[PATCH] bcm43xx: Abstract the locking mechanism.

This is the starting point to make the driver out-of-order-MMIO-stores safe.
There are more mmiowb() needed.

Signed-off-by: Michael Buesch <mbuesch@freenet.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/drivers/net/wireless/bcm43xx/bcm43xx.h b/drivers/net/wireless/bcm43xx/bcm43xx.h
index fd9754b52951..5f8c63fab836 100644
--- a/drivers/net/wireless/bcm43xx/bcm43xx.h
+++ b/drivers/net/wireless/bcm43xx/bcm43xx.h
@@ -619,7 +619,9 @@ struct bcm43xx_private {
         void __iomem *mmio_addr;
         unsigned int mmio_len;
 
-        spinlock_t lock;
+        /* Do not use the lock directly. Use the bcm43xx_lock* helper
+         * functions, to be MMIO-safe. */
+        spinlock_t _lock;
 
         /* Driver status flags. */
         u32 initialized:1,              /* init_board() succeed */
@@ -721,6 +723,22 @@ struct bcm43xx_private {
 #endif
 };
 
+/* bcm43xx_(un)lock() protect struct bcm43xx_private.
+ * Note that _NO_ MMIO writes are allowed. If you want to
+ * write to the device through MMIO in the critical section, use
+ * the *_mmio lock functions.
+ * MMIO read-access is allowed, though.
+ */
+#define bcm43xx_lock(bcm, flags)        spin_lock_irqsave(&(bcm)->_lock, flags)
+#define bcm43xx_unlock(bcm, flags)      spin_unlock_irqrestore(&(bcm)->_lock, flags)
+/* bcm43xx_(un)lock_mmio() protect struct bcm43xx_private and MMIO.
+ * MMIO write-access to the device is allowed.
+ * All MMIO writes are flushed on unlock, so it is guaranteed to not
+ * interfere with other threads writing MMIO registers.
+ */
+#define bcm43xx_lock_mmio(bcm, flags)   bcm43xx_lock(bcm, flags)
+#define bcm43xx_unlock_mmio(bcm, flags) do { mmiowb(); bcm43xx_unlock(bcm, flags); } while (0)
+
 static inline
 struct bcm43xx_private * bcm43xx_priv(struct net_device *dev)
 {