Hi Brian,
On 11/13/2012 08:54 AM, Brian Norris wrote:
On Mon, Nov 12, 2012 at 3:18 PM, Sylwester Nawrocki
<sylvester.nawrocki@xxxxxxxxx> wrote:
On 10/22/2012 09:28 AM, Juergen Beisert wrote:
Sylwester Nawrocki wrote:
[...]
[ 2.455000] NAND device: Manufacturer ID: 0xec, Chip ID: 0xf1 (Samsung
NAND 128MiB 3,3V 8-bit), 8
[ 2.460000] 4 cmdlinepart partitions found on MTD device nand
[ 2.465000] Creating 4 MTD partitions on "nand":
[ 2.470000] 0x000000000000-0x000000080000 : "barebox"
[ 2.475000] mtd: partition "barebox" doesn't end on an erase block --
force read-only
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This "force read-only" doesn't happen with v3.6.
This looks to me the NAND database uses a wrong block size for this NAND
device. This device has 128 kiB block sizes. So, a 512 kiB partition
*is* block aligned.
Maybe you should take a look into the generic code, what block size the
3.7-rc1 uses for this NAND.
Thanks a lot for these pointers. I've found that the commit causing this
regression is this one:
commit e2d3a35ee427aaba99b6c68a56609ce276c51270
Author: Brian Norris<computersforpeace@xxxxxxxxx>
Date: Mon Sep 24 20:40:55 2012 -0700
mtd: nand: detect Samsung K9GBG08U0A, K9GAG08U0F ID
Yes, this patch is already known to cause at least one type of
regression. There's been a fix for a while but David still has
neglected to send it to Linus. It seems that you have quoted it below,
though, and it may not fix your particular regression.
No, it wasn't helpful for me.
When I revert it the crash is gone and everything works well. The Flash
chip is K9F1G08U0C and according to the datasheet it has 5 byte ID.
However nand_id_len() returns 6 and id_data[] is: ec, f1, 00, 95, 40, ec.
Samsung seems to have created some problems by under-specifying the ID
on their NAND. Your NAND is not detected as 5-byte ID for good reason:
the ID wraps around after 6 bytes, not 5. But that's partly
speculation, as you have not provided the full ID.
Can you please list a full 8-byte string of id_data[]? This will be
very helpful. I know of at least one solution that will fix your
problem, but I need to know your full ID to help lay this issue to
rest for good.
Indeed, I wish there was good hardware documentation, still it seems
an exception rather than a rule for some hardware vendors...
Here is my id_data[] dump:
ec, f1, 00, 95, 40, ec, ec, f1
Looks a bit strange, I hope you know how to handle this. :)
I've found a mail thread where similar issue has been discussed [1]. It
seems
the mentioned chunk in commit
"mtd: nand: add generic READ ID length calculation functions"
is missing. Still it doesn't fix the problem for me.
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ec6841d..93d6df3 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2989,7 +2989,8 @@ static void nand_decode_ext_id(struct mtd_info *mtd,
struct nand_chip *chip,
* Check for ID length, cell type, and Hynix/Samsung ID to decide
what
* to do.
*/
- if (id_len == 6&& id_data[0] == NAND_MFR_SAMSUNG) {
+ if (id_len == 6&& id_data[0] == NAND_MFR_SAMSUNG&&
+ id_data[5] != 0x00) {
/* Calc pagesize */
mtd->writesize = 2048<< (extid& 0x03);
extid>>= 2;
...
The following change eliminates the problem for this particular chip,
however it will likely break others.
From efab2f7d0a9049588c8b155fab21f8f8c2433b19 Mon Sep 17 00:00:00 2001
From: Sylwester Nawrocki<sylvester.nawrocki@xxxxxxxxx>
Date: Tue, 13 Nov 2012 00:10:06 +0100
Subject: [PATCH] mtd: Change calculation of length of nand id with repeated
pattern
Corrects ID length calculation for Samsung K9F1G08U0C NAND Flash,
ID: [ec, f1, 00, 95, 40], ec.
Signed-off-by: Sylwester Nawrocki<sylvester.nawrocki@xxxxxxxxx>
---
drivers/mtd/nand/nand_base.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ec6841d..884e951 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2954,7 +2954,7 @@ static int nand_id_len(u8 *id_data, int arrlen)
/* There's a repeated pattern */
if (period< arrlen)
- return period;
+ return period - 1;
/* There are trailing zeros */
if (last_nonzero< arrlen - 1)
You're right, this patch is not correct. The period of repetition
*should* be equal to the ID length, but it seems in your case that
your NAND repeats at 'period + 1'. So we have to figure out something
else.
OK. BTW, is this comment in drivers/mtd/nand_base.c
/*
* nand_id_has_period - Check if an ID string has a given wraparound period
...
* specific repetition interval period (e.g., {0x20,0x01,0x7F,0x20} has a
* period of 2). This is a helper function for nand_id_len(). Returns
non-zero
...
correct ? Shouldn't it be "has a period of 3" ? Since there are 3 different
values and then it repeats starting with 0x20 ?
--
Thanks,
Sylwester
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