b43: flush PHY writes when needed

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/b43/phy_common.c

@@ -231,6 +231,7 @@ void b43_radio_maskset(struct b43_wldev *dev, u16 offset, u16 mask, u16 set)
 u16 b43_phy_read(struct b43_wldev *dev, u16 reg)
 {
 	assert_mac_suspended(dev);
+	dev->phy.writes_counter = 0;
 	return dev->phy.ops->phy_read(dev, reg);
 }
 
@@ -238,6 +239,10 @@ void b43_phy_write(struct b43_wldev *dev, u16 reg, u16 value)
 {
 	assert_mac_suspended(dev);
 	dev->phy.ops->phy_write(dev, reg, value);
+	if (++dev->phy.writes_counter == B43_MAX_WRITES_IN_ROW) {
+		b43_read16(dev, B43_MMIO_PHY_VER);
+		dev->phy.writes_counter = 0;
+	}
 }
 
 void b43_phy_copy(struct b43_wldev *dev, u16 destreg, u16 srcreg)

drivers/net/wireless/b43/phy_common.h

@@ -39,6 +39,9 @@ struct b43_c32 { s32 i, q; };
 #define B43_PHYVER_TYPE_SHIFT		8
 #define B43_PHYVER_VERSION		0x00FF
 
+/* PHY writes need to be flushed if we reach limit */
+#define B43_MAX_WRITES_IN_ROW		24
+
 /**
  * enum b43_interference_mitigation - Interference Mitigation mode
  *
@@ -232,6 +235,9 @@ struct b43_phy {
 	/* PHY revision number. */
 	u8 rev;
 
+	/* Count writes since last read */
+	u8 writes_counter;
+
 	/* Radio versioning */
 	u16 radio_manuf;	/* Radio manufacturer */
 	u16 radio_ver;		/* Radio version */