[PATCHJ] [MTD] [OneNAND] Allow for controller errors when reading

[PATCHJ] [MTD] [OneNAND] Allow for controller errors when reading

[Adrian Hunter]

Controller errors while reading can be caused by
corruption caused by a previous powerloss. Because
upper level software like JFFS2 treat -EIO as fatal,
it is necessary to treat the error as an ECC error.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
---
 drivers/mtd/onenand/onenand_base.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 15a62db..daf1965 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -329,6 +329,16 @@ static int onenand_wait(struct mtd_info *mtd, int state)
 		printk(KERN_ERR "onenand_wait: controller error = 0x%04x\n", ctrl);
 		if (ctrl & ONENAND_CTRL_LOCK)
 			printk(KERN_ERR "onenand_wait: it's locked error.\n");
+		if (state == FL_READING) {
+			/*
+			 * Controller errors while reading can be caused by
+			 * corruption caused by a previous powerloss. Because
+			 * upper level software like JFFS2 treat -EIO as fatal,
+			 * it is necessary to treat the error as an ECC error.
+			 */
+			mtd->ecc_stats.failed++;
+			return -EBADMSG;
+		}
 		return -EIO;
 	}
 
-- 
1.5.2.5

Re: [PATCHJ] [MTD] [OneNAND] Allow for controller errors when reading

[Kyungmin Park]

Hi,

On Fri, Apr 11, 2008 at 8:05 PM, Adrian Hunter
<ext-adrian.hunter@nokia.com> wrote:
> Controller errors while reading can be caused by
>  corruption caused by a previous powerloss. Because
>  upper level software like JFFS2 treat -EIO as fatal,
>  it is necessary to treat the error as an ECC error.
>

Umm interesting. You mean it occurs controller error before ecc error
at power loss case.
And it needs to define the terminology the Sudden Power Off Recovery
or POR shortly.
I'm not sure a previous powerloss means POR.

Anyway could you show the controller error value? Since it needs to
distinguish others e.g., initial bad blocks condition.

Thank you,
Kyungmin Park

Re: [PATCHJ] [MTD] [OneNAND] Allow for controller errors when reading

[Adrian Hunter]

Kyungmin Park wrote:
> On Fri, Apr 11, 2008 at 8:05 PM, Adrian Hunter
> <ext-adrian.hunter@nokia.com> wrote:
>> Controller errors while reading can be caused by
>>  corruption caused by a previous powerloss. Because
>>  upper level software like JFFS2 treat -EIO as fatal,
>>  it is necessary to treat the error as an ECC error.
>>
> 
> Umm interesting. You mean it occurs controller error before ecc error
> at power loss case.
> And it needs to define the terminology the Sudden Power Off Recovery
> or POR shortly.
> I'm not sure a previous powerloss means POR.

No it is not what I meant.  I have sent another patch which I hope is
clearer.

> Anyway could you show the controller error value?

The controller error value is still printed.

> Since it needs to
> distinguish others e.g., initial bad blocks condition.

The bbt scan has its own wait function - I guess it is
possible to get a controller error while reading oob
from an eraseblock that is not actually a bad block.
I am not sure how it would be possible to tell the
difference.

Re: [PATCHJ] [MTD] [OneNAND] Allow for controller errors when reading

[Adrian Hunter]

Kyungmin Park wrote:
> Hi,
> 
> On Fri, Apr 11, 2008 at 8:05 PM, Adrian Hunter
> <ext-adrian.hunter@nokia.com> wrote:
>> Controller errors while reading can be caused by
>>  corruption caused by a previous powerloss. Because
>>  upper level software like JFFS2 treat -EIO as fatal,
>>  it is necessary to treat the error as an ECC error.
>>
> 
> Umm interesting. You mean it occurs controller error before ecc error
> at power loss case.
> And it needs to define the terminology the Sudden Power Off Recovery
> or POR shortly.
> I'm not sure a previous powerloss means POR.
> 
> Anyway could you show the controller error value? 

0x2440

Since it needs to
> distinguish others e.g., initial bad blocks condition.
> 
> Thank you,
> Kyungmin Park