From patchwork Wed Jul 13 16:31:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Fricke X-Patchwork-Id: 12916955 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 B03C7C433EF for ; Wed, 13 Jul 2022 16:32:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237180AbiGMQcY (ORCPT ); Wed, 13 Jul 2022 12:32:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230114AbiGMQcW (ORCPT ); Wed, 13 Jul 2022 12:32:22 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D284C2B604; Wed, 13 Jul 2022 09:32:21 -0700 (PDT) Received: from localhost (dynamic-002-247-252-243.2.247.pool.telefonica.de [2.247.252.243]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: sebastianfricke) by madras.collabora.co.uk (Postfix) with ESMTPSA id 4B99A660191C; Wed, 13 Jul 2022 17:32:20 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1657729940; bh=dIzwKmgbXSEkeJxn4p/FQB/B/V+b2M0cBePpVdA5mgE=; h=From:To:Cc:Subject:Date:From; b=iku7kOjHUvAD7+D/BODOjWHZslQRXb7UfbF1HSjv41HaCqGg0CpgjSenu50rlKn1d 2db/FNN8L6TrGdl1rw5QfrLh5QN8SvdbKXlb0ZNDgN/R2qNvlAjcYwQhbWorgr2L7V ZL+LO4rmvAMh569pyL1jatslnrmQHdjfJigouTs310LHCdTrMBIdOn7m9Fj89T14r2 xb3fbgJUNLVFvxo5zGGl6CREebx30q44PXVp87jJkxwE4M7//JVQxPnPPUesQqnrgI nxHhzY7gumtvkffVS6kgM3hHF/2/U0v6eIrFnwIphbwwzIYF86WuxCtvwDxXGSU5dk JNw8+9GWDK97A== From: Sebastian Fricke To: linux-media@vger.kernel.org Cc: jernej.skrabec@gmail.com, knaerzche@gmail.com, kernel@collabora.com, bob.beckett@collabora.com, ezequiel@vanguardiasur.com.ar, mchehab@kernel.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev, nicolas.dufresne@collabora.com, Sebastian Fricke , Yury Norov , Andy Shevchenko , Rasmus Villemoes Subject: [PATCH 3/6] bitops: bitmap helper to set variable length values Date: Wed, 13 Jul 2022 18:31:59 +0200 Message-Id: <20220713163201.136202-1-sebastian.fricke@collabora.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Add a new helper to set variable length values within a bitmap, that can overflow the borders of a single BITS_PER_LONG container. This function makes it easier to write values to hardware memory blobs that do not require alignment. Add tests to the lib/test_bitmap.c kselftest module to verify proper function. Signed-off-by: Sebastian Fricke --- include/linux/bitmap.h | 40 +++++++++++++++++++++++++++++++++++ lib/test_bitmap.c | 48 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+) diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 2e6cd5681040..9f8d635b70a9 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -76,6 +76,7 @@ struct device; * bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst * bitmap_get_value8(map, start) Get 8bit value from map at start * bitmap_set_value8(map, value, start) Set 8bit value to map at start + * bitmap_set_value(map, value, start, nbits) Set a variable length value to map at start * * Note, bitmap_zero() and bitmap_fill() operate over the region of * unsigned longs, that is, bits behind bitmap till the unsigned long @@ -573,6 +574,45 @@ static inline void bitmap_set_value8(unsigned long *map, unsigned long value, map[index] |= value << offset; } +/** + * bitmap_set_value - set a variable length value within a memory region + * @map: address to the bitmap memory region + * @value: the variable length value + * @start: bit offset of the value + * @length: Length of the value + */ +static inline void bitmap_set_value(unsigned long *map, unsigned long value, + unsigned long start, unsigned char length) +{ + size_t index = BIT_WORD(start); + unsigned long offset = start % BITS_PER_LONG; + int diff_to_max = 0; + + if (!length) + return; + + + if (length < BITS_PER_LONG) + value &= (BIT(length) - 1); + + while (length > 0) { + diff_to_max = BITS_PER_LONG - offset; + map[index] &= ~((BIT(length) - 1) << offset); + if (length > diff_to_max) { + unsigned long tmp = value & (BIT(diff_to_max) - 1); + + map[index] |= tmp << offset; + value >>= diff_to_max; + length -= diff_to_max; + index += 1; + offset = 0; + } else { + map[index] |= value << offset; + length = 0; + } + } +} + #endif /* __ASSEMBLY__ */ #endif /* __LINUX_BITMAP_H */ diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index d5923a640457..509317ad2f72 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -869,6 +869,53 @@ static void __init test_bitmap_print_buf(void) } } +struct test_bitmap_set_value_sample { + unsigned long value[2]; + unsigned char length[2]; + unsigned int offset[2]; + unsigned long expected[2][2]; + int amount; +}; + +static const struct test_bitmap_set_value_sample test_set[] __initconst = { + /* Check that multiple values can be chained up */ + { {10, 20}, {4, 5}, {0, 4}, {{10, 330}}, 2 }, + /* Check that a value can be set across two BITS_PER_LONG chunks */ + { {10, 6}, {4, 3}, {0, 63}, {{10, 10}, {0, 3}}, 2 }, + /* Set a value with length shorter than the given length */ + { {3, 6}, {4, 10}, {0, 4}, {{3, 99}}, 1 }, + /* Set a value with length longer than the given length */ + { {15}, {2}, {0}, {{3}}, 1 }, + /* Check that values are properly overwritten */ + { {15, 12}, {4, 4}, {0, 2}, {{15, 51}}, 2 }, + /* Check that a set without a length doesn't change anything */ + { {10}, {0}, {0}, {{0}}, 1 }, +}; + +static void __init test_bitmap_set_value(void) +{ + int i, j, k; + int correct_tests = 0; + + for (i = 0; i < ARRAY_SIZE(test_set); i++) { + const struct test_bitmap_set_value_sample *t = &test_set[i]; + int test_correct = 1; + DECLARE_BITMAP(map, BITS_PER_LONG * 2); + + bitmap_zero(map, BITS_PER_LONG * 2); + for (j = 0; j < t->amount; j++) { + bitmap_set_value(map, t->value[j], t->offset[j], t->length[j]); + for (k = 0; k < 2; k++) { + if (expect_eq_uint(map[k], t->expected[k][j])) + test_correct = 0; + } + } + if (test_correct) + correct_tests += 1; + } + pr_err("set_value: %d/%ld tests correct\n", correct_tests, ARRAY_SIZE(test_set)); +} + static void __init selftest(void) { test_zero_clear(); @@ -884,6 +931,7 @@ static void __init selftest(void) test_for_each_set_clump8(); test_bitmap_cut(); test_bitmap_print_buf(); + test_bitmap_set_value(); } KSTM_MODULE_LOADERS(test_bitmap);