2 files changed, 67 insertions, 0 deletions

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 74fc3069cb42..7104604914ab 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -1831,11 +1831,77 @@ static const struct attribute_group musb_attr_group = {
 	.attrs = musb_attributes,
 };
 
+#define MUSB_QUIRK_B_INVALID_VBUS_91	(MUSB_DEVCTL_BDEVICE | \
+					 (2 << MUSB_DEVCTL_VBUS_SHIFT) | \
+					 MUSB_DEVCTL_SESSION)
+#define MUSB_QUIRK_A_DISCONNECT_19	((3 << MUSB_DEVCTL_VBUS_SHIFT) | \
+					 MUSB_DEVCTL_SESSION)
+
+/*
+ * Check the musb devctl session bit to determine if we want to
+ * allow PM runtime for the device. In general, we want to keep things
+ * active when the session bit is set except after host disconnect.
+ *
+ * Only called from musb_irq_work. If this ever needs to get called
+ * elsewhere, proper locking must be implemented for musb->session.
+ */
+static void musb_pm_runtime_check_session(struct musb *musb)
+{
+	u8 devctl, s;
+	int error;
+
+	devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
+
+	/* Handle session status quirks first */
+	s = MUSB_DEVCTL_FSDEV | MUSB_DEVCTL_LSDEV |
+		MUSB_DEVCTL_HR;
+	switch (devctl & ~s) {
+	case MUSB_QUIRK_B_INVALID_VBUS_91:
+		if (musb->session)
+			break;
+		musb_dbg(musb, "Allow PM as device with invalid vbus: %02x",
+			devctl);
+		return;
+	case MUSB_QUIRK_A_DISCONNECT_19:
+		if (!musb->session)
+			break;
+		musb_dbg(musb, "Allow PM on possible host mode disconnect");
+		pm_runtime_mark_last_busy(musb->controller);
+		pm_runtime_put_autosuspend(musb->controller);
+		musb->session = false;
+		return;
+	default:
+		break;
+	}
+
+	/* No need to do anything if session has not changed */
+	s = devctl & MUSB_DEVCTL_SESSION;
+	if (s == musb->session)
+		return;
+
+	/* Block PM or allow PM? */
+	if (s) {
+		musb_dbg(musb, "Block PM on active session: %02x", devctl);
+		error = pm_runtime_get_sync(musb->controller);
+		if (error < 0)
+			dev_err(musb->controller, "Could not enable: %i\n",
+				error);
+	} else {
+		musb_dbg(musb, "Allow PM with no session: %02x", devctl);
+		pm_runtime_mark_last_busy(musb->controller);
+		pm_runtime_put_autosuspend(musb->controller);
+	}
+
+	musb->session = s;
+}
+
 /* Only used to provide driver mode change events */
 static void musb_irq_work(struct work_struct *data)
 {
 	struct musb *musb = container_of(data, struct musb, irq_work);
 
+	musb_pm_runtime_check_session(musb);
+
 	if (musb->xceiv->otg->state != musb->xceiv_old_state) {
 		musb->xceiv_old_state = musb->xceiv->otg->state;
 		sysfs_notify(&musb->controller->kobj, NULL, "mode");
diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index b55a776b03eb..65288a53c19b 100644
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -378,6 +378,7 @@ struct musb {
 	u8			min_power;	/* vbus for periph, in mA/2 */
 
 	int			port_mode;	/* MUSB_PORT_MODE_* */
+	bool			session;
 	bool			is_host;
 
 	int			a_wait_bcon;	/* VBUS timeout in msecs */