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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A436AC433E1 for ; Fri, 15 May 2020 11:33:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88E5820709 for ; Fri, 15 May 2020 11:33:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726097AbgEOLdA (ORCPT ); Fri, 15 May 2020 07:33:00 -0400 Received: from mga17.intel.com ([192.55.52.151]:20782 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725986AbgEOLc7 (ORCPT ); Fri, 15 May 2020 07:32:59 -0400 IronPort-SDR: XqeWr7S/fqOBGflO8ApSAhWwiaBR2ZEZjVT78CRk11D6mgUgoqR6Zfnxghtl5zZvaiwWCdOH1T i6BerGzpoS/g== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 May 2020 04:32:58 -0700 IronPort-SDR: 0gS0OaFJiuv3OfG2ljoqjSB4HKx6CLP4K3KFhfm6vWhg8PAp9Nw/f+wW4k3a8VLZLakldEI3/w +/CncU4PobkQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,395,1583222400"; d="scan'208";a="464700264" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by fmsmga005.fm.intel.com with ESMTP; 15 May 2020 04:32:55 -0700 Received: from andy by smile with local (Exim 4.93) (envelope-from ) id 1jZYaH-006qe0-KA; Fri, 15 May 2020 14:32:57 +0300 Date: Fri, 15 May 2020 14:32:57 +0300 From: Andy Shevchenko To: Syed Nayyar Waris Cc: akpm@linux-foundation.org, vilhelm.gray@gmail.com, michal.simek@xilinx.com, arnd@arndb.de, rrichter@marvell.com, linus.walleij@linaro.org, bgolaszewski@baylibre.com, yamada.masahiro@socionext.com, rui.zhang@intel.com, daniel.lezcano@linaro.org, amit.kucheria@verdurent.com, linux-arch@vger.kernel.org, linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org Subject: Re: [PATCH v6 0/4] Introduce the for_each_set_clump macro Message-ID: <20200515113257.GP185537@smile.fi.intel.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri, May 15, 2020 at 04:46:03AM +0530, Syed Nayyar Waris wrote: > This patchset introduces a new generic version of for_each_set_clump. > The previous version of for_each_set_clump8 used a fixed size 8-bit > clump, but the new generic version can work with clump of any size but > less than or equal to BITS_PER_LONG. The patchset utilizes the new macro > in several GPIO drivers. > > The earlier 8-bit for_each_set_clump8 facilitated a > for-loop syntax that iterates over a memory region entire groups of set > bits at a time. > > For example, suppose you would like to iterate over a 32-bit integer 8 > bits at a time, skipping over 8-bit groups with no set bit, where > XXXXXXXX represents the current 8-bit group: > > Example: 10111110 00000000 11111111 00110011 > First loop: 10111110 00000000 11111111 XXXXXXXX > Second loop: 10111110 00000000 XXXXXXXX 00110011 > Third loop: XXXXXXXX 00000000 11111111 00110011 > > Each iteration of the loop returns the next 8-bit group that has at > least one set bit. > > But with the new for_each_set_clump the clump size can be different from 8 bits. > Moreover, the clump can be split at word boundary in situations where word > size is not multiple of clump size. Following are examples showing the working > of new macro for clump sizes of 24 bits and 6 bits. > > Example 1: > clump size: 24 bits, Number of clumps (or ports): 10 > bitmap stores the bit information from where successive clumps are retrieved. > > /* bitmap memory region */ > 0x00aa0000ff000000; /* Most significant bits */ > 0xaaaaaa0000ff0000; > 0x000000aa000000aa; > 0xbbbbabcdeffedcba; /* Least significant bits */ > > Different iterations of for_each_set_clump:- > 'offset' is the bit position and 'clump' is the 24 bit clump from the > above bitmap. > Iteration first: offset: 0 clump: 0xfedcba > Iteration second: offset: 24 clump: 0xabcdef > Iteration third: offset: 48 clump: 0xaabbbb > Iteration fourth: offset: 96 clump: 0xaa > Iteration fifth: offset: 144 clump: 0xff > Iteration sixth: offset: 168 clump: 0xaaaaaa > Iteration seventh: offset: 216 clump: 0xff > Loop breaks because in the end the remaining bits (0x00aa) size was less > than clump size of 24 bits. > > In above example it can be seen that in iteration third, the 24 bit clump > that was retrieved was split between bitmap[0] and bitmap[1]. This example > also shows that 24 bit zeroes if present in between, were skipped (preserving > the previous for_each_set_macro8 behaviour). > > Example 2: > clump size = 6 bits, Number of clumps (or ports) = 3. > > /* bitmap memory region */ > 0x00aa0000ff000000; /* Most significant bits */ > 0xaaaaaa0000ff0000; > 0x0f00000000000000; > 0x0000000000000ac0; /* Least significant bits */ > > Different iterations of for_each_set_clump: > 'offset' is the bit position and 'clump' is the 6 bit clump from the > above bitmap. > Iteration first: offset: 6 clump: 0x2b > Loop breaks because 6 * 3 = 18 bits traversed in bitmap. > Here 6 * 3 is clump size * no. of clumps. Thank you! Overall looks good to me, though I gave tags per individual patches (I'm not familiar with that GPIO drivers, so, I may not tag them). > > Changes in v6: > - [Patch 2/4]: Make 'for loop' inside test_for_each_set_clump more > succinct. > > Changes in v5: > - [Patch 4/4]: Minor change: Hardcode value for better code readability. > > Changes in v4: > - [Patch 2/4]: Use 'for' loop in test function of for_each_set_clump. > - [Patch 3/4]: Minor change: Inline value for better code readability. > - [Patch 4/4]: Minor change: Inline value for better code readability. > > Changes in v3: > - [Patch 3/4]: Change datatype of some variables from u64 to unsigned long > in function thunderx_gpio_set_multiple. > > CHanges in v2: > - [Patch 2/4]: Unify different tests for 'for_each_set_clump'. Pass test data as > function parameters. > - [Patch 2/4]: Remove unnecessary bitmap_zero calls. > > Syed Nayyar Waris (4): > bitops: Introduce the the for_each_set_clump macro > lib/test_bitmap.c: Add for_each_set_clump test cases > gpio: thunderx: Utilize for_each_set_clump macro > gpio: xilinx: Utilize for_each_set_clump macro > > drivers/gpio/gpio-thunderx.c | 11 ++- > drivers/gpio/gpio-xilinx.c | 62 ++++++------- > include/asm-generic/bitops/find.h | 19 ++++ > include/linux/bitmap.h | 61 +++++++++++++ > include/linux/bitops.h | 13 +++ > lib/find_bit.c | 14 +++ > lib/test_bitmap.c | 142 ++++++++++++++++++++++++++++++ > 7 files changed, 288 insertions(+), 34 deletions(-) > > > base-commit: 5f458e572071a54841b93f41e25fbe8ded82df79 > -- > 2.26.2 > -- With Best Regards, Andy Shevchenko