From patchwork Mon Nov 22 15:53:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 12632481 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 DF514C433EF for ; Mon, 22 Nov 2021 16:03:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233330AbhKVQGQ (ORCPT ); Mon, 22 Nov 2021 11:06:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229955AbhKVQGP (ORCPT ); Mon, 22 Nov 2021 11:06:15 -0500 X-Greylist: delayed 447 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 22 Nov 2021 08:03:08 PST Received: from newton.telenet-ops.be (newton.telenet-ops.be [IPv6:2a02:1800:120:4::f00:d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCAE8C061574 for ; Mon, 22 Nov 2021 08:03:08 -0800 (PST) Received: from laurent.telenet-ops.be (laurent.telenet-ops.be [IPv6:2a02:1800:110:4::f00:19]) by newton.telenet-ops.be (Postfix) with ESMTPS id 4HyX1723ySzMrQKj for ; Mon, 22 Nov 2021 16:55:39 +0100 (CET) Received: from ramsan.of.borg ([IPv6:2a02:1810:ac12:ed20:e4da:38c:79e9:48bf]) by laurent.telenet-ops.be with bizsmtp id MTux2600m4yPVd601TuykH; Mon, 22 Nov 2021 16:55:39 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan.of.borg with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1mpBe5-00EL3L-Rf; Mon, 22 Nov 2021 16:54:17 +0100 Received: from geert by rox.of.borg with local (Exim 4.93) (envelope-from ) id 1mpBe5-00HGy7-BC; Mon, 22 Nov 2021 16:54:17 +0100 From: Geert Uytterhoeven To: Tony Lindgren , Russell King , Rajendra Nayak , Paul Walmsley , Michael Turquette , Stephen Boyd , Nicolas Ferre , Alexandre Belloni , Ludovic Desroches , Tero Kristo , Jonathan Cameron , Lars-Peter Clausen , Lorenzo Bianconi , Benoit Parrot , Mauro Carvalho Chehab , Adrian Hunter , Andrew Jeffery , Ulf Hansson , Joel Stanley , Ping-Ke Shih , Kalle Valo , "David S . Miller" , Jakub Kicinski , Linus Walleij , Liam Girdwood , Mark Brown , Magnus Damm , Eduardo Valentin , Keerthy , "Rafael J . Wysocki" , Daniel Lezcano , Amit Kucheria , Zhang Rui , Jaroslav Kysela , Takashi Iwai Cc: linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-iio@vger.kernel.org, linux-media@vger.kernel.org, linux-mmc@vger.kernel.org, linux-aspeed@lists.ozlabs.org, openbmc@lists.ozlabs.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-gpio@vger.kernel.org, linux-pm@vger.kernel.org, alsa-devel@alsa-project.org, Geert Uytterhoeven Subject: [PATCH 01/17] bitfield: Add non-constant field_{prep,get}() helpers Date: Mon, 22 Nov 2021 16:53:54 +0100 Message-Id: <3a54a6703879d10f08cf0275a2a69297ebd2b1d4.1637592133.git.geert+renesas@glider.be> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The existing FIELD_{GET,PREP}() macros are limited to compile-time constants. However, it is very common to prepare or extract bitfield elements where the bitfield mask is not a compile-time constant. To avoid this limitation, the AT91 clock driver already has its own field_{prep,get}() macros. Make them available for general use by moving them to , and improve them slightly: 1. Avoid evaluating macro parameters more than once, 2. Replace "ffs() - 1" by "__ffs()", as the latter operates on "unsigned long", just like BIT() and GENMASK(). Signed-off-by: Geert Uytterhoeven --- Using __ffs() actually reduces code size (16 bytes for each of drivers/clk/at91/clk-{generated,peripheral}.o), as __ffs() doesn't need to verify that the value passed is non-zero. --- drivers/clk/at91/clk-peripheral.c | 1 + drivers/clk/at91/pmc.h | 3 --- include/linux/bitfield.h | 30 ++++++++++++++++++++++++++++++ 3 files changed, 31 insertions(+), 3 deletions(-) diff --git a/drivers/clk/at91/clk-peripheral.c b/drivers/clk/at91/clk-peripheral.c index e14fa5ac734cead7..e2f33498139a1b8c 100644 --- a/drivers/clk/at91/clk-peripheral.c +++ b/drivers/clk/at91/clk-peripheral.c @@ -3,6 +3,7 @@ * Copyright (C) 2013 Boris BREZILLON */ +#include #include #include #include diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h index 3a1bf6194c287d09..1256e1ab91526a25 100644 --- a/drivers/clk/at91/pmc.h +++ b/drivers/clk/at91/pmc.h @@ -114,9 +114,6 @@ struct at91_clk_pms { unsigned int parent; }; -#define field_get(_mask, _reg) (((_reg) & (_mask)) >> (ffs(_mask) - 1)) -#define field_prep(_mask, _val) (((_val) << (ffs(_mask) - 1)) & (_mask)) - #define ndck(a, s) (a[s - 1].id + 1) #define nck(a) (a[ARRAY_SIZE(a) - 1].id + 1) struct pmc_data *pmc_data_allocate(unsigned int ncore, unsigned int nsystem, diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h index 4e035aca6f7e6000..f03b0712e4babec1 100644 --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -156,4 +156,34 @@ __MAKE_OP(64) #undef __MAKE_OP #undef ____MAKE_OP +/** + * field_prep() - prepare a bitfield element + * @_mask: shifted mask defining the field's length and position + * @_val: value to put in the field + * + * field_prep() masks and shifts up the value. The result should be + * combined with other fields of the bitfield using logical OR. + * Unlike FIELD_PREP(), @_mask is not limited to a compile-time constant. + */ +#define field_prep(_mask, _val) \ + ({ \ + typeof(_mask) ___mask = (_mask); \ + (((_val) << __ffs(___mask)) & (___mask)); \ + }) + +/** + * field_get() - extract a bitfield element + * @_mask: shifted mask defining the field's length and position + * @_reg: value of entire bitfield + * + * field_get() extracts the field specified by @_mask from the + * bitfield passed in as @_reg by masking and shifting it down. + * Unlike FIELD_GET(), @_mask is not limited to a compile-time constant. + */ +#define field_get(_mask, _reg) \ + ({ \ + typeof(_mask) ___mask = _mask; \ + (((_reg) & (___mask)) >> __ffs(___mask)); \ + }) + #endif