From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59020C433FE for ; Tue, 29 Mar 2022 13:22:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236130AbiC2NYb (ORCPT ); Tue, 29 Mar 2022 09:24:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235104AbiC2NYa (ORCPT ); Tue, 29 Mar 2022 09:24:30 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08B0E5A17C for ; Tue, 29 Mar 2022 06:22:48 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: dmitry.osipenko) with ESMTPSA id 906B41F427D0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1648560166; bh=fkYLreROLaT3/ibZDuXdX+BsL1eXrW9BPtkQObOUCLI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=SH2cosC88mdr4JJm9YuIlwoNjheKrDyBxC/UwAl3gfENxnzbYLa3augL9iNYg7xcR MVQC5j09cDSp6eId5pdWMsktMXaM4BK59ObEKqu4aq/z2WCvpBgbPt/NK7HNL4/jFs AerULpX/HvC6XH0M6JmPJUGeQqC6RWuuyXNuQcokzL2Ic5Vgu0fuxkBfrjDCHlbWoS f27WFyR/56vhRuHA7tyh/gOiC/V5sCHLVYAA5bzYLD7RvcOU5RgFp6FLXqLc6t7FYH lTTkCeeDd8VbwmG4kstNqKmbOjE2GQJf07VKQhB98ciN4ZHprKweQVbaFk99KzrgGl u26dLk8elbCww== Message-ID: <72850490-44aa-32b3-a963-6e1d38d35db7@collabora.com> Date: Tue, 29 Mar 2022 16:22:43 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v9 01/23] clk: rk3568: Mark hclk_vo as critical Content-Language: en-US To: Sascha Hauer , dri-devel@lists.freedesktop.org Cc: devicetree@vger.kernel.org, Benjamin Gaignard , Peter Geis , Sandy Huang , linux-rockchip@lists.infradead.org, Michael Riesch , kernel@pengutronix.de, Andy Yan , linux-arm-kernel@lists.infradead.org References: <20220328151116.2034635-1-s.hauer@pengutronix.de> <20220328151116.2034635-2-s.hauer@pengutronix.de> From: Dmitry Osipenko In-Reply-To: <20220328151116.2034635-2-s.hauer@pengutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 3/28/22 18:10, Sascha Hauer wrote: > Whenever pclk_vo is enabled hclk_vo must be enabled as well. This is > described in the Reference Manual as: > > | 2.8.6 NIU Clock gating reliance > | > | A part of niu clocks have a dependence on another niu clock in order to > | sharing the internal bus. When these clocks are in use, another niu > | clock must be opened, and cannot be gated. These clocks and the special > | clock on which they are relied are as following: > | > | Clocks which have dependency The clock which can not be gated > | ----------------------------------------------------------------- > | ... > | pclk_vo_niu, hclk_vo_s_niu hclk_vo_niu > | ... > > The clock framework doesn't offer a way to enable clock B whenever clock A is > enabled, at least not when B is not an ancestor of A. Workaround this by > marking hclk_vo as critical so it is never disabled. This is suboptimal in > terms of power consumption, but a stop gap solution until the clock framework > has a way to deal with this. > > We have this clock tree: > > | aclk_vo 2 2 0 300000000 0 0 50000 Y > | aclk_hdcp 0 0 0 300000000 0 0 50000 N > | pclk_vo 2 3 0 75000000 0 0 50000 Y > | pclk_edp_ctrl 0 0 0 75000000 0 0 50000 N > | pclk_dsitx_1 0 0 0 75000000 0 0 50000 N > | pclk_dsitx_0 1 2 0 75000000 0 0 50000 Y > | pclk_hdmi_host 1 2 0 75000000 0 0 50000 Y > | pclk_hdcp 0 0 0 75000000 0 0 50000 N > | hclk_vo 2 5 0 150000000 0 0 50000 Y > | hclk_hdcp 0 0 0 150000000 0 0 50000 N > | hclk_vop 0 2 0 150000000 0 0 50000 N > > Without this patch the edp, dsitx, hdmi and hdcp driver would enable their > clocks which then enables pclk_vo, but hclk_vo stays disabled and register > accesses just hang. hclk_vo is enabled by the VOP2 driver, so reproducibility > of this issue depends on the probe order. > > Signed-off-by: Sascha Hauer > --- > > Notes: > Changes since v8: > - new patch > > drivers/clk/rockchip/clk-rk3568.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/clk/rockchip/clk-rk3568.c b/drivers/clk/rockchip/clk-rk3568.c > index 63dfbeeeb06d9..62694d95173ab 100644 > --- a/drivers/clk/rockchip/clk-rk3568.c > +++ b/drivers/clk/rockchip/clk-rk3568.c > @@ -1591,6 +1591,7 @@ static const char *const rk3568_cru_critical_clocks[] __initconst = { > "hclk_php", > "pclk_php", > "hclk_usb", > + "hclk_vo", > }; > > static const char *const rk3568_pmucru_critical_clocks[] __initconst = { Nice! That's much better than the DT hacks, IMO, thank you. Reviewed-by: Dmitry Osipenko