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From: motobud@gmail.com
To: boris.brezillon@free-electrons.com
Cc: Brent Taylor <motobud@gmail.com>,
	Richard Weinberger <richard@nod.at>,
	David Woodhouse <dwmw2@infradead.org>,
	Brian Norris <computersforpeace@gmail.com>,
	Marek Vasut <marek.vasut@gmail.com>,
	Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] Fix writing mtdoops to nand flash.
Date: Sun, 29 Oct 2017 23:23:43 -0500	[thread overview]
Message-ID: <20171030042343.24551-1-motobud@gmail.com> (raw)

From: Brent Taylor <motobud@gmail.com>

When mtdoops calls mtd_panic_write, it eventually calls
panic_nand_write in nand_base.c.  In order to properly
wait for the nand chip to be ready in panic_nand_wait,
the chip must first be selected.

When using the atmel nand flash controller, a panic
would occur due to a NULL pointer exception.

Signed-off-by: Brent Taylor <motobud@gmail.com>
---
 drivers/mtd/nand/nand_base.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 12edaae17d81..0a8058a66d93 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2802,9 +2802,14 @@ static int panic_nand_write(struct mtd_info *mtd, loff_t to, size_t len,
 	struct mtd_oob_ops ops;
 	int ret;
 
+	int chipnr = (int)(to >> chip->chip_shift);
+	chip->select_chip(mtd, chipnr);
+
 	/* Wait for the device to get ready */
 	panic_nand_wait(mtd, chip, 400);
 
+	chip->select_chip(mtd, -1);
+
 	/* Grab the device */
 	panic_nand_get_device(chip, mtd, FL_WRITING);
 
-- 
2.14.2

             reply	other threads:[~2017-10-30  4:24 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-30  4:23 motobud [this message]
2017-10-30  8:23 ` [PATCH] Fix writing mtdoops to nand flash Boris Brezillon
2017-10-30 12:46   ` Brent Taylor
2017-10-30 13:15     ` Boris Brezillon
2017-10-31  3:32 ` [PATCH v2] mtd: nand: " motobud
2017-10-31 10:18   ` Boris Brezillon
2017-11-02 10:48   ` Boris Brezillon

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