From patchwork Fri Aug 10 01:36:16 2012
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Subject: Kernel crashes when CONFIG_MTD_NAND_VERIFY_WRITE=y
Date: Thu, 09 Aug 2012 15:36:16 -0000
From: Fabio Estevam <festevam@gmail.com>
X-Patchwork-Id: 176307
Message-Id: <CAOMZO5BCjV6iLUiQ74GskkOdgGpdqbo2ZB=7eu6VeY=mNwWf0Q@mail.gmail.com>
To: Marek Vasut <marex@denx.de>
Cc: Shawn Guo <shawn.guo@linaro.org>, Subodh Nijsure <snijsure@grid-net.com>, 
 Huang Shijie <b32955@freescale.com>, linux-mtd@lists.infradead.org,
 Sascha Hauer <kernel@pengutronix.de>, computersforpeace@gmail.com

Hi Marek,

On Thu, Aug 9, 2012 at 8:53 PM, Marek Vasut <marex@denx.de> wrote:

> This problem is there because the GPMI NAND code doesn't implement verify buffer
> function and defaults to nand_verify_buf() call in nand_base.c:

Yes, you are right.

> Now the chip->IO_ADDR_R is zero, making the kernel access bogus location, and
> therefore crash. So the correct solution is to properly implement the struct
> nand_chip *'s verify_buf function.

Right, the patch below prevents the kernel to happen:


Now we need to come up with a real  gpmi_verify_buf function ;-)

Regards,

Fabio Estevam


--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
@@ -857,6 +857,15 @@ static uint8_t gpmi_read_byte(struct mtd_info *mtd)
        return buf[0];
 }

+/* Used by the upper layer to verify the data in NAND Flash
+ * with the data in the buf. */
+static int gpmi_verify_buf(struct mtd_info *mtd,
+                               const u_char *buf, int len)
+{
+       /* TODO: implement verify_buf mechanism */
+       return 0;
+}
+
 /*
  * Handles block mark swapping.
  * It can be called in swapping the block mark, or swapping it back,
@@ -1568,6 +1577,7 @@ static int __devinit gpmi_nfc_init(struct
gpmi_nand_data *this)
        chip->ecc.size          = 1;
        chip->ecc.strength      = 8;
        chip->ecc.layout        = &gpmi_hw_ecclayout;
+       chip->verify_buf        = gpmi_verify_buf;
        if (of_get_nand_on_flash_bbt(this->dev->of_node))
                chip->bbt_options |= NAND_BBT_USE_FLASH | NAND_BBT_NO_OOB;