From patchwork Mon Oct 19 07:39:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dylan Hung X-Patchwork-Id: 1384018 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4CF7v23xgQz9sS8 for ; Mon, 19 Oct 2020 18:39:42 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=aspeedtech.com Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4CF7v21rZtzDqbF for ; Mon, 19 Oct 2020 18:39:42 +1100 (AEDT) X-Original-To: linux-aspeed@lists.ozlabs.org Delivered-To: linux-aspeed@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=fail (SPF fail - not authorized) smtp.mailfrom=aspeedtech.com (client-ip=211.20.114.71; helo=twspam01.aspeedtech.com; envelope-from=dylan_hung@aspeedtech.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=aspeedtech.com Received: from twspam01.aspeedtech.com (twspam01.aspeedtech.com [211.20.114.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4CF7tv71NvzDqPM for ; Mon, 19 Oct 2020 18:39:33 +1100 (AEDT) Received: from mail.aspeedtech.com ([192.168.0.24]) by twspam01.aspeedtech.com with ESMTP id 09J7anxl039002; Mon, 19 Oct 2020 15:36:49 +0800 (GMT-8) (envelope-from dylan_hung@aspeedtech.com) Received: from localhost.localdomain (192.168.10.9) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 19 Oct 2020 15:39:25 +0800 From: Dylan Hung To: , , , , , , Subject: [PATCH] net: ftgmac100: Fix missing TX-poll issue Date: Mon, 19 Oct 2020 15:39:08 +0800 Message-ID: <20201019073908.32262-1-dylan_hung@aspeedtech.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [192.168.10.9] X-ClientProxiedBy: TWMBX02.aspeed.com (192.168.0.24) To TWMBX02.aspeed.com (192.168.0.24) X-DNSRBL: X-MAIL: twspam01.aspeedtech.com 09J7anxl039002 X-BeenThere: linux-aspeed@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux ASPEED SoC development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: BMC-SW@aspeedtech.com Errors-To: linux-aspeed-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linux-aspeed" The cpu accesses the register and the memory via different bus/path on aspeed soc. So we can not guarantee that the tx-poll command (register access) is always behind the tx descriptor (memory). In other words, the HW may start working even the data is not yet ready. By adding a dummy read after the last data write, we can ensure the data are pushed to the memory, then guarantee the processing sequence Signed-off-by: Dylan Hung --- drivers/net/ethernet/faraday/ftgmac100.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c index 00024dd41147..9a99a87f29f3 100644 --- a/drivers/net/ethernet/faraday/ftgmac100.c +++ b/drivers/net/ethernet/faraday/ftgmac100.c @@ -804,7 +804,8 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb, * before setting the OWN bit on the first descriptor. */ dma_wmb(); - first->txdes0 = cpu_to_le32(f_ctl_stat); + WRITE_ONCE(first->txdes0, cpu_to_le32(f_ctl_stat)); + READ_ONCE(first->txdes0); /* Update next TX pointer */ priv->tx_pointer = pointer;