linux-kernel - Re: [PATCHv2 09/21] mmc: sdhci-of-dwcmshc: add reset call back for rockchip Socs

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Date:   Fri, 6 May 2022 14:37:52 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Sebastian Reichel <sebastian.reichel@...labora.com>,
        Rob Herring <robh+dt@...nel.org>
Cc:     Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Heiko Stuebner <heiko@...ech.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-clk@...r.kernel.org,
        linux-mmc@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Yifeng Zhao <yifeng.zhao@...k-chips.com>, kernel@...labora.com
Subject: Re: [PATCHv2 09/21] mmc: sdhci-of-dwcmshc: add reset call back for
 rockchip Socs

On Fri, 6 May 2022 at 11:18, Sebastian Reichel
<sebastian.reichel@...labora.com> wrote:
>
> Hi,
>
> On Fri, May 06, 2022 at 10:52:42AM +0200, Ulf Hansson wrote:
> > On Wed, 4 May 2022 at 23:33, Sebastian Reichel
> > <sebastian.reichel@...labora.com> wrote:
> > >
> > > From: Yifeng Zhao <yifeng.zhao@...k-chips.com>
> > >
> > > The reset function build in the SDHCI will not reset the logic
> > > circuit related to the tuning function, which may cause data
> > > reading errors. Resetting the complete SDHCI controller through
> > > the reset controller fixes the issue.
> > >
> > > Signed-off-by: Yifeng Zhao <yifeng.zhao@...k-chips.com>
> > > [rebase, use optional variant of reset getter]
> > > Acked-by: Adrian Hunter <adrian.hunter@...el.com>
> > > Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
> >
> > I think this needs a corresponding update of the DT docs. Otherwise
> > this looks good to me.
>
> I do have 'resets' and 'reset-names' properties in the rk3588s.dtsi
> for the sdhci interface and 'make dtbs_check' did not complain about
> anything but missing 'arm,sdei-1.0' compatible for the rk3588 EVB
> (sdei binding has not yet been converted to yaml). Thus I assume the
> resets property is inferred from somewhere?

I don't think it should, but I may be wrong.

How about if you extend the example in the DT doc with a reset
property, will that cause the DT tools to complain?

Kind regards
Uffe

>
> -- Sebastian
>
> >
> > Kind regards
> > Uffe
> >
> > > ---
> > >  drivers/mmc/host/sdhci-of-dwcmshc.c | 26 +++++++++++++++++++++++++-
> > >  1 file changed, 25 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
> > > index bac874ab0b33..3a1b5ba36405 100644
> > > --- a/drivers/mmc/host/sdhci-of-dwcmshc.c
> > > +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
> > > @@ -15,6 +15,7 @@
> > >  #include <linux/module.h>
> > >  #include <linux/of.h>
> > >  #include <linux/of_device.h>
> > > +#include <linux/reset.h>
> > >  #include <linux/sizes.h>
> > >
> > >  #include "sdhci-pltfm.h"
> > > @@ -63,6 +64,7 @@
> > >  struct rk3568_priv {
> > >         /* Rockchip specified optional clocks */
> > >         struct clk_bulk_data rockchip_clks[RK3568_MAX_CLKS];
> > > +       struct reset_control *reset;
> > >         u8 txclk_tapnum;
> > >  };
> > >
> > > @@ -255,6 +257,21 @@ static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock
> > >         sdhci_writel(host, extra, DWCMSHC_EMMC_DLL_STRBIN);
> > >  }
> > >
> > > +static void rk35xx_sdhci_reset(struct sdhci_host *host, u8 mask)
> > > +{
> > > +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> > > +       struct dwcmshc_priv *dwc_priv = sdhci_pltfm_priv(pltfm_host);
> > > +       struct rk35xx_priv *priv = dwc_priv->priv;
> > > +
> > > +       if (mask & SDHCI_RESET_ALL && priv->reset) {
> > > +               reset_control_assert(priv->reset);
> > > +               udelay(1);
> > > +               reset_control_deassert(priv->reset);
> > > +       }
> > > +
> > > +       sdhci_reset(host, mask);
> > > +}
> > > +
> > >  static const struct sdhci_ops sdhci_dwcmshc_ops = {
> > >         .set_clock              = sdhci_set_clock,
> > >         .set_bus_width          = sdhci_set_bus_width,
> > > @@ -269,7 +286,7 @@ static const struct sdhci_ops sdhci_dwcmshc_rk3568_ops = {
> > >         .set_bus_width          = sdhci_set_bus_width,
> > >         .set_uhs_signaling      = dwcmshc_set_uhs_signaling,
> > >         .get_max_clock          = sdhci_pltfm_clk_get_max_clock,
> > > -       .reset                  = sdhci_reset,
> > > +       .reset                  = rk35xx_sdhci_reset,
> > >         .adma_write_desc        = dwcmshc_adma_write_desc,
> > >  };
> > >
> > > @@ -292,6 +309,13 @@ static int dwcmshc_rk3568_init(struct sdhci_host *host, struct dwcmshc_priv *dwc
> > >         int err;
> > >         struct rk3568_priv *priv = dwc_priv->priv;
> > >
> > > +       priv->reset = devm_reset_control_array_get_optional_exclusive(mmc_dev(host->mmc));
> > > +       if (IS_ERR(priv->reset)) {
> > > +               err = PTR_ERR(priv->reset);
> > > +               dev_err(mmc_dev(host->mmc), "failed to get reset control %d\n", err);
> > > +               return err;
> > > +       }
> > > +
> > >         priv->rockchip_clks[0].id = "axi";
> > >         priv->rockchip_clks[1].id = "block";
> > >         priv->rockchip_clks[2].id = "timer";
> > > --
> > > 2.35.1
> > >