From mboxrd@z Thu Jan 1 00:00:00 1970 From: alexandre.belloni@bootlin.com (Alexandre Belloni) Date: Tue, 20 Nov 2018 21:40:49 +0100 Subject: [PATCH] ARM: dts: at91: sama5d2: use the divided clock for SMC In-Reply-To: References: <20181120165737.4998-1-romain.izard.pro@gmail.com> <20181120171612.GF8367@piout.net> Message-ID: <20181120204049.GG8367@piout.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 20/11/2018 19:01:32+0100, Romain Izard wrote: > Le mar. 20 nov. 2018 ? 18:16, Alexandre Belloni > a ?crit : > > > > 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 > > > --- > > > 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 { > > I guess you're right but this will only reach mainline in 4.21. I get slow > flash access with 4.19 as well... > Ok, this is super annoying, I'll try to get that as fixes on v4.20 and I'll rebase at91-dt on top of that... -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com