[PATCH 03/16] e1000/base: try more times to get HW mailbox lock

[Wenzhuo Lu <wenzhuo.lu@intel.com>]

The driver shouldn't just give up if it fails to get the
hardware mailbox lock. This can happen in a situation
where the PF-VF communication channel is heavily loaded
and causes complete communications failure between the PF
and VF drivers.

Add a counter and a delay. The driver will now retry ten
times, waiting one millsecond between retries.

Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
---
 drivers/net/e1000/base/e1000_mbx.c | 36 +++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/net/e1000/base/e1000_mbx.c b/drivers/net/e1000/base/e1000_mbx.c
index 6daf16b..a92fd22 100644
--- a/drivers/net/e1000/base/e1000_mbx.c
+++ b/drivers/net/e1000/base/e1000_mbx.c
@@ -430,15 +430,21 @@ STATIC s32 e1000_check_for_rst_vf(struct e1000_hw *hw,
 STATIC s32 e1000_obtain_mbx_lock_vf(struct e1000_hw *hw)
 {
 	s32 ret_val = -E1000_ERR_MBX;
+	int count = 10;
 
 	DEBUGFUNC("e1000_obtain_mbx_lock_vf");
 
-	/* Take ownership of the buffer */
-	E1000_WRITE_REG(hw, E1000_V2PMAILBOX(0), E1000_V2PMAILBOX_VFU);
+	do {
+		/* Take ownership of the buffer */
+		E1000_WRITE_REG(hw, E1000_V2PMAILBOX(0), E1000_V2PMAILBOX_VFU);
 
-	/* reserve mailbox for vf use */
-	if (e1000_read_v2p_mailbox(hw) & E1000_V2PMAILBOX_VFU)
-		ret_val = E1000_SUCCESS;
+		/* reserve mailbox for vf use */
+		if (e1000_read_v2p_mailbox(hw) & E1000_V2PMAILBOX_VFU) {
+			ret_val = E1000_SUCCESS;
+			break;
+		}
+		usec_delay(1000);
+	} while (count-- > 0);
 
 	return ret_val;
 }
@@ -645,18 +651,26 @@ STATIC s32 e1000_obtain_mbx_lock_pf(struct e1000_hw *hw, u16 vf_number)
 {
 	s32 ret_val = -E1000_ERR_MBX;
 	u32 p2v_mailbox;
+	int count = 10;
 
 	DEBUGFUNC("e1000_obtain_mbx_lock_pf");
 
-	/* Take ownership of the buffer */
-	E1000_WRITE_REG(hw, E1000_P2VMAILBOX(vf_number), E1000_P2VMAILBOX_PFU);
+	do {
+		/* Take ownership of the buffer */
+		E1000_WRITE_REG(hw, E1000_P2VMAILBOX(vf_number),
+				E1000_P2VMAILBOX_PFU);
 
-	/* reserve mailbox for vf use */
-	p2v_mailbox = E1000_READ_REG(hw, E1000_P2VMAILBOX(vf_number));
-	if (p2v_mailbox & E1000_P2VMAILBOX_PFU)
-		ret_val = E1000_SUCCESS;
+		/* reserve mailbox for pf use */
+		p2v_mailbox = E1000_READ_REG(hw, E1000_P2VMAILBOX(vf_number));
+		if (p2v_mailbox & E1000_P2VMAILBOX_PFU) {
+			ret_val = E1000_SUCCESS;
+			break;
+		}
+		usec_delay(1000);
+	} while (count-- > 0);
 
 	return ret_val;
+
 }
 
 /**
-- 
1.9.3