netdev - [PATCH 7/7] octeontx2-af: Modify rvu_reg_poll() to check reg atleast twice

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Message-Id: <1583133568-5674-8-git-send-email-sunil.kovvuri@gmail.com>
Date:   Mon,  2 Mar 2020 12:49:28 +0530
From:   sunil.kovvuri@...il.com
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, Sunil Goutham <sgoutham@...vell.com>
Subject: [PATCH 7/7] octeontx2-af: Modify rvu_reg_poll() to check reg atleast twice

From: Sunil Goutham <sgoutham@...vell.com>

Currently on the first check if the operation is still not
finished, the poll goes to sleep for 2-5 usecs. But if for
some reason (due to other priority stuff like interrupts etc) by
the time the poll wakes up the 10ms time is expired then we don't
check if operation is finished or not and return failure.

This patch modifies poll logic to check HW operation after sleep so
that the status is checked atleast twice.

Signed-off-by: Sunil Goutham <sgoutham@...vell.com>
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
index 3b794df..5ff25bf 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
@@ -88,13 +88,15 @@ int rvu_poll_reg(struct rvu *rvu, u64 block, u64 offset, u64 mask, bool zero)
 	u64 reg_val;
 
 	reg = rvu->afreg_base + ((block << 28) | offset);
-	while (time_before(jiffies, timeout)) {
-		reg_val = readq(reg);
-		if (zero && !(reg_val & mask))
-			return 0;
-		if (!zero && (reg_val & mask))
-			return 0;
+again:
+	reg_val = readq(reg);
+	if (zero && !(reg_val & mask))
+		return 0;
+	if (!zero && (reg_val & mask))
+		return 0;
+	if (time_before(jiffies, timeout)) {
 		usleep_range(1, 5);
+		goto again;
 	}
 	return -EBUSY;
 }
-- 
2.7.4