diff options
author | Jeffrey Carlyle <jcarlyle@google.com> | 2016-05-18 18:55:13 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@google.com> | 2016-05-18 18:59:22 -0700 |
commit | e16715c135d80aafea867849f938b080d4f4eadb (patch) | |
tree | 99ecb0aba76d6f5a0c9c369d1a6ff4796b1bd626 | |
parent | 9bc63b7ff56f7a1cad5dbf062d1d5dd7a81d7d93 (diff) | |
download | linux-e16715c135d80aafea867849f938b080d4f4eadb.tar.bz2 |
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: Jeffrey Carlyle <jcarlyle@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
-rw-r--r-- | drivers/staging/greybus/interface.c | 3 | ||||
-rw-r--r-- | drivers/staging/greybus/module.c | 21 |
2 files changed, 22 insertions, 2 deletions
diff --git a/drivers/staging/greybus/interface.c b/drivers/staging/greybus/interface.c index a1435e94f5a1..3b5669375ed3 100644 --- a/drivers/staging/greybus/interface.c +++ b/drivers/staging/greybus/interface.c @@ -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: diff --git a/drivers/staging/greybus/module.c b/drivers/staging/greybus/module.c index 5077253037c8..ea5895475181 100644 --- a/drivers/staging/greybus/module.c +++ b/drivers/staging/greybus/module.c @@ -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); - ret = gb_interface_activate(intf); + 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; } |