From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kwmUP-0006It-FS for barebox@lists.infradead.org; Tue, 05 Jan 2021 13:35:10 +0000 Date: Tue, 5 Jan 2021 14:35:07 +0100 Message-ID: <20210105133507.GF19063@pengutronix.de> References: <20201229202328.13857-1-dev@lynxeye.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201229202328.13857-1-dev@lynxeye.de> From: Sascha Hauer List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] ARM: imx8mq: reclock ARM PLL to 800MHz To: Lucas Stach Cc: barebox@lists.infradead.org On Tue, Dec 29, 2020 at 09:23:28PM +0100, Lucas Stach wrote: > The BootROM sets up the ARM PLL to run at 1.6GHz and then uses the > divider after the PLL the achieve a CPU clock rate of 800MHz. New Linux > kernels (>= 5.8) switch to a clock path that bypasses the divider, as > the divider should not be used for CPU clock frequencies >1GHz. If the > BootROM setup is left unchanged this causes the CPU clock to jump to > the full 1.6GHz until CPUfreq takes over and reprograms the PLL. This > rate is outside of the chip specification and leads to crashes. > > Fix this by reclocking the ARM PLL to 800MHz. > > Signed-off-by: Lucas Stach > --- > arch/arm/dts/imx8mq.dtsi | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) Applied, thanks Sascha > > diff --git a/arch/arm/dts/imx8mq.dtsi b/arch/arm/dts/imx8mq.dtsi > index ec8347f38fa8..e56cdfe1308e 100644 > --- a/arch/arm/dts/imx8mq.dtsi > +++ b/arch/arm/dts/imx8mq.dtsi > @@ -17,7 +17,9 @@ > <&clk IMX8MQ_CLK_USDHC2>, > <&clk IMX8MQ_CLK_ENET_AXI>, > <&clk IMX8MQ_CLK_ENET_TIMER>, > - <&clk IMX8MQ_CLK_ENET_REF>; > + <&clk IMX8MQ_CLK_ENET_REF>, > + <&clk IMX8MQ_ARM_PLL>, > + <&clk IMX8MQ_CLK_A53_DIV>; > > assigned-clock-parents = <&clk IMX8MQ_SYS1_PLL_400M>, > <&clk IMX8MQ_SYS1_PLL_400M>, > @@ -29,5 +31,7 @@ > <200000000>, > <266000000>, > <25000000>, > - <125000000>; > + <125000000>, > + <800000000>, > + <800000000>; > }; > -- > 2.29.2 > > > _______________________________________________ > barebox mailing list > barebox@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/barebox > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox