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 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 ECD43C43381 for ; Sat, 30 Mar 2019 19:23:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C174E2183F for ; Sat, 30 Mar 2019 19:23:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553973807; bh=pT7JrHyPh+VPRx38K7VMU3ItseHPiIKmyAvA3NeRXyk=; h=Subject:To:Cc:From:Date:List-ID:From; b=sk8DCzycLSiRXgRteI7/tDZWXJiFWSt9UhvfjWzu8DhMvYdrJKNcmbybkY/N2on4g ZT6bd83sxy9is2XImZDXQSpNhHTpmchovHDwyvBytiDvpYZqONl0Y+1SL73zvQbYXR 6K3mUchBg4xfYlfCw9qzBNy4V8RA0+Cm9xfSp/WI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730875AbfC3TX1 (ORCPT ); Sat, 30 Mar 2019 15:23:27 -0400 Received: from out4-smtp.messagingengine.com ([66.111.4.28]:51271 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730542AbfC3TX1 (ORCPT ); Sat, 30 Mar 2019 15:23:27 -0400 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id E6D8521A09; Sat, 30 Mar 2019 15:23:25 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute6.internal (MEProxy); Sat, 30 Mar 2019 15:23:25 -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=qZTkeH l9a25/otTbPpDaooIs23t7YCtpGb6H7FIoNaw=; b=egGkHdexoVkkMkngZhlXg2 RY3wJ0AQtgJUVQaWEohVWExAMBcKm3E37r+8snI/ROWaFtDzluQ/LdPKSKgYTWXe 6k1j0wJmkpc0yr8ePnaoPxFp15bDh6TzCnn1WchwYzUCLxUTA4sxvHxbjrwxMP0H hBXlPhXj04O2tD4v5NXs62gq8/bKZMsydf+0Q6gchVSwuA5eIZuNwEhH5bSkJb8W g7dVgQhNcOPru1b4XY26dOmDumtnQz9pkbn5uiDqA5GsPqfjukBlPpbkr3+0Lvqa /auwFBA84xTJiYQ7b3yjlzrx7wIC6z2b8//3Rsk16WG9OU05pX7QQJfyJ3SRGAow == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedutddrkeelgdduvdehucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecukfhppeeivddrudduledrudeiiedrleenucfrrghrrghmpehmrghilhhfrhhomh epghhrvghgsehkrhhorghhrdgtohhmnecuvehluhhsthgvrhfuihiivgepie X-ME-Proxy: Received: from localhost (unknown [62.119.166.9]) by mail.messagingengine.com (Postfix) with ESMTPA id 0289FE442F; Sat, 30 Mar 2019 15:23:24 -0400 (EDT) Subject: FAILED: patch "[PATCH] tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is" failed to apply to 4.4-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 20:22:23 +0100 Message-ID: <1553973743139174@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 4.4-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); } }