libertas: add sd8686 reset_card support

At http://dev.laptop.org/ticket/10748 we are seeing a case of the
libertas firmware randomly stopping responding to commands after
resume. Careful monitoring of communications indicates a firmware or
hardware bug, which has been reported to Marvell.

Work around this issue by adding a reset_card method; this is
automatically called when command timeouts are detected and provides an
instant recovery to this situation.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/drivers/net/wireless/libertas/if_sdio.c b/drivers/net/wireless/libertas/if_sdio.c
index 224e9853c48..387786e1b39 100644
--- a/drivers/net/wireless/libertas/if_sdio.c
+++ b/drivers/net/wireless/libertas/if_sdio.c
@@ -892,6 +892,37 @@ static int if_sdio_reset_deep_sleep_wakeup(struct lbs_private *priv)
 
 }
 
+static struct mmc_host *reset_host;
+
+static void if_sdio_reset_card_worker(struct work_struct *work)
+{
+        /*
+         * The actual reset operation must be run outside of lbs_thread. This
+         * is because mmc_remove_host() will cause the device to be instantly
+         * destroyed, and the libertas driver then needs to end lbs_thread,
+         * leading to a deadlock.
+         *
+         * We run it in a workqueue totally independent from the if_sdio_card
+         * instance for that reason.
+         */
+
+        pr_info("Resetting card...");
+        mmc_remove_host(reset_host);
+        mmc_add_host(reset_host);
+}
+static DECLARE_WORK(card_reset_work, if_sdio_reset_card_worker);
+
+static void if_sdio_reset_card(struct lbs_private *priv)
+{
+        struct if_sdio_card *card = priv->card;
+
+        if (work_pending(&card_reset_work))
+                return;
+
+        reset_host = card->func->card->host;
+        schedule_work(&card_reset_work);
+}
+
 /*******************************************************************/
 /* SDIO callbacks                                                  */
 /*******************************************************************/
@@ -1065,6 +1096,7 @@ static int if_sdio_probe(struct sdio_func *func,
         priv->enter_deep_sleep = if_sdio_enter_deep_sleep;
         priv->exit_deep_sleep = if_sdio_exit_deep_sleep;
         priv->reset_deep_sleep_wakeup = if_sdio_reset_deep_sleep_wakeup;
+        priv->reset_card = if_sdio_reset_card;
 
         sdio_claim_host(func);
 
@@ -1301,6 +1333,8 @@ static void __exit if_sdio_exit_module(void)
         /* Set the flag as user is removing this module. */
         user_rmmod = 1;
 
+        cancel_work_sync(&card_reset_work);
+
         sdio_unregister_driver(&if_sdio_driver);
 
         lbs_deb_leave(LBS_DEB_SDIO);