b43legacy: fix DMA for 30/32-bit DMA engines

This checks if the DMA address is bigger than what the controller can manage.
It will reallocate the buffers in the GFP_DMA zone in that case.

The patch by Michael Buesch has been ported to b43legacy.
Thanks to Matti Viljanen for reporting this.

Cc: Matti Viljanen <viljanen.matti@gmail.com>
Signed-off-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/b43legacy/dma.h

@@ -218,6 +218,12 @@ struct b43legacy_dma_ops {
 	void (*set_current_rxslot)(struct b43legacy_dmaring *ring, int slot);
 };
 
+enum b43legacy_dmatype {
+	B43legacy_DMA_30BIT = 30,
+	B43legacy_DMA_32BIT = 32,
+	B43legacy_DMA_64BIT = 64,
+};
+
 struct b43legacy_dmaring {
 	/* Lowlevel DMA ops. */
 	const struct b43legacy_dma_ops *ops;
@@ -250,8 +256,8 @@ struct b43legacy_dmaring {
 	int index;
 	/* Boolean. Is this a TX ring? */
 	bool tx;
-	/* Boolean. 64bit DMA if true, 32bit DMA otherwise. */
-	bool dma64;
+	/* The type of DMA engine used. */
+	enum b43legacy_dmatype type;
 	/* Boolean. Is this ring stopped at ieee80211 level? */
 	bool stopped;
 	/* Lock, only used for TX. */
@@ -284,15 +290,6 @@ void b43legacy_dma_write(struct b43legacy_dmaring *ring,
 int b43legacy_dma_init(struct b43legacy_wldev *dev);
 void b43legacy_dma_free(struct b43legacy_wldev *dev);
 
-int b43legacy_dmacontroller_rx_reset(struct b43legacy_wldev *dev,
-				     u16 dmacontroller_mmio_base,
-				     int dma64);
-int b43legacy_dmacontroller_tx_reset(struct b43legacy_wldev *dev,
-				     u16 dmacontroller_mmio_base,
-				     int dma64);
-
-u16 b43legacy_dmacontroller_base(int dma64bit, int dmacontroller_idx);
-
 void b43legacy_dma_tx_suspend(struct b43legacy_wldev *dev);
 void b43legacy_dma_tx_resume(struct b43legacy_wldev *dev);
 
@@ -320,20 +317,6 @@ void b43legacy_dma_free(struct b43legacy_wldev *dev)
 {
 }
 static inline
-int b43legacy_dmacontroller_rx_reset(struct b43legacy_wldev *dev,
-				     u16 dmacontroller_mmio_base,
-				     int dma64)
-{
-	return 0;
-}
-static inline
-int b43legacy_dmacontroller_tx_reset(struct b43legacy_wldev *dev,
-				     u16 dmacontroller_mmio_base,
-				     int dma64)
-{
-	return 0;
-}
-static inline
 void b43legacy_dma_get_tx_stats(struct b43legacy_wldev *dev,
 				struct ieee80211_tx_queue_stats *stats)
 {