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=-5.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D4797C433E7 for ; Sun, 18 Oct 2020 21:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 924B222269 for ; Sun, 18 Oct 2020 21:37:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="knyO+DuY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727254AbgJRVhv (ORCPT ); Sun, 18 Oct 2020 17:37:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726249AbgJRVhu (ORCPT ); Sun, 18 Oct 2020 17:37:50 -0400 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8AB01C061755; Sun, 18 Oct 2020 14:37:50 -0700 (PDT) Received: by mail-pf1-x442.google.com with SMTP id e15so1597189pfh.6; Sun, 18 Oct 2020 14:37:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=ihQGJxo3JZrn4cqgJ3fEKTBsZo1j40mfYYWZF1c6FZ4=; b=knyO+DuYt1uvvdKpxN0UpMnUhFH9H291MuqezMLS5P86ZKs1a6Drsn2+9uKzkg8+gq Rx6ZSS83JFN/Zj9zu+w8ZoKBW6pbn1q6PP5qAnkXH9liHnvnAIdM1aVCy4F4ECc/CPXU 8X0KfWxEZ69+ZJ/a3616Jq8LF2q86Ii75byej47C8MwqmC19fpOqUSwJYVfyg7Dmq6jw zbWAaYYomvUJwl4hOHKTeABnUXPuPl/+jI6Mx+PackihYKx+jIoSFhViiJq1jKNmHqhk JAFDMC0OEiKjcpjrsqFr+DhJOMZbFyLKqmzmQXkVU41DF81/3DJvCeGsTuIFOx+5QMFu j/sw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=ihQGJxo3JZrn4cqgJ3fEKTBsZo1j40mfYYWZF1c6FZ4=; b=HtLUbOZwiYWjzIhiIuPMs4ie69jbNo9qDamMFEhSK+vVKxzeObxJWlJ+bgZqvXgEI+ 6+/2wDf+61HgXB4uPKvaPZ9/2x54eKty/lm6oFS9NBxM6LuwXKOS+wvFM1JBBw7nJHJG mF+tWGysSOlY4Ey8BRJMo7OhiodXvtGwPLp7tlEwEicBUTAhPSr7zWmnqVPrOAIjXk0h rhukVfyQ0dtRBJPwPYh2BQhvfUMHtyfLb6UIuKlTdkHj6OxxkD9clQN7lFC2G0LP5I+0 mzhkiLiz46gxI+/ADBXJAdNX1BWHOVLTlvG2vOiqkloaeO10BrFEaXP0P2f4+/EASqs0 UxQg== X-Gm-Message-State: AOAM53142yyETWo+pfFCbr4DeOgeUMs5a6375jgVNxi0i6i0RyhuEusX p3ufgaNYLdMVfkJdfXjOI+E= X-Google-Smtp-Source: ABdhPJy6jzHV/dSSCjWff0nzBU5ZlH45mh2zd/zQcpHBaFpYMydRDsxCsGgvKzhTwkmtQiq6BBV5lQ== X-Received: by 2002:a63:68e:: with SMTP id 136mr11929130pgg.211.1603057069917; Sun, 18 Oct 2020 14:37:49 -0700 (PDT) Received: from syed ([2401:4900:47f3:e624:90f9:25c2:806b:19c8]) by smtp.gmail.com with ESMTPSA id 92sm9995465pjv.32.2020.10.18.14.37.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 18 Oct 2020 14:37:49 -0700 (PDT) Date: Mon, 19 Oct 2020 03:07:24 +0530 From: Syed Nayyar Waris To: linus.walleij@linaro.org, akpm@linux-foundation.org Cc: andriy.shevchenko@linux.intel.com, 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: [PATCH v12 0/4] Introduce the for_each_set_clump macro Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org 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 (n-bits) having size between 1 and BITS_PER_LONG inclusive. size less than 1 or more than BITS_PER_LONG causes undefined behaviour. The patchset utilizes the new macro in some 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 v12: - [Patch 1/4]: Format and modify comments. - [Patch 1/4]: Optimize code using '<<' operator with GENMASK. - [Patch 4/4]: Remove extra empty newline. Changes in v11: - [Patch 1/4]: Document range of values 'nbits' can take. - [Patch 4/4]: Change variable name 'flag' to 'flags'. Changes in v10: - Patchset based on v5.9-rc1. 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 | 65 +++++++------- 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 | 144 ++++++++++++++++++++++++++++++ 7 files changed, 290 insertions(+), 37 deletions(-) base-commit: 9123e3a74ec7b934a4a099e98af6a61c2f80bbf5 -- 2.26.2