greybus: interface: avoid I/O to bootrom during removal

Add an interface quirk flag to suppress I/O during interface disable.

This is needed to prevent I/O to the bootrom during controlled
connection tear down (e.g. eject or driver unbind). This will be more
obvious with the new connection tear-down procedure.

Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/interface.c

@@ -221,8 +221,8 @@ static int gb_interface_read_and_clear_init_status(struct gb_interface *intf)
 	 * Check if the interface is executing the quirky ES3 bootrom that,
 	 * for example, requires E2EFC, CSD and CSV to be disabled.
 	 */
-	bootrom_quirks = GB_INTERFACE_QUIRK_NO_CPORT_FEATURES;
-
+	bootrom_quirks = GB_INTERFACE_QUIRK_NO_CPORT_FEATURES |
+				GB_INTERFACE_QUIRK_FORCED_DISABLE;
 	switch (init_status) {
 	case GB_INIT_BOOTROM_UNIPRO_BOOT_STARTED:
 	case GB_INIT_BOOTROM_FALLBACK_UNIPRO_BOOT_STARTED:
@@ -674,6 +674,10 @@ void gb_interface_disable(struct gb_interface *intf)
 
 	trace_gb_interface_disable(intf);
 
+	/* Set disconnected flag to avoid I/O during connection tear down. */
+	if (intf->quirks & GB_INTERFACE_QUIRK_FORCED_DISABLE)
+		intf->disconnected = true;
+
 	list_for_each_entry_safe(bundle, next, &intf->bundles, links)
 		gb_bundle_destroy(bundle);
 

drivers/staging/greybus/interface.h

@@ -13,6 +13,7 @@
 #define GB_INTERFACE_QUIRK_NO_CPORT_FEATURES		BIT(0)
 #define GB_INTERFACE_QUIRK_NO_INIT_STATUS		BIT(1)
 #define GB_INTERFACE_QUIRK_NO_ARA_IDS			BIT(2)
+#define GB_INTERFACE_QUIRK_FORCED_DISABLE		BIT(3)
 
 struct gb_interface {
 	struct device dev;