net: hns3: add waiting time before cmdq memory is released

After the cmdq registers are cleared, the firmware may take time to
clear out possible left over commands in the cmdq. Driver must release
cmdq memory only after firmware has completed processing of left over
commands.

Fixes: 232d0d55 ("net: hns3: uninitialize command queue while unloading PF driver")
Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c

@@ -573,9 +573,13 @@ static void hclge_cmd_uninit_regs(struct hclge_hw *hw)
 
 void hclge_cmd_uninit(struct hclge_dev *hdev)
 {
+	set_bit(HCLGE_STATE_CMD_DISABLE, &hdev->state);
+	/* wait to ensure that the firmware completes the possible left
+	 * over commands.
+	 */
+	msleep(HCLGE_CMDQ_CLEAR_WAIT_TIME);
 	spin_lock_bh(&hdev->hw.cmq.csq.lock);
 	spin_lock(&hdev->hw.cmq.crq.lock);
-	set_bit(HCLGE_STATE_CMD_DISABLE, &hdev->state);
 	hclge_cmd_uninit_regs(&hdev->hw);
 	spin_unlock(&hdev->hw.cmq.crq.lock);
 	spin_unlock_bh(&hdev->hw.cmq.csq.lock);

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.h

@@ -9,6 +9,7 @@
 #include "hnae3.h"
 
 #define HCLGE_CMDQ_TX_TIMEOUT		30000
+#define HCLGE_CMDQ_CLEAR_WAIT_TIME	200
 #define HCLGE_DESC_DATA_LEN		6
 
 struct hclge_dev;

drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_cmd.c

@@ -507,12 +507,17 @@ static void hclgevf_cmd_uninit_regs(struct hclgevf_hw *hw)
 
 void hclgevf_cmd_uninit(struct hclgevf_dev *hdev)
 {
+	set_bit(HCLGEVF_STATE_CMD_DISABLE, &hdev->state);
+	/* wait to ensure that the firmware completes the possible left
+	 * over commands.
+	 */
+	msleep(HCLGEVF_CMDQ_CLEAR_WAIT_TIME);
 	spin_lock_bh(&hdev->hw.cmq.csq.lock);
 	spin_lock(&hdev->hw.cmq.crq.lock);
-	set_bit(HCLGEVF_STATE_CMD_DISABLE, &hdev->state);
 	hclgevf_cmd_uninit_regs(&hdev->hw);
 	spin_unlock(&hdev->hw.cmq.crq.lock);
 	spin_unlock_bh(&hdev->hw.cmq.csq.lock);
+
 	hclgevf_free_cmd_desc(&hdev->hw.cmq.csq);
 	hclgevf_free_cmd_desc(&hdev->hw.cmq.crq);
 }

drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_cmd.h

@@ -8,6 +8,7 @@
 #include "hnae3.h"
 
 #define HCLGEVF_CMDQ_TX_TIMEOUT		30000
+#define HCLGEVF_CMDQ_CLEAR_WAIT_TIME	200
 #define HCLGEVF_CMDQ_RX_INVLD_B		0
 #define HCLGEVF_CMDQ_RX_OUTVLD_B	1