Re: regression caused by: "amlogic: mmc: meson-gx: add signal resampling"

[Andreas Fenkart <afenkart@gmail.com>]

From 7ea0b63ddfc841251cbcc33c8ed0151e52e372f2 Mon Sep 17 00:00:00 2001
From: Andreas Fenkart <afenkart@gmail.com>
Date: Thu, 17 Jan 2019 15:39:52 +0100
Subject: [PATCH] mmc: meson-gx: enable signal re-sampling together with tuning

card detection fails on "BeeLink Mini M8 SII" if enabled too early
mmc1: error -110 whilst initialising MMC card

Fixes: 71645e65729f ("mmc: meson-gx: add signal resampling")
Signed-off-by: Andreas Fenkart <afenkart@gmail.com>
---
 drivers/mmc/host/meson-gx-mmc.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index c2690c1a50ff..dba499009d0c 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -738,6 +738,11 @@ static int meson_mmc_clk_phase_tuning(struct
mmc_host *mmc, u32 opcode,
 static int meson_mmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
 {
  struct meson_host *host = mmc_priv(mmc);
+ int adj = 0;
+
+ /* enable signal resampling w/o delay */
+ adj = ADJUST_ADJ_EN;
+ writel(adj, host->regs + host->data->adjust);

  return meson_mmc_clk_phase_tuning(mmc, opcode, host->rx_clk);
 }
@@ -768,6 +773,9 @@ static void meson_mmc_set_ios(struct mmc_host
*mmc, struct mmc_ios *ios)
  if (!IS_ERR(mmc->supply.vmmc))
  mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, ios->vdd);

+ /* disable signal resampling */
+ writel(0, host->regs + host->data->adjust);
+
  /* Reset rx phase */
  clk_set_phase(host->rx_clk, 0);

@@ -1166,7 +1174,7 @@ static int meson_mmc_get_cd(struct mmc_host *mmc)

 static void meson_mmc_cfg_init(struct meson_host *host)
 {
- u32 cfg = 0, adj = 0;
+ u32 cfg = 0;

  cfg |= FIELD_PREP(CFG_RESP_TIMEOUT_MASK,
    ilog2(SD_EMMC_CFG_RESP_TIMEOUT));
@@ -1177,10 +1185,6 @@ static void meson_mmc_cfg_init(struct meson_host *host)
  cfg |= CFG_ERR_ABORT;

  writel(cfg, host->regs + SD_EMMC_CFG);
-
- /* enable signal resampling w/o delay */
- adj = ADJUST_ADJ_EN;
- writel(adj, host->regs + host->data->adjust);
 }

 static int meson_mmc_card_busy(struct mmc_host *mmc)
-- 
2.20.1

Am Do., 17. Jan. 2019 um 16:08 Uhr schrieb Jerome Brunet <jbrunet@baylibre.com>:
>
> On Thu, 2019-01-17 at 15:47 +0100, Andreas Fenkart wrote:
> > From: Andreas Fenkart <afenkart@gmail.com>
> > Date: Thu, 17 Jan 2019 15:39:52 +0100
> > Subject: [PATCH] mmc: meson-gx: enable signal re-sampling together with
> > tuning
> >
> > card detection fails on some p212 derived boards if enabled too early
>
> Please clearly mention what board you are using, this is too vague.
>
> > mmc1: error -110 whilst initialising MMC card
> >
>
> missing the 'Fixes' tag here
>
> > Signed-off-by: Andreas Fenkart <afenkart@gmail.com>
> > ---
> >  drivers/mmc/host/meson-gx-mmc.c | 16 ++++++++++------
> >  1 file changed, 10 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-
> > mmc.c
> > index c2690c1a50ff..b65ec4bea980 100644
> > --- a/drivers/mmc/host/meson-gx-mmc.c
> > +++ b/drivers/mmc/host/meson-gx-mmc.c
> > @@ -709,7 +709,8 @@ static int meson_mmc_find_tuning_point(unsigned long
> > *test)
> >  static int meson_mmc_clk_phase_tuning(struct mmc_host *mmc, u32 opcode,
> >         struct clk *clk)
> >  {
> > - int point, ret;
> > + struct meson_host *host = mmc_priv(mmc);
> > + int point, ret, adj = 0;
> >   DECLARE_BITMAP(test, CLK_PHASE_POINT_NUM);
> >
> >   dev_dbg(mmc_dev(mmc), "%s phase/delay tunning...\n",
> > @@ -729,6 +730,10 @@ static int meson_mmc_clk_phase_tuning(struct
> > mmc_host *mmc, u32 opcode,
> >   if (point < 0)
> >   return point; /* tuning failed */
> >
> > + /* enable signal resampling w/o delay */
> > + adj = ADJUST_ADJ_EN;
> > + writel(adj, host->regs + host->data->adjust);
> > +
>
> That's really what I meant.
>
> Here, you are enabling the signal resampling after the tuning.
> Several boards won't tune without signal resampling.
>
> This should be done at the very beginning of the function at least.
> I would prefer if it was done in meson_mmc_execute_tuning() before calling
> meson_mmc_clk_phase_tuning()
>
> Signal resampling should not be dealt with in the unrelated phase tuning
> function
>
> >   clk_set_phase(clk, point * CLK_PHASE_STEP);
> >   dev_dbg(mmc_dev(mmc), "success with phase: %d\n",
> >   clk_get_phase(clk));
> > @@ -768,6 +773,9 @@ static void meson_mmc_set_ios(struct mmc_host
> > *mmc, struct mmc_ios *ios)
> >   if (!IS_ERR(mmc->supply.vmmc))
> >   mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, ios->vdd);
> >
> > + /* disable signal resampling w/o delay */
>
> nitpick : 'disable signal resampling' is enough.
> when disabled, the delay does not matter.
>
> > + writel(0, host->regs + host->data->adjust);
> > +
> >   /* Reset rx phase */
> >   clk_set_phase(host->rx_clk, 0);
> >
> > @@ -1166,7 +1174,7 @@ static int meson_mmc_get_cd(struct mmc_host *mmc)
> >
> >  static void meson_mmc_cfg_init(struct meson_host *host)
> >  {
> > - u32 cfg = 0, adj = 0;
> > + u32 cfg = 0;
> >
> >   cfg |= FIELD_PREP(CFG_RESP_TIMEOUT_MASK,
> >     ilog2(SD_EMMC_CFG_RESP_TIMEOUT));
> > @@ -1177,10 +1185,6 @@ static void meson_mmc_cfg_init(struct meson_host
> > *host)
> >   cfg |= CFG_ERR_ABORT;
> >
> >   writel(cfg, host->regs + SD_EMMC_CFG);
> > -
> > - /* enable signal resampling w/o delay */
> > - adj = ADJUST_ADJ_EN;
> > - writel(adj, host->regs + host->data->adjust);
> >  }
> >
> >  static int meson_mmc_card_busy(struct mmc_host *mmc)
>
>

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