1 files changed, 0 insertions, 184 deletions
diff --git a/target/linux/generic/pending-3.18/092-02-spi-Pump-transfers-inside-calling-context-for-spi_sy.patch b/target/linux/generic/pending-3.18/092-02-spi-Pump-transfers-inside-calling-context-for-spi_sy.patch
deleted file mode 100644
index b74b4cb93b..0000000000
--- a/target/linux/generic/pending-3.18/092-02-spi-Pump-transfers-inside-calling-context-for-spi_sy.patch
+++ /dev/null
@@ -1,184 +0,0 @@
-From: Mark Brown <broonie@kernel.org>
-Date: Tue, 9 Dec 2014 21:38:05 +0000
-Subject: [PATCH] spi: Pump transfers inside calling context for spi_sync()
-
-If we are using the standard SPI message pump (which all drivers should be
-transitioning over to) then special case the message enqueue and instead of
-starting the worker thread to push messages to the hardware do so in the
-context of the caller if the controller is idle. This avoids a context
-switch in the common case where the controller has a single user in a
-single thread, for short PIO transfers there may be no need to context
-switch away from the calling context to complete the transfer.
-
-The code is a bit more complex than is desirable in part due to the need
-to handle drivers not using the standard queue and in part due to handling
-the various combinations of bus locking and asynchronous submission in
-interrupt context.
-
-It is still suboptimal since it will still wake the message pump for each
-transfer in order to schedule idling of the hardware and if multiple
-contexts are using the controller simultaneously a caller may end up
-pumping a message for some random other thread rather than for itself,
-and if the thread ends up deferring due to another context idling the
-hardware then it will just busy wait.  It can, however, have the benefit
-of aggregating power up and down of the hardware when a caller performs
-a series of transfers back to back without any need for the use of
-spi_async().
-
-Signed-off-by: Mark Brown <broonie@kernel.org>
----
-
---- a/drivers/spi/spi.c
-+++ b/drivers/spi/spi.c
-@@ -882,6 +882,9 @@ EXPORT_SYMBOL_GPL(spi_finalize_current_t
-  * needs processing and if so call out to the driver to initialize hardware
-  * and transfer each message.
-  *
-+ * Note that it is called both from the kthread itself and also from
-+ * inside spi_sync(); the queue extraction handling at the top of the
-+ * function should deal with this safely.
-  */
- static void spi_pump_messages(struct kthread_work *work)
- {
-@@ -900,6 +903,13 @@ static void spi_pump_messages(struct kth
- 		return;
- 	}
- 
-+	/* If another context is idling the device then defer */
-+	if (master->idling) {
-+		queue_kthread_work(&master->kworker, &master->pump_messages);
-+		spin_unlock_irqrestore(&master->queue_lock, flags);
-+		return;
-+	}
-+
- 	/* Check if the queue is idle */
- 	if (list_empty(&master->queue) || !master->running) {
- 		if (!master->busy) {
-@@ -907,7 +917,9 @@ static void spi_pump_messages(struct kth
- 			return;
- 		}
- 		master->busy = false;
-+		master->idling = true;
- 		spin_unlock_irqrestore(&master->queue_lock, flags);
-+
- 		kfree(master->dummy_rx);
- 		master->dummy_rx = NULL;
- 		kfree(master->dummy_tx);
-@@ -921,6 +933,10 @@ static void spi_pump_messages(struct kth
- 			pm_runtime_put_autosuspend(master->dev.parent);
- 		}
- 		trace_spi_master_idle(master);
-+
-+		spin_lock_irqsave(&master->queue_lock, flags);
-+		master->idling = false;
-+		spin_unlock_irqrestore(&master->queue_lock, flags);
- 		return;
- 	}
- 
-@@ -1166,12 +1182,9 @@ static int spi_destroy_queue(struct spi_
- 	return 0;
- }
- 
--/**
-- * spi_queued_transfer - transfer function for queued transfers
-- * @spi: spi device which is requesting transfer
-- * @msg: spi message which is to handled is queued to driver queue
-- */
--static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
-+static int __spi_queued_transfer(struct spi_device *spi,
-+				 struct spi_message *msg,
-+				 bool need_pump)
- {
- 	struct spi_master *master = spi->master;
- 	unsigned long flags;
-@@ -1186,13 +1199,23 @@ static int spi_queued_transfer(struct sp
- 	msg->status = -EINPROGRESS;
- 
- 	list_add_tail(&msg->queue, &master->queue);
--	if (!master->busy)
-+	if (!master->busy && need_pump)
- 		queue_kthread_work(&master->kworker, &master->pump_messages);
- 
- 	spin_unlock_irqrestore(&master->queue_lock, flags);
- 	return 0;
- }
- 
-+/**
-+ * spi_queued_transfer - transfer function for queued transfers
-+ * @spi: spi device which is requesting transfer
-+ * @msg: spi message which is to handled is queued to driver queue
-+ */
-+static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
-+{
-+	return __spi_queued_transfer(spi, msg, true);
-+}
-+
- static int spi_master_initialize_queue(struct spi_master *master)
- {
- 	int ret;
-@@ -2104,19 +2127,46 @@ static int __spi_sync(struct spi_device
- 	DECLARE_COMPLETION_ONSTACK(done);
- 	int status;
- 	struct spi_master *master = spi->master;
-+	unsigned long flags;
-+
-+	status = __spi_validate(spi, message);
-+	if (status != 0)
-+		return status;
- 
- 	message->complete = spi_complete;
- 	message->context = &done;
-+	message->spi = spi;
- 
- 	if (!bus_locked)
- 		mutex_lock(&master->bus_lock_mutex);
- 
--	status = spi_async_locked(spi, message);
-+	/* If we're not using the legacy transfer method then we will
-+	 * try to transfer in the calling context so special case.
-+	 * This code would be less tricky if we could remove the
-+	 * support for driver implemented message queues.
-+	 */
-+	if (master->transfer == spi_queued_transfer) {
-+		spin_lock_irqsave(&master->bus_lock_spinlock, flags);
-+
-+		trace_spi_message_submit(message);
-+
-+		status = __spi_queued_transfer(spi, message, false);
-+
-+		spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
-+	} else {
-+		status = spi_async_locked(spi, message);
-+	}
- 
- 	if (!bus_locked)
- 		mutex_unlock(&master->bus_lock_mutex);
- 
- 	if (status == 0) {
-+		/* Push out the messages in the calling context if we
-+		 * can.
-+		 */
-+		if (master->transfer == spi_queued_transfer)
-+			spi_pump_messages(&master->pump_messages);
-+
- 		wait_for_completion(&done);
- 		status = message->status;
- 	}
---- a/include/linux/spi/spi.h
-+++ b/include/linux/spi/spi.h
-@@ -260,6 +260,7 @@ static inline void spi_unregister_driver
-  * @pump_messages: work struct for scheduling work to the message pump
-  * @queue_lock: spinlock to syncronise access to message queue
-  * @queue: message queue
-+ * @idling: the device is entering idle state
-  * @cur_msg: the currently in-flight message
-  * @cur_msg_prepared: spi_prepare_message was called for the currently
-  *                    in-flight message
-@@ -425,6 +426,7 @@ struct spi_master {
- 	spinlock_t			queue_lock;
- 	struct list_head		queue;
- 	struct spi_message		*cur_msg;
-+	bool				idling;
- 	bool				busy;
- 	bool				running;
- 	bool				rt;