1 files changed, 0 insertions, 382 deletions
diff --git a/target/linux/generic/patches-2.6.33/910-backport-spi-bus-locking-api.patch b/target/linux/generic/patches-2.6.33/910-backport-spi-bus-locking-api.patch
deleted file mode 100644
index 23becab917..0000000000
--- a/target/linux/generic/patches-2.6.33/910-backport-spi-bus-locking-api.patch
+++ /dev/null
@@ -1,382 +0,0 @@
-From cf32b71e981ca63e8f349d8585ca2a3583b556e0 Mon Sep 17 00:00:00 2001
-From: Ernst Schwab <eschwab@online.de>
-Date: Mon, 28 Jun 2010 17:49:29 -0700
-Subject: [PATCH] spi/mmc_spi: SPI bus locking API, using mutex
-
-SPI bus locking API to allow exclusive access to the SPI bus, especially, but
-not limited to, for the mmc_spi driver.
-
-Coded according to an outline from Grant Likely; here is his
-specification (accidentally swapped function names corrected):
-
-It requires 3 things to be added to struct spi_master.
-- 1 Mutex
-- 1 spin lock
-- 1 flag.
-
-The mutex protects spi_sync, and provides sleeping "for free"
-The spinlock protects the atomic spi_async call.
-The flag is set when the lock is obtained, and checked while holding
-the spinlock in spi_async().  If the flag is checked, then spi_async()
-must fail immediately.
-
-The current runtime API looks like this:
-spi_async(struct spi_device*, struct spi_message*);
-spi_sync(struct spi_device*, struct spi_message*);
-
-The API needs to be extended to this:
-spi_async(struct spi_device*, struct spi_message*)
-spi_sync(struct spi_device*, struct spi_message*)
-spi_bus_lock(struct spi_master*)  /* although struct spi_device* might
-be easier */
-spi_bus_unlock(struct spi_master*)
-spi_async_locked(struct spi_device*, struct spi_message*)
-spi_sync_locked(struct spi_device*, struct spi_message*)
-
-Drivers can only call the last two if they already hold the spi_master_lock().
-
-spi_bus_lock() obtains the mutex, obtains the spin lock, sets the
-flag, and releases the spin lock before returning.  It doesn't even
-need to sleep while waiting for "in-flight" spi_transactions to
-complete because its purpose is to guarantee no additional
-transactions are added.  It does not guarantee that the bus is idle.
-
-spi_bus_unlock() clears the flag and releases the mutex, which will
-wake up any waiters.
-
-The difference between spi_async() and spi_async_locked() is that the
-locked version bypasses the check of the lock flag.  Both versions
-need to obtain the spinlock.
-
-The difference between spi_sync() and spi_sync_locked() is that
-spi_sync() must hold the mutex while enqueuing a new transfer.
-spi_sync_locked() doesn't because the mutex is already held.  Note
-however that spi_sync must *not* continue to hold the mutex while
-waiting for the transfer to complete, otherwise only one transfer
-could be queued up at a time!
-
-Almost no code needs to be written.  The current spi_async() and
-spi_sync() can probably be renamed to __spi_async() and __spi_sync()
-so that spi_async(), spi_sync(), spi_async_locked() and
-spi_sync_locked() can just become wrappers around the common code.
-
-spi_sync() is protected by a mutex because it can sleep
-spi_async() needs to be protected with a flag and a spinlock because
-it can be called atomically and must not sleep
-
-Signed-off-by: Ernst Schwab <eschwab@online.de>
-[grant.likely@secretlab.ca: use spin_lock_irqsave()]
-Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
-Tested-by: Matt Fleming <matt@console-pimps.org>
-Tested-by: Antonio Ospite <ospite@studenti.unina.it>
----
- drivers/spi/spi.c       |  225 ++++++++++++++++++++++++++++++++++++++++-------
- include/linux/spi/spi.h |   12 +++
- 2 files changed, 204 insertions(+), 33 deletions(-)
-
---- a/drivers/spi/spi.c
-+++ b/drivers/spi/spi.c
-@@ -524,6 +524,10 @@ int spi_register_master(struct spi_maste
- 		dynamic = 1;
- 	}
- 
-+	spin_lock_init(&master->bus_lock_spinlock);
-+	mutex_init(&master->bus_lock_mutex);
-+	master->bus_lock_flag = 0;
-+
- 	/* register the device, then userspace will see it.
- 	 * registration fails if the bus ID is in use.
- 	 */
-@@ -663,6 +667,35 @@ int spi_setup(struct spi_device *spi)
- }
- EXPORT_SYMBOL_GPL(spi_setup);
- 
-+static int __spi_async(struct spi_device *spi, struct spi_message *message)
-+{
-+	struct spi_master *master = spi->master;
-+
-+	/* Half-duplex links include original MicroWire, and ones with
-+	 * only one data pin like SPI_3WIRE (switches direction) or where
-+	 * either MOSI or MISO is missing.  They can also be caused by
-+	 * software limitations.
-+	 */
-+	if ((master->flags & SPI_MASTER_HALF_DUPLEX)
-+			|| (spi->mode & SPI_3WIRE)) {
-+		struct spi_transfer *xfer;
-+		unsigned flags = master->flags;
-+
-+		list_for_each_entry(xfer, &message->transfers, transfer_list) {
-+			if (xfer->rx_buf && xfer->tx_buf)
-+				return -EINVAL;
-+			if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
-+				return -EINVAL;
-+			if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
-+				return -EINVAL;
-+		}
-+	}
-+
-+	message->spi = spi;
-+	message->status = -EINPROGRESS;
-+	return master->transfer(spi, message);
-+}
-+
- /**
-  * spi_async - asynchronous SPI transfer
-  * @spi: device with which data will be exchanged
-@@ -695,33 +728,68 @@ EXPORT_SYMBOL_GPL(spi_setup);
- int spi_async(struct spi_device *spi, struct spi_message *message)
- {
- 	struct spi_master *master = spi->master;
-+	int ret;
-+	unsigned long flags;
- 
--	/* Half-duplex links include original MicroWire, and ones with
--	 * only one data pin like SPI_3WIRE (switches direction) or where
--	 * either MOSI or MISO is missing.  They can also be caused by
--	 * software limitations.
--	 */
--	if ((master->flags & SPI_MASTER_HALF_DUPLEX)
--			|| (spi->mode & SPI_3WIRE)) {
--		struct spi_transfer *xfer;
--		unsigned flags = master->flags;
-+	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
- 
--		list_for_each_entry(xfer, &message->transfers, transfer_list) {
--			if (xfer->rx_buf && xfer->tx_buf)
--				return -EINVAL;
--			if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
--				return -EINVAL;
--			if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
--				return -EINVAL;
--		}
--	}
-+	if (master->bus_lock_flag)
-+		ret = -EBUSY;
-+	else
-+		ret = __spi_async(spi, message);
- 
--	message->spi = spi;
--	message->status = -EINPROGRESS;
--	return master->transfer(spi, message);
-+	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
-+
-+	return ret;
- }
- EXPORT_SYMBOL_GPL(spi_async);
- 
-+/**
-+ * spi_async_locked - version of spi_async with exclusive bus usage
-+ * @spi: device with which data will be exchanged
-+ * @message: describes the data transfers, including completion callback
-+ * Context: any (irqs may be blocked, etc)
-+ *
-+ * This call may be used in_irq and other contexts which can't sleep,
-+ * as well as from task contexts which can sleep.
-+ *
-+ * The completion callback is invoked in a context which can't sleep.
-+ * Before that invocation, the value of message->status is undefined.
-+ * When the callback is issued, message->status holds either zero (to
-+ * indicate complete success) or a negative error code.  After that
-+ * callback returns, the driver which issued the transfer request may
-+ * deallocate the associated memory; it's no longer in use by any SPI
-+ * core or controller driver code.
-+ *
-+ * Note that although all messages to a spi_device are handled in
-+ * FIFO order, messages may go to different devices in other orders.
-+ * Some device might be higher priority, or have various "hard" access
-+ * time requirements, for example.
-+ *
-+ * On detection of any fault during the transfer, processing of
-+ * the entire message is aborted, and the device is deselected.
-+ * Until returning from the associated message completion callback,
-+ * no other spi_message queued to that device will be processed.
-+ * (This rule applies equally to all the synchronous transfer calls,
-+ * which are wrappers around this core asynchronous primitive.)
-+ */
-+int spi_async_locked(struct spi_device *spi, struct spi_message *message)
-+{
-+	struct spi_master *master = spi->master;
-+	int ret;
-+	unsigned long flags;
-+
-+	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
-+
-+	ret = __spi_async(spi, message);
-+
-+	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
-+
-+	return ret;
-+
-+}
-+EXPORT_SYMBOL_GPL(spi_async_locked);
-+
- 
- /*-------------------------------------------------------------------------*/
- 
-@@ -735,6 +803,32 @@ static void spi_complete(void *arg)
- 	complete(arg);
- }
- 
-+static int __spi_sync(struct spi_device *spi, struct spi_message *message,
-+		      int bus_locked)
-+{
-+	DECLARE_COMPLETION_ONSTACK(done);
-+	int status;
-+	struct spi_master *master = spi->master;
-+
-+	message->complete = spi_complete;
-+	message->context = &done;
-+
-+	if (!bus_locked)
-+		mutex_lock(&master->bus_lock_mutex);
-+
-+	status = spi_async_locked(spi, message);
-+
-+	if (!bus_locked)
-+		mutex_unlock(&master->bus_lock_mutex);
-+
-+	if (status == 0) {
-+		wait_for_completion(&done);
-+		status = message->status;
-+	}
-+	message->context = NULL;
-+	return status;
-+}
-+
- /**
-  * spi_sync - blocking/synchronous SPI data transfers
-  * @spi: device with which data will be exchanged
-@@ -758,21 +852,86 @@ static void spi_complete(void *arg)
-  */
- int spi_sync(struct spi_device *spi, struct spi_message *message)
- {
--	DECLARE_COMPLETION_ONSTACK(done);
--	int status;
--
--	message->complete = spi_complete;
--	message->context = &done;
--	status = spi_async(spi, message);
--	if (status == 0) {
--		wait_for_completion(&done);
--		status = message->status;
--	}
--	message->context = NULL;
--	return status;
-+	return __spi_sync(spi, message, 0);
- }
- EXPORT_SYMBOL_GPL(spi_sync);
- 
-+/**
-+ * spi_sync_locked - version of spi_sync with exclusive bus usage
-+ * @spi: device with which data will be exchanged
-+ * @message: describes the data transfers
-+ * Context: can sleep
-+ *
-+ * This call may only be used from a context that may sleep.  The sleep
-+ * is non-interruptible, and has no timeout.  Low-overhead controller
-+ * drivers may DMA directly into and out of the message buffers.
-+ *
-+ * This call should be used by drivers that require exclusive access to the
-+ * SPI bus. It has to be preceeded by a spi_bus_lock call. The SPI bus must
-+ * be released by a spi_bus_unlock call when the exclusive access is over.
-+ *
-+ * It returns zero on success, else a negative error code.
-+ */
-+int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
-+{
-+	return __spi_sync(spi, message, 1);
-+}
-+EXPORT_SYMBOL_GPL(spi_sync_locked);
-+
-+/**
-+ * spi_bus_lock - obtain a lock for exclusive SPI bus usage
-+ * @master: SPI bus master that should be locked for exclusive bus access
-+ * Context: can sleep
-+ *
-+ * This call may only be used from a context that may sleep.  The sleep
-+ * is non-interruptible, and has no timeout.
-+ *
-+ * This call should be used by drivers that require exclusive access to the
-+ * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
-+ * exclusive access is over. Data transfer must be done by spi_sync_locked
-+ * and spi_async_locked calls when the SPI bus lock is held.
-+ *
-+ * It returns zero on success, else a negative error code.
-+ */
-+int spi_bus_lock(struct spi_master *master)
-+{
-+	unsigned long flags;
-+
-+	mutex_lock(&master->bus_lock_mutex);
-+
-+	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
-+	master->bus_lock_flag = 1;
-+	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
-+
-+	/* mutex remains locked until spi_bus_unlock is called */
-+
-+	return 0;
-+}
-+EXPORT_SYMBOL_GPL(spi_bus_lock);
-+
-+/**
-+ * spi_bus_unlock - release the lock for exclusive SPI bus usage
-+ * @master: SPI bus master that was locked for exclusive bus access
-+ * Context: can sleep
-+ *
-+ * This call may only be used from a context that may sleep.  The sleep
-+ * is non-interruptible, and has no timeout.
-+ *
-+ * This call releases an SPI bus lock previously obtained by an spi_bus_lock
-+ * call.
-+ *
-+ * It returns zero on success, else a negative error code.
-+ */
-+int spi_bus_unlock(struct spi_master *master)
-+{
-+	master->bus_lock_flag = 0;
-+
-+	mutex_unlock(&master->bus_lock_mutex);
-+
-+	return 0;
-+}
-+EXPORT_SYMBOL_GPL(spi_bus_unlock);
-+
- /* portable code must never pass more than 32 bytes */
- #define	SPI_BUFSIZ	max(32,SMP_CACHE_BYTES)
- 
---- a/include/linux/spi/spi.h
-+++ b/include/linux/spi/spi.h
-@@ -261,6 +261,13 @@ struct spi_master {
- #define SPI_MASTER_NO_RX	BIT(1)		/* can't do buffer read */
- #define SPI_MASTER_NO_TX	BIT(2)		/* can't do buffer write */
- 
-+	/* lock and mutex for SPI bus locking */
-+	spinlock_t		bus_lock_spinlock;
-+	struct mutex		bus_lock_mutex;
-+
-+	/* flag indicating that the SPI bus is locked for exclusive use */
-+	bool			bus_lock_flag;
-+
- 	/* Setup mode and clock, etc (spi driver may call many times).
- 	 *
- 	 * IMPORTANT:  this may be called when transfers to another
-@@ -541,6 +548,8 @@ static inline void spi_message_free(stru
- 
- extern int spi_setup(struct spi_device *spi);
- extern int spi_async(struct spi_device *spi, struct spi_message *message);
-+extern int spi_async_locked(struct spi_device *spi,
-+			    struct spi_message *message);
- 
- /*---------------------------------------------------------------------------*/
- 
-@@ -550,6 +559,9 @@ extern int spi_async(struct spi_device *
-  */
- 
- extern int spi_sync(struct spi_device *spi, struct spi_message *message);
-+extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message);
-+extern int spi_bus_lock(struct spi_master *master);
-+extern int spi_bus_unlock(struct spi_master *master);
- 
- /**
-  * spi_write - SPI synchronous write