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{ "id": 2224352, "url": "http://patchwork.ozlabs.org/api/1.2/covers/2224352/?format=api", "web_url": "http://patchwork.ozlabs.org/project/sparclinux/cover/20260417102423.40984-1-john.ogness@linutronix.de/", "project": { "id": 10, "url": "http://patchwork.ozlabs.org/api/1.2/projects/10/?format=api", "name": "Linux SPARC Development ", "link_name": "sparclinux", "list_id": "sparclinux.vger.kernel.org", "list_email": "sparclinux@vger.kernel.org", "web_url": null, "scm_url": null, "webscm_url": null, "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260417102423.40984-1-john.ogness@linutronix.de>", "list_archive_url": null, "date": "2026-04-17T10:24:13", "name": "[tty,v3,0/6] 8250: Add console flow control", "submitter": { "id": 207, "url": "http://patchwork.ozlabs.org/api/1.2/people/207/?format=api", "name": "John Ogness", "email": "john.ogness@linutronix.de" }, "mbox": "http://patchwork.ozlabs.org/project/sparclinux/cover/20260417102423.40984-1-john.ogness@linutronix.de/mbox/", "series": [ { "id": 500302, "url": "http://patchwork.ozlabs.org/api/1.2/series/500302/?format=api", "web_url": "http://patchwork.ozlabs.org/project/sparclinux/list/?series=500302", "date": "2026-04-17T10:24:15", "name": "8250: Add console flow control", "version": 3, "mbox": "http://patchwork.ozlabs.org/series/500302/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2224352/comments/", "headers": { "Return-Path": "\n <SRS0=ita4=CQ=vger.kernel.org=sparclinux+bounces-6722-patchwork-incoming=ozlabs.org@ozlabs.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "sparclinux@vger.kernel.org" ], "Delivered-To": [ "patchwork-incoming@legolas.ozlabs.org", "patchwork-incoming@ozlabs.org" ], "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256\n header.s=2020 header.b=sVYorXF1;\n\tdkim=pass header.d=linutronix.de header.i=@linutronix.de\n header.a=ed25519-sha256 header.s=2020e header.b=Oeidtc+T;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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arc=none smtp.client-ip=193.142.43.55" ], "From": "John Ogness <john.ogness@linutronix.de>", "DKIM-Signature": [ "v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de;\n\ts=2020; t=1776421464;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\t to:to:cc:cc:mime-version:mime-version:\n\t content-transfer-encoding:content-transfer-encoding;\n\tbh=sT89vdNi1tSkKoKmWLBjgb2FXe2g6tBONEq1VPMnDwU=;\n\tb=sVYorXF1yw9POGgD1GvSzasC9FsBfzUA53utmab5zqdwZK09rO+r3uPwzEpQyEYAeLf3yR\n\teXDLqT33zCItMiS7JxvQMSHMUET4Wkx6Pewb1RLEVX2rKls19HyK/3ogBxzsN74VdYmftR\n\tNU6p4B9WLYGVCqqWZTb0epZ+mq839WiX9ptIUN4hO6NxdBMyxxo5lOmaE8Jy3JdbFg+l33\n\t/IVaLuMEG8/+iBh517EXEgMO0FOIwt4yJsjeHhtbRAycsMG2pBGbNGd5zRIurDQleytEX8\n\tXt+HuK1GwBj+5Ob1HSUJyNzbk6cjt7ukNgndGos3sRiPv6fBGzCq0L8Az9hiBA==", "v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de;\n\ts=2020e; t=1776421464;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\t to:to:cc:cc:mime-version:mime-version:\n\t content-transfer-encoding:content-transfer-encoding;\n\tbh=sT89vdNi1tSkKoKmWLBjgb2FXe2g6tBONEq1VPMnDwU=;\n\tb=Oeidtc+T3Qo4Nmp1Qb9eB2oio0COfltJZ2ZdzoWqP+QM7mOtmHpofaaeXCHCAWtMukIEmu\n\tXA3ALkr512woVkBQ==" ], "To": "\"Greg Kroah-Hartman\" <gregkh@linuxfoundation.org>,\n\tJiri Slaby <jirislaby@kernel.org>", "Cc": "linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,\n Krzysztof Kozlowski <krzk@kernel.org>, Alim Akhtar <alim.akhtar@samsung.com>,\n \"David S. Miller\" <davem@davemloft.net>,\n =?utf-8?q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>,\n Andy Shevchenko <andriy.shevchenko@linux.intel.com>,\n Thomas Fourier <fourier.thomas@gmail.com>, Kees Cook <kees@kernel.org>,\n linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org,\n sparclinux@vger.kernel.org, Biju Das <biju.das.jz@bp.renesas.com>,\n Geert Uytterhoeven <geert+renesas@glider.be>,\n Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,\n Wolfram Sang <wsa+renesas@sang-engineering.com>,\n Thierry Bultel <thierry.bultel.yh@bp.renesas.com>,\n Thomas Gleixner <tglx@kernel.org>,\n Osama Abdelkader <osama.abdelkader@gmail.com>,\n Xin Zhao <jackzxcui1989@163.com>, Ingo Molnar <mingo@kernel.org>,\n Andy Shevchenko <andy.shevchenko@gmail.com>,\n Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>,\n Gerhard Engleder <eg@keba.com>, Lukas Wunner <lukas@wunner.de>,\n \"Dr. David Alan Gilbert\" <linux@treblig.org>,\n Joseph Tilahun <jtilahun@astranis.com>", "Subject": "[PATCH tty v3 0/6] 8250: Add console flow control", "Date": "Fri, 17 Apr 2026 12:30:13 +0206", "Message-ID": "<20260417102423.40984-1-john.ogness@linutronix.de>", "Precedence": "bulk", "X-Mailing-List": "sparclinux@vger.kernel.org", "List-Id": "<sparclinux.vger.kernel.org>", "List-Subscribe": "<mailto:sparclinux+subscribe@vger.kernel.org>", "List-Unsubscribe": "<mailto:sparclinux+unsubscribe@vger.kernel.org>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Spam-Status": "No, score=-0.6 required=5.0 tests=ARC_SIGNED,ARC_VALID,\n\tDKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DMARC_PASS,\n\tHEADER_FROM_DIFFERENT_DOMAINS,INVALID_DATE_TZ_ABSURD,\n\tMAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=disabled\n\tversion=4.0.1", "X-Spam-Checker-Version": "SpamAssassin 4.0.1 (2024-03-25) on gandalf.ozlabs.org" }, "content": "Hi,\n\nThis is v3 of a series to implement console flow control for the\n8250 serial driver. v2 is here [0].\n\nThe 8250 driver already has code in place to support console flow\ncontrol. However, there is no way to activate it and it is\nincomplete. This series provides the necessary missing pieces while\nattempting to be as conservative as possible, so as not to introduce\nany side effects into the many 8250 variants or other non-8250 serial\ndrivers.\n\nNote that as of v3 I am now deprecating UPF_CONS_FLOW in favor of a\nseparate boolean field. In the commit message (patch 1) I explain my\nreasoning for this decision.\n\nFor patch 2 I used the following Coccinelle script to perform the\nmodifications...\n\n===== BEGIN cons_flow.cocci =====\n// SPDX-License-Identifier: GPL-2.0-only\n// Options: --all-includes\n\nvirtual patch\n\n@r1@\ntype T1;\nidentifier U;\n@@\n\nT1 {\n ...\n struct uart_port U;\n ...\n};\n\n@r2@\nr1.T1 *E;\n@@\n\n- (E->port.flags & UPF_CONS_FLOW)\n+ uart_get_cons_flow(&E->port)\n\n@r3@\nstruct uart_port *U;\n@@\n\n- (U->flags & UPF_CONS_FLOW)\n+ uart_get_cons_flow(U)\n\n@r4@\nstruct uart_port *U;\n@@\n\n- U->flags |= UPF_CONS_FLOW\n+ uart_set_cons_flow(U, true)\n===== END cons_flow.cocci =====\n\nChanges since v2:\n\n- Deprecate UPF_CONS_FLOW. Provide separate boolean with wrappers as\n alternative.\n\n- Update all UPF_CONS_FLOW users to new cons_flow wrappers.\n\n- Use irqsave variant of spin lock for status update.\n\n- When 8250 console flow control is not specified, clear the policy.\n\nChanges since v1:\n\n- Prepend a patch to perform an extra LSR wait after CTS assertion if\n the initial LSR wait timed out.\n\n- Close a window in serial8250_register_8250_port() where console\n flow control was briefly disabled.\n\n- Add port lock synchronization to the port->status RMW update in\n uart_set_options().\n\nJohn Ogness\n\n[0] https://lore.kernel.org/lkml/20260410144949.16581-1-john.ogness@linutronix.de\n\nJohn Ogness (6):\n serial: core: Add dedicated uart_port field for console flow\n serial: Replace driver usage of UPF_CONS_FLOW\n serial: sh-sci: Avoid deprecated UPF_CONS_FLOW\n serial: 8250: Set cons_flow on port registration\n serial: 8250: Check LSR timeout on console flow control\n serial: 8250: Add support for console flow control\n\n drivers/tty/serial/8250/8250_core.c | 6 ++++++\n drivers/tty/serial/8250/8250_port.c | 21 +++++++++++++++++----\n drivers/tty/serial/bcm63xx_uart.c | 2 +-\n drivers/tty/serial/omap-serial.c | 2 +-\n drivers/tty/serial/pch_uart.c | 2 +-\n drivers/tty/serial/pxa.c | 2 +-\n drivers/tty/serial/samsung_tty.c | 8 ++++----\n drivers/tty/serial/serial_core.c | 21 ++++++++++++++++++++-\n drivers/tty/serial/serial_txx9.c | 4 ++--\n drivers/tty/serial/sh-sci.c | 5 ++++-\n drivers/tty/serial/sunsu.c | 2 +-\n include/linux/serial_core.h | 20 ++++++++++++++++++++\n 12 files changed, 78 insertions(+), 17 deletions(-)\n\n\nbase-commit: a1a81aef99e853dec84241d701fbf587d713eb5b" }