Re: GPMI iMX6ull timeout on DMA

[Miquel Raynal <miquel.raynal@xxxxxxxxxxx>]

Hi Michael,

Michael Nazzareno Trimarchi <michael@xxxxxxxxxxxxxxxxxxxx> wrote on
Mon, 29 Jul 2019 15:00:04 +0200:

> Hi Miquel
> 
> On Mon, Jul 29, 2019 at 2:55 PM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
> >
> > 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.
> >  
> 
> I said that where a timing mode is not ackolege then the mtd stack should
> send a reset command and fallback to timeing mode 0. The nand does not
> respond anymore.

It depends on what you define by "not acknowledged". What you describe
is the current situation: if either the NAND controller or the NAND
chip do not support the mode requested by the core, the core will try
another (slower) mode until either we found one or we are at timing
mode 0.

Unfortunately, we cannot check that "all operation with these timings
will work" at boot time, it would be very time consuming; especially
for something that is very likely to be a controller driver issue, and
that is what happens here: both the controller and the chip acknowledge
the new timings.

> 
> > Are you telling me that you already tried mode 0 and that it did not
> > work better than other timings?
> >  
> 
> I force only to use different mode but never try mode 0 ;) just
> because should be
> the normal fallback

Unless there is a timing calculation issue in the controller driver.
Greg, can you please find the quickest working mode (starting from 0,
of course, to ensure mode 0 is stable).

[...]

> > > > > >
> > > > > > 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?

Michael, what did you mean here?


Thanks,
Miquèl

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