From patchwork Sun Nov 4 18:26:40 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Jernej_=C5=A0krabec?= X-Patchwork-Id: 10667101 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8286513B5 for ; Sun, 4 Nov 2018 18:42:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 74F4B296A9 for ; Sun, 4 Nov 2018 18:42:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 68C69296B6; Sun, 4 Nov 2018 18:42:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 1D8E4296A9 for ; Sun, 4 Nov 2018 18:42:58 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8D6376E0A9; Sun, 4 Nov 2018 18:42:34 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail.siol.net (mailoutvs9.siol.net [185.57.226.200]) by gabe.freedesktop.org (Postfix) with ESMTPS id 24EAD6E03C for ; Sun, 4 Nov 2018 18:27:41 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mail.siol.net (Postfix) with ESMTP id 4F0CC52126B; Sun, 4 Nov 2018 19:27:39 +0100 (CET) X-Virus-Scanned: amavisd-new at psrvmta11.zcs-production.pri Received: from mail.siol.net ([127.0.0.1]) by localhost (psrvmta11.zcs-production.pri [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id jXw0uIsmYZEw; Sun, 4 Nov 2018 19:27:39 +0100 (CET) Received: from mail.siol.net (localhost [127.0.0.1]) by mail.siol.net (Postfix) with ESMTPS id CB24D521270; Sun, 4 Nov 2018 19:27:38 +0100 (CET) Received: from localhost.localdomain (cpe1-8-82.cable.triera.net [213.161.8.82]) (Authenticated sender: 031275009) by mail.siol.net (Postfix) with ESMTPSA id 5211052126B; Sun, 4 Nov 2018 19:27:36 +0100 (CET) From: Jernej Skrabec To: maxime.ripard@bootlin.com, wens@csie.org Subject: [PATCH v3 03/28] clk: sunxi-ng: Use u64 for calculation of NM rate Date: Sun, 4 Nov 2018 19:26:40 +0100 Message-Id: <20181104182705.18047-4-jernej.skrabec@siol.net> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181104182705.18047-1-jernej.skrabec@siol.net> References: <20181104182705.18047-1-jernej.skrabec@siol.net> MIME-Version: 1.0 X-Mailman-Approved-At: Sun, 04 Nov 2018 18:42:21 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, sboyd@kernel.org, mturquette@baylibre.com, jernej.skrabec@siol.net, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, airlied@linux.ie, linux-sunxi@googlegroups.com, robh+dt@kernel.org, Laurent.pinchart@ideasonboard.com, stable@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP Allwinner H6 SoC has multiplier N range between 1 and 254. Since parent rate is 24MHz, intermediate result when calculating final rate easily overflows 32 bit variable. Because of that, introduce function for calculating clock rate which uses 64 bit variable for intermediate result. Fixes: 6174a1e24b0d ("clk: sunxi-ng: Add N-M-factor clock support") Fixes: ee28648cb2b4 ("clk: sunxi-ng: Remove the use of rational computations") CC: Signed-off-by: Jernej Skrabec --- drivers/clk/sunxi-ng/ccu_nm.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c index 6fe3c14f7b2d..424d8635b053 100644 --- a/drivers/clk/sunxi-ng/ccu_nm.c +++ b/drivers/clk/sunxi-ng/ccu_nm.c @@ -19,6 +19,17 @@ struct _ccu_nm { unsigned long m, min_m, max_m; }; +static unsigned long ccu_nm_calc_rate(unsigned long parent, + unsigned long n, unsigned long m) +{ + u64 rate = parent; + + rate *= n; + do_div(rate, m); + + return rate; +} + static void ccu_nm_find_best(unsigned long parent, unsigned long rate, struct _ccu_nm *nm) { @@ -28,7 +39,8 @@ static void ccu_nm_find_best(unsigned long parent, unsigned long rate, for (_n = nm->min_n; _n <= nm->max_n; _n++) { for (_m = nm->min_m; _m <= nm->max_m; _m++) { - unsigned long tmp_rate = parent * _n / _m; + unsigned long tmp_rate = ccu_nm_calc_rate(parent, + _n, _m); if (tmp_rate > rate) continue; @@ -100,7 +112,7 @@ static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw, if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm)) rate = ccu_sdm_helper_read_rate(&nm->common, &nm->sdm, m, n); else - rate = parent_rate * n / m; + rate = ccu_nm_calc_rate(parent_rate, n, m); if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV) rate /= nm->fixed_post_div; @@ -149,7 +161,7 @@ static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate, _nm.max_m = nm->m.max ?: 1 << nm->m.width; ccu_nm_find_best(*parent_rate, rate, &_nm); - rate = *parent_rate * _nm.n / _nm.m; + rate = ccu_nm_calc_rate(*parent_rate, _nm.n, _nm.m); if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV) rate /= nm->fixed_post_div;