greybus: svc: keep interfaces registered during mode switch

Keep a detected interface registered until it is physically removed.
Specifically, do not re-register an interface that is switching mode.

Note that this also allows us to get rid of some nasty hacks from core.
The Ara VID/PID bootrom hack for ES2 will continue to work, but is now
mostly confined to the bootrom driver.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/interface.c

@@ -426,8 +426,9 @@ void gb_interface_deactivate(struct gb_interface *intf)
 }
 
 /*
- * Enable an interface by enabling its control connection and fetching the
- * manifest and other information over it.
+ * Enable an interface by enabling its control connection, fetching the
+ * manifest and other information over it, and finally registering its child
+ * devices.
  */
 int gb_interface_enable(struct gb_interface *intf)
 {
@@ -499,6 +500,19 @@ int gb_interface_enable(struct gb_interface *intf)
 	if (ret)
 		goto err_destroy_bundles;
 
+	/* Register the control device and any bundles */
+	ret = gb_control_add(intf->control);
+	if (ret)
+		goto err_destroy_bundles;
+
+	list_for_each_entry_safe_reverse(bundle, tmp, &intf->bundles, links) {
+		ret = gb_bundle_add(bundle);
+		if (ret) {
+			gb_bundle_destroy(bundle);
+			continue;
+		}
+	}
+
 	kfree(manifest);
 
 	intf->enabled = true;
@@ -546,10 +560,9 @@ void gb_interface_disable(struct gb_interface *intf)
 	intf->enabled = false;
 }
 
-/* Register an interface and its bundles. */
+/* Register an interface. */
 int gb_interface_add(struct gb_interface *intf)
 {
-	struct gb_bundle *bundle, *tmp;
 	int ret;
 
 	ret = device_add(&intf->dev);
@@ -563,17 +576,6 @@ int gb_interface_add(struct gb_interface *intf)
 	dev_info(&intf->dev, "DDBL1 Manufacturer=0x%08x, Product=0x%08x\n",
 		 intf->ddbl1_manufacturer_id, intf->ddbl1_product_id);
 
-	/* NOTE: ignoring errors for now */
-	gb_control_add(intf->control);
-
-	list_for_each_entry_safe_reverse(bundle, tmp, &intf->bundles, links) {
-		ret = gb_bundle_add(bundle);
-		if (ret) {
-			gb_bundle_destroy(bundle);
-			continue;
-		}
-	}
-
 	return 0;
 }
 

drivers/staging/greybus/svc.c

@@ -452,8 +452,6 @@ static void gb_svc_process_intf_hotplug(struct gb_operation *operation)
 	struct gb_host_device *hd = connection->hd;
 	struct gb_interface *intf;
 	u8 intf_id;
-	u32 vendor_id = 0;
-	u32 product_id = 0;
 	int ret;
 
 	/* The request message size has already been verified. */
@@ -464,27 +462,15 @@ static void gb_svc_process_intf_hotplug(struct gb_operation *operation)
 
 	intf = gb_interface_find(hd, intf_id);
 	if (intf) {
-		/* HACK: Save Ara VID/PID for ES2 hack below */
-		vendor_id = intf->vendor_id;
-		product_id = intf->product_id;
-
-		/*
-		 * We have received a hotplug request for an interface that
-		 * already exists.
-		 *
-		 * This can happen in cases like:
-		 * - bootrom loading the firmware image and booting into that,
-		 *   which only generates a hotplug event. i.e. no hot-unplug
-		 *   event.
-		 * - Or the firmware on the module crashed and sent hotplug
-		 *   request again to the SVC, which got propagated to AP.
-		 *
-		 * Remove the interface and add it again, and let user know
-		 * about this with a print message.
-		 */
-		dev_info(&svc->dev, "removing interface %u to add it again\n",
+		dev_info(&svc->dev, "mode switch detected on interface %u\n",
 				intf_id);
-		gb_svc_intf_remove(svc, intf);
+
+		/* Mark as disconnected to prevent I/O during disable. */
+		intf->disconnected = true;
+		gb_interface_disable(intf);
+		intf->disconnected = false;
+
+		goto enable_interface;
 	}
 
 	intf = gb_interface_create(hd, intf_id);
@@ -498,19 +484,15 @@ static void gb_svc_process_intf_hotplug(struct gb_operation *operation)
 	if (ret) {
 		dev_err(&svc->dev, "failed to activate interface %u: %d\n",
 				intf_id, ret);
-		goto err_interface_add;
+		gb_interface_add(intf);
+		return;
 	}
 
-	/*
-	 * HACK: Use Ara VID/PID from earlier boot stage.
-	 *
-	 * FIXME: remove quirk with ES2 support
-	 */
-	if (intf->quirks & GB_INTERFACE_QUIRK_NO_ARA_IDS) {
-		intf->vendor_id = vendor_id;
-		intf->product_id = product_id;
-	}
+	ret = gb_interface_add(intf);
+	if (ret)
+		goto err_interface_deactivate;
 
+enable_interface:
 	ret = gb_interface_enable(intf);
 	if (ret) {
 		dev_err(&svc->dev, "failed to enable interface %u: %d\n",
@@ -518,19 +500,10 @@ static void gb_svc_process_intf_hotplug(struct gb_operation *operation)
 		goto err_interface_deactivate;
 	}
 
-	ret = gb_interface_add(intf);
-	if (ret) {
-		gb_interface_disable(intf);
-		gb_interface_deactivate(intf);
-		return;
-	}
-
 	return;
 
 err_interface_deactivate:
 	gb_interface_deactivate(intf);
-err_interface_add:
-	gb_interface_add(intf);
 }
 
 static void gb_svc_process_intf_hot_unplug(struct gb_operation *operation)