Re: GPMI iMX6ull timeout on DMA

[Michael Nazzareno Trimarchi <michael@amarulasolutions.com>]

Hi all

On Mon, Jul 29, 2019 at 10:36 AM Miquel Raynal
<miquel.raynal@bootlin.com> 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?
>

I have patches reverted as I mention in the email. The step to
reproduce is simple.

Just reboot every successful boot.

Michael

> Greg Ungerer <gerg@kernel.org> 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.
>
> > 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.
>
> >
> > As per the email thread I pointed to above I looked at reverting
> > those patches, but that was not at all easy given how much the gpmi
> > driver code had moved. So instead I modified the code with this:
> >
> > --- a/linux/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c
> > +++ b/linux/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c
> > @@ -481,6 +481,7 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
> >     void gpmi_nfc_apply_timings(struct gpmi_nand_data *this)
> >   {
> > +#if 0
> >          struct gpmi_nfc_hardware_timing *hw = &this->hw;
> >          struct resources *r = &this->resources;
> >          void __iomem *gpmi_regs = r->gpmi_regs;
> > @@ -505,6 +512,7 @@ void gpmi_nfc_apply_timings(struct gpmi_nand_data *this)
> >            /* Wait for the DLL to settle. */
> >          udelay(dll_wait_time_us);
> > +#endif
> >   }
> >     int gpmi_setup_data_interface(struct nand_chip *chip, int chipnr,
> >
> > So far after a couple of days of testing with this I no longer
> > see the DMA timeout.
> >
> > Any thoughts?
> >
> > Regards
> > Greg
> >
>
> Thanks,
> Miquèl



-- 
| Michael Nazzareno Trimarchi                     Amarula Solutions BV |
| COO  -  Founder                                      Cruquiuskade 47 |
| +31(0)851119172                                 Amsterdam 1018 AM NL |
|                  [`as] http://www.amarulasolutions.com               |

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