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mtd_peb_write broken on dataflash

PATCH Ladislav Michl 2 participants 3 messages Sep 20, 2018 – Sep 21, 2018 Memory technology devices (MTD)

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Ladislav Michl

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#0 lore raw

As mtd_peb_write checks for alignment, it fails writing to dataflash:
barebox$ state -s
ERROR: state: Failed to write PEB 0, -22
ERROR: state: Failed to write circular to 0 length 48, -22
WARNING: state: Failed to write state backend bucket, -22
ERROR: state: Failed to write PEB 1, -22
ERROR: state: Failed to write circular to 0 length 48, -22
WARNING: state: Failed to write state backend bucket, -22
ERROR: state: Failed to write PEB 2, -22
ERROR: state: Failed to write circular to 0 length 48, -22
WARNING: state: Failed to write state backend bucket, -22
ERROR: state: Failed to write state to at least 1 buckets. Successfully written to 0 buckets
ERROR: state: Failed to write packed state, -5
state: I/O error

Patch bellow is a naive fix just to show where problem is.

There's also problem erasing dataflash:
barebox$ erase /dev/dataflash0.barebox-state
erase: Invalid argument

I guess we'll run into similar issue for MTD_RAM, so question is whenever we want such a strict check here at all. Opinions?

Thank you.

---
 drivers/mtd/peb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/mtd/peb.c +1 -1
index c35b63f2f..6035fbc45 100644
@@ -376,7 +376,7 @@ int mtd_peb_write(struct mtd_info *mtd, const void *buf, int pnum, int offset,
 		return -EINVAL;
 	if (len <= 0)
 		return -EINVAL;
-	if (len % (mtd->writesize >> mtd->subpage_sft))
+	if (mtd->type != MTD_DATAFLASH && len % (mtd->writesize >> mtd->subpage_sft))
 		return -EINVAL;
 	if (mtd_peb_is_bad(mtd, pnum))
 		return -EINVAL;
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2.19.0


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#1 lore raw

Hi Ladis,

Quoted 10 lines · Ladislav Michl

As mtd_peb_write checks for alignment, it fails writing to dataflash:
barebox$ state -s
ERROR: state: Failed to write PEB 0, -22
ERROR: state: Failed to write circular to 0 length 48, -22
WARNING: state: Failed to write state backend bucket, -22
ERROR: state: Failed to write PEB 1, -22
ERROR: state: Failed to write circular to 0 length 48, -22
WARNING: state: Failed to write state backend bucket, -22
ERROR: state: Failed to write PEB 2, -22
ERROR: state: Failed to write circular to 0 length 48, -22

How I read the code the length should be writesize aligned...

drivers/mtd/peb.c int mtd_peb_write(struct mtd_info *mtd, const void *buf, int pnum, int offset, · line 379

Quoted 10 lines
drivers/mtd/peb.c +1 -1
index c35b63f2f..6035fbc45 100644
@@ -376,7 +376,7 @@ int mtd_peb_write(struct mtd_info *mtd, const void *buf, int pnum, int offset,
 		return -EINVAL;
 	if (len <= 0)
 		return -EINVAL;
-	if (len % (mtd->writesize >> mtd->subpage_sft))
+	if (mtd->type != MTD_DATAFLASH && len % (mtd->writesize >> mtd->subpage_sft))

So how big is mtd->writesize here and is this value correct?

In state_storage_mtd_buckets_init() we have:

        if (circular)
                writesize = meminfo->writesize;
        else
                writesize = meminfo->erasesize;

How big are meminfo->writesize and meminfo->erasesize here and which path is chosen?

Sascha

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author
#2 lore raw
Quoted 14 lines · Sascha Hauer

Hi Ladis,

Quoted 10 lines · Ladislav Michl

As mtd_peb_write checks for alignment, it fails writing to dataflash:
barebox$ state -s
ERROR: state: Failed to write PEB 0, -22
ERROR: state: Failed to write circular to 0 length 48, -22
WARNING: state: Failed to write state backend bucket, -22
ERROR: state: Failed to write PEB 1, -22
ERROR: state: Failed to write circular to 0 length 48, -22
WARNING: state: Failed to write state backend bucket, -22
ERROR: state: Failed to write PEB 2, -22
ERROR: state: Failed to write circular to 0 length 48, -22

Quoted 1 line

How I read the code the length should be writesize aligned...

It is perfectly valid to write less to dataflash... But see bellow.

Quoted 4 lines
Quoted 4 lines
drivers/mtd/peb.c +0 -0
index c35b63f2f..6035fbc45 100644
Quoted 8 lines

drivers/mtd/peb.c int mtd_peb_write(struct mtd_info *mtd, const void *buf, int pnum, int offset, · line 379

Quoted 6 lines
drivers/mtd/peb.c +1 -1
@@ -376,7 +376,7 @@ int mtd_peb_write(struct mtd_info *mtd, const void *buf, int pnum, int offset,
 		return -EINVAL;
 	if (len <= 0)
 		return -EINVAL;
-	if (len % (mtd->writesize >> mtd->subpage_sft))
+	if (mtd->type != MTD_DATAFLASH && len % (mtd->writesize >> mtd->subpage_sft))

So how big is mtd->writesize here and is this value correct?

Yes, it is correct:
dataflash@00: AT45DB041x (528 KBytes) pagesize 264 bytes (OTP)

Quoted 9 lines

In state_storage_mtd_buckets_init() we have:

        if (circular)
                writesize = meminfo->writesize;
        else
                writesize = meminfo->erasesize;

How big are meminfo->writesize and meminfo->erasesize here and which path is chosen?

writesize: 264
erasesize: 264
subpage_sft: 0
circular: true

But later we are trying to write 48 bytes:
dataflash0.barebox-state: write 48 bytes to PEB 0:0

ladis

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