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: 10667055 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 D37BA15E9 for ; Sun, 4 Nov 2018 18:30:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C50EF29641 for ; Sun, 4 Nov 2018 18:30:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B6E3929649; Sun, 4 Nov 2018 18:30:21 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5D43F29641 for ; Sun, 4 Nov 2018 18:30:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387450AbeKEDnf (ORCPT ); Sun, 4 Nov 2018 22:43:35 -0500 Received: from mailoutvs53.siol.net ([185.57.226.244]:47128 "EHLO mail.siol.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387432AbeKEDne (ORCPT ); Sun, 4 Nov 2018 22:43:34 -0500 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 Cc: robh+dt@kernel.org, mturquette@baylibre.com, sboyd@kernel.org, airlied@linux.ie, architt@codeaurora.org, a.hajda@samsung.com, Laurent.pinchart@ideasonboard.com, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-sunxi@googlegroups.com, jernej.skrabec@siol.net, stable@vger.kernel.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 Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org 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;