Patch "mtd: spi-nor: fix spansion quad enable" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

mtd: spi-nor: fix spansion quad enable

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mtd-spi-nor-fix-spansion-quad-enable.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: =?UTF-8?q?Jo=C3=ABl=20Esponde?= <[email protected]>
Date: Wed, 23 Nov 2016 12:47:40 +0100
Subject: mtd: spi-nor: fix spansion quad enable
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From: Joël Esponde <[email protected]>

commit 807c16253319ee6ccf8873ae64f070f7eb532cd5 upstream.

With the S25FL127S nor flash part, each writing to the configuration register takes hundreds of ms. During that time, no more accesses to the flash should be done (even reads).

This commit adds a wait loop after the register writing until the flash finishes its work.

This issue could make rootfs mounting fail when the latter was done too much closely to this quad enable bit setting step. And in this case, a driver as UBIFS may try to recover the filesystem and may broke it completely.

---
 drivers/mtd/spi-nor/spi-nor.c |    7 +++++++
 1 file changed, 7 insertions(+)

@@ -1255,6 +1255,13 @@ static int spansion_quad_enable(struct s
 		return -EINVAL;
 	}
 
+	ret = spi_nor_wait_till_ready(nor);
+	if (ret) {
+		dev_err(nor->dev,
+			"timeout while writing configuration register\n");
+		return ret;
+	}
+
 	/* read back and check it */
 	ret = read_cr(nor);
 	if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/mtd-spi-nor-fix-spansion-quad-enable.patch