linux-kernel - [PATCH v3 2/5] mtd: rawnand: brcmnand: Fix potential false time out warning

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Message-Id: <20230627193738.19596-3-william.zhang@broadcom.com>
Date:   Tue, 27 Jun 2023 12:37:35 -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 v3 2/5] 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>
---

Changes in v3: None
Changes in v2: None

 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 69709419516a..37c2c7cfa00e 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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