[PATCH 4/5] net/hns3: fix receive multiple firmware reset interrupts

[Dongdong Liu <liudongdong3@huawei.com>]

From: Chengwen Feng <fengchengwen@huawei.com>

In the firmware (also known as IMP) reset scenario, driver interrupt
processing and firmware watchdog initialization are asynchronous.

If the driver interrupt processing is faster than firmware watchdog
initialization (that is, the driver clears the firmware reset
interrupt source before the firmware watchdog is initialized), the
driver will receive multiple firmware reset interrupts.

In the Kunpeng 920 platform, the above situation does not exist. But
it does on the newer platforms. So we add 5ms delay before drivers
clears the IMP reset interrupt source.

As for the impact of 5ms, the number of PFs managed by a firmware is
limited. Therefore, even if a DPDK process takes over all the PFs
which managed by the firmware, the delay is controllable.

Cc: stable@dpdk.org

Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
---
 drivers/net/hns3/hns3_ethdev.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/hns3/hns3_ethdev.c b/drivers/net/hns3/hns3_ethdev.c
index 5ef66f96c6..664226a6ef 100644
--- a/drivers/net/hns3/hns3_ethdev.c
+++ b/drivers/net/hns3/hns3_ethdev.c
@@ -286,6 +286,19 @@ hns3_handle_mac_tnl(struct hns3_hw *hw)
 	}
 }
 
+static void
+hns3_delay_before_clear_event_cause(struct hns3_hw *hw, uint32_t event_type, uint32_t regclr)
+{
+#define IMPRESET_WAIT_MS_TIME	5
+
+	if (event_type == HNS3_VECTOR0_EVENT_RST &&
+	    regclr & BIT(HNS3_VECTOR0_IMPRESET_INT_B) &&
+	    hw->revision >= PCI_REVISION_ID_HIP09_A) {
+		rte_delay_ms(IMPRESET_WAIT_MS_TIME);
+		hns3_dbg(hw, "wait firmware watchdog initialization completed.");
+	}
+}
+
 static void
 hns3_interrupt_handler(void *param)
 {
@@ -305,6 +318,7 @@ hns3_interrupt_handler(void *param)
 	vector0_int = hns3_read_dev(hw, HNS3_VECTOR0_OTHER_INT_STS_REG);
 	ras_int = hns3_read_dev(hw, HNS3_RAS_PF_OTHER_INT_STS_REG);
 	cmdq_int = hns3_read_dev(hw, HNS3_VECTOR0_CMDQ_SRC_REG);
+	hns3_delay_before_clear_event_cause(hw, event_cause, clearval);
 	hns3_clear_event_cause(hw, event_cause, clearval);
 	/* vector 0 interrupt is shared with reset and mailbox source events. */
 	if (event_cause == HNS3_VECTOR0_EVENT_ERR) {
-- 
2.22.0