[PATCH net] net: rnpgbe: fix mailbox endianness handling

[Dong Yibo <dong100@mucse.com>]

Mailbox data is exchanged through 32-bit MMIO accesses but the
mailbox payload is defined using little-endian FW structures with
__le16 and __le32 fields.

The mailbox read/write helpers previously operated on raw u32
buffers without performing endian conversion. On big-endian
systems this causes mailbox payload fields to be byte-swapped in
memory, resulting in corrupted FW command and reply structures.

Convert mailbox data between CPU-endian MMIO values and the
little-endian mailbox wire format using cpu_to_le32() on reads and
le32_to_cpu() on writes.

Also switch the helper interfaces to use void */const void * since
the mailbox transport layer operates on opaque payload buffers
rather than native-endian u32 arrays.

Fixes: 4543534c3ef5 ("net: rnpgbe: Add basic mbx ops support")
Signed-off-by: Dong Yibo <dong100@mucse.com>
---
 drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c   | 16 ++++++++++------
 drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h   |  5 +++--
 .../net/ethernet/mucse/rnpgbe/rnpgbe_mbx_fw.c    |  7 +++----
 3 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c
index de5e29230b3c..0fccfc49ffc7 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.c
@@ -166,10 +166,12 @@ static void mucse_mbx_inc_pf_ack(struct mucse_hw *hw)
  *
  * Return: 0 on success, negative errno on failure
  **/
-static int mucse_read_mbx_pf(struct mucse_hw *hw, u32 *msg, u16 size)
+static int mucse_read_mbx_pf(struct mucse_hw *hw, void *msg, u16 size)
 {
 	const int size_in_words = size / sizeof(u32);
 	struct mucse_mbx_info *mbx = &hw->mbx;
+	int off = MUCSE_MBX_FWPF_SHM;
+	__le32 *msg_le32 = msg;
 	int err;
 
 	err = mucse_obtain_mbx_lock_pf(hw);
@@ -177,7 +179,7 @@ static int mucse_read_mbx_pf(struct mucse_hw *hw, u32 *msg, u16 size)
 		return err;
 
 	for (int i = 0; i < size_in_words; i++)
-		msg[i] = mbx_data_rd32(mbx, MUCSE_MBX_FWPF_SHM + 4 * i);
+		msg_le32[i] = cpu_to_le32(mbx_data_rd32(mbx, off + 4 * i));
 	/* Hw needs write data_reg at last */
 	mbx_data_wr32(mbx, MUCSE_MBX_FWPF_SHM, 0);
 	/* flush reqs as we have read this request data */
@@ -236,7 +238,7 @@ static int mucse_poll_for_msg(struct mucse_hw *hw)
  * Return: 0 if it successfully received a message notification and
  * copied it into the receive buffer, negative errno on failure
  **/
-int mucse_poll_and_read_mbx(struct mucse_hw *hw, u32 *msg, u16 size)
+int mucse_poll_and_read_mbx(struct mucse_hw *hw, void *msg, u16 size)
 {
 	int err;
 
@@ -290,10 +292,11 @@ static void mucse_mbx_inc_pf_req(struct mucse_hw *hw)
  * Return: 0 if it successfully copied message into the buffer,
  * negative errno on failure
  **/
-static int mucse_write_mbx_pf(struct mucse_hw *hw, u32 *msg, u16 size)
+static int mucse_write_mbx_pf(struct mucse_hw *hw, const void *msg, u16 size)
 {
 	const int size_in_words = size / sizeof(u32);
 	struct mucse_mbx_info *mbx = &hw->mbx;
+	const __le32 *msg_le32 = msg;
 	int err;
 
 	err = mucse_obtain_mbx_lock_pf(hw);
@@ -301,7 +304,8 @@ static int mucse_write_mbx_pf(struct mucse_hw *hw, u32 *msg, u16 size)
 		return err;
 
 	for (int i = 0; i < size_in_words; i++)
-		mbx_data_wr32(mbx, MUCSE_MBX_FWPF_SHM + i * 4, msg[i]);
+		mbx_data_wr32(mbx, MUCSE_MBX_FWPF_SHM + i * 4,
+			      le32_to_cpu(msg_le32[i]));
 
 	/* flush acks as we are overwriting the message buffer */
 	hw->mbx.fw_ack = mucse_mbx_get_fwack(mbx);
@@ -360,7 +364,7 @@ static int mucse_poll_for_ack(struct mucse_hw *hw)
  * Return: 0 if it successfully copied message into the buffer and
  * received an ack to that message within delay * timeout_cnt period
  **/
-int mucse_write_and_wait_ack_mbx(struct mucse_hw *hw, u32 *msg, u16 size)
+int mucse_write_and_wait_ack_mbx(struct mucse_hw *hw, const void *msg, u16 size)
 {
 	int err;
 
diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h
index e6fcc8d1d3ca..25bfc97c24c0 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx.h
@@ -14,7 +14,8 @@
 #define MUCSE_MBX_REQ             BIT(0) /* Request a req to mailbox */
 #define MUCSE_MBX_PFU             BIT(3) /* PF owns the mailbox buffer */
 
-int mucse_write_and_wait_ack_mbx(struct mucse_hw *hw, u32 *msg, u16 size);
+int mucse_write_and_wait_ack_mbx(struct mucse_hw *hw,
+				 const void *msg, u16 size);
 void mucse_init_mbx_params_pf(struct mucse_hw *hw);
-int mucse_poll_and_read_mbx(struct mucse_hw *hw, u32 *msg, u16 size);
+int mucse_poll_and_read_mbx(struct mucse_hw *hw, void *msg, u16 size);
 #endif /* _RNPGBE_MBX_H */
diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx_fw.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx_fw.c
index 8c8bd5e8e1db..2ac97915a098 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx_fw.c
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_mbx_fw.c
@@ -28,12 +28,11 @@ static int mucse_fw_send_cmd_wait_resp(struct mucse_hw *hw,
 	int err;
 
 	mutex_lock(&hw->mbx.lock);
-	err = mucse_write_and_wait_ack_mbx(hw, (u32 *)req, len);
+	err = mucse_write_and_wait_ack_mbx(hw, req, len);
 	if (err)
 		goto out;
 	do {
-		err = mucse_poll_and_read_mbx(hw, (u32 *)reply,
-					      sizeof(*reply));
+		err = mucse_poll_and_read_mbx(hw, reply, sizeof(*reply));
 		if (err)
 			goto out;
 		/* mucse_write_and_wait_ack_mbx return 0 means fw has
@@ -125,7 +124,7 @@ int mucse_mbx_powerup(struct mucse_hw *hw, bool is_powerup)
 
 	len = le16_to_cpu(req.datalen);
 	mutex_lock(&hw->mbx.lock);
-	err = mucse_write_and_wait_ack_mbx(hw, (u32 *)&req, len);
+	err = mucse_write_and_wait_ack_mbx(hw, &req, len);
 	mutex_unlock(&hw->mbx.lock);
 
 	return err;
-- 
2.25.1