Patch "wifi: mt76: mt7915: add locking for accessing mapped registers" has been added to the 6.8-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 6.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     wifi-mt76-mt7915-add-locking-for-accessing-mapped-re.patch
and it can be found in the queue-6.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 9a7496ae72905d00d7580b5043713ae775e1e694
Author: Shayne Chen <shayne.chen@xxxxxxxxxxxx>
Date:   Tue Aug 15 17:28:30 2023 +0800

    wifi: mt76: mt7915: add locking for accessing mapped registers
    
    [ Upstream commit 0937f95ab07af6e663ae932d592f630d9eb591da ]
    
    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@xxxxxxxxxxxx>
    Signed-off-by: Peter Chiu <chui-hao.chiu@xxxxxxxxxxxx>
    Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c b/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
index 3039f53e22454..dceb505987b19 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
+++ b/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))
@@ -514,15 +519,30 @@ 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)
@@ -530,7 +550,14 @@ 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)
@@ -538,7 +565,14 @@ 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
@@ -707,6 +741,7 @@ 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:
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h b/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h
index 4727d9c7b11de..6e79bc65f5a51 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h
+++ b/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;