From patchwork Fri Apr 5 07:56:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Esben Haabendal X-Patchwork-Id: 786388 Received: from www530.your-server.de (www530.your-server.de [188.40.30.78]) (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 C43891428F5 for ; Fri, 5 Apr 2024 07:56:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=188.40.30.78 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712303804; cv=none; b=AGCstgl9OtTcBMK5aggp788MiqjXSpWgFYCYsRgl0tf+DiaWuYtuf0f+RTc4ryxycmTlksjdV1VHVVVirevHVEokGI+0qAYsU9mGjAeKDlQ1RYnFApMXmf88Dbro/WWR6Qv6oXqRGQ2gA1sY+L1N1BaCM1xIVR6WeHUT6BQpfAI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712303804; c=relaxed/simple; bh=62/kBfCFqywb6RolU+elMlCQFqop7JIerJ8T2hSZePU=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DogVLjKL5WlQ5xLwahVnJtOOr9IPU4cYY7ECSTF0RoHUeKEVWdVTrVbhFg+TJoY+imOrWbDcvxZzP+0Ysxmy1JMBGZ4RiUvJ7WyZcBqBfJ6fjeUSTB5K0QStnoHtKUjs2qXbvWLf489OMXwbhHYvt3Z6bWtSyVHFnwfm1NE5yv8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=geanix.com; spf=pass smtp.mailfrom=geanix.com; dkim=pass (2048-bit key) header.d=geanix.com header.i=@geanix.com header.b=yPsDqkxr; arc=none smtp.client-ip=188.40.30.78 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=geanix.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=geanix.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=geanix.com header.i=@geanix.com header.b="yPsDqkxr" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=geanix.com; s=default2211; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-ID:Date:Subject:To:From:Sender:Reply-To:Cc:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID; bh=A+KMB3ZPLg0xQOTlbKLq4wkG6MWTg/99Psbp1VqQgYk=; b=yPsDqkxrgtjpAqOlxUSFBeaIIm DjpqwsmWGYdPkbqTiJy8LrkgxRTO5yXPaMQdhZZt5h/BMVjbuT5VC0SfNhuHPuynLtTt2joBINJiY 3rk2TbGlCDZOuWdCG5BbmYHe8L3GnPNRntvUxQgbQRaJv1SaWp5QNcw+NztHm/yyv47ou4oCyJdQy JwvEXzoz5l6uNs2b/l8qZ4NcRTF5nmhbmQZcUSc9m70lWgso0CniV0M6ecqKgS0/rDzKws76dGEis 7FBXl5Y6FlV+TA4hqX4pcaqLYglXMP20lO3bGelaFSfgIDNrz4s5RjRTOjtk07m21CW7/NSwdVuEJ 8r02modg==; Received: from sslproxy04.your-server.de ([78.46.152.42]) by www530.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rseRB-0005Lr-DC; Fri, 05 Apr 2024 09:56:37 +0200 Received: from [185.17.218.86] (helo=localhost) by sslproxy04.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rseRB-0006IH-0H; Fri, 05 Apr 2024 09:56:37 +0200 From: Esben Haabendal To: linux-rt-users@vger.kernel.org, Marc Kleine-Budde , John Ogness Subject: [RFC PATCH v2 1/2] serial: imx: Introduce timeout when waiting on transmitter empty Date: Fri, 5 Apr 2024 09:56:37 +0200 Message-ID: <7bfab9fb4313e64d8998a78e49411bdc7f9bd7c7.1712303358.git.esben@geanix.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-rt-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Authenticated-Sender: esben@geanix.com X-Virus-Scanned: Clear (ClamAV 0.103.10/27235/Thu Apr 4 10:24:59 2024) By waiting at most 1 second for USR2_TXDC to be set, we avoid a potentital deadlock. In case of the timeout, there is not much we can do, so we simply ignore the transmitter state and optimistically try to continue. Signed-off-by: Esben Haabendal Acked-by: Marc Kleine-Budde --- drivers/tty/serial/imx.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 54b760d845c0..f7e4f38f08f3 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include @@ -1995,7 +1996,7 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) struct imx_port *sport = imx_uart_ports[co->index]; struct imx_port_ucrs old_ucr; unsigned long flags; - unsigned int ucr1; + unsigned int ucr1, usr2; int locked = 1; if (sport->port.sysrq) @@ -2026,8 +2027,8 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) * Finally, wait for transmitter to become empty * and restore UCR1/2/3 */ - while (!(imx_uart_readl(sport, USR2) & USR2_TXDC)); - + read_poll_timeout_atomic(imx_uart_readl, usr2, usr2 & USR2_TXDC, + 0, 1000000, false, sport, USR2); imx_uart_ucrs_restore(sport, &old_ucr); if (locked)