From nobody Wed Dec 17 09:46:14 2025 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) (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 8BFE95D8F1; Tue, 16 Jan 2024 21:30:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.243.120.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705440623; cv=none; b=daSwaaNY0EzbWz0u99kVyfQPftSKNaX5AIiJM8aIK8OOdj73EDTlWemyM2gqJHSp9RL0QysxH/Vqn8eZWMWkuLjhZzHrwCYIbEw5ECxkqRFOjFXT57Qb2496ggrqPn2uayLz6csY+ao0dk9McSOQYYmMWSpbsza9faIi2/nvkDM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705440623; c=relaxed/simple; bh=Ekm1pWojkGVN85gQNWE1XXW2dWBTUCiXzPsg832oXl4=; h=DKIM-Signature:Received:From:To:Cc:Date:Message-Id:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding: X-SA-Exim-Connect-IP:X-SA-Exim-Mail-From:X-Spam-Checker-Version: X-Spam-Level:X-Spam-Report:X-Spam-Status:Subject:X-SA-Exim-Version: X-SA-Exim-Scanned; b=Wp4KJUYKNg8KyLH1xxPlPXMDDj8Ut+kN/SxTeXjHAiDROADSUzRQepKdq439LZqN4NfiizPLkzoV1diDVuNCx1er4IWbvli4PqWPhX8cZmg0nJRMfIw61NTXYZ7L/YDM50HFmnpy00qxqr+mjlKy2PUx4wOhiUEN/do5OJrUshM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hugovil.com; spf=pass smtp.mailfrom=hugovil.com; dkim=pass (1024-bit key) header.d=hugovil.com header.i=@hugovil.com header.b=iZCshsRW; arc=none smtp.client-ip=162.243.120.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hugovil.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hugovil.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hugovil.com header.i=@hugovil.com header.b="iZCshsRW" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=hugovil.com ; s=x; h=Subject:Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Cc:To :From:subject:date:message-id:reply-to; bh=99qxuCnYU+0nTighHkHeSz50qP2ibLYD2/rfjv4LZXY=; b=iZCshsRWGamXZd6WywC48e+8RC fbgHxn6qeLjqo0ZPMrNwzvbuzLpakbp6J+KwYRQqY9i+jHpx/wUeFwN/N+Caejoeaig5+6rMVhF6O PGhV4wv8qGHeJ+HYHr8J7DQXzpHVjSIbATqzUAuMOnhpK2FsvErq8F5jmU5HwWNWqlqE=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:47418 helo=pettiford.lan) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1rPr0c-0002ia-K7; Tue, 16 Jan 2024 16:30:11 -0500 From: Hugo Villeneuve To: gregkh@linuxfoundation.org, jirislaby@kernel.org, jan.kundrat@cesnet.cz, shc_work@mail.ru Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, hugo@hugovil.com, Hugo Villeneuve , stable@vger.kernel.org Date: Tue, 16 Jan 2024 16:30:01 -0500 Message-Id: <20240116213001.3691629-5-hugo@hugovil.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240116213001.3691629-1-hugo@hugovil.com> References: <20240116213001.3691629-1-hugo@hugovil.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com X-Spam-Level: X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * -0.0 T_SCC_BODY_TEXT_LINE No description available. Subject: [PATCH 4/4] serial: max310x: prevent infinite while() loop in port startup X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) Content-Type: text/plain; charset="utf-8" From: Hugo Villeneuve If there is a problem after resetting a port, the do/while() loop that checks the default value of DIVLSB register may run forever and spam the I2C bus. Add a delay before each read of DIVLSB, and a maximum number of tries to prevent that situation from happening. Also fail probe if port reset is unsuccessful. Fixes: 10d8b34a4217 ("serial: max310x: Driver rework") Cc: Signed-off-by: Hugo Villeneuve --- drivers/tty/serial/max310x.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index 552e153a24e0..10bf6d75bf9e 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -237,6 +237,10 @@ #define MAX310x_REV_MASK (0xf8) #define MAX310X_WRITE_BIT 0x80 =20 +/* Port startup definitions */ +#define MAX310X_PORT_STARTUP_WAIT_RETRIES 20 /* Number of retries */ +#define MAX310X_PORT_STARTUP_WAIT_DELAY_MS 10 /* Delay between retries */ + /* Crystal-related definitions */ #define MAX310X_XTAL_WAIT_RETRIES 20 /* Number of retries */ #define MAX310X_XTAL_WAIT_DELAY_MS 10 /* Delay between retries */ @@ -1346,6 +1350,9 @@ static int max310x_probe(struct device *dev, const st= ruct max310x_devtype *devty goto out_clk; =20 for (i =3D 0; i < devtype->nr; i++) { + bool started =3D false; + unsigned int try =3D 0, val =3D 0; + /* Reset port */ regmap_write(regmaps[i], MAX310X_MODE2_REG, MAX310X_MODE2_RST_BIT); @@ -1354,8 +1361,17 @@ static int max310x_probe(struct device *dev, const s= truct max310x_devtype *devty =20 /* Wait for port startup */ do { - regmap_read(regmaps[i], MAX310X_BRGDIVLSB_REG, &ret); - } while (ret !=3D 0x01); + msleep(MAX310X_PORT_STARTUP_WAIT_DELAY_MS); + regmap_read(regmaps[i], MAX310X_BRGDIVLSB_REG, &val); + + if (val =3D=3D 0x01) + started =3D true; + } while (!started && (++try < MAX310X_PORT_STARTUP_WAIT_RETRIES)); + + if (!started) { + ret =3D dev_err_probe(dev, -EAGAIN, "port reset failed\n"); + goto out_uart; + } =20 regmap_write(regmaps[i], MAX310X_MODE1_REG, devtype->mode1); } --=20 2.39.2