Re: GPMI iMX6ull timeout on DMA

Michael Nazzareno Trimarchi
2019-07-29T12:20:45Z

Hi

On Mon, Jul 29, 2019 at 2:19 PM Greg Ungerer <gerg@kernel.org> wrote:
>
> Hi Michael,
>
> On 29/7/19 6:42 pm, Michael Nazzareno Trimarchi wrote:
> > 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.
>
> Testing like this how often does it occur?
>

Not more then 60 reboot ;). The problem is how is done the code the
system can not rebooting without an hardware watchdog

MIchael

> Regards
> Greg
>
>
> > 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
> >
> >
> >

--
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