From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Romain Izard <romain.izard.pro@gmail.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>,
Tudor Ambarus <Tudor.Ambarus@microchip.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: dts: at91: sama5d2: use the divided clock for SMC
Date: Tue, 20 Nov 2018 18:16:12 +0100 [thread overview]
Message-ID: <20181120171612.GF8367@piout.net> (raw)
In-Reply-To: <20181120165737.4998-1-romain.izard.pro@gmail.com>
Hello Romain,
On 20/11/2018 17:57:37+0100, Romain Izard wrote:
> The SAMA5D2 is different from SAMA5D3 and SAMA5D4, as there are two
> different clocks for the peripherals in the SoC. The Static Memory
> controller is connected to the divided master clock.
>
> Unfortunately, the device tree does not correctly show this and uses the
> master clock directly. This clock is then used by the code for the NAND
> controller to calculate the timings for the controller, and we end up with
> slow NAND Flash access.
>
> Fix the device tree, and the performance of Flash access is improved.
>
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
> ---
> arch/arm/boot/dts/sama5d2.dtsi | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/sama5d2.dtsi b/arch/arm/boot/dts/sama5d2.dtsi
> index 61f68e5c48e9..b405992eb601 100644
> --- a/arch/arm/boot/dts/sama5d2.dtsi
> +++ b/arch/arm/boot/dts/sama5d2.dtsi
> @@ -308,7 +308,7 @@
> 0x1 0x0 0x60000000 0x10000000
> 0x2 0x0 0x70000000 0x10000000
> 0x3 0x0 0x80000000 0x10000000>;
> - clocks = <&mck>;
> + clocks = <&h32ck>;
You will have to rebase on top of at91-dt. And if I'm not mistaken, this
line should be:
+ clocks = <&pmc PMC_TYPE_CORE PMC_MCK2>;
> status = "disabled";
>
> nand_controller: nand-controller {
> --
> 2.17.1
>
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
next prev parent reply other threads:[~2018-11-20 17:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-20 16:57 [PATCH] ARM: dts: at91: sama5d2: use the divided clock for SMC Romain Izard
2018-11-20 17:16 ` Alexandre Belloni [this message]
2018-11-20 18:01 ` Romain Izard
2018-11-20 20:40 ` Alexandre Belloni
2018-11-21 11:00 ` Alexandre Belloni
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