linux-kernel - [PATCH v14 02/10] platform/chrome: cros_ec

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230322104639.221402-3-treapking@chromium.org>
Date:   Wed, 22 Mar 2023 18:46:31 +0800
From:   Pin-yen Lin <treapking@...omium.org>
To:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Daniel Scally <djrscally@...il.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Prashant Malani <pmalani@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>
Cc:     Xin Ji <xji@...logixsemi.com>, linux-kernel@...r.kernel.org,
        Thomas Zimmermann <tzimmermann@...e.de>,
        linux-acpi@...r.kernel.org,
        Javier Martinez Canillas <javierm@...hat.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Pin-yen Lin <treapking@...omium.org>,
        Hsin-Yi Wang <hsinyi@...omium.org>,
        Lyude Paul <lyude@...hat.com>,
        Nícolas F . R . A . Prado 
        <nfraprado@...labora.com>, Allen Chen <allen.chen@....com.tw>,
        dri-devel@...ts.freedesktop.org, Marek Vasut <marex@...x.de>,
        Stephen Boyd <swboyd@...omium.org>,
        chrome-platform@...ts.linux.dev, devicetree@...r.kernel.org,
        Chen-Yu Tsai <wenst@...omium.org>
Subject: [PATCH v14 02/10] platform/chrome: cros_ec_typec: Purge blocking switch devlinks

From: Prashant Malani <pmalani@...omium.org>

When using OF graph, the fw_devlink code will create links between the
individual port driver (cros-ec-typec here) and the parent device for
a Type-C switch (like mode-switch). Since the mode-switch will in turn
have the usb-c-connector (i.e the child of the port driver) as a
supplier, fw_devlink will not be able to resolve the cyclic dependency
correctly.

As a result, the mode-switch driver probe() never runs, so mode-switches
are never registered. Because of that, the port driver probe constantly
fails with -EPROBE_DEFER, because the Type-C connector class requires all
switch devices to be registered prior to port registration.

To break this deadlock and allow the mode-switch registration to occur,
purge all the usb-c-connector nodes' absent suppliers. This eliminates
the connector as a supplier for a switch and allows it to be probed.

Signed-off-by: Prashant Malani <pmalani@...omium.org>
Signed-off-by: Pin-yen Lin <treapking@...omium.org>
Reviewed-by: Chen-Yu Tsai <wenst@...omium.org>
Tested-by: Chen-Yu Tsai <wenst@...omium.org>
Acked-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

---

(no changes since v11)

Changes in v11:
- Collected Acked-by tag

Changes in v10:
- Collected Reviewed-by and Tested-by tags

Changes in v7:
- Fix the long comment lines

Changes in v6:
- New in v6

 drivers/platform/chrome/cros_ec_typec.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index a673c3342470..5911cd9640cb 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -325,6 +325,16 @@ static int cros_typec_init_ports(struct cros_typec_data *typec)
 		return -EINVAL;
 	}
 
+	/*
+	 * OF graph may have set up some device links with switches,
+	 * since connectors have their own compatible. Purge these
+	 * to avoid a deadlock in switch probe (the switch mistakenly
+	 * assumes the connector is a supplier).
+	 */
+	if (dev_of_node(dev))
+		device_for_each_child_node(dev, fwnode)
+			fw_devlink_purge_absent_suppliers(fwnode);
+
 	/* DT uses "reg" to specify port number. */
 	port_prop = dev->of_node ? "reg" : "port-number";
 	device_for_each_child_node(dev, fwnode) {
-- 
2.40.0.rc1.284.g88254d51c5-goog