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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
        Vignesh Raghavendra <vigneshr@ti.com>
Subject: [PATCH 5.4 194/222] mtd: cfi_cmdset_0002: only check errors when ready in cfi_check_err_status()
Date:   Wed, 22 Jan 2020 10:29:40 +0100
Message-Id: <20200122092847.592021002@linuxfoundation.org>
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From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

commit 72914a8cff7e1d910c58e125e15a0da409e3135f upstream.

Cypress S26K{L|S}P{128|256|512}S datasheet says that the error bits in
the status register are only valid when the "device ready" bit 7 is set.
Add the check for the device ready bit in cfi_check_err_status() as that
function isn't always called with this bit set.

Fixes: 4844ef80305d ("mtd: cfi_cmdset_0002: Add support for polling status register")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/mtd/chips/cfi_cmdset_0002.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -136,6 +136,10 @@ static void cfi_check_err_status(struct
 			 cfi->device_type, NULL);
 	status = map_read(map, adr);
 
+	/* The error bits are invalid while the chip's busy */
+	if (!map_word_bitsset(map, status, CMD(CFI_SR_DRB)))
+		return;
+
 	if (map_word_bitsset(map, status, CMD(0x3a))) {
 		unsigned long chipstatus = MERGESTATUS(status);