Commit e16715c1 authored by Jeffrey Carlyle's avatar Jeffrey Carlyle Committed by Greg Kroah-Hartman
Browse files

greybus: interface: retry enumeration of UniPro-only modules 



Greybus modules will sometimes fail to send the mailbox poke and
erroneously be enumerated as UniPro-only modules. The root cause for
this on the module side is not fully understand, but it seems that this
may be due to "the bootrom bug:" a known problem with the bootrom where
linkup will occasionally fail because of a race condition.

Before the new hotplug code was implemented in the firmware, the SVC
would retry enumeration of modules that did not send the mailbox poke;
this patch ports that functionality to the AP.

Signed-off-by: default avatarJeffrey Carlyle <jcarlyle@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 9bc63b7f

drivers/staging/greybus/interface.c

+2 −1
Original line number Diff line number Diff line
@@ -447,7 +447,8 @@ static int gb_interface_activate_operation(struct gb_interface *intf) 
		return -ENODEV;

	case GB_SVC_INTF_TYPE_UNIPRO:

		dev_err(&intf->dev, "interface type UniPro not supported\n");

		return -ENODEV;

		/* FIXME: check if this is a Toshiba bridge before retrying? */

		return -EAGAIN;

	case GB_SVC_INTF_TYPE_GREYBUS:

		break;

	default:

drivers/staging/greybus/module.c

+20 −1
Original line number Diff line number Diff line
@@ -138,13 +138,32 @@ static void gb_module_register_interface(struct gb_interface *intf) 
	struct gb_module *module = intf->module;

	u8 intf_id = intf->interface_id;

	int ret;

	int retries = 3;



	mutex_lock(&intf->mutex);



	while (retries--) {

		ret = gb_interface_activate(intf);

		if (ret != -EAGAIN)

			break;

	}

	if (ret) {

		dev_err(&module->dev, "failed to activate interface %u: %d\n",

				intf_id, ret);



		/*

		 * -EAGAIN indicates that the Greybus operation

		 * interface_activate determined the remote interface to be

		 * UniPro-only.  At present, we assume a UniPro-only module

		 * to be a Greybus module that failed to send its mailbox

		 * poke.  There is some reason to believe that this is

		 * because of a bug in the ES3 bootrom.  If we exhause our

		 * retries trying to activate such an interface, convert

		 * the error code back into a "no device" error.

		 */

		if (ret == -EAGAIN)

			ret = -ENODEV;



		gb_interface_add(intf);

		goto err_unlock;

	}