RE: [PATCH v3 01/11] mtd: cfi_cmdset_0002: Change do_write_oneword() to use chip_good()

["Tokunori Ikegami" <ikegami_to@yahoo.co.jp>]

Hi Jocke-san,

Thanks for your advice.

To make sure let me confirm below.

The OpenWrt code includes your patch below.

  f69cd2d30a80 2018-05-01 12:58:18 -0700 mtd: cfi: cmdset_0002: Do not allow read/write to suspend erase block.  [Joakim Tjernlund]

Do you mean that it is possible to be needed an additional change more based on this?
Or is it not related to the patch fixed by you?
  Note: Sorry now I am not able to check the patches to try sent by you before.

> I have lost track of all the details regarding this issue. I just want to
> add:
> 
> There is a max number of suspend/resume cycles one can do during an
> erase(possibly also for write)
> and once that number is hit you get an error. One way to avoid this could
> be to
> wait after each resume until the erase has started again(look in status
> register)
> before continuing.
> 
> If this has anything to do with this problem, I do not know.
> 
>  Jocke

Regards,
Ikegami

> -----Original Message-----
> From: Joakim Tjernlund [mailto:Joakim.Tjernlund@infinera.com]
> Sent: Wednesday, January 23, 2019 1:58 AM
> To: boris.brezillon@bootlin.com; ikegami_to@yahoo.co.jp
> Cc: linux-mtd@lists.infradead.org; chris.packham@alliedtelesis.co.nz;
> fbettoni@gmail.com; nbd@nbd.name; stable@vger.kernel.org;
> hauke@hauke-m.de; koen.vandeputte@ncentric.com;
> boris.brezillon@free-electrons.com
> Subject: Re: [PATCH v3 01/11] mtd: cfi_cmdset_0002: Change
> do_write_oneword() to use chip_good()
> 
> On Wed, 2019-01-23 at 00:49 +0900, Tokunori Ikegami wrote:
> >
> >
> > Hi Boris-san,
> >
> > Very sorry for too late to update about this.
> > But could you please let me consult below about this patch?
> >
> > I have tried to investigate the issue root cause and confirmed below but
> > still the root cause seems not clear.
> >
> >   1. Without the change the write oneword is retried and recovered by
> the
> > current existing chip_good() checking.
> >      But after the 1,001 times recovery it was continued to fail recovery
> > with the 3 times retry.
> 
> I have lost track of all the details regarding this issue. I just want to
> add:
> 
> There is a max number of suspend/resume cycles one can do during an
> erase(possibly also for write)
> and once that number is hit you get an error. One way to avoid this could
> be to
> wait after each resume until the erase has started again(look in status
> register)
> before continuing.
> 
> If this has anything to do with this problem, I do not know.
> 
>  Jocke
> 
> >   2. By the patch change the recovery failure can be avoided and the write
> > oneword works correctly without any failure.
> >      There are different from the original chip_good() checking as the
> > original code resets the chip before the retry.
> >      The patch change wait the chip_good() status until the timeout expiry
> > without the chip reset.
> >        Note: There is a different from the original OpenWrt patch and
> needed
> > to be changed as same and it will be done by the next v4 patch.
> >
> >   3. To narrow down the cause I have added some delays into the original
> > code to check the chip ready and good status.
> >      But the failure behavior was not changed so it seems that the issue
> is
> > not depended to the timing. (But not sure)
> >
> >   4. On the OpenWrt the write buffer is disabled but to narrow down the
> > issue I have changed to enable the write buffer.
> >      Then the flash error was not happened by the write buffer operation
> so
> > it seems that the flash driver works correctly.
> >      But another issue was caused and it is similar issue with the original
> > OpenWrt behavior with the patch change.
> >        Note: On the original OpenWrt needs to wait the file system
> > completion to build but it was not finished with the write buffer. (But
> not
> > sure about this behavior)
> >
> > Do you have any comment about this result?
> >
> > If you can agree about the patch change basically with the current
> situation
> > I will do send the v4 patch set later with fix for the comments.
> >
> > But it seems that it is difficult to investigate the root cause more at
> this
> > moment to me.
> > Since but the behavior looks depended on the flash chip hardware behavior
> > and I cannot debug the hardware behavior more I think.
> >   Note: Now I can reproduce the flash error issue behavior on the OpenWrt
> > unit.
> >
> > > > >     It is depended on the actual flash chip behavior so the root
> cause
> > > > is
> > > > >     unknown.
> > > >
> > > > Yes, and that's what I'd like you to figure out, or at least have
> a
> > > > good idea why this doesn't work on some chips but works on others.
> > >
> > > I see.
> > > But it is a little bit difficult situation since I do not have the failure
> > > environment locally at this moment.
> > > But if needed I may ask to get the help for this to Fabio-san.
> >
> > Regards,
> > Ikegami
> >
> > > -----Original Message-----
> > > From: IKEGAMI Tokunori [mailto:ikegami@allied-telesis.co.jp]
> > > Sent: Tuesday, November 6, 2018 6:47 PM
> > > To: Boris Brezillon; ikegami_to@yahoo.co.jp
> > > Cc: boris.brezillon@free-electrons.com; Felix Fietkau; Hauke Mehrtens;
> > > stable@vger.kernel.org; Joakim Tjernlund; PACKHAM Chris;
> > > linux-mtd@lists.infradead.org; Koen Vandeputte; Fabio Bettoni
> > > Subject: RE: [PATCH v3 01/11] mtd: cfi_cmdset_0002: Change
> > > do_write_oneword() to use chip_good()
> > >
> > > Sorry let me resend the mail below by changing the email address of
> > > Felix-san.
> > >
> > > -----Original Message-----
> > > From: IKEGAMI Tokunori
> > > Sent: Tuesday, November 06, 2018 6:37 PM
> > > To: 'Boris Brezillon'; 'ikegami_to@yahoo.co.jp'
> > > Cc: boris.brezillon@free-electrons.com; Felix Fietkau; Hauke Mehrtens;
> > > stable@vger.kernel.org; Joakim Tjernlund; PACKHAM Chris;
> > > linux-mtd@lists.infradead.org; Koen Vandeputte; Fabio Bettoni
> > > Subject: RE: [PATCH v3 01/11] mtd: cfi_cmdset_0002: Change
> > > do_write_oneword() to use chip_good()
> > >
> > > Hi Boris-san,
> > >
> > > > -----Original Message-----
> > > > From: stable-owner@vger.kernel.org
> > > > [mailto:stable-owner@vger.kernel.org] On Behalf Of Boris Brezillon
> > > > Sent: Tuesday, November 06, 2018 5:34 PM
> > > > To: IKEGAMI Tokunori
> > > > Cc: boris.brezillon@free-electrons.com; Felix Fietkau; Hauke
> Mehrtens;
> > > > stable@vger.kernel.org; Joakim Tjernlund; PACKHAM Chris;
> > > > linux-mtd@lists.infradead.org; Koen Vandeputte; Fabio Bettoni
> > > > Subject: Re: [PATCH v3 01/11] mtd: cfi_cmdset_0002: Change
> > > > do_write_oneword() to use chip_good()
> > > >
> > > > Hi IKEGAMI,
> > > >
> > > > On Tue, 6 Nov 2018 00:25:43 +0000
> > > > IKEGAMI Tokunori <ikegami@allied-telesis.co.jp> wrote:
> > > >
> > > > > > > Also the issue can be fixed by using chip_good() instead of
> > > > chip_ready().
> > > > > > > The chip_ready() just checks the value from flash memory twice.
> > > > > > > And the chip_good() checks the value with the expected value.
> > > > > > > Probably the issue can be fixed as checked correctly by the
> > > chip_good().
> > > > > > > So change to use chip_good() instead of chip_ready().
> > > > > >
> > > > > > Well, that's not really explaining why you think chip_good() should
> > > > be
> > > > > > used instead of chip_ready(). So I went on and looked at the
> > > > > > chip_good(), chip_ready() and do_write_oneword() implementation,
> and
> > > > > > also looked at users of do_write_oneword(). It seems this function
> > > is
> > > > > > used to write data to the flash, and apparently the "one bit should
> > > > > > toggle to reflect a busy state" does not apply when writing things
> > > to
> > > > > > the memory array (it's probably working for other CFI commands,
> but
> > > > I
> > > > > > guess it takes more time to actually change the level of a NOR
> cell,
> > > > > > hence the result of 2 identical reads does not mean that the write
> > > is
> > > > > > done).
> > > > > >
> > > > > > Also, it seems that cmdset_0001 is not implementing chip_ready()
> the
> > > > > > same way, and I wonder if cmdset_0002 implementation is correct
> to
> > > > > > start with. Or maybe I don't get what chip_ready() is for.
> > > > > >
> > > > > > Anyway, this is the sort of clarification I'd like to have.
> > > > >
> > > > > I am thinking to update the commit message as below.
> > > > >
> > > > >     mtd: cfi_cmdset_0002: Use chip_good() to retry in
> > > do_write_oneword()
> > > > >     As reported by the OpenWRT team, write requests sometimes fail
> on
> > > > some
> > > > >     platforms.
> > > > >     Currently to check the state chip_ready() is used correctly
> as
> > > > described by
> > > > >     the flash memory S29GL256P11TFI01 datasheet.
> > > >
> > > > I had a look at the S29GL256P datasheet here [1], and if I'm correct,
> > > > it's using cmdset 0001.
> > >
> > > No actually the cmdset 0002 is used on the flash chip.
> > > The manufacturer ID xx01h and Device ID 2201h are used to decide.
> > >
> > > There is information from Fobis-san below also about this.
> > >
> > > On forum thread musashino posted picture of flash chip:
> > >
> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fforum
> .openwrt.org%2Ft%2Fimpossible-to-install-update-any-packages-&amp;data
> =02%7C01%7Cjoakim.tjernlund%40infinera.com%7C916af968b27a402da8cf08d68
> 0812fce%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C1%7C63683768968012655
> 7&amp;sdata=NNGSYgq1VTuofPPMMlyKIm9W1DJHQFw0s94Ernq5cts%3D&amp;reserve
> d=0
> > > on-wzr-hp-g300nh-18-06-1
> > >
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.cy
> press.com%2Fpart%2Fs29gl256p11tfi010&amp;data=02%7C01%7Cjoakim.tjernlu
> nd%40infinera.com%7C916af968b27a402da8cf08d680812fce%7C285643de5f5b4b0
> 3a1530ae2dc8aaf77%7C1%7C1%7C636837689680126557&amp;sdata=Twk1VUEESz14U
> pdJjU4ohuhiQ5jN1uHLh0cAhlAznW0%3D&amp;reserved=0
> > >
> > > [    0.862264] physmap platform flash device: 02000000 at 1e000000
> > > [    0.868331] physmap-flash: Found 1 x16 devices at 0x0 in 16-bit
> > > bank. Manufacturer ID 0x000001 Chip ID 0x002201
> > > [    0.878493] Amd/Fujitsu Extended Query Table at 0x0040
> > > [    0.883668]   Amd/Fujitsu Extended Query version 1.3.
> > > [    0.888768] number of CFI chips: 1
> > > [    0.894557] Searching for RedBoot partition table in physmap-flash
> > > at offset 0x1fc0000
> > > [    0.918009] Searching for RedBoot partition table in physmap-flash
> > > at offset 0x1fe0000
> > > [    0.941464] No RedBoot partition table detected in physmap-flash
> > > [    0.947926] Creating 5 MTD partitions on "physmap-flash":
> > > [    0.953384] 0x000000000000-0x000000040000 : "u-boot"
> > > [    0.960853] 0x000000040000-0x000000060000 : "u-boot-env"
> > > [    0.968803] 0x000000060000-0x000001fc0000 : "firmware"
> > > [    0.981859] 2 uimage-fw partitions found on MTD device firmware
> > > [    0.987900] 0x000000060000-0x0000001b5706 : "kernel"
> > > [    0.994916] 0x0000001b5706-0x000001fc0000 : "rootfs"
> > > [    1.001986] mtd: device 4 (rootfs) set to be root filesystem
> > > [    1.007789] 1 squashfs-split partitions found on MTD device rootfs
> > > [    1.014014] 0x0000003c0000-0x000001fc0000 : "rootfs_data"
> > > [    1.022093] 0x000001fc0000-0x000001fe0000 : "user_property"
> > > [    1.030283] 0x000001fe0000-0x000002000000 : "art"
> > >
> > > Maybe you could post links to forum thread, and data sheet.
> > >
> > > > >     Also chip_good() is used to check if the write is succeeded
> and
> > > it
> > > > was
> > > > >     implemented by the commit fb4a90bfcd6d8 ("[MTD] CFI-0002 -
> Improve
> > > > error
> > > > >     checking").
> > > > >     But actually the write failure is caused on some platforms and
> > also
> > > > it can
> > > > >     be fixed by using chip_good() to check the state and retry
> > instead.
> > > > Do you know on which NOR chips this happens? Do you have access to
> the
> > > > datasheet?
> > >
> > > But it looks SST49LF008A [3] from the changes below but I am not sure
> at
> > > this moment and probably it should be confirmed to the authr Eric W.
> > > Biedermann <ebiederman@lnxi.com> to make sure.
> > >
> > > +#define SST49LF008A            0x005a
> > >
> > >  static int cfi_amdstd_read (struct mtd_info *, loff_t, size_t, size_t
> *,
> > > u_char *);
> > >  static int cfi_amdstd_write_words(struct mtd_info *, loff_t, size_t,
> > > size_t *, const u_char *);
> > > @@ -191,6 +192,7 @@ static struct cfi_fixup cfi_fixup_table[] = {
> > >  };
> > >  static struct cfi_fixup jedec_fixup_table[] = {
> > >         { MANUFACTURER_SST, SST49LF004B, fixup_use_fwh_lock, NULL, },
> > > +       { MANUFACTURER_SST, SST49LF008A, fixup_use_fwh_lock, NULL, },
> > >
> > > > >     It is depended on the actual flash chip behavior so the root
> cause
> > > > is
> > > > >     unknown.
> > > >
> > > > Yes, and that's what I'd like you to figure out, or at least have
> a
> > > > good idea why this doesn't work on some chips but works on others.
> > >
> > > I see.
> > > But it is a little bit difficult situation since I do not have the failure
> > > environment locally at this moment.
> > > But if needed I may ask to get the help for this to Fabio-san.
> > >
> > > > > If any comment please let me know.
> > > > >
> > > > > > > Signed-off-by: Tokunori Ikegami <ikegami@allied-telesis.co.jp>
> > > > > > > Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
> > > > > > > Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
> > > > > > > Signed-off-by: Fabio Bettoni <fbettoni@gmail.com>
> > > > > >
> > > > > > Has the patch really gone through all those people? SoB is used
> when
> > > > you
> > > > > > apply a patch in your tree or when you're the original author.
> > > > >
> > > > > I have just checked the OpenWRT git log again and it looks that
> it was
> > > > originally
> > > > > implemented by Felix Fietkau <nbd@openwrt.org> by the patch below
> so
> > > I
> > > > will update the Signed-off-by tag as so.
> > >
> <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.
> openwrt.org%2F%3Fp%3Dopenwrt%2Fopenwrt.git%3Ba%3Dcommitdiff%3Bh%3D2530
> 640&amp;data=02%7C01%7Cjoakim.tjernlund%40infinera.com%7C916af968b27a4
> 02da8cf08d680812fce%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C1%7C63683
> 7689680126557&amp;sdata=w13ZTKwD1NiUQzxQfUou92KVDlW80qGUiZVIcjU%2BGPA%
> 3D&amp;reserved=0
> > > > f07cd2b3b14fe9ec03fa63a586452cc5f>
> > > > > > > Co-Developed-by: Hauke Mehrtens <hauke@hauke-m.de>
> > > > > > > Co-Developed-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
> > > > > > > Co-Developed-by: Fabio Bettoni <fbettoni@gmail.com>
> > > > > >
> > > > > > Not sure we want to add new undocumented tags, but you can mention
> > > > > > that all those people helped you find/debug the issue. They can
> also
> > > > > > add their Reviewed-by/Tested-by if they like.
> > > >
> > > > My bad, I just noticed these are valid flags [2], so you can keep
> them,
> > > > and according to the doc, you should also keep the SoB.
> > >
> > > I see.
> > > Yes I had also checked it.
> > >
> > > By the way in near future my company email address will be not able
> to
> > use.
> > > So I will change the mail address to my personal email address [4] after
> > > that or before.
> > >
> > > Regards,
> > > Ikegami
> > >
> > > > Regards,
> > > >
> > > > Boris
> > > >
> > > >
> [1]https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww
> .cypress.com%2Ffile%2F219926%2Fdownload&amp;data=02%7C01%7Cjoakim.tjer
> nlund%40infinera.com%7C916af968b27a402da8cf08d680812fce%7C285643de5f5b
> 4b03a1530ae2dc8aaf77%7C1%7C1%7C636837689680126557&amp;sdata=ILqgA75bFH
> Zz9GnswZiDnknzEb3Dryha6CFuVb5Hvhs%3D&amp;reserved=0
> > > >
> > >
> [2]https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgi
> t.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git
> %2F&amp;data=02%7C01%7Cjoakim.tjernlund%40infinera.com%7C916af968b27a4
> 02da8cf08d680812fce%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C1%7C63683
> 7689680126557&amp;sdata=xRCLc%2FnYHeLAiyKoj3obuOuY19JnZPZFZAYrZh%2BJXU
> I%3D&amp;reserved=0
> > > > tree/Documentation/process/submitting-patches.rst?h=v4.20-rc1#n546
> > >
> > >
> [3]https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fww
> w.microchip.com%2Fwwwproducts%2Fen%2FSST49LF008A&amp;data=02%7C01%7Cjo
> akim.tjernlund%40infinera.com%7C916af968b27a402da8cf08d680812fce%7C285
> 643de5f5b4b03a1530ae2dc8aaf77%7C1%7C1%7C636837689680126557&amp;sdata=3
> v3AaOaxogw4PAydIISO3PTmkzXo4Tdbux2D0Q1V5sg%3D&amp;reserved=0
> > > [4]ikegami_to@yahoo.co.jp



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