wifi: mt76: mt7915: add locking for accessing mapped registers

[ Upstream commit 0937f95 ]

Sicne the mapping is global, mapped register access needs to be protected
against concurrent access, otherwise a race condition might cause the reads
or writes to go towards the wrong register

Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/wireless/mediatek/mt76/mt7915/mmio.c

@@ -490,6 +490,11 @@ static u32 __mt7915_reg_addr(struct mt7915_dev *dev, u32 addr)
 		return dev->reg.map[i].maps + ofs;
 	}
 
+	return 0;
+}
+
+static u32 __mt7915_reg_remap_addr(struct mt7915_dev *dev, u32 addr)
+{
 	if ((addr >= MT_INFRA_BASE && addr < MT_WFSYS0_PHY_START) ||
 	    (addr >= MT_WFSYS0_PHY_START && addr < MT_WFSYS1_PHY_START) ||
 	    (addr >= MT_WFSYS1_PHY_START && addr <= MT_WFSYS1_PHY_END))
@@ -514,31 +519,60 @@ void mt7915_memcpy_fromio(struct mt7915_dev *dev, void *buf, u32 offset,
 {
 	u32 addr = __mt7915_reg_addr(dev, offset);
 
-	memcpy_fromio(buf, dev->mt76.mmio.regs + addr, len);
+	if (addr) {
+		memcpy_fromio(buf, dev->mt76.mmio.regs + addr, len);
+		return;
+	}
+
+	spin_lock_bh(&dev->reg_lock);
+	memcpy_fromio(buf, dev->mt76.mmio.regs +
+			   __mt7915_reg_remap_addr(dev, offset), len);
+	spin_unlock_bh(&dev->reg_lock);
 }
 
 static u32 mt7915_rr(struct mt76_dev *mdev, u32 offset)
 {
 	struct mt7915_dev *dev = container_of(mdev, struct mt7915_dev, mt76);
-	u32 addr = __mt7915_reg_addr(dev, offset);
+	u32 addr = __mt7915_reg_addr(dev, offset), val;
 
-	return dev->bus_ops->rr(mdev, addr);
+	if (addr)
+		return dev->bus_ops->rr(mdev, addr);
+
+	spin_lock_bh(&dev->reg_lock);
+	val = dev->bus_ops->rr(mdev, __mt7915_reg_remap_addr(dev, offset));
+	spin_unlock_bh(&dev->reg_lock);
+
+	return val;
 }
 
 static void mt7915_wr(struct mt76_dev *mdev, u32 offset, u32 val)
 {
 	struct mt7915_dev *dev = container_of(mdev, struct mt7915_dev, mt76);
 	u32 addr = __mt7915_reg_addr(dev, offset);
 
-	dev->bus_ops->wr(mdev, addr, val);
+	if (addr) {
+		dev->bus_ops->wr(mdev, addr, val);
+		return;
+	}
+
+	spin_lock_bh(&dev->reg_lock);
+	dev->bus_ops->wr(mdev, __mt7915_reg_remap_addr(dev, offset), val);
+	spin_unlock_bh(&dev->reg_lock);
 }
 
 static u32 mt7915_rmw(struct mt76_dev *mdev, u32 offset, u32 mask, u32 val)
 {
 	struct mt7915_dev *dev = container_of(mdev, struct mt7915_dev, mt76);
 	u32 addr = __mt7915_reg_addr(dev, offset);
 
-	return dev->bus_ops->rmw(mdev, addr, mask, val);
+	if (addr)
+		return dev->bus_ops->rmw(mdev, addr, mask, val);
+
+	spin_lock_bh(&dev->reg_lock);
+	val = dev->bus_ops->rmw(mdev, __mt7915_reg_remap_addr(dev, offset), mask, val);
+	spin_unlock_bh(&dev->reg_lock);
+
+	return val;
 }
 
 #ifdef CONFIG_NET_MEDIATEK_SOC_WED
@@ -813,6 +847,7 @@ static int mt7915_mmio_init(struct mt76_dev *mdev,
 
 	dev = container_of(mdev, struct mt7915_dev, mt76);
 	mt76_mmio_init(&dev->mt76, mem_base);
+	spin_lock_init(&dev->reg_lock);
 
 	switch (device_id) {
 	case 0x7915:

drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h

@@ -287,6 +287,7 @@ struct mt7915_dev {
 
 	struct list_head sta_rc_list;
 	struct list_head twt_list;
+	spinlock_t reg_lock;
 
 	u32 hw_pattern;