linux-kernel - [PATCH 02/12] mtd: rawnand: brcmnand: Fix potential false time out warning

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Date:   Tue,  6 Jun 2023 16:12:42 -0700
From:   William Zhang <william.zhang@...adcom.com>
To:     Broadcom Kernel List <bcm-kernel-feedback-list@...adcom.com>,
        Linux MTD List <linux-mtd@...ts.infradead.org>
Cc:     f.fainelli@...il.com, rafal@...ecki.pl, kursad.oney@...adcom.com,
        joel.peshkin@...adcom.com, computersforpeace@...il.com,
        anand.gore@...adcom.com, dregan@...l.com, kamal.dasu@...adcom.com,
        tomer.yacoby@...adcom.com, dan.beygelman@...adcom.com,
        William Zhang <william.zhang@...adcom.com>,
        Florian Fainelli <florian.fainelli@...adcom.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        linux-kernel@...r.kernel.org,
        Vignesh Raghavendra <vigneshr@...com>,
        Richard Weinberger <richard@....at>,
        Boris Brezillon <bbrezillon@...nel.org>,
        Kamal Dasu <kdasu.kdev@...il.com>
Subject: [PATCH 02/12] mtd: rawnand: brcmnand: Fix potential false time out warning

If system is busy during the command status polling function, the driver
may not get the chance to poll the status register till the end of time
out and return the premature status.  Do a final check after time out
happens to ensure reading the correct status.

Fixes: 9d2ee0a60b8b ("mtd: nand: brcmnand: Check flash #WP pin status before nand erase/program")
Signed-off-by: William Zhang <william.zhang@...adcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@...adcom.com>
---

 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index b2cde1082b3b..b6346a8b9833 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -1080,6 +1080,14 @@ static int bcmnand_ctrl_poll_status(struct brcmnand_controller *ctrl,
 		cpu_relax();
 	} while (time_after(limit, jiffies));
 
+	/*
+	 * do a final check after time out in case CPU is busy and driver does
+	 * not get the enough time to poll to avoid false alarm
+	 */
+	val = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS);
+	if ((val & mask) == expected_val)
+		return 0;
+
 	dev_warn(ctrl->dev, "timeout on status poll (expected %x got %x)\n",
 		 expected_val, val & mask);
 
-- 
2.37.3


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