From patchwork Sat Mar 6 14:03:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Syed Nayyar Waris X-Patchwork-Id: 395270 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=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 ED7B9C433DB for ; Sat, 6 Mar 2021 14:04:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B100D6501B for ; Sat, 6 Mar 2021 14:04:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230461AbhCFOEJ (ORCPT ); Sat, 6 Mar 2021 09:04:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230329AbhCFODi (ORCPT ); Sat, 6 Mar 2021 09:03:38 -0500 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7ADE3C06174A; Sat, 6 Mar 2021 06:03:38 -0800 (PST) Received: by mail-pg1-x536.google.com with SMTP id a4so3318652pgc.11; Sat, 06 Mar 2021 06:03:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=D0pZU+ZO0WgdHXG31w5r3xEY8crDm6hiwwf6wN5RCb8=; b=hVa2JCQ2tOWnTU6fSY/qwcgDvdVV3hXXPyCM0r9Q+mrQ6kGGmutniWxTX11UCXPtJq 7qewfwAqt/1rTdekMsbUT6QMxV8NmH81DTmkcPRLV1UlR4ro12YDyhkeOYS5qzUfpxe1 VPeyt2jylcgj3q47/0I++UbaUv5vzWV4LM2cDR/0gkmUBCtjlV60F9DB++nDjh3t4GUO ug0fWpJ95JaxlTjGgBOGICz8ABiMR/078z8lY61g1l26WPyoiR2Gw1yWfCvZaM3z9ghm 3Zxsah09qQYs4/0e2RWuP6xb4o0qOcYm611gTRQgzK8yFd1+imQBdVma1Mg73duGnTZE 6/2Q== 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:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=D0pZU+ZO0WgdHXG31w5r3xEY8crDm6hiwwf6wN5RCb8=; b=KLVKD0AL/Q7kI2krPzCQeVuW2/1AUxT3xeD1e7O+FnxNn2Eo464xGEPySy69XXjG8C xIUIeUB/TSYlJHWKKXAOMCNxP/W1P8B1BECCJ0dVTXaCtpZKBqT6Ojp+81Q44H3bY0L/ Z03FnaAPUXLmo+kMp3QPL1uNy9fog9ykQaRFsN+cgJ2YSRL0bE1M1tzM2EtaqWocCbue oQb3AHm7lJZO5Z8ReVuq+lEsJIgf4tNq7bVGvBRz5hN9DfFuprqymiRdcatrTfzXqoQc Irfy29UtAf8JjyJEKgYOtXwmtn1YuX3tdhQuqtpkXiQ+XlkskXiN+f3PLVuiZW/tQePL s/Pw== X-Gm-Message-State: AOAM531VyQowob5clqNsHu7tqleixkzuUprYf6vn1VOLg8UHeaidul3F 1FXc4dtM2ztnTfpzSTLuNC4= X-Google-Smtp-Source: ABdhPJxxZ7QdbnjHZSmZqOs8ue74mR6BLZ9IKfUOpDcu7AdvjnvL8pXrBlkxI1lrXoNQGHkVcmV81Q== X-Received: by 2002:aa7:8503:0:b029:1ee:6e6c:694b with SMTP id v3-20020aa785030000b02901ee6e6c694bmr13347227pfn.18.1615039417964; Sat, 06 Mar 2021 06:03:37 -0800 (PST) Received: from syed.domain.name ([103.201.127.38]) by smtp.gmail.com with ESMTPSA id j17sm3977739pfn.70.2021.03.06.06.03.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 06 Mar 2021 06:03:37 -0800 (PST) Date: Sat, 6 Mar 2021 19:33:20 +0530 From: Syed Nayyar Waris To: bgolaszewski@baylibre.com 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, akpm@linux-foundation.org, 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 v3 1/3] gpiolib: Introduce the for_each_set_nbits macro Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org This macro iterates for each group of bits (clump) with set bits, within a bitmap memory region. For each iteration, "start" is set to the bit offset of the found clump, while the respective clump value is stored to the location pointed by "clump". Additionally, the bitmap_get_value() and bitmap_set_value() functions are introduced to respectively get and set a value of n-bits in a bitmap memory region. The n-bits can have any size from 1 to BITS_PER_LONG. size less than 1 or more than BITS_PER_LONG causes undefined behaviour. Moreover, during setting value of n-bit in bitmap, if a situation arise that the width of next n-bit is exceeding the word boundary, then it will divide itself such that some portion of it is stored in that word, while the remaining portion is stored in the next higher word. Similar situation occurs while retrieving the value from bitmap. Cc: Linus Walleij Cc: Bartosz Gołaszewski Cc: Arnd Bergmann Cc: Andy Shevchenko Signed-off-by: Syed Nayyar Waris Acked-by: William Breathitt Gray --- drivers/gpio/gpiolib.c | 90 ++++++++++++++++++++++++++++++++++++++++++ drivers/gpio/gpiolib.h | 28 +++++++++++++ 2 files changed, 118 insertions(+) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index b02cc2abd3b6..1e3cfc6bc73f 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -148,6 +148,96 @@ struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, } EXPORT_SYMBOL_GPL(gpiochip_get_desc); +/** + * bitmap_get_value - get a value of n-bits from the memory region + * @map: address to the bitmap memory region + * @start: bit offset of the n-bit value + * @nbits: size of value in bits (must be between 1 and BITS_PER_LONG inclusive). + * + * Returns value of nbits located at the @start bit offset within the @map + * memory region. + */ +unsigned long bitmap_get_value(const unsigned long *map, + unsigned long start, + unsigned long nbits) +{ + const size_t index = BIT_WORD(start); + const unsigned long offset = start % BITS_PER_LONG; + const unsigned long ceiling = round_up(start + 1, BITS_PER_LONG); + const unsigned long space = ceiling - start; + unsigned long value_low, value_high; + + if (space >= nbits) + return (map[index] >> offset) & GENMASK(nbits - 1, 0); + else { + value_low = map[index] & BITMAP_FIRST_WORD_MASK(start); + value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits); + return (value_low >> offset) | (value_high << space); + } +} +EXPORT_SYMBOL_GPL(bitmap_get_value); + +/** + * bitmap_set_value - set value within a memory region + * @map: address to the bitmap memory region + * @nbits: size of map in bits + * @value: value of clump + * @value_width: size of value in bits (must be between 1 and BITS_PER_LONG inclusive) + * @start: bit offset of the value + */ +void bitmap_set_value(unsigned long *map, unsigned long nbits, + unsigned long value, unsigned long value_width, + unsigned long start) +{ + const unsigned long index = BIT_WORD(start); + const unsigned long length = BIT_WORD(nbits); + const unsigned long offset = start % BITS_PER_LONG; + const unsigned long ceiling = round_up(start + 1, BITS_PER_LONG); + const unsigned long space = ceiling - start; + + value &= GENMASK(value_width - 1, 0); + + if (space >= value_width) { + map[index] &= ~(GENMASK(value_width - 1, 0) << offset); + map[index] |= value << offset; + } else { + map[index + 0] &= ~BITMAP_FIRST_WORD_MASK(start); + map[index + 0] |= value << offset; + + if (index + 1 >= length) + return; + + map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + value_width); + map[index + 1] |= value >> space; + } +} +EXPORT_SYMBOL_GPL(bitmap_set_value); + +/** + * find_next_clump - find next clump with set bits in a memory region + * @clump: location to store copy of found clump + * @addr: address to base the search on + * @size: bitmap size in number of bits + * @offset: bit offset at which to start searching + * @clump_size: clump size in bits + * + * Returns the bit offset for the next set clump; the found clump value is + * copied to the location pointed by @clump. If no bits are set, returns @size. + */ +unsigned long find_next_clump(unsigned long *clump, const unsigned long *addr, + unsigned long size, unsigned long offset, + unsigned long clump_size) +{ + offset = find_next_bit(addr, size, offset); + if (offset == size) + return size; + + offset = rounddown(offset, clump_size); + *clump = bitmap_get_value(addr, offset, clump_size); + return offset; +} +EXPORT_SYMBOL_GPL(find_next_clump); + /** * desc_to_gpio - convert a GPIO descriptor to the integer namespace * @desc: GPIO descriptor diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 30bc3f80f83e..af79784dfce3 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -141,6 +141,34 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce); int gpiod_hog(struct gpio_desc *desc, const char *name, unsigned long lflags, enum gpiod_flags dflags); +unsigned long bitmap_get_value(const unsigned long *map, + unsigned long start, + unsigned long nbits); + +void bitmap_set_value(unsigned long *map, unsigned long nbits, + unsigned long value, unsigned long value_width, + unsigned long start); + +unsigned long find_next_clump(unsigned long *clump, const unsigned long *addr, + unsigned long size, unsigned long offset, + unsigned long clump_size); + +#define find_first_clump(clump, bits, size, clump_size) \ + find_next_clump((clump), (bits), (size), 0, (clump_size)) + +/** + * for_each_set_nbits - iterate over bitmap for each clump with set bits + * @start: bit offset to start search and to store the current iteration offset + * @clump: location to store copy of current 8-bit clump + * @bits: bitmap address to base the search on + * @size: bitmap size in number of bits + * @clump_size: clump size in bits + */ +#define for_each_set_nbits(start, clump, bits, size, clump_size) \ + for ((start) = find_first_clump(&(clump), (bits), (size), (clump_size)); \ + (start) < (size); \ + (start) = find_next_clump(&(clump), (bits), (size), (start) + (clump_size), (clump_size))) + /* * Return the GPIO number of the passed descriptor relative to its chip */