Re: GPMI iMX6ull timeout on DMA

Michael Nazzareno Trimarchi
2021-10-15T20:13:42Z

Hi

On Fri, Oct 15, 2021 at 10:05 PM Michael Trimarchi
<michael@amarulasolutions.com> wrote:
>
> Hi
>
> On Mon, Feb 01, 2021 at 04:14:33PM +0100, Miquel Raynal wrote:
> > Hi Michael,
> >
> > Michael Nazzareno Trimarchi <michael@amarulasolutions.com> wrote on
> > Mon, 1 Feb 2021 16:08:23 +0100:
> >
> > > Hi
> > >
> > > On Mon, Feb 1, 2021 at 3:32 PM Michael Nazzareno Trimarchi
> > > <michael@amarulasolutions.com> wrote:
> > > >
> > > > Hi
> > > >
> > > > On Mon, Feb 1, 2021 at 3:13 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> > > > >
> > > > > Hi Michael,
> > > > >
> > > > > Michael Nazzareno Trimarchi <michael@amarulasolutions.com> wrote on
> > > > > Sat, 30 Jan 2021 10:41:29 +0100:
> > > > >
> > > > > > Hi Miquel
> > > > > >
> > > > > > commit f8e6ad14388067f91b26d044185d95623fbc9535
> > > > > > Author: Michael Trimarchi <michael@amarulasolutions.com>
> > > > > > Date: Fri Jan 29 08:46:53 2021 +0100
> > > > > >
> > > > > > mtd: nand: Calculate the clock before enable it
> > > > > >
> > > > > > Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
> > > > > > Change-Id: I79b0da39de0a9b32ea0b002fa200d7f44d4f8ce7
> > > > > >
> > > > > > diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c
> > > > > > b/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c
> > > > > > index 322a008290e5..0bca52b3bc8f 100644
> > > > > > --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c
> > > > > > +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-lib.c
> > > > > > @@ -377,6 +377,7 @@ static void gpmi_nfc_compute_timings(struct
> > > > > > gpmi_nand_data *this,
> > > > > > const struct nand_sdr_timings *sdr)
> > > > > > {
> > > > > > struct gpmi_nfc_hardware_timing *hw = &this->hw;
> > > > > > + struct resources *r = &this->resources;
> > > > > > unsigned int dll_threshold_ps = this->devdata->max_chain_delay;
> > > > > > unsigned int period_ps, reference_period_ps;
> > > > > > unsigned int data_setup_cycles, data_hold_cycles, addr_setup_cycles;
> > > > > > @@ -440,6 +441,8 @@ static void gpmi_nfc_compute_timings(struct
> > > > > > gpmi_nand_data *this,
> > > > > > hw->ctrl1n |= BF_GPMI_CTRL1_RDN_DELAY(sample_delay_factor) |
> > > > > > BM_GPMI_CTRL1_DLL_ENABLE |
> > > > > > (use_half_period ? BM_GPMI_CTRL1_HALF_PERIOD : 0);
> > > > > > +
> > > > > > + clk_set_rate(r->clock[0], hw->clk_rate);
> > > > > > }
> > > > > >
> > > > > > void gpmi_nfc_apply_timings(struct gpmi_nand_data *this)
> > > > > > @@ -449,8 +452,6 @@ void gpmi_nfc_apply_timings(struct gpmi_nand_data *this)
> > > > > > void __iomem *gpmi_regs = r->gpmi_regs;
> > > > > > unsigned int dll_wait_time_us;
> > > > > >
> > > > > > - clk_set_rate(r->clock[0], hw->clk_rate);
> > > > > > -
> > > > > > writel(hw->timing0, gpmi_regs + HW_GPMI_TIMING0);
> > > > > > writel(hw->timing1, gpmi_regs + HW_GPMI_TIMING1);
> > > > > >
> > > > > > Right now I have this change applied and seems fine. That is the only
> > > > > > difference I get. Clock is apply a bit earlier that when is enabled
> > > > > > it.
> > > > >
> > > > > This is very interesting. So this would mean the issue you are
> > > > > experiencing comes from the clock driver which kind of returns too
> > > > > early from clk_set_rate()? Could you report this to the clk ML/NXP clk
> > > > > maintainers and keep us in copy? If it is as global as it sounds, we
> > > > > might not be the only ones affected.
> > > > >
> > > >
> > > > The imx28 is broken too, so it's a general problem. I need to trace it down
> > > > I have a reverting for lts but it\s not the way to go
> > > >
> > >
> > > For imx28 you ask to set the rate to 22Mhz but you don't care about the clock
> > > that you get back. You get back 12Mhz because the base clock is 24 Mhz and seems
> > > that it can not get the point. You need to check if the clock
> > > requested is in range or ask
> > > for set_rate_clk_min to avoid to have somenthing lower. Then for
> > > imx6ull because is sporadic
> > > I think that is more connected to the clk_set_rate and when you change
> > > the register. Can not be a
> > > setting time?
> >
> > So, if I understand correctly, we face two different problems:
> > - imx6*: seems like a clock issue regarding the clock settlement
> > - imx28: actual NAND driver issue (does not check the validity of the
> > new frequency). This should be handled properly in
> > ->setup_interface().
> >
>
> Somenthing like this? Not compile/tested
>
> diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> index 4d08e4ab5c1b..cc8146ab1b78 100644
> --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> @@ -644,7 +644,7 @@ static int bch_set_geometry(struct gpmi_nand_data *this)
> * RDN_DELAY = ----------------------- {3}
> * RP
> */
> -static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
> +static int gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
> const struct nand_sdr_timings *sdr)
> {
> struct gpmi_nfc_hardware_timing *hw = &this->hw;
> @@ -656,6 +656,7 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
> int sample_delay_ps, sample_delay_factor;
> u16 busy_timeout_cycles;
> u8 wrn_dly_sel;
> + long clk_rate;
>
> if (sdr->tRC_min >= 30000) {
> /* ONFI non-EDO modes [0-3] */
> @@ -671,6 +672,10 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
> wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY;
> }
>
> + clk_rate = clk_round_rate(r->clock[0], hw->clk_rate);
> + if (clk_rate < hw->clk_rate || clk_rate <= 0)
> + return -ENOTSUPP;
> +
> /* SDR core timings are given in picoseconds */
> period_ps = div_u64((u64)NSEC_PER_SEC * 1000, hw->clk_rate);

Not sure here or:

period_ps = div_u64((u64)NSEC_PER_SEC * 1000, clk_rate);

Michael

>
> @@ -746,6 +751,7 @@ static int gpmi_setup_interface(struct nand_chip *chip, int chipnr,
> {
> struct gpmi_nand_data *this = nand_get_controller_data(chip);
> const struct nand_sdr_timings *sdr;
> + int ret = 0;
>
> /* Retrieve required NAND timings */
> sdr = nand_get_sdr_timings(conf);
> @@ -761,11 +767,11 @@ static int gpmi_setup_interface(struct nand_chip *chip, int chipnr,
> return 0;
>
> /* Do the actual derivation of the controller timings */
> - gpmi_nfc_compute_timings(this, sdr);
> -
> - this->hw.must_apply_timings = true;
> + ret = gpmi_nfc_compute_timings(this, sdr);
> + if (!ret)
> + this->hw.must_apply_timings = true;
>
> - return 0;
> + return ret;
> }
>
> /* Clears a BCH interrupt. */
> > Thanks,
> > Miquèl