3 files changed, 92 insertions, 0 deletions

diff --git a/drivers/net/wimax/i2400m/driver.c b/drivers/net/wimax/i2400m/driver.c
index 1674dba43f83..d83fe84407bf 100644
--- a/drivers/net/wimax/i2400m/driver.c
+++ b/drivers/net/wimax/i2400m/driver.c
@@ -395,6 +395,16 @@ retry:
         result = i2400m_dev_initialize(i2400m);
         if (result < 0)
                 goto error_dev_initialize;
+
+        /* We don't want any additional unwanted error recovery triggered
+         * from any other context so if anything went wrong before we come
+         * here, let's keep i2400m->error_recovery untouched and leave it to
+         * dev_reset_handle(). See dev_reset_handle(). */
+
+        atomic_dec(&i2400m->error_recovery);
+        /* Every thing works so far, ok, now we are ready to
+         * take error recovery if it's required. */
+
         /* At this point, reports will come for the device and set it
          * to the right state if it is different than UNINITIALIZED */
         d_fnend(3, dev, "(net_dev %p [i2400m %p]) = %d\n",
@@ -770,6 +780,66 @@ int i2400m_dev_reset_handle(struct i2400m *i2400m, const char *reason)
 EXPORT_SYMBOL_GPL(i2400m_dev_reset_handle);
 
 
+ /*
+ * The actual work of error recovery.
+ *
+ * The current implementation of error recovery is to trigger a bus reset.
+ */
+static
+void __i2400m_error_recovery(struct work_struct *ws)
+{
+        struct i2400m_work *iw = container_of(ws, struct i2400m_work, ws);
+        struct i2400m *i2400m = iw->i2400m;
+
+        i2400m_reset(i2400m, I2400M_RT_BUS);
+
+        i2400m_put(i2400m);
+        kfree(iw);
+        return;
+}
+
+/*
+ * Schedule a work struct for error recovery.
+ *
+ * The intention of error recovery is to bring back the device to some
+ * known state whenever TX sees -110 (-ETIMEOUT) on copying the data to
+ * the device. The TX failure could mean a device bus stuck, so the current
+ * error recovery implementation is to trigger a bus reset to the device
+ * and hopefully it can bring back the device.
+ *
+ * The actual work of error recovery has to be in a thread context because
+ * it is kicked off in the TX thread (i2400ms->tx_workqueue) which is to be
+ * destroyed by the error recovery mechanism (currently a bus reset).
+ *
+ * Also, there may be already a queue of TX works that all hit
+ * the -ETIMEOUT error condition because the device is stuck already.
+ * Since bus reset is used as the error recovery mechanism and we don't
+ * want consecutive bus resets simply because the multiple TX works
+ * in the queue all hit the same device erratum, the flag "error_recovery"
+ * is introduced for preventing unwanted consecutive bus resets.
+ *
+ * Error recovery shall only be invoked again if previous one was completed.
+ * The flag error_recovery is set when error recovery mechanism is scheduled,
+ * and is checked when we need to schedule another error recovery. If it is
+ * in place already, then we shouldn't schedule another one.
+ */
+void i2400m_error_recovery(struct i2400m *i2400m)
+{
+        struct device *dev = i2400m_dev(i2400m);
+
+        if (atomic_add_return(1, &i2400m->error_recovery) == 1) {
+                if (i2400m_schedule_work(i2400m, __i2400m_error_recovery,
+                        GFP_ATOMIC, NULL, 0) < 0) {
+                        dev_err(dev, "run out of memory for "
+                                "scheduling an error recovery ?\n");
+                        atomic_dec(&i2400m->error_recovery);
+                }
+        } else
+                atomic_dec(&i2400m->error_recovery);
+        return;
+}
+EXPORT_SYMBOL_GPL(i2400m_error_recovery);
+
 /*
  * Alloc the command and ack buffers for boot mode
  *
@@ -839,6 +909,10 @@ void i2400m_init(struct i2400m *i2400m)
         atomic_set(&i2400m->bus_reset_retries, 0);
 
         i2400m->alive = 0;
+
+        /* initialize error_recovery to 1 for denoting we
+         * are not yet ready to take any error recovery */
+        atomic_set(&i2400m->error_recovery, 1);
 }
 EXPORT_SYMBOL_GPL(i2400m_init);
 
diff --git a/drivers/net/wimax/i2400m/i2400m.h b/drivers/net/wimax/i2400m/i2400m.h
index ad8e6a3be1e3..7a9c2c5b25cb 100644
--- a/drivers/net/wimax/i2400m/i2400m.h
+++ b/drivers/net/wimax/i2400m/i2400m.h
@@ -545,6 +545,15 @@ struct i2400m_barker_db;
  *      all the device reboot events detected can be still handled properly
  *      by either dev_reset_handle() or .pre_reset/.post_reset as long as
  *      the driver presents. It is set 0 along with @updown in dev_stop().
+ *
+ * @error_recovery: flag to denote if we are ready to take an error recovery.
+ *      0 for ready to take an error recovery; 1 for not ready. It is
+ *      initialized to 1 while probe() since we don't tend to take any error
+ *      recovery during probe(). It is decremented by 1 whenever dev_start()
+ *      succeeds to indicate we are ready to take error recovery from now on.
+ *      It is checked every time we wanna schedule an error recovery. If an
+ *      error recovery is already in place (error_recovery was set 1), we
+ *      should not schedule another one until the last one is done.
  */
 struct i2400m {
         struct wimax_dev wimax_dev;     /* FIRST! See doc */
@@ -625,6 +634,10 @@ struct i2400m {
 
         /* if the device is expected to be alive */
         unsigned alive;
+
+        /* 0 if we are ready for error recovery; 1 if not ready  */
+        atomic_t error_recovery;
+
 };
 
 
@@ -847,6 +860,7 @@ void i2400m_put(struct i2400m *i2400m)
 extern int i2400m_dev_reset_handle(struct i2400m *, const char *);
 extern int i2400m_pre_reset(struct i2400m *);
 extern int i2400m_post_reset(struct i2400m *);
+extern void i2400m_error_recovery(struct i2400m *);
 
 /*
  * _setup()/_release() are called by the probe/disconnect functions of
diff --git a/drivers/net/wimax/i2400m/sdio-tx.c b/drivers/net/wimax/i2400m/sdio-tx.c
index 412b6a8eaef2..b53cd1c80e3e 100644
--- a/drivers/net/wimax/i2400m/sdio-tx.c
+++ b/drivers/net/wimax/i2400m/sdio-tx.c
@@ -98,6 +98,10 @@ void i2400ms_tx_submit(struct work_struct *ws)
                                 tx_msg_size, result);
                 }
 
+                if (result == -ETIMEDOUT) {
+                        i2400m_error_recovery(i2400m);
+                        break;
+                }
                 d_printf(2, dev, "TX: %zub submitted\n", tx_msg_size);
         }