[PATCH 1/2] usb: cdns3: Fix hw based role switch

[Roger Quadros]

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
 drivers/usb/cdns3/core.c | 76 ++++++++++++++++++++++++++--------------
 drivers/usb/cdns3/core.h |  2 ++
 drivers/usb/cdns3/drd.c  |  2 +-
 3 files changed, 52 insertions(+), 28 deletions(-)

diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
index b132acca60f1..07f8d8f23930 100644
--- a/drivers/usb/cdns3/core.c
+++ b/drivers/usb/cdns3/core.c
@@ -97,7 +97,7 @@ static void cdns3_exit_roles(struct cdns3 *cdns)
 	cdns3_drd_exit(cdns);
 }
 
-enum usb_role cdsn3_real_role_switch_get(struct device *dev);
+static enum usb_role cdsn3_hw_role_state_machine(struct cdns3 *cdns);
 
 /**
  * cdns3_core_init_role - initialize role of operation
@@ -176,7 +176,7 @@ static int cdns3_core_init_role(struct cdns3 *cdns)
 	if (ret)
 		goto err;
 
-	cdns->role = cdsn3_real_role_switch_get(cdns->dev);
+	cdns->role = cdsn3_hw_role_state_machine(cdns);
 
 	ret = cdns3_role_start(cdns, cdns->role);
 	if (ret) {
@@ -192,15 +192,14 @@ static int cdns3_core_init_role(struct cdns3 *cdns)
 }
 
 /**
- * cdsn3_real_role_switch_get - get real role of controller based on hardware
- *   settings.
- * @dev: Pointer to device structure
+ * cdsn3_hw_role_state_machine - role switch state machine based on hw events
  *
- * Returns role
+ * @cdns: Pointer to controller structure
+ *
+ * Returns next role to be entered based on hw events.
  */
-enum usb_role cdsn3_real_role_switch_get(struct device *dev)
+static enum usb_role cdsn3_hw_role_state_machine(struct cdns3 *cdns)
 {
-	struct cdns3 *cdns = dev_get_drvdata(dev);
 	enum usb_role role;
 	int id, vbus;
 
@@ -253,46 +252,40 @@ enum usb_role cdsn3_real_role_switch_get(struct device *dev)
 }
 
 /**
- * cdns3_role_switch_set - work queue handler for role switch
+ * cdns3_hw_role_switch - switch roles based on HW state
  *
- * @dev: pointer to device object
- * @role - the previous role
- * Handles below events:
- * - Role switch for dual-role devices
- * - USB_ROLE_GADGET <--> USB_ROLE_NONE for peripheral-only devices
+ * @cdns: controller
  */
-static int cdns3_role_switch_set(struct device *dev, enum usb_role role)
+int cdns3_hw_role_switch(struct cdns3 *cdns)
 {
-	struct cdns3 *cdns = dev_get_drvdata(dev);
-	enum usb_role real_role = USB_ROLE_NONE;
-	enum usb_role current_role;
+	enum usb_role real_role, current_role;
 	int ret = 0;
 
 	/* Check if dr_mode was changed.*/
+	/* FIXME: why do we need this call? */
 	ret = cdns3_drd_update_mode(cdns);
 	if (ret)
 		return ret;
 
+	/* FIXME: don't do anything if userspace role switch has override */
 	pm_runtime_get_sync(cdns->dev);
 
-	real_role = cdsn3_real_role_switch_get(cdns->dev);
+	current_role = cdns->role;
+	real_role = cdsn3_hw_role_state_machine(cdns);
 
 	/* Do nothing if nothing changed */
-	if (cdns->role == real_role)
+	if (current_role == real_role)
 		goto exit;
 
 	cdns3_role_stop(cdns);
 
-	real_role = cdsn3_real_role_switch_get(cdns->dev);
-
-	current_role = role;
-	dev_dbg(cdns->dev, "Switching role");
+	dev_dbg(cdns->dev, "Switching role %d -> %d", current_role, real_role);
 
 	ret = cdns3_role_start(cdns, real_role);
 	if (ret) {
 		/* Back to current role */
 		dev_err(cdns->dev, "set %d has failed, back to %d\n",
-			role, current_role);
+			real_role, current_role);
 		ret = cdns3_role_start(cdns, current_role);
 		if (ret)
 			dev_err(cdns->dev, "back to %d failed too\n",
@@ -303,9 +296,38 @@ static int cdns3_role_switch_set(struct device *dev, enum usb_role role)
 	return ret;
 }
 
+/**
+ * cdsn3_role_get - get current role of controller.
+ *
+ * @dev: Pointer to device structure
+ *
+ * Returns role
+ */
+static enum usb_role cdns3_role_get(struct device *dev)
+{
+	struct cdns3 *cdns = dev_get_drvdata(dev);
+
+	return cdns->role;
+}
+
+/**
+ * cdns3_role_set - set current role of controller.
+ *
+ * @dev: pointer to device object
+ * @role - the previous role
+ * Handles below events:
+ * - Role switch for dual-role devices
+ * - USB_ROLE_GADGET <--> USB_ROLE_NONE for peripheral-only devices
+ */
+static int cdns3_role_set(struct device *dev, enum usb_role role)
+{
+	/* FIXME: doing nothing for now */
+	return -EPERM;
+}
+
 static const struct usb_role_switch_desc cdns3_switch_desc = {
-	.set = cdns3_role_switch_set,
-	.get = cdsn3_real_role_switch_get,
+	.set = cdns3_role_set,
+	.get = cdns3_role_get,
 	.allow_userspace_control = true,
 };
 
diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
index 2a35f025b0a5..e0d23f2934bb 100644
--- a/drivers/usb/cdns3/core.h
+++ b/drivers/usb/cdns3/core.h
@@ -103,4 +103,6 @@ struct cdns3 {
 	struct usb_role_switch		*role_sw;
 };
 
+int cdns3_hw_role_switch(struct cdns3 *cdns);
+
 #endif /* __LINUX_CDNS3_CORE_H */
diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
index 77f8a1516140..780fc7d59932 100644
--- a/drivers/usb/cdns3/drd.c
+++ b/drivers/usb/cdns3/drd.c
@@ -265,7 +265,7 @@ static irqreturn_t cdns3_drd_thread_irq(int irq, void *data)
 {
 	struct cdns3 *cdns = data;
 
-	usb_role_switch_set_role(cdns->role_sw, cdns->role);
+	cdns3_hw_role_switch(cdns);
 
 	return IRQ_HANDLED;
 }