linux-kernel - [PATCH v1 1/1] usb: typec: ucsi: Check capabilities before cable and identity discovery

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Message-ID: <20240314235554.90079-2-jthies@google.com>
Date: Thu, 14 Mar 2024 23:55:54 +0000
From: Jameson Thies <jthies@...gle.com>
To: heikki.krogerus@...ux.intel.com, linux-usb@...r.kernel.org
Cc: jthies@...gle.com, pmalani@...omium.org, bleung@...gle.com, 
	abhishekpandit@...omium.org, andersson@...nel.org, 
	dmitry.baryshkov@...aro.org, fabrice.gasnier@...s.st.com, 
	gregkh@...uxfoundation.org, hdegoede@...hat.com, neil.armstrong@...aro.org, 
	rajaram.regupathy@...el.com, saranya.gopal@...el.com, 
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/1] usb: typec: ucsi: Check capabilities before cable and
 identity discovery

Check the UCSI_CAP_GET_PD_MESSAGE bit before sending GET_PD_MESSAGE to
discover partner and cable identity, check UCSI_CAP_CABLE_DETAILS before
sending GET_CABLE_PROPERTY to discover the cable and check
UCSI_CAP_ALT_MODE_DETAILS before registering the a cable plug.

Suggested-by: Neil Armstrong <neil.armstrong@...aro.org>
Signed-off-by: Jameson Thies <jthies@...gle.com>
---
Confirmed a device which supports GET_PD_MESSAGE, GET_CABLE_PROPERTY and
GET_ALTERNATE_MODES still requested identity and cable information.

This moves 8 bits from "reserved_1" to "features" in the ucsi_capability
struct. Really, this should be 24 bits to reflect the field size in UCSI.
But, as of UCSI 3.0, this will not overflow becasue the bmOptionalFeatures
description only defines 14 bits.

 drivers/usb/typec/ucsi/ucsi.c | 34 +++++++++++++++++++++-------------
 drivers/usb/typec/ucsi/ucsi.h |  5 +++--
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index cf52cb34d2859..958dc82989b60 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -1133,17 +1133,21 @@ static int ucsi_check_cable(struct ucsi_connector *con)
 	if (ret < 0)
 		return ret;
 
-	ret = ucsi_get_cable_identity(con);
-	if (ret < 0)
-		return ret;
+	if (con->ucsi->cap.features & UCSI_CAP_GET_PD_MESSAGE) {
+		ret = ucsi_get_cable_identity(con);
+		if (ret < 0)
+			return ret;
+	}
 
-	ret = ucsi_register_plug(con);
-	if (ret < 0)
-		return ret;
+	if (con->ucsi->cap.features & UCSI_CAP_ALT_MODE_DETAILS) {
+		ret = ucsi_register_plug(con);
+		if (ret < 0)
+			return ret;
 
-	ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP_P);
-	if (ret < 0)
-		return ret;
+		ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP_P);
+		if (ret < 0)
+			return ret;
+	}
 
 	return 0;
 }
@@ -1189,8 +1193,10 @@ static void ucsi_handle_connector_change(struct work_struct *work)
 			ucsi_register_partner(con);
 			ucsi_partner_task(con, ucsi_check_connection, 1, HZ);
 			ucsi_partner_task(con, ucsi_check_connector_capability, 1, HZ);
-			ucsi_partner_task(con, ucsi_get_partner_identity, 1, HZ);
-			ucsi_partner_task(con, ucsi_check_cable, 1, HZ);
+			if (con->ucsi->cap.features & UCSI_CAP_GET_PD_MESSAGE)
+				ucsi_partner_task(con, ucsi_get_partner_identity, 1, HZ);
+			if (con->ucsi->cap.features & UCSI_CAP_CABLE_DETAILS)
+				ucsi_partner_task(con, ucsi_check_cable, 1, HZ);
 
 			if (UCSI_CONSTAT_PWR_OPMODE(con->status.flags) ==
 			    UCSI_CONSTAT_PWR_OPMODE_PD)
@@ -1589,8 +1595,10 @@ static int ucsi_register_port(struct ucsi *ucsi, struct ucsi_connector *con)
 		ucsi_register_partner(con);
 		ucsi_pwr_opmode_change(con);
 		ucsi_port_psy_changed(con);
-		ucsi_get_partner_identity(con);
-		ucsi_check_cable(con);
+		if (con->ucsi->cap.features & UCSI_CAP_GET_PD_MESSAGE)
+			ucsi_get_partner_identity(con);
+		if (con->ucsi->cap.features & UCSI_CAP_CABLE_DETAILS)
+			ucsi_check_cable(con);
 	}
 
 	/* Only notify USB controller if partner supports USB data */
diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index 32daf5f586505..0e7c92eb1b227 100644
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -206,7 +206,7 @@ struct ucsi_capability {
 #define UCSI_CAP_ATTR_POWER_OTHER		BIT(10)
 #define UCSI_CAP_ATTR_POWER_VBUS		BIT(14)
 	u8 num_connectors;
-	u8 features;
+	u16 features;
 #define UCSI_CAP_SET_UOM			BIT(0)
 #define UCSI_CAP_SET_PDM			BIT(1)
 #define UCSI_CAP_ALT_MODE_DETAILS		BIT(2)
@@ -215,7 +215,8 @@ struct ucsi_capability {
 #define UCSI_CAP_CABLE_DETAILS			BIT(5)
 #define UCSI_CAP_EXT_SUPPLY_NOTIFICATIONS	BIT(6)
 #define UCSI_CAP_PD_RESET			BIT(7)
-	u16 reserved_1;
+#define UCSI_CAP_GET_PD_MESSAGE		BIT(8)
+	u8 reserved_1;
 	u8 num_alt_modes;
 	u8 reserved_2;
 	u16 bc_version;
-- 
2.44.0.291.gc1ea87d7ee-goog