target/linux/generic/patches-2.6.32/910-backport-spi-bus-locking-api.patch


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.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */This patch causes STA mode interfaces to disassociate if transmission of assoc/auth
critical packets failed.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

--- a/ath/if_ath.c
+++ b/ath/if_ath.c
@@ -8315,6 +8315,18 @@
 #endif
 				if (ts->ts_status & HAL_TXERR_XRETRY) {
 					sc->sc_stats.ast_tx_xretries++;
+					if (SKB_CB(bf->bf_skb)->auth_pkt && (ni->ni_vap->iv_opmode == IEEE80211_M_STA)) {
+						struct ieee80211com *ic = &sc->sc_ic;
+
+						/* if roaming is enabled, try reassociating, otherwise
+						 * disassociate and go back to the scan state */
+						IEEE80211_VAPS_LOCK_BH(ic);
+						if (ic->ic_roaming == IEEE80211_ROAMING_AUTO)
+							ni->ni_vap->iv_newstate(ni->ni_vap, IEEE80211_S_ASSOC, 1);
+						else
+							ni->ni_vap->iv_newstate(ni->ni_vap, IEEE80211_S_SCAN, 0);
+						IEEE80211_VAPS_UNLOCK_BH(ic);
+					}
 					if (ni->ni_flags & IEEE80211_NODE_UAPSD_TRIG) {
 						ni->ni_stats.ns_tx_eosplost++;
 						DPRINTF(sc, ATH_DEBUG_UAPSD,
--- a/net80211/ieee80211_linux.c
+++ b/net80211/ieee80211_linux.c
@@ -156,6 +156,7 @@
 		if (off != 0)
 			skb_reserve(skb, align - off);
 
+		SKB_CB(skb)->auth_pkt = 0;
 		SKB_CB(skb)->ni = NULL;
 		SKB_CB(skb)->flags = 0;
 		SKB_CB(skb)->next = NULL;
--- a/net80211/ieee80211_linux.h
+++ b/net80211/ieee80211_linux.h
@@ -393,6 +393,7 @@
 	void		(*next_destructor)(struct sk_buff *skb);
 #endif
 	struct sk_buff *next;			/* fast frame sk_buf chain */
+	u_int8_t auth_pkt;
 };
 
 
--- a/net80211/ieee80211_output.c
+++ b/net80211/ieee80211_output.c
@@ -778,6 +778,8 @@
 	else
 		hdrsize = sizeof(struct ieee80211_frame);
 
+	SKB_CB(skb)->auth_pkt = (eh.ether_type == __constant_htons(ETHERTYPE_PAE));
+
 	switch (vap->iv_opmode) {
 	case IEEE80211_M_IBSS:
 	case IEEE80211_M_AHDEMO:
@@ -1622,6 +1624,7 @@
 	ie->param_len = frm - &ie->param_oui[0];
 	return frm;
 }
+
 #endif
 /*
  * Send a probe request frame with the specified ssid
@@ -1886,6 +1889,7 @@
 				sizeof(u_int16_t)+IEEE80211_CHALLENGE_LEN : 0));
 		if (skb == NULL)
 			senderr(ENOMEM, is_tx_nobuf);
+		SKB_CB(skb)->auth_pkt = 1;
 
 		((__le16 *)frm)[0] =
 			(is_shared_key) ? htole16(IEEE80211_AUTH_ALG_SHARED)
@@ -1960,6 +1964,7 @@
 			vap->app_ie[IEEE80211_APPIE_FRAME_ASSOC_REQ].length);
 		if (skb == NULL)
 			senderr(ENOMEM, is_tx_nobuf);
+		SKB_CB(skb)->auth_pkt = 1;
 
 		capinfo = 0;
 		if (vap->iv_opmode == IEEE80211_M_IBSS)
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