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Date: Fri, 15 Mar 2024 17:18:35 +0000
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Subject: [PATCH v2 1/1] usb: typec: ucsi: Check capabilities before cable and
 identity discovery
From: Jameson Thies <jthies@google.com>
To: heikki.krogerus@linux.intel.com, linux-usb@vger.kernel.org
Cc: jthies@google.com, pmalani@chromium.org, bleung@google.com, 
	abhishekpandit@chromium.org, andersson@kernel.org, 
	dmitry.baryshkov@linaro.org, fabrice.gasnier@foss.st.com, 
	gregkh@linuxfoundation.org, hdegoede@redhat.com, neil.armstrong@linaro.org, 
	rajaram.regupathy@intel.com, saranya.gopal@intel.com, 
	linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"

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. Additionally,
move 8 bits from reserved_1 to features in the ucsi_capability struct. This
makes the field 16 bits, still 8 short of the 24 bits allocated for it in
UCSI v3.0, but it will not overflow because UCSI only defines 14 bits in
bmOptionalFeatures.

Fixes: 38ca416597b0 ("usb: typec: ucsi: Register cables based on GET_CABLE_PROPERTY")
Link: https://lore.kernel.org/linux-usb/44e8142f-d9b3-487b-83fe-39deadddb492@linaro.org
Suggested-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Jameson Thies <jthies@google.com>
---
Confirmed a device which supports GET_PD_MESSAGE, GET_CABLE_PROPERTY and
GET_ALTERNATE_MODES still requested identity and cable information.

 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