Re: GPMI iMX6ull timeout on DMA

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Greg Ungerer <gerg@kernel.org>
Cc: s.hauer@pengutronix.de,
	Boris Brezillon <boris.brezillon@collabora.com>,
	linux-mtd@lists.infradead.org,
	Michael Nazzareno Trimarchi <michael@amarulasolutions.com>,
	Boris Brezillon <bbrezillon@kernel.org>
Subject: Re: GPMI iMX6ull timeout on DMA
Date: Wed, 7 Aug 2019 18:05:52 +0200	[thread overview]
Message-ID: <20190807180552.4d85fe28@xps13> (raw)
In-Reply-To: <b739696d-bb1d-bb04-cd45-3019712e29ad@kernel.org>

Hi Greg,

Greg Ungerer <gerg@kernel.org> wrote on Mon, 5 Aug 2019 15:51:05 +1000:

> Hi Boris,
> 
> On 2/8/19 10:51 pm, Boris Brezillon wrote:
> > On Fri, 2 Aug 2019 22:34:57 +1000
> > Greg Ungerer <gerg@kernel.org> wrote:  
> >> On 31/7/19 4:28 pm, Boris Brezillon wrote:  
> >>> On Wed, 31 Jul 2019 12:05:44 +1000
> >>> Greg Ungerer <gerg@kernel.org> wrote:  
> >>>> On 30/7/19 6:38 pm, Miquel Raynal wrote:  
> >>>>> Greg Ungerer <gerg@kernel.org> wrote on Tue, 30 Jul 2019 16:06:55 +1000:  
> >>>>>> 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@kernel.org> wrote on Mon, 29 Jul 2019 22:33:56 +1000:  
> >>>>>>>>>> On 29/7/19 6:36 pm, Miquel Raynal wrote:  
> >>>>>>>>>>> Greg Ungerer <gerg@kernel.org> wrote on Mon, 29 Jul 2019 16:41:51 +1000:  
> >>>>>>> [snip]  
> >>>> Note that this was generated on a normal boot up (not failure).  
> >>>
> >>> The values looks good. Can you try with the below diff applied?  
> >>> --->8---  
> >>> diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> >>> index 334fe3130285..9771f6a82abe 100644
> >>> --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> >>> +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> >>> @@ -721,12 +721,10 @@ static void gpmi_nfc_apply_timings(struct gpmi_nand_data *this)
> >>>           writel(hw->ctrl1n, gpmi_regs + HW_GPMI_CTRL1_SET);  
> >>>    >>>           /* Wait 64 clock cycles before using the GPMI after enabling the DLL */  
> >>> -       dll_wait_time_us = USEC_PER_SEC / hw->clk_rate * 64;
> >>> -       if (!dll_wait_time_us)
> >>> -               dll_wait_time_us = 1;
> >>> +       dll_wait_time_us = DIV_ROUND_UP(USEC_PER_SEC * 64, hw->clk_rate);  
> >>>    >>>           /* Wait for the DLL to settle. */  
> >>> -       udelay(dll_wait_time_us);
> >>> +       usleep_range(dll_wait_time_us, dll_wait_time_us * 10);
> >>>    }  
> >>>    >>>    static int gpmi_setup_data_interface(struct nand_chip *chip, int chipnr,  
> >>
> >> Eventually it failed, in the same way with with same errors.
> >> Took quite a while, over 600 boot cycles.
> >>
> >> Note also that I had to hand merge the changes, since in 5.1.14 that
> >> gpmi_nfc_apply_timings() is in gpmi-lib.c. But it was trivial to do.  
> > 
> > Oh well. I guess the next thing to do would be to dump the timing regs
> > and clk rate that are set by the bootloader (before the driver override
> > them) or those applied by an older kernel (one that didn't have that
> > issue).  
> 
> Is this useful?
> 
> With attached patch, I get the following dump of the timing
> settings in use:
> 
> ...
> drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c(490): gpmi_nfc_apply_timings()
>    HW_GPMI_TIMING0=0x00010203  (calculated=0x00020101)
>    HW_GPMI_TIMING1=0x00000000  (calculated=0x60000000)
>    HW_GPMI_CTRL1_SET=0x01c4000c  (calculated=0x00000000)
>    r->clock[0]=22000000  (calculated=22000000)
> random: fast init done
> 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
> drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c(490): gpmi_nfc_apply_timings()
>    HW_GPMI_TIMING0=0x00010203  (calculated=0x00020101)
>    HW_GPMI_TIMING1=0x00000000  (calculated=0xb0000000)
>    HW_GPMI_CTRL1_SET=0x01c4000c  (calculated=0x00000000)
>    r->clock[0]=22000000  (calculated=22000000)
> drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c(490): gpmi_nfc_apply_timings()
>    HW_GPMI_TIMING0=0x00010203  (calculated=0x00010101)
>    HW_GPMI_TIMING1=0x00000000  (calculated=0xe0000000)
>    HW_GPMI_CTRL1_SET=0x01c4000c  (calculated=0x00c28000)
>    r->clock[0]=22000000  (calculated=100000000)

Why are the registers not updated? Is it the same situation when we
get all the failures?

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