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Diffstat (limited to 'drivers/net/wimax/i2400m/driver.c')
-rw-r--r--drivers/net/wimax/i2400m/driver.c74
1 files changed, 74 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);