[dpdk-dev] [PATCH 15/17] net/hns3: fix cmdq cleared during firmware process

[Lijun Ou]

From: Chengchang Tang <tangchengchang at huawei.com>

There are two scenarios that command queue uninit performed
concurrently with the firmware command: asynchronous command
and timeout command.

For asynchronous command, if a large number of functions send
commands, these commands may need to be queued to wait for
firmware processing. If a function is uninited suddenly, CMDQ
clearing and firmware processing may be performed concurrently.

For timeout command, if the command failed due to busy scheduling
of firmware, this command will be processed in the next scheduling.
And this may lead to concurrency.

The preceding concurrency may lead to a firmware exceptions.

This patch add a waiting time to ensure the firmware complete the
processing of left over command when PMD uninit.

Fixes: 737f30e1c3ab ("net/hns3: support command interface with firmware")
Cc: stable at dpdk.org

Signed-off-by: Chengchang Tang <tangchengchang at huawei.com>
Signed-off-by: Lijun Ou <oulijun at huawei.com>
---
 drivers/net/hns3/hns3_cmd.c | 14 +++++++++++++-
 drivers/net/hns3/hns3_cmd.h |  1 +
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/hns3/hns3_cmd.c b/drivers/net/hns3/hns3_cmd.c
index 3d6ffc0..32cd56b 100644
--- a/drivers/net/hns3/hns3_cmd.c
+++ b/drivers/net/hns3/hns3_cmd.c
@@ -582,9 +582,21 @@ hns3_cmd_destroy_queue(struct hns3_hw *hw)
 void
 hns3_cmd_uninit(struct hns3_hw *hw)
 {
+	__atomic_store_n(&hw->reset.disable_cmd, 1, __ATOMIC_RELAXED);
+
+	/*
+	 * A delay is added to ensure that the register cleanup operations
+	 * will not be performed concurrently with the firmware command and
+	 * ensure that all the reserved commands are executed.
+	 * Concurrency may occur in two scenarios: asynchronous command and
+	 * timeout command. If the command fails to be executed due to busy
+	 * scheduling, the command will be processed in the next scheduling
+	 * of the firmware.
+	 */
+	rte_delay_ms(HNS3_CMDQ_CLEAR_WAIT_TIME);
+
 	rte_spinlock_lock(&hw->cmq.csq.lock);
 	rte_spinlock_lock(&hw->cmq.crq.lock);
-	__atomic_store_n(&hw->reset.disable_cmd, 1, __ATOMIC_RELAXED);
 	hns3_cmd_clear_regs(hw);
 	rte_spinlock_unlock(&hw->cmq.crq.lock);
 	rte_spinlock_unlock(&hw->cmq.csq.lock);
diff --git a/drivers/net/hns3/hns3_cmd.h b/drivers/net/hns3/hns3_cmd.h
index c6c4093..7f567cb 100644
--- a/drivers/net/hns3/hns3_cmd.h
+++ b/drivers/net/hns3/hns3_cmd.h
@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 #define HNS3_CMDQ_TX_TIMEOUT		30000
+#define HNS3_CMDQ_CLEAR_WAIT_TIME	200
 #define HNS3_CMDQ_RX_INVLD_B		0
 #define HNS3_CMDQ_RX_OUTVLD_B		1
 #define HNS3_CMD_DESC_ALIGNMENT		4096
-- 
2.7.4