+/* Locking: Caller holds the interface mutex. */
+static int gb_interface_legacy_mode_switch(struct gb_interface *intf)
+{
+ int ret;
+
+ dev_info(&intf->dev, "legacy mode switch detected\n");
+
+ /* Mark as disconnected to prevent I/O during disable. */
+ intf->disconnected = true;
+ gb_interface_disable(intf);
+ intf->disconnected = false;
+
+ ret = gb_interface_enable(intf);
+ if (ret) {
+ dev_err(&intf->dev, "failed to re-enable interface: %d\n", ret);
+ gb_interface_deactivate(intf);
+ }
+
+ return ret;
+}
+
+void gb_interface_mailbox_event(struct gb_interface *intf, u16 result,
+ u32 mailbox)
+{
+ mutex_lock(&intf->mutex);
+
+ if (result) {
+ dev_warn(&intf->dev,
+ "mailbox event with UniPro error: 0x%04x\n",
+ result);
+ goto err_disable;
+ }
+
+ if (mailbox != GB_SVC_INTF_MAILBOX_GREYBUS) {
+ dev_warn(&intf->dev,
+ "mailbox event with unexpected value: 0x%08x\n",
+ mailbox);
+ goto err_disable;
+ }
+
+ if (intf->quirks & GB_INTERFACE_QUIRK_LEGACY_MODE_SWITCH) {
+ gb_interface_legacy_mode_switch(intf);
+ goto out_unlock;
+ }
+
+ if (!intf->mode_switch) {
+ dev_warn(&intf->dev, "unexpected mailbox event: 0x%08x\n",
+ mailbox);
+ goto err_disable;
+ }
+
+ dev_info(&intf->dev, "mode switch detected\n");
+
+ complete(&intf->mode_switch_completion);
+
+out_unlock:
+ mutex_unlock(&intf->mutex);
+
+ return;
+
+err_disable:
+ gb_interface_disable(intf);
+ gb_interface_deactivate(intf);
+ mutex_unlock(&intf->mutex);
+}
+
+static void gb_interface_mode_switch_work(struct work_struct *work)
+{
+ struct gb_interface *intf;
+ struct gb_control *control;
+ unsigned long timeout;
+ int ret;
+
+ intf = container_of(work, struct gb_interface, mode_switch_work);
+
+ mutex_lock(&intf->mutex);
+ /* Make sure interface is still enabled. */
+ if (!intf->enabled) {
+ dev_dbg(&intf->dev, "mode switch aborted\n");
+ intf->mode_switch = false;
+ mutex_unlock(&intf->mutex);
+ goto out_interface_put;
+ }
+
+ /*
+ * Prepare the control device for mode switch and make sure to get an
+ * extra reference before it goes away during interface disable.
+ */
+ control = gb_control_get(intf->control);
+ gb_control_mode_switch_prepare(control);
+ gb_interface_disable(intf);
+ mutex_unlock(&intf->mutex);
+
+ timeout = msecs_to_jiffies(GB_INTERFACE_MODE_SWITCH_TIMEOUT);
+ ret = wait_for_completion_interruptible_timeout(
+ &intf->mode_switch_completion, timeout);
+
+ /* Finalise control-connection mode switch. */
+ gb_control_mode_switch_complete(control);
+ gb_control_put(control);
+
+ if (ret < 0) {
+ dev_err(&intf->dev, "mode switch interrupted\n");
+ goto err_deactivate;
+ } else if (ret == 0) {
+ dev_err(&intf->dev, "mode switch timed out\n");
+ goto err_deactivate;
+ }
+
+ /* Re-enable (re-enumerate) interface if still active. */
+ mutex_lock(&intf->mutex);
+ intf->mode_switch = false;
+ if (intf->active) {
+ ret = gb_interface_enable(intf);
+ if (ret) {
+ dev_err(&intf->dev, "failed to re-enable interface: %d\n",
+ ret);
+ gb_interface_deactivate(intf);
+ }
+ }
+ mutex_unlock(&intf->mutex);
+
+out_interface_put:
+ gb_interface_put(intf);
+
+ return;
+
+err_deactivate:
+ mutex_lock(&intf->mutex);
+ intf->mode_switch = false;
+ gb_interface_deactivate(intf);
+ mutex_unlock(&intf->mutex);
+
+ gb_interface_put(intf);
+}
+
+int gb_interface_request_mode_switch(struct gb_interface *intf)
+{
+ int ret = 0;
+
+ mutex_lock(&intf->mutex);
+ if (intf->mode_switch) {
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+
+ intf->mode_switch = true;
+ reinit_completion(&intf->mode_switch_completion);
+
+ /*
+ * Get a reference to the interface device, which will be put once the
+ * mode switch is complete.
+ */
+ get_device(&intf->dev);
+
+ if (!queue_work(system_long_wq, &intf->mode_switch_work)) {
+ put_device(&intf->dev);
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+
+out_unlock:
+ mutex_unlock(&intf->mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gb_interface_request_mode_switch);
+
projects / cascardo / linux.git / commitdiff