wifi: rtw88: Drop h2c.lock

The h2c.lock spinlock is used in rtw_fw_send_h2c_command() and
rtw_fw_send_h2c_packet().  Most callers call this with rtwdev->mutex
held, except from one callsite in the debugfs code. The debugfs code
alone doesn't justify the extra lock, so acquire rtwdev->mutex in
debugfs and drop the now unnecessary spinlock.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221202081224.2779981-5-s.hauer@pengutronix.de

drivers/net/wireless/realtek/rtw88/debug.c

@@ -392,7 +392,9 @@ static ssize_t rtw_debugfs_set_h2c(struct file *filp,
 		return -EINVAL;
 	}
 
+	mutex_lock(&rtwdev->mutex);
 	rtw_fw_h2c_cmd_dbg(rtwdev, param);
+	mutex_unlock(&rtwdev->mutex);
 
 	return count;
 }

drivers/net/wireless/realtek/rtw88/fw.c

@@ -322,7 +322,7 @@ static void rtw_fw_send_h2c_command(struct rtw_dev *rtwdev,
 		h2c[3], h2c[2], h2c[1], h2c[0],
 		h2c[7], h2c[6], h2c[5], h2c[4]);
 
-	spin_lock(&rtwdev->h2c.lock);
+	lockdep_assert_held(&rtwdev->mutex);
 
 	box = rtwdev->h2c.last_box_num;
 	switch (box) {
@@ -344,7 +344,7 @@ static void rtw_fw_send_h2c_command(struct rtw_dev *rtwdev,
 		break;
 	default:
 		WARN(1, "invalid h2c mail box number\n");
-		goto out;
+		return;
 	}
 
 	ret = read_poll_timeout_atomic(rtw_read8, box_state,
@@ -353,7 +353,7 @@ static void rtw_fw_send_h2c_command(struct rtw_dev *rtwdev,
 
 	if (ret) {
 		rtw_err(rtwdev, "failed to send h2c command\n");
-		goto out;
+		return;
 	}
 
 	rtw_write32(rtwdev, box_ex_reg, le32_to_cpu(h2c_cmd->msg_ext));
@@ -361,9 +361,6 @@ static void rtw_fw_send_h2c_command(struct rtw_dev *rtwdev,
 
 	if (++rtwdev->h2c.last_box_num >= 4)
 		rtwdev->h2c.last_box_num = 0;
-
-out:
-	spin_unlock(&rtwdev->h2c.lock);
 }
 
 void rtw_fw_h2c_cmd_dbg(struct rtw_dev *rtwdev, u8 *h2c)
@@ -375,15 +372,13 @@ static void rtw_fw_send_h2c_packet(struct rtw_dev *rtwdev, u8 *h2c_pkt)
 {
 	int ret;
 
-	spin_lock(&rtwdev->h2c.lock);
+	lockdep_assert_held(&rtwdev->mutex);
 
 	FW_OFFLOAD_H2C_SET_SEQ_NUM(h2c_pkt, rtwdev->h2c.seq);
 	ret = rtw_hci_write_data_h2c(rtwdev, h2c_pkt, H2C_PKT_SIZE);
 	if (ret)
 		rtw_err(rtwdev, "failed to send h2c packet\n");
 	rtwdev->h2c.seq++;
-
-	spin_unlock(&rtwdev->h2c.lock);
 }
 
 void

drivers/net/wireless/realtek/rtw88/main.c

@@ -2067,7 +2067,6 @@ int rtw_core_init(struct rtw_dev *rtwdev)
 	skb_queue_head_init(&rtwdev->coex.queue);
 	skb_queue_head_init(&rtwdev->tx_report.queue);
 
-	spin_lock_init(&rtwdev->h2c.lock);
 	spin_lock_init(&rtwdev->txq_lock);
 	spin_lock_init(&rtwdev->tx_report.q_lock);
 

drivers/net/wireless/realtek/rtw88/main.h

@@ -2020,8 +2020,6 @@ struct rtw_dev {
 	struct {
 		/* incicate the mail box to use with fw */
 		u8 last_box_num;
-		/* protect to send h2c to fw */
-		spinlock_t lock;
 		u32 seq;
 	} h2c;