From mboxrd@z Thu Jan 1 00:00:00 1970 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 03AFC151CDC; Tue, 20 Feb 2024 21:38:37 +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=1708465117; cv=none; b=fD5YTIKNZ6qQLZX2F1yGq+2n0L2+AYhfigMePpsAFF4EMvyUR8eCkDip8JUFN5SPXg/+X9tAp9+9qx8kHZBQQQ0TszCZPJjuEQpQIiKwbaJu0hMC4Dd/WT+0lnWtw9tMyMaDMpJ7g1nCMsyoLeliJDs0zE56LPibdZUTmzBw98o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708465117; c=relaxed/simple; bh=wwyg8qD+K7IfnslEZZuDR4lAR2Fw0/0B6pp5rZoz3UE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H6kBoEE/ByUr2jwmSTh/JAFFozp5yo+Uo/TxZnwszoHV2wecPnH+vwpTmukb8XK42cP+IY4YHpNgOqACXutHvyYGqlygnZTKW+WEHP2EABKzDdnW4OprsyAVNXReRoyeYH1ZFLE4aK1NRgKSqf0QD8D4LfCCltyr0BPe0+njRZ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lT0WgZ5x; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="lT0WgZ5x" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EB89C433F1; Tue, 20 Feb 2024 21:38:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708465116; bh=wwyg8qD+K7IfnslEZZuDR4lAR2Fw0/0B6pp5rZoz3UE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lT0WgZ5xkuLJQy0KLqnhteWKZtPCcUnD55OOaVnLNb/ByiDasNJQWwf+HaeqUlGCy 9tx2Ij/qKD9gfTu/HebraBJzaYA7PDw2NO5bfinOMh7ABFUoBei+WvmVU/cc4x+VgH 0LR/Tg0wHztsnyLHJ6i2R3CCEE7X5XNEMMD5cS9k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hugo Villeneuve Subject: [PATCH 6.7 224/309] serial: max310x: prevent infinite while() loop in port startup Date: Tue, 20 Feb 2024 21:56:23 +0100 Message-ID: <20240220205640.166971715@linuxfoundation.org> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240220205633.096363225@linuxfoundation.org> References: <20240220205633.096363225@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hugo Villeneuve commit b35f8dbbce818b02c730dc85133dc7754266e084 upstream. 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: stable@vger.kernel.org Signed-off-by: Hugo Villeneuve Link: https://lore.kernel.org/r/20240116213001.3691629-5-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/max310x.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) --- 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 +/* 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 * goto out_clk; for (i = 0; i < devtype->nr; i++) { + bool started = false; + unsigned int try = 0, val = 0; + /* Reset port */ regmap_write(regmaps[i], MAX310X_MODE2_REG, MAX310X_MODE2_RST_BIT); @@ -1354,8 +1361,17 @@ static int max310x_probe(struct device * /* Wait for port startup */ do { - regmap_read(regmaps[i], MAX310X_BRGDIVLSB_REG, &ret); - } while (ret != 0x01); + msleep(MAX310X_PORT_STARTUP_WAIT_DELAY_MS); + regmap_read(regmaps[i], MAX310X_BRGDIVLSB_REG, &val); + + if (val == 0x01) + started = true; + } while (!started && (++try < MAX310X_PORT_STARTUP_WAIT_RETRIES)); + + if (!started) { + ret = dev_err_probe(dev, -EAGAIN, "port reset failed\n"); + goto out_uart; + } regmap_write(regmaps[i], MAX310X_MODE1_REG, devtype->mode1); }