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[2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id x10-20020a50d60a000000b0055a6b9e4f8esi6782206edi.163.2024.02.01.02.57.01 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Feb 2024 02:57:01 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-47991-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=Jm3hRClr; arc=pass (i=1 dkim=pass dkdomain=kernel.org); spf=pass (google.com: domain of linux-kernel+bounces-47991-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-47991-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id E4B801F261ED for ; Thu, 1 Feb 2024 10:56:21 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 902BE15CD6A; Thu, 1 Feb 2024 10:56:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Jm3hRClr" Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D2411A28; Thu, 1 Feb 2024 10:56:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706784961; cv=none; b=ONW8I8IHx5s4xf5obDO1GpCgre5ZFgejn3y1fV/ESe6uHrlgjOMBCrC1d46+JYmEbOckvifYobD1nfAcg2zfcn8nH7YOIn13jyfx4+GrXrPH/luMwViVGDbSGmxZUPcXTcRcDP+mxNxcGzDnKJO3JFg2lFoCYoqZqSwIxomi550= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706784961; c=relaxed/simple; bh=8xZUfd2otuKI9fuM5EHBBR4C7/ZhTByLG9LSNa2l4UE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=dnp1iLaxQKdVZ1RTel6WK1AJwr8YjpFuuw92jbbLC/STxludBkvh1w99lzcgTMcqmjYJdnd7a8dfyA02S2UM5R6GLW9e8VEr+h90SeDaCi9AEq1sBOMy1Gb8bd+27Qe1jvHDxI/9Aorb7PYlSgcYwLLoEiIPXH/sa1sNkdu4C2g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Jm3hRClr; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0520FC433F1; Thu, 1 Feb 2024 10:55:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706784961; bh=8xZUfd2otuKI9fuM5EHBBR4C7/ZhTByLG9LSNa2l4UE=; h=From:To:Cc:Subject:Date:From; b=Jm3hRClreZUu5y+yJN+HH+aXnnZ8EdHuJI90VKlKqEoaAUd3jsbQ9klI6ewfQv3+R +/1Ps+qfOXne2oYtGCEkXoaXQfD8v08UtwGIji4D5MTgBDIcoQe9SrmxXPHXox1HBj /gbKg5qnvHhZN75Gmk2d/+VLPAUXmaJInF5/I6iuH/DBW3HreL1XIpNXWNWOTlQGzi flUYes2xnqYKp2uKU6OLz/S4FjDmyHxDzjT0XnNEExQCkfSKRxSc/ZGw5Y+4gi2cHP stsp/qGv9AYzDkuPyrwBSXWwo/cTF9yepX5uJztvSBJyn3P5Hbi9ufLqAghiTx8uhP GEQvCqZ6jRhrg== From: "Jiri Slaby (SUSE)" To: gregkh@linuxfoundation.org Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, "Jiri Slaby (SUSE)" , Emil Kronborg Subject: [PATCH v2 1/2] serial: core: introduce uart_port_tx_flags() Date: Thu, 1 Feb 2024 11:55:56 +0100 Message-ID: <20240201105557.28043-1-jirislaby@kernel.org> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1789693811012066368 X-GMAIL-MSGID: 1789693811012066368 And an enum with a flag: UART_TX_NOSTOP. To NOT call __port->ops->stop_tx() when the circular buffer is empty. mxs-uart needs this (see the next patch). Signed-off-by: Jiri Slaby (SUSE) Cc: Emil Kronborg Tested-by: Emil Kronborg --- Notes: [v2] fix/invert the condition include/linux/serial_core.h | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 536b2581d3e2..55b1f3ba48ac 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -748,8 +748,17 @@ struct uart_driver { void uart_write_wakeup(struct uart_port *port); -#define __uart_port_tx(uport, ch, tx_ready, put_char, tx_done, for_test, \ - for_post) \ +/** + * enum UART_TX_FLAGS -- flags for uart_port_tx_flags() + * + * @UART_TX_NOSTOP: don't call port->ops->stop_tx() on empty buffer + */ +enum UART_TX_FLAGS { + UART_TX_NOSTOP = BIT(0), +}; + +#define __uart_port_tx(uport, ch, flags, tx_ready, put_char, tx_done, \ + for_test, for_post) \ ({ \ struct uart_port *__port = (uport); \ struct circ_buf *xmit = &__port->state->xmit; \ @@ -777,7 +786,7 @@ void uart_write_wakeup(struct uart_port *port); if (pending < WAKEUP_CHARS) { \ uart_write_wakeup(__port); \ \ - if (pending == 0) \ + if (!((flags) & UART_TX_NOSTOP) && pending == 0) \ __port->ops->stop_tx(__port); \ } \ \ @@ -812,7 +821,7 @@ void uart_write_wakeup(struct uart_port *port); */ #define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \ unsigned int __count = (count); \ - __uart_port_tx(port, ch, tx_ready, put_char, tx_done, __count, \ + __uart_port_tx(port, ch, 0, tx_ready, put_char, tx_done, __count, \ __count--); \ }) @@ -826,8 +835,21 @@ void uart_write_wakeup(struct uart_port *port); * See uart_port_tx_limited() for more details. */ #define uart_port_tx(port, ch, tx_ready, put_char) \ - __uart_port_tx(port, ch, tx_ready, put_char, ({}), true, ({})) + __uart_port_tx(port, ch, 0, tx_ready, put_char, ({}), true, ({})) + +/** + * uart_port_tx_flags -- transmit helper for uart_port with flags + * @port: uart port + * @ch: variable to store a character to be written to the HW + * @flags: %UART_TX_NOSTOP or similar + * @tx_ready: can HW accept more data function + * @put_char: function to write a character + * + * See uart_port_tx_limited() for more details. + */ +#define uart_port_tx_flags(port, ch, flags, tx_ready, put_char) \ + __uart_port_tx(port, ch, flags, tx_ready, put_char, ({}), true, ({})) /* * Baud rate helpers. */ From patchwork Thu Feb 1 10:55:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Slaby X-Patchwork-Id: 195245 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:2719:b0:106:209c:c626 with SMTP id hl25csp72984dyb; Thu, 1 Feb 2024 03:11:20 -0800 (PST) X-Google-Smtp-Source: AGHT+IHTXusmp/bG9m5Za0uG7YBOryxqqL7YoGTx15eYHl/C1pglBo0nIrxXo20ae2Fc4hOwgujJ X-Received: by 2002:a17:90a:e50e:b0:290:6895:aff6 with SMTP id t14-20020a17090ae50e00b002906895aff6mr3821697pjy.48.1706785880241; Thu, 01 Feb 2024 03:11:20 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1706785880; cv=pass; d=google.com; s=arc-20160816; b=X8D1B92bjGlbCmirwN0uOtmCZgcwp0EmBemgF9SCIRWE8OjpwQTQMn7xFAVUOcsIdQ XZX705XEPlX4KFW+pfqiwY5W3VdWOqN7R9GnD8utsnTj/2m5RrlCk9VYME2Mz0sX1qXE nmUfLWuYNjS5WdogLdQk0cuJ2aXW3iepoYKUsMKA9Z4/58c0Jpu1MF6A/NhWtUz+pyhY SugYz1VzYpQCqpkzDtV+qAhTG/bB5hsSeO2MeoKSFpHDnVda+OSlc0G0cPOsiIc6jv60 X1G+tfsF/PcmwWl1DgLGTEfO5KnOF1RWDdQV2ukHvRBtDrBZ3zfyqtsu2xvK0xLV3lh1 W3hA== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:list-unsubscribe :list-subscribe:list-id:precedence:references:in-reply-to:message-id :date:subject:cc:to:from:dkim-signature; bh=1RKaxNCFWEvZIzSwmgrR3pWvf/z7eu3LhgzQRfT4iyw=; fh=Oe66JGPGe+i475v9dsbq4+ueqX3vOm8SqnLUAF+BRLg=; b=TUH3CKRvdpMCJ0EopIWPge/qfA5rXzriXRyt6ZwM5elDoZYLMx2yDA1T+8vRlKCNJf vPJxWbNvR/tYWfBmkzwgBVadna63OdGeQHcWsoZWPTM0CV5NKJfhl3rOwJqMuAtrl2X8 /KAIiTdJLHx4yYyf/HiBtpxvvzbtGGxoUHGjHGZiJOIaN2mYIuB53w/ZR3UdkwUWUR/6 d59d950W9OeZq1hElisvk+nFypQVjuIORWTBcn7Z/gfN1nLb3VJ6aw82ZiJjMblol0T1 xCty9nP5sLzmlyqo5FL8lI6+c9fu2ohc24mK1jE9Ee+qbGJX19OWr/glGXcuf+lTwhuE Heqg==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=QUaKph8x; arc=pass (i=1 dkim=pass dkdomain=kernel.org); spf=pass (google.com: domain of linux-kernel+bounces-47992-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) smtp.mailfrom="linux-kernel+bounces-47992-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Forwarded-Encrypted: i=1; AJvYcCVflwdl0IwPHXSbbf6azHPHmXgnqjQu5bulyZdyew0iVB6Iy0C/1ug8n32gBYiK7RM1oo8AlJeRH8so20PO2qD0YMG0Aw== Received: from sy.mirrors.kernel.org (sy.mirrors.kernel.org. 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When I TX from the board and measure on the TX pin, it seems like the HW fifo is not emptied before the transmission is stopped. MXS performs weird things with stop_tx(). The driver makes it conditional on uart_tx_stopped(). So the driver needs special handling. Pass the brand new UART_TX_NOSTOP to uart_port_tx_flags() and handle the stop on its own. Signed-off-by: Jiri Slaby (SUSE) Reported-by: Emil Kronborg Fixes: 2d141e683e9a ("tty: serial: use uart_port_tx() helper") Closes: https://lore.kernel.org/all/miwgbnvy3hjpnricubg76ytpn7xoceehwahupy25bubbduu23s@om2lptpa26xw/ Tested-by: Emil Kronborg Tested-by: Stefan Wahren --- drivers/tty/serial/mxs-auart.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 3ec725555bcc..4749331fe618 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -605,13 +605,16 @@ static void mxs_auart_tx_chars(struct mxs_auart_port *s) return; } - pending = uart_port_tx(&s->port, ch, + pending = uart_port_tx_flags(&s->port, ch, UART_TX_NOSTOP, !(mxs_read(s, REG_STAT) & AUART_STAT_TXFF), mxs_write(ch, s, REG_DATA)); if (pending) mxs_set(AUART_INTR_TXIEN, s, REG_INTR); else mxs_clr(AUART_INTR_TXIEN, s, REG_INTR); + + if (uart_tx_stopped(&s->port)) + mxs_auart_stop_tx(&s->port); } static void mxs_auart_rx_char(struct mxs_auart_port *s)