Date:   Thu, 9 Feb 2023 08:51:44 +0100
From:   Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
To:     Gatien Chevallier <gatien.chevallier@foss.st.com>
Cc:     Oleksii_Moisieiev@epam.com, gregkh@linuxfoundation.org,
        herbert@gondor.apana.org.au, davem@davemloft.net,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        alexandre.torgue@foss.st.com, vkoul@kernel.org, jic23@kernel.org,
        olivier.moysan@foss.st.com, arnaud.pouliquen@foss.st.com,
        mchehab@kernel.org, fabrice.gasnier@foss.st.com,
        ulf.hansson@linaro.org, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, linux-crypto@vger.kernel.org,
        devicetree@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        dmaengine@vger.kernel.org, linux-i2c@vger.kernel.org,
        linux-iio@vger.kernel.org, alsa-devel@alsa-project.org,
        linux-media@vger.kernel.org, linux-mmc@vger.kernel.org,
        netdev@vger.kernel.org, linux-phy@lists.infradead.org,
        linux-serial@vger.kernel.org, linux-spi@vger.kernel.org,
        linux-usb@vger.kernel.org, kernel@pengutronix.de
Subject: Re: [PATCH v3 5/6] ARM: dts: stm32: add ETZPC as a system bus for
 STM32MP15x boards
Message-ID: <20230209075144.cuw3xsxa6qgbttgq@pengutronix.de>
References: <20230127164040.1047583-1-gatien.chevallier@foss.st.com>
 <20230127164040.1047583-6-gatien.chevallier@foss.st.com>
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Hello,

On Fri, Jan 27, 2023 at 05:40:39PM +0100, Gatien Chevallier wrote:
> The STM32 System Bus is an internal bus on which devices are connected.
> ETZPC is a peripheral overseeing the firewall bus that configures
> and control access to the peripherals connected on it.
>=20
> For more information on which peripheral is securable, please read
> the STM32MP15 reference manual.

it might be naive, but I somehow expected that when showing at the
resulting commit with git show -b that the patch gets quite small.

Is it really intended that &etzpc (which has reg =3D <0x5c007000 0x400>;)
is the parent bus of the devices with feature-domains =3D <&etzpc XX>; even
though their addresses are out of &etzpc's range? Doesn't a bus usually
have a ranges property and a base address that matches its contained
devices?

Looking at imx6qdl.dtsi there is:

	aips1: bus@2000000 { /* AIPS1 */
		...
		reg =3D <0x02000000 0x100000>;
		ranges;

		spba-bus@2000000 {
			...
			reg =3D <0x02000000 0x40000>;
			...
		};

		...

		sdma: dma-controller@20ec000 {
			...
			reg =3D <0x020ec000 0x4000>;
			...
		};
	};

and the registers configuring the aips1 bus are (I think) in

                        aipstz@207c000 { /* AIPSTZ1 */
                                reg =3D <0x0207c000 0x4000>;
                        };

Maybe this change could be made less intrusive by using a similar setup
here?

Best regards
Uwe

--=20
Pengutronix e.K.                           | Uwe Kleine-K=F6nig            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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