[dpdk-stable] [PATCH v2] net/i40e: fix global register recovery

[beilei.xing at intel.com]

From: Beilei Xing <beilei.xing at intel.com>

PMD configures the global register I40E_GLINT_CTL during
device initialization to work around the Rx write back
issue. But when a device is bound from DPDK to kernel,
the global register is not recovered to the original
state, it will cause kernel driver performance drop issue.
This patch fixes this issue.

Fixes: be6c228d4da3 ("i40e: support Rx interrupt")
Fixes: 4ab831449a1c ("net/i40e: fix interrupt conflict with multi-driver")
Cc: stable at dpdk.org

Signed-off-by: Beilei Xing <beilei.xing at intel.com>
---

v2 change:
 - refine commit log

 drivers/net/i40e/i40e_ethdev.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
index f54769c29d..2cb18ecc03 100644
--- a/drivers/net/i40e/i40e_ethdev.c
+++ b/drivers/net/i40e/i40e_ethdev.c
@@ -763,6 +763,21 @@ static inline void i40e_config_automask(struct i40e_pf *pf)
 	I40E_WRITE_REG(hw, I40E_GLINT_CTL, val);
 }
 
+static inline void i40e_clear_automask(struct i40e_pf *pf)
+{
+	struct i40e_hw *hw = I40E_PF_TO_HW(pf);
+	uint32_t val;
+
+	val = I40E_READ_REG(hw, I40E_GLINT_CTL);
+	val &= ~(I40E_GLINT_CTL_DIS_AUTOMASK_PF0_MASK |
+		 I40E_GLINT_CTL_DIS_AUTOMASK_VF0_MASK);
+
+	if (!pf->support_multi_driver)
+		val &= ~I40E_GLINT_CTL_DIS_AUTOMASK_N_MASK;
+
+	I40E_WRITE_REG(hw, I40E_GLINT_CTL, val);
+}
+
 #define I40E_FLOW_CONTROL_ETHERTYPE  0x8808
 
 /*
@@ -2741,6 +2756,8 @@ i40e_dev_close(struct rte_eth_dev *dev)
 	/* Remove all Traffic Manager configuration */
 	i40e_tm_conf_uninit(dev);
 
+	i40e_clear_automask(pf);
+
 	hw->adapter_closed = 1;
 	return ret;
 }
-- 
2.26.2