
>
>   .../devicetree/bindings/hwlock/hwlock.txt          | 27 +++++--
>   .../bindings/hwlock/st,stm32-hwspinlock.txt        |  6 +-
>   Documentation/hwspinlock.txt                       | 10 ++-
>   arch/arm/boot/dts/stm32mp157-pinctrl.dtsi          |  2 +
>   arch/arm/boot/dts/stm32mp157c.dtsi                 |  9 +++
>   drivers/hwspinlock/hwspinlock_core.c               | 82 +++++++++++++++++-----
>   drivers/hwspinlock/hwspinlock_internal.h           |  2 +
>   7 files changed, 107 insertions(+), 31 deletions(-)
>

      parent reply	other threads:[~2019-05-13  9:14 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-25  9:17 Fabien Dessenne
2019-04-25  9:17 ` [PATCH v2 1/6] dt-bindings: hwlock: add support of shared locks Fabien Dessenne
2019-04-25  9:17 ` [PATCH v2 2/6] hwspinlock: allow sharing of hwspinlocks Fabien Dessenne
2019-04-25  9:17 ` [PATCH v2 3/6] dt-bindings: hwlock: update STM32 #hwlock-cells value Fabien Dessenne
2019-04-25  9:17 ` [PATCH v2 4/6] ARM: dts: stm32: Add hwspinlock node for stm32mp157 SoC Fabien Dessenne
2019-04-25  9:17 ` [PATCH v2 5/6] ARM: dts: stm32: Add hwlock for irqchip on stm32mp157 Fabien Dessenne
2019-04-25  9:17 ` [PATCH v2 6/6] ARM: dts: stm32: hwlocks for GPIO for stm32mp157 Fabien Dessenne
2019-05-13  9:13 ` Fabien DESSENNE [this message]

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