From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Thu, 18 Sep 2025 08:01:42 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uz7iA-004Ldt-19 for lore@lore.pengutronix.de; Thu, 18 Sep 2025 08:01:42 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1uz7i9-0007JA-MZ for lore@pengutronix.de; Thu, 18 Sep 2025 08:01:42 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:To:From:Reply-To:Cc:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=tAOGydkTKbV9PTq+9qIg6TRHN5GumJSEvg9vsrPhS/o=; b=F8bZZ6Ch5NRF+ik3P8T+vMfdWm 6MavT2T+TtIxFKnwLFwtVp6MidWF1/2lBPWZlSIsFuWfXIr3evEtLaiLnjKz0JF83VFvflwDUNK2f wm7U/QCsgNSQRK62+02aX7mAgrcugYT5XM1W9+V+tryM0odbHXsI+hDQ6TdgYpbk/3apxTWo0Q0mn 3n7WAwUu+hVik2PM4xnUuSzJwvRHUGBvOCSfWXOoNyvtLGDuGiy3Uh+Hf6q23JTqhwTf4rl8d5UwF FKPsodt0W8n2XC3zu0HzWzUTJxa3LUwpmlkOKKNFUH6evx4R8NGbazCngLbEN9fiz1swcaa5mlIAv RdJIN7LQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uz7hS-0000000GN1E-32Y7; Thu, 18 Sep 2025 06:00:58 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uz7hP-0000000GN0D-0wLG for barebox@lists.infradead.org; Thu, 18 Sep 2025 06:00:56 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1uz7hN-0006zD-5j; Thu, 18 Sep 2025 08:00:53 +0200 Received: from dude02.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::28]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uz7hM-001sfW-3D; Thu, 18 Sep 2025 08:00:53 +0200 Received: from localhost ([::1] helo=dude02.red.stw.pengutronix.de) by dude02.red.stw.pengutronix.de with esmtp (Exim 4.98.2) (envelope-from ) id 1uz7hM-0000000DCXK-3ibg; Thu, 18 Sep 2025 08:00:52 +0200 From: Sascha Hauer To: Barebox List Date: Thu, 18 Sep 2025 08:00:52 +0200 Message-ID: <20250918060052.3146447-1-s.hauer@pengutronix.de> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250917_230055_261141_35368829 X-CRM114-Status: GOOD ( 13.88 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.4 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_LOW,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH] crc-itu-t: fix typo in CRC ITU-T polynomial comment X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Based on Linux commit 77991645952c2 ("crc-itu-t: fix typo in CRC ITU-T polynomial comment"): | The code comment says that the polynomial is x^16 + x^12 + x^15 + 1, but | the correct polynomial is x^16 + x^12 + x^5 + 1. Quoting from page 2 in | the ITU-T V.41 specification [1]: | | 2 Encoding and checking process | | The service bits and information bits, taken in conjunction, | correspond to the coefficients of a message polynomial having terms | from x^(n-1) (n = total number of bits in a block or sequence) down to | x^16. This polynomial is divided, modulo 2, by the generating | polynomial x^16 + x^12 + x^5 + 1. | | The hex (truncated) polynomial 0x1021 and CRC code implementation are | correct, however. | | [1] https://www.itu.int/rec/T-REC-V.41-198811-I/en | | Signed-off-by: Roger Knecht | Acked-by: Randy Dunlap | Signed-off-by: Jason A. Donenfeld Signed-off-by: Sascha Hauer --- crypto/crc-itu-t.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/crypto/crc-itu-t.c b/crypto/crc-itu-t.c index 837a6464b6..fcbed706a9 100644 --- a/crypto/crc-itu-t.c +++ b/crypto/crc-itu-t.c @@ -12,7 +12,7 @@ static u16 crc_itu_t_table[256]; /* * Implements the standard CRC ITU-T V.41: * Width 16 - * Poly 0x1021 (x^16 + x^12 + x^15 + 1) + * Poly 0x1021 (x^16 + x^12 + x^5 + 1) * Init 0 */ static u16 crc_itu_t_byte(u16 crc, const u8 data) -- 2.47.3