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 48FB4C77B7A for ; Fri, 26 May 2023 17:11:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242272AbjEZRLH (ORCPT ); Fri, 26 May 2023 13:11:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230144AbjEZRLC (ORCPT ); Fri, 26 May 2023 13:11:02 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00EA0F3; Fri, 26 May 2023 10:11:00 -0700 (PDT) Received: from jupiter.universe (dyndsl-091-248-132-021.ewe-ip-backbone.de [91.248.132.21]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) (Authenticated sender: sre) by madras.collabora.co.uk (Postfix) with ESMTPSA id 918536606E95; Fri, 26 May 2023 18:10:59 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1685121059; bh=T4lpsRVLH6x7IReX3htoV7ctOeRMnG2Z8G+kSXW+NWE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CQMmdb+lt47Nfyk60vuz43mxBRGxAFCuth1e7EdEYjEs4yei18dyATChn8dt2sqYz mTXJthprnnFujc8KXNsnukL+v6lc7oOLF1EH5FWqiCCNsILbqkBG82sQAlOGNiTFRU iGZ37UJspuNS561holzqTqRltGh7PCKgwi7lfznv7aS8LDOQhfH6tohw5YhezK1UzG kU/ifwIaMRaWzDU432gRJTscGZZpQXOkmRjlp5B1R/Bq/js+2gjnwLC2hUXzEVub70 pmxTBTJTW42CuKlTRDs5pRSyQR/ez5QtzAZK1kqx83gUfFLY0iDBfSIIaIuilxB7xw fy1IZcNMojGdA== Received: by jupiter.universe (Postfix, from userid 1000) id D41714807E3; Fri, 26 May 2023 19:10:57 +0200 (CEST) From: Sebastian Reichel To: Michael Turquette , Stephen Boyd , linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Christopher Obbard , David Laight , Sebastian Reichel , kernel@collabora.com Subject: [PATCH v2 2/2] clk: divider: Fix divisions Date: Fri, 26 May 2023 19:10:57 +0200 Message-Id: <20230526171057.66876-3-sebastian.reichel@collabora.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230526171057.66876-1-sebastian.reichel@collabora.com> References: <20230526171057.66876-1-sebastian.reichel@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The clock framework handles clock rates as "unsigned long", so u32 on 32-bit architectures and u64 on 64-bit architectures. The current code pointlessly casts the dividend to u64 on 32-bit architectures and thus pointlessly reducing the performance. On the other hand on 64-bit architectures the divisor is masked and only the lower 32-bit are used. Thus requesting a frequency >= 4.3GHz results in incorrect values. For example requesting 4300000000 (4.3 GHz) will effectively request ca. 5 MHz. Requesting clk_round_rate(clk, ULONG_MAX) is a bit of a special case, since that still returns correct values as long as the parent clock is below 8.5 GHz. Signed-off-by: Sebastian Reichel --- drivers/clk/clk-divider.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index a2c2b5203b0a..c38e8aa60e54 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -220,7 +220,7 @@ static int _div_round_up(const struct clk_div_table *table, unsigned long parent_rate, unsigned long rate, unsigned long flags) { - int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate); + int div = DIV_ROUND_UP(parent_rate, rate); if (flags & CLK_DIVIDER_POWER_OF_TWO) div = __roundup_pow_of_two(div); @@ -237,7 +237,7 @@ static int _div_round_closest(const struct clk_div_table *table, int up, down; unsigned long up_rate, down_rate; - up = DIV_ROUND_UP_ULL((u64)parent_rate, rate); + up = DIV_ROUND_UP(parent_rate, rate); down = parent_rate / rate; if (flags & CLK_DIVIDER_POWER_OF_TWO) { @@ -473,7 +473,7 @@ int divider_get_val(unsigned long rate, unsigned long parent_rate, { unsigned int div, value; - div = DIV_ROUND_UP_ULL((u64)parent_rate, rate); + div = DIV_ROUND_UP(parent_rate, rate); if (!_is_valid_div(table, div, flags)) return -EINVAL; -- 2.39.2