From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from ns.lynxeye.de ([87.118.118.114] helo=lynxeye.de) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kuLXL-0003qn-SF for barebox@lists.infradead.org; Tue, 29 Dec 2020 20:24:08 +0000 Received: from astat.fritz.box (a89-183-40-219.net-htp.de [89.183.40.219]) by lynxeye.de (Postfix) with ESMTPA id 1E1A5E74225 for ; Tue, 29 Dec 2020 21:23:32 +0100 (CET) From: Lucas Stach Date: Tue, 29 Dec 2020 21:23:28 +0100 Message-Id: <20201229202328.13857-1-dev@lynxeye.de> MIME-Version: 1.0 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: [PATCH] ARM: imx8mq: reclock ARM PLL to 800MHz To: barebox@lists.infradead.org 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(-) 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