Re: GPMI iMX6ull timeout on DMA

[Miquel Raynal <miquel.raynal@xxxxxxxxxxx>]

Hi Greg,

Greg Ungerer <gerg@xxxxxxxxxx> wrote on Tue, 30 Jul 2019 16:06:55 +1000:

> Hi Miquel,
> 
> On 30/7/19 10:41 am, Greg Ungerer wrote:
> > On 30/7/19 10:28 am, Greg Ungerer wrote:  
> >> On 29/7/19 10:47 pm, Miquel Raynal wrote:  
> >>> Greg Ungerer <gerg@xxxxxxxxxx> wrote on Mon, 29 Jul 2019 22:33:56 +1000:  
> >>>> On 29/7/19 6:36 pm, Miquel Raynal wrote:  
> >>>>> Greg Ungerer <gerg@xxxxxxxxxx> wrote on Mon, 29 Jul 2019 16:41:51 +1000:  
> > [snip]  
> >>>>>> 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.
> >>>
> >>> [1] https://elixir.bootlin.com/linux/v5.3-rc1/source/drivers/mtd/nand/raw/nand_base.c#L933  
> >>
> >> The normal behavior - which usually works - has
> >> chip->onfi_timing_mode_default=5 here. So in other words on the first pass
> >> through this loop it is checking mode 5, and setting it as the default.
> >>
> >> I am running a test/reboot loop now waiting for failure to see
> >> if it is still using mode 5 in that case.  
> > 
> > With this trace in place:
> > 
> > --- a/linux/drivers/mtd/nand/raw/nand_base.c
> > +++ b/linux/drivers/mtd/nand/raw/nand_base.c
> > @@ -910,6 +910,7 @@ static int nand_init_data_interface(struct nand_chip *chip)
> >          }
> > 
> >          for (mode = fls(modes) - 1; mode >= 0; mode--) {
> > +               printk("%s(%d): checking mode=%d\n", __FILE__, __LINE__, mode);
> >                  ret = onfi_fill_data_interface(chip, NAND_SDR_IFACE, mode);
> >                  if (ret)
> >                          continue;
> > @@ -923,10 +924,12 @@ static int nand_init_data_interface(struct nand_chip *chip)
> >                                                   &chip->data_interface);
> >                  if (!ret) {
> >                          chip->onfi_timing_mode_default = mode;
> > +                       printk("%s(%d): BREAKING AT mode=%d\n", __FILE__, __LINE__, mode);
> >                          break;
> >                  }
> >          }
> > 
> > +       printk("%s(%d): chip->onfi_timing_mode_default=%d\n", __FILE__, __LINE__, chip->onfi_timing_mode_default);
> >          return 0;
> >   }
> > 
> > 
> > First NAND failure gives 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: use legacy bch geometry
> > drivers/mtd/nand/raw/nand_base.c(913): checking mode=5
> > drivers/mtd/nand/raw/nand_base.c(927): BREAKING AT mode=5
> > drivers/mtd/nand/raw/nand_base.c(932): chip->onfi_timing_mode_default=5
> > 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 : 0x00000100
> > 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
> > gpmi-nand 1806000.gpmi-nand: Chip: 0, Error -22  
> 
> Not sure if this is a useful data point... But I modified that
> nand_init_data_interface() loop to start checking from data mode 4.
> So now on every boot it defaults to mode 4. That has been running
> most of the day, up to 900 boot cycles now, no failures.

Ok so after having chatted quite a bit with Boris, it is very likely
that, for these chips, the timings in mode 5 are too tight. It could
fail the GET_FEATURES once in mode 5. Can you please dump every single
intermediate value in gpmi_nfc_compute_timings() (period, *_cycles,
use of half pêriods, tRP, sample delay, etc) as well as the content
of /sys/kernel/debug/clk/clk_summary (you'll need debugfs support
enabled and mounted).

Also, can you be sure that the NAND chip is powered with 3.3V?

Thanks,
Miquèl

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