From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-9101.amazon.com ([207.171.184.25]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gjZ8M-0001EZ-0D for linux-mtd@lists.infradead.org; Wed, 16 Jan 2019 00:32:43 +0000 Date: Wed, 16 Jan 2019 00:32:11 +0000 From: Przemyslaw Sobon To: David Woodhouse , Brian Norris , Marek Vasut , "Richard Weinberger" , CC: Subject: [PATCH] mtd: cfi: Fixed endless loop problem in CFI when value was written but corrupted. Message-ID: <20190116003211.GA57460@dev-dsk-psobon-2c-1dd9f399.us-west-2.amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , There was an endless loop in CFI Flash driver when a value was written incorrectly. In such case chip_ready returns true but chip_good returns false and we never get out of the loop. The solution was to break the loop in 2 cases, either device is ready or device is not ready and timeout elapsed. The correctness of the write is checked after the loop ended. That way we ensure the loop always ends. Signed-off-by: Przemyslaw Sobon --- drivers/mtd/chips/cfi_cmdset_0002.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c index 72428b6bfc47..6cc31d2057e9 100644 --- a/drivers/mtd/chips/cfi_cmdset_0002.c +++ b/drivers/mtd/chips/cfi_cmdset_0002.c @@ -1879,15 +1879,18 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip, if (time_after(jiffies, timeo) && !chip_ready(map, adr)) break; - if (chip_good(map, adr, datum)) { - xip_enable(map, chip, adr); - goto op_done; - } + if (chip_ready(map, adr)) + break; /* Latency issues. Drop the lock, wait a while and retry */ UDELAY(map, chip, adr, 1); } + if (chip_good(map, adr, datum)) { + xip_enable(map, chip, adr); + goto op_done; + } + /* * Recovery from write-buffer programming failures requires * the write-to-buffer-reset sequence. Since the last part -- 2.16.5