From mboxrd@z Thu Jan 1 00:00:00 1970 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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 5751DC43381 for ; Sat, 30 Mar 2019 19:23:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D3142183F for ; Sat, 30 Mar 2019 19:23:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553973800; bh=LYPJiv1ytYAk1WQVs3rZwk5iIjkFdRVJE6lB13HBl9o=; h=Subject:To:Cc:From:Date:List-ID:From; b=zBClXnJWNaOry5+Jy5batMVX0wYab+KB9Z0oaxrdCWhhuLkKdonO6/3qf9NiTcwcW DmAg18O+FK9KV02rlsL32HTPHoKz906ikDp8nT099DL7wf8QXUTMB/yE9DEk8KHemu meJCzk7QDxg2ibNhChjbyjUgDpV6qOFj9FDUodDw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730852AbfC3TXT (ORCPT ); Sat, 30 Mar 2019 15:23:19 -0400 Received: from out4-smtp.messagingengine.com ([66.111.4.28]:37163 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730542AbfC3TXT (ORCPT ); Sat, 30 Mar 2019 15:23:19 -0400 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id 02A2420ED2; Sat, 30 Mar 2019 15:23:19 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute6.internal (MEProxy); Sat, 30 Mar 2019 15:23:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=SUDHnd gpH2K9mSGy/4bSvAKLQwPFD4HXL11p1YSg3us=; b=waGx4Y8jVRJ/CT25CE8hbf +FFgkA4VZ8AlE5G7ZD2w9wIWDKnxn57tdJrJbHwHzlQjX7CrH0X8t8bgkesimLaf b9A0mRZqmkseMxMC4sPV4fRph26efU2HoSe91gJJ3AqI89a+788y5bX5nXVcIUbp UTMUp/62sNJyR2G7F2RgVgXJ4ra9kgiFSP0JryEEqm5IFPA794gSOCmfGJR3+dJA BiIjH7eopXupe1iHt8A7yqwX2iMzvD1qZ1QCAZWDg+ov6izVzFO9ZpprguTh/wnz ksqs3cTWwQwG9JwlNbxInsjNjFuCdNOaoJ/0ZgEm64jyuUxNMYE7XyYYJTe4Asyw == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedutddrkeelgdduvdehucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecukfhppeeivddrudduledrudeiiedrleenucfrrghrrghmpehmrghilhhfrhhomh epghhrvghgsehkrhhorghhrdgtohhmnecuvehluhhsthgvrhfuihiivgepge X-ME-Proxy: Received: from localhost (unknown [62.119.166.9]) by mail.messagingengine.com (Postfix) with ESMTPA id EF7DEE442F; Sat, 30 Mar 2019 15:23:17 -0400 (EDT) Subject: FAILED: patch "[PATCH] tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is" failed to apply to 4.9-stable tree To: razvan.stefanescu@microchip.com, gregkh@linuxfoundation.org, richard.genoud@gmail.com, stable@vger.kernel.org Cc: From: Date: Sat, 30 Mar 2019 20:22:22 +0100 Message-ID: <155397374235122@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 69646d7a3689fbe1a65ae90397d22ac3f1b8d40f Mon Sep 17 00:00:00 2001 From: Razvan Stefanescu Date: Tue, 19 Mar 2019 15:20:35 +0200 Subject: [PATCH] tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped In half-duplex operation, RX should be started after TX completes. If DMA is used, there is a case when the DMA transfer completes but the TX FIFO is not emptied, so the RX cannot be restarted just yet. Use a boolean variable to store this state and rearm TX interrupt mask to be signaled again that the transfer finished. In interrupt transmit handler this variable is used to start RX. A warning message is generated if RX is activated before TX fifo is cleared. Fixes: b389f173aaa1 ("tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done") Signed-off-by: Razvan Stefanescu Acked-by: Richard Genoud Cc: stable Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 55ca3416113f..0b4f36905321 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -166,6 +166,8 @@ struct atmel_uart_port { unsigned int pending_status; spinlock_t lock_suspended; + bool hd_start_rx; /* can start RX during half-duplex operation */ + /* ISO7816 */ unsigned int fidi_min; unsigned int fidi_max; @@ -933,8 +935,13 @@ static void atmel_complete_tx_dma(void *arg) if (!uart_circ_empty(xmit)) atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx); else if (atmel_uart_is_half_duplex(port)) { - /* DMA done, stop TX, start RX for RS485 */ - atmel_start_rx(port); + /* + * DMA done, re-enable TXEMPTY and signal that we can stop + * TX and start RX for RS485 + */ + atmel_port->hd_start_rx = true; + atmel_uart_writel(port, ATMEL_US_IER, + atmel_port->tx_done_mask); } spin_unlock_irqrestore(&port->lock, flags); @@ -1382,9 +1389,20 @@ atmel_handle_transmit(struct uart_port *port, unsigned int pending) struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (pending & atmel_port->tx_done_mask) { - /* Either PDC or interrupt transmission */ atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask); + + /* Start RX if flag was set and FIFO is empty */ + if (atmel_port->hd_start_rx) { + if (!(atmel_uart_readl(port, ATMEL_US_CSR) + & ATMEL_US_TXEMPTY)) + dev_warn(port->dev, "Should start RX, but TX fifo is not empty\n"); + + atmel_port->hd_start_rx = false; + atmel_start_rx(port); + return; + } + atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx); } }