Re: GPMI iMX6ull timeout on DMA

[Miquel Raynal <miquel.raynal@xxxxxxxxxxx>]

Hi Michael,

Michael Nazzareno Trimarchi <michael@xxxxxxxxxxxxxxxxxxxx> wrote on
Mon, 29 Jul 2019 14:49:19 +0200:

> Hi Miguel
> 
> On Mon, Jul 29, 2019 at 2:47 PM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
> >
> > Hi Greg,
> >
> > + Boris
> >
> > Greg Ungerer <gerg@xxxxxxxxxx> wrote on Mon, 29 Jul 2019 22:33:56 +1000:
> >  
> > > Hi Miquel,
> > >
> > > On 29/7/19 6:36 pm, Miquel Raynal wrote:  
> > > > Hi Greg,
> > > >
> > > > One question below.
> > > >
> > > > +Michael
> > > > +Sascha
> > > >
> > > > Hello Michael, here is a similar issue to yours, I know you did not
> > > > have enough time to share your solution but here we have someone else
> > > > reproducing the issue, would you mind sharing a branch or a patch, even
> > > > a WIP one, just to help debugging?
> > > >
> > > > Greg Ungerer <gerg@xxxxxxxxxx> wrote on Mon, 29 Jul 2019 16:41:51 +1000:
> > > >  
> > > >> Hi Miquel,
> > > >>
> > > >> I am experiencing a problem with NAND flash DMA timeouts on
> > > >> iMX6ull based boards. The problem is very similar to that
> > > >> described in:
> > > >>
> > > >>     https://linux-mtd.infradead.narkive.com/JIUulfFB/gpmi-imx6ull-timeout-on-dma
> > > >>
> > > >> That didn't come to any specific resolution that I could see
> > > >> in that thread.
> > > >>
> > > >> The boot trace on the console for me looks like this:
> > > >>
> > > >> nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xda
> > > >> nand: Micron MT29F2G08ABAEAWP
> > > >> nand: 256 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
> > > >> gpmi-nand 1806000.gpmi-nand: DMA timeout, last DMA
> > > >> gpmi-nand 1806000.gpmi-nand: Show GPMI registers :
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x000 : 0x20830002
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x010 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x020 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x030 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x040 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x050 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x060 : 0x01c6800c
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x070 : 0x00010101
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x080 : 0xe0000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x090 : 0x23023336
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0a0 : 0x000001ee
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0b0 : 0xff000001
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0c0 : 0x00000001
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0d0 : 0x05020000
> > > >> gpmi-nand 1806000.gpmi-nand: Show BCH registers :
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x000 : 0x00000100
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x010 : 0x00000010
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x020 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x030 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x040 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x050 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x060 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x070 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x080 : 0x030a2080
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x090 : 0x083e2080
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0a0 : 0x070a4080
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0b0 : 0x10da4080
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0c0 : 0x070a4080
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0d0 : 0x10da4080
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0e0 : 0x070a4080
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x0f0 : 0x10da4080
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x100 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x110 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x120 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x130 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x140 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x150 : 0x20484342
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x160 : 0x01000000
> > > >> gpmi-nand 1806000.gpmi-nand: offset 0x170 : 0x00000000
> > > >> gpmi-nand 1806000.gpmi-nand: BCH Geometry :
> > > >> GF length              : 13
> > > >> ECC Strength           : 8
> > > >> Page Size in Bytes     : 2110
> > > >> Metadata Size in Bytes : 10
> > > >> ECC Chunk0 Size in Bytes: 512
> > > >> ECC Chunkn Size in Bytes: 512
> > > >> ECC Chunk Count        : 4
> > > >> Payload Size in Bytes  : 2048
> > > >> Auxiliary Size in Bytes: 16
> > > >> Auxiliary Status Offset: 12
> > > >> Block Mark Byte Offset : 1999
> > > >> Block Mark Bit Offset  : 0
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -110
> > > >> nand: timing mode 5 not acknowledged by the NAND chip  
> > > >
> > > > What is the final timing mode used? Most of us tested in mode 5 I
> > > > guess, maybe mode 4 is broken (don't know if this is the one used here,
> > > > neither why mode 5 is refused). Can you please try by limiting the mode
> > > > to 0, 1, 2... until, hopefully, we narrow down to the failing mode.  
> > >
> > > Sure, how to do that?  
> >
> > This loop [1] tries to configure each mode (5, 4, ...) until one
> > succeeds (default is 0: must always work). Please try to limit mode to
> > 0, 1, etc.
> >
> > Mode 0 should work.
> >  
> 
> This is not correct. When all the mode fail it fallback to 0 that does
> not work. Already check
> So the fallback is created for this situation

Sorry but I don't understand what you are saying.

Are you telling me that you already tried mode 0 and that it did not
work better than other timings?

> 
> > [1] https://elixir.bootlin.com/linux/v5.3-rc1/source/drivers/mtd/nand/raw/nand_base.c#L933
> >  
> > >
> > >  
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22
> > > >> Scanning device for bad blocks
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22
> > > >> ....
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22
> > > >> gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22
> > > >> 5 fixed-partitions partitions found on MTD device gpmi-nand
> > > >> Creating 5 MTD partitions on "gpmi-nand":
> > > >> 0x000000000000-0x000000500000 : "u-boot"
> > > >> 0x000000500000-0x000000600000 : "u-boot-env"
> > > >> 0x000000600000-0x000000800000 : "log"
> > > >> 0x000000800000-0x000010000000 : "flash"
> > > >> 0x000000000000-0x000010000000 : "all"
> > > >> gpmi-nand 1806000.gpmi-nand: driver registered.
> > > >>
> > > >>
> > > >> This is using a linux kernel v5.1.14. I have seen this happen on
> > > >> a number of boards I have here - but it is only occasional. It
> > > >> only happens once in a while on boot, maybe 1 in 40 or more times.
> > > >> So it can take quite a while to reproduce (using a boot loop setup).  
> > > >
> > > > That's strange... I don't get what would produce such unstable issue.  
> > >
> > > My initial guess is that the calculated timing is very marginal.  
> >
> > What do you mean by "marginal"?
> >  
> 
> I don't think that is timing calculation. I have tried to use the same timing
> as before but when those are applide. Is it possible?

                                      ^
I suppose the end of the sentence is missing?


Thanks,
Miquèl

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