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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 38CDEC433E0 for ; Fri, 10 Jul 2020 08:05:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07C0F2083B for ; Fri, 10 Jul 2020 08:05:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YvxH9ESy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727772AbgGJIFK (ORCPT ); Fri, 10 Jul 2020 04:05:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726004AbgGJIFJ (ORCPT ); Fri, 10 Jul 2020 04:05:09 -0400 Received: from mail-il1-x143.google.com (mail-il1-x143.google.com [IPv6:2607:f8b0:4864:20::143]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C2A6C08C5CE; Fri, 10 Jul 2020 01:05:09 -0700 (PDT) Received: by mail-il1-x143.google.com with SMTP id x9so4357913ila.3; Fri, 10 Jul 2020 01:05:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=5+G1uuop498qwxWK2qrr1h0MxQXkOdDS2Ry0PGIWZu8=; b=YvxH9ESyKpS9/V9ii1PS6FtzJiZYFA9wClEEPvL0ONzCRrvtIAMoymOPopdNGOU9es cCl/HDFzk52+lGUbBZ+KmCmFp+UFDkGYrQQ3LWsgLQzvzybigUzJT6u/ULtzOQ1Es58P xvVaBNoICUYtGdRBHgOLhP3tRs6xjwLg5iqZ+RPvY7re1B+fPSavTcqfOIAa1LOetTAt zT7LT7aaF8tICr7NRKZD4I49axIwa1877DsXecpUN9kN+S5lxOsp8h9vKCz1oQuSdjQO 6KENMzaEJM2UZnXDkTVJBWfFDVKZPM8CyTwus9kcN1b66+hHvLMgDJTw8mNcfKqN/xXt yU4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=5+G1uuop498qwxWK2qrr1h0MxQXkOdDS2Ry0PGIWZu8=; b=eFJ23Eq2mDGJ8DRm+CvF4xbgcrIY+RnSarIRAedN5sGpYp80Boj9c0I4aF8pyISnPt O3HnNWCjhM4htbJbdNBDDl0fhfVHEAqGOfBc/Weq35ge3Td5H9LHUYvr3unGb481JHAU 54dUD2jFEVLVQ1XQhS34CJSaT8S4wuMKnT6KQdoMnp8itRkAucmsJrRuuIkCBSVrsUaV UUFOSXyHhowPUXs+szAkdtURNcv9MmvpB8gX5dC5BvNjmbuDSFanGhD8/EDa6u5pJykz nxTv6Obi0sGADdf1p2+W1ph/6r53COSNj8u7tG4bdfaDJiEK//uVsoc0SUBcH+MHiGB7 Ndqw== X-Gm-Message-State: AOAM531XBKe96fAkICnE91RoD9xX7t9H9AhK3CXv8bJcecZV8AQZVm8/ Hl2pgpC8DmbkPtkFzEJ/erixpCy8kl2V7RyF7hw= X-Google-Smtp-Source: ABdhPJwQ7A/l6ebIgnp1a0yl+jTVZOrJKIN8Eqvyz9/+o7LaU3fFKI251S+kcR6ZFj4ZommmbaR0Ib6nr+7bNly3SpI= X-Received: by 2002:a92:c7c3:: with SMTP id g3mr51239040ilk.164.1594368308678; Fri, 10 Jul 2020 01:05:08 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Syed Nayyar Waris Date: Fri, 10 Jul 2020 13:34:57 +0530 Message-ID: Subject: Re: [PATCH v9 0/4] Introduce the for_each_set_clump macro To: Linus Walleij , Andrew Morton Cc: Andy Shevchenko , William Breathitt Gray , Michal Simek , Arnd Bergmann , rrichter@marvell.com, Bartosz Golaszewski , Masahiro Yamada , "Zhang, Rui" , Daniel Lezcano , Amit Kucheria , Linux-Arch , "open list:GPIO SUBSYSTEM" , Linux Kernel Mailing List , linux-arm Mailing List , Linux PM Content-Type: text/plain; charset="UTF-8" Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Sat, Jun 27, 2020 at 1:40 PM Syed Nayyar Waris wrote: > > Hello Linus, > > Since this patchset primarily affects GPIO drivers, would you like > to pick it up through your GPIO tree? > > 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. > > Changes in v9: > - [Patch 4/4]: Remove looping of 'for_each_set_clump' and instead process two > halves of a 64-bit bitmap separately or individually. Use normal spin_lock > call for second inner lock. And take the spin_lock_init call outside the 'if' > condition in the probe function of driver. > > Changes in v8: > - [Patch 2/4]: Minor change: Use '__initdata' for correct section mismatch > in 'clump_test_data' array. > > Changes in v7: > - [Patch 2/4]: Minor changes: Use macro 'DECLARE_BITMAP()' and split 'struct' > definition and test data. > > 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 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 generic bitmap_get_value and _set_value. > > drivers/gpio/gpio-thunderx.c | 11 ++- > drivers/gpio/gpio-xilinx.c | 66 +++++++------- > 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 | 145 ++++++++++++++++++++++++++++++ > 7 files changed, 292 insertions(+), 37 deletions(-) > > > base-commit: b3a9e3b9622ae10064826dccb4f7a52bd88c7407 > -- > 2.26.2 > Hi Andrew, Linus What do you think about this patchset on 'for_each_set_clump' ? if there's anything else you think that should be changed in this, or if this version looks good to you to pick up, kindly, let me know. Regards Syed Nayyar Waris