usb: core: add phy notify connect and disconnect

In Realtek SoC, the parameter of usb phy is designed to can dynamic
tuning base on port status. Therefore, add a notify callback of generic
phy driver when usb device connect and disconnect change.

The Realtek phy driver is designed to dynamically adjust disconnection
level and calibrate phy parameters. When the device connected bit changes
and when the disconnected bit changes, do connection change notification:

Check if portstatus is USB_PORT_STAT_CONNECTION and portchange is
USB_PORT_STAT_C_CONNECTION.
1. The device is connected, the driver lowers the disconnection level and
calibrates the phy parameters.
2. The device disconnects, the driver increases the disconnect level and
calibrates the phy parameters.

Generic phy driver in usb core framework does not support device connect
and disconnect notifications. Therefore, we add an api to notify phy
the connection changes.

Additionally, the generic phy only specifies primary_hcd in the original
design. Added specific "usb2-phy" on primary_hcd and "usb3-phy" on
shared_hcd.

Signed-off-by: Stanley Chang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/core/hcd.c

···
 	struct usb_device *rhdev;
 	struct usb_hcd *shared_hcd;
 
-	if (!hcd->skip_phy_initialization && usb_hcd_is_primary_hcd(hcd)) {
-		hcd->phy_roothub = usb_phy_roothub_alloc(hcd->self.sysdev);
-		if (IS_ERR(hcd->phy_roothub))
-			return PTR_ERR(hcd->phy_roothub);
+	if (!hcd->skip_phy_initialization) {
+		if (usb_hcd_is_primary_hcd(hcd)) {
+			hcd->phy_roothub = usb_phy_roothub_alloc(hcd->self.sysdev);
+			if (IS_ERR(hcd->phy_roothub))
+				return PTR_ERR(hcd->phy_roothub);
+		} else {
+			hcd->phy_roothub = usb_phy_roothub_alloc_usb3_phy(hcd->self.sysdev);
+			if (IS_ERR(hcd->phy_roothub))
+				return PTR_ERR(hcd->phy_roothub);
+		}
 
 		retval = usb_phy_roothub_init(hcd->phy_roothub);
 		if (retval)

drivers/usb/core/hub.c

···
 #include <asm/byteorder.h>
 
 #include "hub.h"
+#include "phy.h"
 #include "otg_productlist.h"
 
 #define USB_VENDOR_GENESYS_LOGIC		0x05e3
···
 		ret = 0;
 	}
 	mutex_unlock(&hub->status_mutex);
+
+	/*
+	 * There is no need to lock status_mutex here, because status_mutex
+	 * protects hub->status, and the phy driver only checks the port
+	 * status without changing the status.
+	 */
+	if (!ret) {
+		struct usb_device *hdev = hub->hdev;
+
+		/*
+		 * Only roothub will be notified of connection changes,
+		 * since the USB PHY only cares about changes at the next
+		 * level.
+		 */
+		if (is_root_hub(hdev)) {
+			struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
+			bool connect;
+			bool connect_change;
+
+			connect_change = *change & USB_PORT_STAT_C_CONNECTION;
+			connect = *status & USB_PORT_STAT_CONNECTION;
+			if (connect_change && connect)
+				usb_phy_roothub_notify_connect(hcd->phy_roothub, port1 - 1);
+			else if (connect_change)
+				usb_phy_roothub_notify_disconnect(hcd->phy_roothub, port1 - 1);
+		}
+	}
+
 	return ret;
 }
 

drivers/usb/core/phy.c

···
 	struct list_head	list;
 };
 
+/* Allocate the roothub_entry by specific name of phy */
+static int usb_phy_roothub_add_phy_by_name(struct device *dev, const char *name,
+					   struct list_head *list)
+{
+	struct usb_phy_roothub *roothub_entry;
+	struct phy *phy;
+
+	phy = devm_of_phy_get(dev, dev->of_node, name);
+	if (IS_ERR(phy))
+		return PTR_ERR(phy);
+
+	roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
+	if (!roothub_entry)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&roothub_entry->list);
+
+	roothub_entry->phy = phy;
+
+	list_add_tail(&roothub_entry->list, list);
+
+	return 0;
+}
+
 static int usb_phy_roothub_add_phy(struct device *dev, int index,
 				   struct list_head *list)
 {
···
 
 	INIT_LIST_HEAD(&phy_roothub->list);
 
+	if (!usb_phy_roothub_add_phy_by_name(dev, "usb2-phy", &phy_roothub->list))
+		return phy_roothub;
+
 	for (i = 0; i < num_phys; i++) {
 		err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
 		if (err)
···
 	return phy_roothub;
 }
 EXPORT_SYMBOL_GPL(usb_phy_roothub_alloc);
+
+/**
+ * usb_phy_roothub_alloc_usb3_phy - alloc the roothub
+ * @dev: the device of the host controller
+ *
+ * Allocate the usb phy roothub if the host use a generic usb3-phy.
+ *
+ * Return: On success, a pointer to the usb_phy_roothub. Otherwise,
+ * %NULL if no use usb3 phy or %-ENOMEM if out of memory.
+ */
+struct usb_phy_roothub *usb_phy_roothub_alloc_usb3_phy(struct device *dev)
+{
+	struct usb_phy_roothub *phy_roothub;
+	int num_phys;
+
+	if (!IS_ENABLED(CONFIG_GENERIC_PHY))
+		return NULL;
+
+	num_phys = of_count_phandle_with_args(dev->of_node, "phys",
+					      "#phy-cells");
+	if (num_phys <= 0)
+		return NULL;
+
+	phy_roothub = devm_kzalloc(dev, sizeof(*phy_roothub), GFP_KERNEL);
+	if (!phy_roothub)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&phy_roothub->list);
+
+	if (!usb_phy_roothub_add_phy_by_name(dev, "usb3-phy", &phy_roothub->list))
+		return phy_roothub;
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(usb_phy_roothub_alloc_usb3_phy);
 
 int usb_phy_roothub_init(struct usb_phy_roothub *phy_roothub)
 {
···
 	return 0;
 }
 EXPORT_SYMBOL_GPL(usb_phy_roothub_calibrate);
+
+/**
+ * usb_phy_roothub_notify_connect() - connect notification
+ * @phy_roothub: the phy of roothub, if the host use a generic phy.
+ * @port: the port index for connect
+ *
+ * If the phy needs to get connection status, the callback can be used.
+ * Returns: %0 if successful, a negative error code otherwise
+ */
+int usb_phy_roothub_notify_connect(struct usb_phy_roothub *phy_roothub, int port)
+{
+	struct usb_phy_roothub *roothub_entry;
+	struct list_head *head;
+	int err;
+
+	if (!phy_roothub)
+		return 0;
+
+	head = &phy_roothub->list;
+
+	list_for_each_entry(roothub_entry, head, list) {
+		err = phy_notify_connect(roothub_entry->phy, port);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_phy_roothub_notify_connect);
+
+/**
+ * usb_phy_roothub_notify_disconnect() - disconnect notification
+ * @phy_roothub: the phy of roothub, if the host use a generic phy.
+ * @port: the port index for disconnect
+ *
+ * If the phy needs to get connection status, the callback can be used.
+ * Returns: %0 if successful, a negative error code otherwise
+ */
+int usb_phy_roothub_notify_disconnect(struct usb_phy_roothub *phy_roothub, int port)
+{
+	struct usb_phy_roothub *roothub_entry;
+	struct list_head *head;
+	int err;
+
+	if (!phy_roothub)
+		return 0;
+
+	head = &phy_roothub->list;
+
+	list_for_each_entry(roothub_entry, head, list) {
+		err = phy_notify_disconnect(roothub_entry->phy, port);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_phy_roothub_notify_disconnect);
 
 int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub)
 {

drivers/usb/core/phy.h

···
 struct usb_phy_roothub;
 
 struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev);
+struct usb_phy_roothub *usb_phy_roothub_alloc_usb3_phy(struct device *dev);
 
 int usb_phy_roothub_init(struct usb_phy_roothub *phy_roothub);
 int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub);
···
 int usb_phy_roothub_set_mode(struct usb_phy_roothub *phy_roothub,
 			     enum phy_mode mode);
 int usb_phy_roothub_calibrate(struct usb_phy_roothub *phy_roothub);
+int usb_phy_roothub_notify_connect(struct usb_phy_roothub *phy_roothub, int port);
+int usb_phy_roothub_notify_disconnect(struct usb_phy_roothub *phy_roothub, int port);
 int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub);
 void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub);