From patchwork Wed Oct 29 10:45:27 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aisheng Dong X-Patchwork-Id: 5187101 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id ACD959F349 for ; Wed, 29 Oct 2014 11:56:06 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DCC1020254 for ; Wed, 29 Oct 2014 11:56:04 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 48D9F2022D for ; Wed, 29 Oct 2014 11:56:00 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XjRoV-0002xM-QZ; Wed, 29 Oct 2014 11:53:19 +0000 Received: from mail-bl2on0753.outbound.protection.outlook.com ([2a01:111:f400:fc09::753] helo=na01-bl2-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XjRnS-0002Pm-BL for linux-arm-kernel@lists.infradead.org; Wed, 29 Oct 2014 11:52:15 +0000 Received: from DM2PR03MB333.namprd03.prod.outlook.com (10.141.54.16) by DM2PR03MB558.namprd03.prod.outlook.com (10.141.83.155) with Microsoft SMTP Server (TLS) id 15.1.6.9; Wed, 29 Oct 2014 11:51:51 +0000 Received: from BY2PR03CA009.namprd03.prod.outlook.com (10.255.93.26) by DM2PR03MB333.namprd03.prod.outlook.com (10.141.54.16) with Microsoft SMTP Server (TLS) id 15.1.11.9; Wed, 29 Oct 2014 11:51:50 +0000 Received: from BL2FFO11FD008.protection.gbl (10.255.93.4) by BY2PR03CA009.outlook.office365.com (10.255.93.26) with Microsoft SMTP Server (TLS) id 15.1.6.9 via Frontend Transport; Wed, 29 Oct 2014 11:51:49 +0000 Received: from tx30smr01.am.freescale.net (192.88.168.50) by BL2FFO11FD008.mail.protection.outlook.com (10.173.161.4) with Microsoft SMTP Server (TLS) id 15.0.1049.20 via Frontend Transport; Wed, 29 Oct 2014 11:51:49 +0000 Received: from shlinux2.ap.freescale.net (shlinux2.ap.freescale.net [10.192.224.44]) by tx30smr01.am.freescale.net (8.14.3/8.14.0) with ESMTP id s9TBpOFQ024329; Wed, 29 Oct 2014 04:51:44 -0700 From: Dong Aisheng To: Subject: [PATCH 7/7] can: m_can: workaround for transmit data less than 4 bytes Date: Wed, 29 Oct 2014 18:45:27 +0800 Message-ID: <1414579527-31100-7-git-send-email-b29396@freescale.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1414579527-31100-1-git-send-email-b29396@freescale.com> References: <1414579527-31100-1-git-send-email-b29396@freescale.com> X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:192.88.168.50; CTRY:US; IPV:CAL; IPV:NLI; EFV:NLI; SFV:NSPM; SFS:(10019020)(6009001)(189002)(199003)(105606002)(106466001)(2351001)(107046002)(229853001)(104166001)(95666004)(31966008)(4396001)(50226001)(99396003)(76482002)(87286001)(97736003)(120916001)(21056001)(50986999)(76176999)(92726001)(92566001)(93916002)(575784001)(50466002)(48376002)(46102003)(84676001)(64706001)(20776003)(47776003)(89996001)(68736004)(6806004)(44976005)(19580395003)(19580405001)(80022003)(85852003)(33646002)(26826002)(85306004)(110136001)(104016003)(88136002)(36756003)(77156001)(102836001)(87936001)(62966002)(42262002); DIR:OUT; SFP:1102; SCL:1; SRVR:DM2PR03MB333; H:tx30smr01.am.freescale.net; FPR:; MLV:ovrnspm; PTR:InfoDomainNonexistent; MX:1; A:1; LANG:en; MIME-Version: 1.0 X-Microsoft-Antispam: UriScan:;UriScan:; X-Microsoft-Antispam: BCL:0;PCL:0;RULEID:;SRVR:DM2PR03MB333; X-Forefront-PRVS: 03793408BA Received-SPF: Fail (protection.outlook.com: domain of freescale.com does not designate 192.88.168.50 as permitted sender) receiver=protection.outlook.com; client-ip=192.88.168.50; helo=tx30smr01.am.freescale.net; Authentication-Results: spf=fail (sender IP is 192.88.168.50) smtp.mailfrom=Aisheng.Dong@freescale.com; X-Microsoft-Antispam: BCL:0;PCL:0;RULEID:;SRVR:DM2PR03MB558; X-OriginatorOrg: freescale.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141029_045214_683707_F337EE92 X-CRM114-Status: UNSURE ( 8.83 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.0 (/) Cc: netdev@vger.kernel.org, varkabhadram@gmail.com, mkl@pengutronix.de, linux-arm-kernel@lists.infradead.org, socketcan@hartkopp.net, b29396@freescale.com, wg@grandegger.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We meet an IC issue that we have to write the full 8 bytes (whatever value for the second word) in Message RAM to avoid bit error for transmit data less than 4 bytes. Without the workaround, we can easily see the following errors: root@imx6qdlsolo:~# ip link set can0 up type can bitrate 1000000 [ 66.882520] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready root@imx6qdlsolo:~# cansend can0 123#112233 [ 66.935640] m_can 20e8000.can can0: Bit Error Uncorrected Signed-off-by: Dong Aisheng --- drivers/net/can/m_can/m_can.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 219e0e3..f2d9ebe 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1058,10 +1058,19 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb, m_can_fifo_write(priv, 0, M_CAN_FIFO_ID, id); m_can_fifo_write(priv, 0, M_CAN_FIFO_DLC, can_len2dlc(cf->len) << 16); - for (i = 0; i < cf->len; i += 4) + for (i = 0; i < cf->len; i += 4) { m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(i / 4), *(u32 *)(cf->data + i)); + /* FIXME: we meet an IC issue that we have to write the full 8 + * bytes (whatever value for the second word) in Message RAM to + * avoid bit error for transmit data less than 4 bytes + */ + if (cf->len <= 4) + m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(i / 4 + 1), + 0x0); + } + can_put_echo_skb(skb, dev, 0); if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {