[PATCH 6.8 035/143] wifi: mt76: mt7996: add locking for accessing mapped registers

Greg Kroah-Hartman
2024-04-11T10:08:22Z

From: Shayne Chen <shayne.chen@mediatek.com>

[ Upstream commit 3687854d3e7e7fd760d939dd9e5a3520d5ab60fe ]

A race condition was observed when accessing mapped registers, so add
locking to protect against concurrent access.

Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../net/wireless/mediatek/mt76/mt7996/mmio.c | 64 ++++++++++++-------
.../wireless/mediatek/mt76/mt7996/mt7996.h | 3 +-
2 files changed, 43 insertions(+), 24 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mmio.c b/drivers/net/wireless/mediatek/mt76/mt7996/mmio.c
index 9f2abfa273c9b..efd4a767eb37d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mmio.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mmio.c
@@ -140,7 +140,6 @@ static u32 mt7996_reg_map_l1(struct mt7996_dev *dev, u32 addr)
u32 offset = FIELD_GET(MT_HIF_REMAP_L1_OFFSET, addr);
u32 base = FIELD_GET(MT_HIF_REMAP_L1_BASE, addr);

- dev->reg_l1_backup = dev->bus_ops->rr(&dev->mt76, MT_HIF_REMAP_L1);
dev->bus_ops->rmw(&dev->mt76, MT_HIF_REMAP_L1,
MT_HIF_REMAP_L1_MASK,
FIELD_PREP(MT_HIF_REMAP_L1_MASK, base));
@@ -155,7 +154,6 @@ static u32 mt7996_reg_map_l2(struct mt7996_dev *dev, u32 addr)
u32 offset = FIELD_GET(MT_HIF_REMAP_L2_OFFSET, addr);
u32 base = FIELD_GET(MT_HIF_REMAP_L2_BASE, addr);

- dev->reg_l2_backup = dev->bus_ops->rr(&dev->mt76, MT_HIF_REMAP_L2);
dev->bus_ops->rmw(&dev->mt76, MT_HIF_REMAP_L2,
MT_HIF_REMAP_L2_MASK,
FIELD_PREP(MT_HIF_REMAP_L2_MASK, base));
@@ -165,26 +163,10 @@ static u32 mt7996_reg_map_l2(struct mt7996_dev *dev, u32 addr)
return MT_HIF_REMAP_BASE_L2 + offset;
}

-static void mt7996_reg_remap_restore(struct mt7996_dev *dev)
-{
- /* remap to ori status */
- if (unlikely(dev->reg_l1_backup)) {
- dev->bus_ops->wr(&dev->mt76, MT_HIF_REMAP_L1, dev->reg_l1_backup);
- dev->reg_l1_backup = 0;
- }
-
- if (dev->reg_l2_backup) {
- dev->bus_ops->wr(&dev->mt76, MT_HIF_REMAP_L2, dev->reg_l2_backup);
- dev->reg_l2_backup = 0;
- }
-}
-
static u32 __mt7996_reg_addr(struct mt7996_dev *dev, u32 addr)
{
int i;

- mt7996_reg_remap_restore(dev);
-
if (addr < 0x100000)
return addr;

@@ -201,6 +183,11 @@ static u32 __mt7996_reg_addr(struct mt7996_dev *dev, u32 addr)
return dev->reg.map[i].mapped + ofs;
}

+ return 0;
+}
+
+static u32 __mt7996_reg_remap_addr(struct mt7996_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))
@@ -225,28 +212,60 @@ void mt7996_memcpy_fromio(struct mt7996_dev *dev, void *buf, u32 offset,
{
u32 addr = __mt7996_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 +
+ __mt7996_reg_remap_addr(dev, offset), len);
+ spin_unlock_bh(&dev->reg_lock);
}

static u32 mt7996_rr(struct mt76_dev *mdev, u32 offset)
{
struct mt7996_dev *dev = container_of(mdev, struct mt7996_dev, mt76);
+ u32 addr = __mt7996_reg_addr(dev, offset), val;
+
+ if (addr)
+ return dev->bus_ops->rr(mdev, addr);

- return dev->bus_ops->rr(mdev, __mt7996_reg_addr(dev, offset));
+ spin_lock_bh(&dev->reg_lock);
+ val = dev->bus_ops->rr(mdev, __mt7996_reg_remap_addr(dev, offset));
+ spin_unlock_bh(&dev->reg_lock);
+
+ return val;
}

static void mt7996_wr(struct mt76_dev *mdev, u32 offset, u32 val)
{
struct mt7996_dev *dev = container_of(mdev, struct mt7996_dev, mt76);
+ u32 addr = __mt7996_reg_addr(dev, offset);

- dev->bus_ops->wr(mdev, __mt7996_reg_addr(dev, offset), val);
+ if (addr) {
+ dev->bus_ops->wr(mdev, addr, val);
+ return;
+ }
+
+ spin_lock_bh(&dev->reg_lock);
+ dev->bus_ops->wr(mdev, __mt7996_reg_remap_addr(dev, offset), val);
+ spin_unlock_bh(&dev->reg_lock);
}

static u32 mt7996_rmw(struct mt76_dev *mdev, u32 offset, u32 mask, u32 val)
{
struct mt7996_dev *dev = container_of(mdev, struct mt7996_dev, mt76);
+ u32 addr = __mt7996_reg_addr(dev, offset);
+
+ if (addr)
+ return dev->bus_ops->rmw(mdev, addr, mask, val);
+
+ spin_lock_bh(&dev->reg_lock);
+ val = dev->bus_ops->rmw(mdev, __mt7996_reg_remap_addr(dev, offset), mask, val);
+ spin_unlock_bh(&dev->reg_lock);

- return dev->bus_ops->rmw(mdev, __mt7996_reg_addr(dev, offset), mask, val);
+ return val;
}

#ifdef CONFIG_NET_MEDIATEK_SOC_WED
@@ -421,6 +440,7 @@ static int mt7996_mmio_init(struct mt76_dev *mdev,

dev = container_of(mdev, struct mt7996_dev, mt76);
mt76_mmio_init(&dev->mt76, mem_base);
+ spin_lock_init(&dev->reg_lock);

switch (device_id) {
case 0x7990:
diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h b/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
index 8154ad37827f0..36d1f247d55aa 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
@@ -325,8 +325,7 @@ struct mt7996_dev {
u8 n_agrt;
} twt;

- u32 reg_l1_backup;
- u32 reg_l2_backup;
+ spinlock_t reg_lock;

u8 wtbl_size_group;
};
--
2.43.0