[PATCH 2/6] usb: typec: tcpm: Move locking into tcpm_queue_vdm()

[Hans de Goede <hdegoede@xxxxxxxxxx>]

Various callers (all the typec_altmode_ops) take the port-lock just for
the tcpm_queue_vdm() call.

Rename the raw (unlocked) tcpm_queue_vdm() call to
tcpm_queue_vdm_unlocked() and add a new tcpm_queue_vdm() helper which takes
the lock, so that its callers don't have to do this themselves.

This is a preparation patch for fixing an AB BA lock inversion between the
tcpm code and some altmode drivers.

Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
 drivers/usb/typec/tcpm/tcpm.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index fc6455a29c74..30e997d6ea1e 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -958,9 +958,11 @@ static void tcpm_queue_message(struct tcpm_port *port,
 /*
  * VDM/VDO handling functions
  */
-static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
-			   const u32 *data, int cnt)
+static void tcpm_queue_vdm_unlocked(struct tcpm_port *port, const u32 header,
+				    const u32 *data, int cnt)
 {
+	WARN_ON(!mutex_is_locked(&port->lock));
+
 	port->vdo_count = cnt + 1;
 	port->vdo_data[0] = header;
 	memcpy(&port->vdo_data[1], data, sizeof(u32) * cnt);
@@ -971,6 +973,14 @@ static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
 	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
 }
 
+static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
+			   const u32 *data, int cnt)
+{
+	mutex_lock(&port->lock);
+	tcpm_queue_vdm_unlocked(port, header, data, cnt);
+	mutex_unlock(&port->lock);
+}
+
 static void svdm_consume_identity(struct tcpm_port *port, const __le32 *payload,
 				  int cnt)
 {
@@ -1249,7 +1259,7 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port,
 		rlen = tcpm_pd_svdm(port, payload, cnt, response);
 
 	if (rlen > 0)
-		tcpm_queue_vdm(port, response[0], &response[1], rlen - 1);
+		tcpm_queue_vdm_unlocked(port, response[0], &response[1], rlen - 1);
 }
 
 static void tcpm_send_vdm(struct tcpm_port *port, u32 vid, int cmd,
@@ -1263,7 +1273,7 @@ static void tcpm_send_vdm(struct tcpm_port *port, u32 vid, int cmd,
 	/* set VDM header with VID & CMD */
 	header = VDO(vid, ((vid & USB_SID_PD) == USB_SID_PD) ?
 			1 : (PD_VDO_CMD(cmd) <= CMD_ATTENTION), cmd);
-	tcpm_queue_vdm(port, header, data, count);
+	tcpm_queue_vdm_unlocked(port, header, data, count);
 }
 
 static unsigned int vdm_ready_timeout(u32 vdm_hdr)
@@ -1506,13 +1516,10 @@ static int tcpm_altmode_enter(struct typec_altmode *altmode, u32 *vdo)
 	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
 	u32 header;
 
-	mutex_lock(&port->lock);
 	header = VDO(altmode->svid, vdo ? 2 : 1, CMD_ENTER_MODE);
 	header |= VDO_OPOS(altmode->mode);
 
 	tcpm_queue_vdm(port, header, vdo, vdo ? 1 : 0);
-	mutex_unlock(&port->lock);
-
 	return 0;
 }
 
@@ -1521,13 +1528,10 @@ static int tcpm_altmode_exit(struct typec_altmode *altmode)
 	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
 	u32 header;
 
-	mutex_lock(&port->lock);
 	header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
 	header |= VDO_OPOS(altmode->mode);
 
 	tcpm_queue_vdm(port, header, NULL, 0);
-	mutex_unlock(&port->lock);
-
 	return 0;
 }
 
@@ -1536,10 +1540,7 @@ static int tcpm_altmode_vdm(struct typec_altmode *altmode,
 {
 	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
 
-	mutex_lock(&port->lock);
 	tcpm_queue_vdm(port, header, data, count - 1);
-	mutex_unlock(&port->lock);
-
 	return 0;
 }
 
-- 
2.26.2