Re: [PATCH V5] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

[Ulf Hansson]

On Wed, 27 Apr 2022 at 16:42, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>
> On Sun, 24 Apr 2022 at 18:02, Shaik Sajida Bhanu
> <quic_c_sbhanu@xxxxxxxxxxx> wrote:
> >
> > Reset GCC_SDCC_BCR register before every fresh initilazation. This will
> > reset whole SDHC-msm controller, clears the previous power control
> > states and avoids, software reset timeout issues as below.
> >
> > [ 5.458061][ T262] mmc1: Reset 0x1 never completed.
> > [ 5.462454][ T262] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
> > [ 5.469065][ T262] mmc1: sdhci: Sys addr: 0x00000000 | Version: 0x00007202
> > [ 5.475688][ T262] mmc1: sdhci: Blk size: 0x00000000 | Blk cnt: 0x00000000
> > [ 5.482315][ T262] mmc1: sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
> > [ 5.488927][ T262] mmc1: sdhci: Present: 0x01f800f0 | Host ctl: 0x00000000
> > [ 5.495539][ T262] mmc1: sdhci: Power: 0x00000000 | Blk gap: 0x00000000
> > [ 5.502162][ T262] mmc1: sdhci: Wake-up: 0x00000000 | Clock: 0x00000003
> > [ 5.508768][ T262] mmc1: sdhci: Timeout: 0x00000000 | Int stat: 0x00000000
> > [ 5.515381][ T262] mmc1: sdhci: Int enab: 0x00000000 | Sig enab: 0x00000000
> > [ 5.521996][ T262] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int: 0x00000000
> > [ 5.528607][ T262] mmc1: sdhci: Caps: 0x362dc8b2 | Caps_1: 0x0000808f
> > [ 5.535227][ T262] mmc1: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
> > [ 5.541841][ T262] mmc1: sdhci: Resp[0]: 0x00000000 | Resp[1]: 0x00000000
> > [ 5.548454][ T262] mmc1: sdhci: Resp[2]: 0x00000000 | Resp[3]: 0x00000000
> > [ 5.555079][ T262] mmc1: sdhci: Host ctl2: 0x00000000
> > [ 5.559651][ T262] mmc1: sdhci_msm: ----------- VENDOR REGISTER DUMP-----------
> > [ 5.566621][ T262] mmc1: sdhci_msm: DLL sts: 0x00000000 | DLL cfg: 0x6000642c | DLL cfg2: 0x0020a000
> > [ 5.575465][ T262] mmc1: sdhci_msm: DLL cfg3: 0x00000000 | DLL usr ctl: 0x00010800 | DDR cfg: 0x80040873
> > [ 5.584658][ T262] mmc1: sdhci_msm: Vndr func: 0x00018a9c | Vndr func2 : 0xf88218a8 Vndr func3: 0x02626040
> >
> > Fixes: 0eb0d9f4de34 ("mmc: sdhci-msm: Initial support for Qualcomm chipsets")
> > Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@xxxxxxxxxxx>
>
> So this looks good to me, but I can't apply it until I get a patch
> that updates the DT doc too.

Okay, so since we are (I have already queued the patches for v5.19)
moving the DT bindings into the yaml format, I decided to queue
$subject patch, as is, for fixes. Moreover, I added a stable tag to
it.

Please send and patch on top of the new yaml based DT bindings to add
the property for the reset.

Thanks and kind regards
Uffe


>
> Kind regards
> Uffe
>
> > ---
> >
> > Changes since V4:
> >         - Called reset_control_put() in error path.
> >
> > Changes since V3:
> >         - Used reset controller local variable as suggested by
> >           Bjorn Andersson.
> >         - Passed NULL as a parameter to
> >           devm_reset_control_get_optional_exclusive() as suggested by
> >           Bjorn Andersson.
> >         - Replaced devm_reset_control_get_optional_exclusive() with
> >           reset_control_get_optional_exclusive() and called
> >           reset_control_put() before returning to clear the reset
> >           controller as suggested by Bjorn Andersson.
> >
> > Changes since V2:
> >         - Dropped new line after fixes tag as suggested by Bjorn
> >           Andersson.
> >         - Passed device structure instead of passing platform_device
> >           structure as a argument for sdhci_msm_gcc_reset() as suggested
> >           by Bjorn Andersson.
> >         - Replaced dev_err() with dev_err_probe() as suggested by Bjorn
> >           Andersson.
> >
> > Changes since V1:
> >         - Added fixes tag as suggested by Ulf Hansson.
> >         - Replaced devm_reset_control_get() with
> >           devm_reset_control_get_optional_exclusive() as suggested by
> >           Ulf Hansson.
> > ---
> >  drivers/mmc/host/sdhci-msm.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 42 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> > index 50c71e0..ff9f5b6 100644
> > --- a/drivers/mmc/host/sdhci-msm.c
> > +++ b/drivers/mmc/host/sdhci-msm.c
> > @@ -17,6 +17,7 @@
> >  #include <linux/regulator/consumer.h>
> >  #include <linux/interconnect.h>
> >  #include <linux/pinctrl/consumer.h>
> > +#include <linux/reset.h>
> >
> >  #include "sdhci-pltfm.h"
> >  #include "cqhci.h"
> > @@ -2482,6 +2483,43 @@ static inline void sdhci_msm_get_of_property(struct platform_device *pdev,
> >         of_property_read_u32(node, "qcom,dll-config", &msm_host->dll_config);
> >  }
> >
> > +static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
> > +{
> > +       struct reset_control *reset;
> > +       int ret = 0;
> > +
> > +       reset = reset_control_get_optional_exclusive(dev, NULL);
> > +       if (IS_ERR(reset))
> > +               return dev_err_probe(dev, PTR_ERR(reset),
> > +                               "unable to acquire core_reset\n");
> > +
> > +       if (!reset)
> > +               return ret;
> > +
> > +       ret = reset_control_assert(reset);
> > +       if (ret) {
> > +               reset_control_put(reset);
> > +               return dev_err_probe(dev, ret, "core_reset assert failed\n");
> > +       }
> > +
> > +       /*
> > +        * The hardware requirement for delay between assert/deassert
> > +        * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
> > +        * ~125us (4/32768). To be on the safe side add 200us delay.
> > +        */
> > +       usleep_range(200, 210);
> > +
> > +       ret = reset_control_deassert(reset);
> > +       if (ret) {
> > +               reset_control_put(reset);
> > +               return dev_err_probe(dev, ret, "core_reset deassert failed\n");
> > +       }
> > +
> > +       usleep_range(200, 210);
> > +       reset_control_put(reset);
> > +
> > +       return ret;
> > +}
> >
> >  static int sdhci_msm_probe(struct platform_device *pdev)
> >  {
> > @@ -2529,6 +2567,10 @@ static int sdhci_msm_probe(struct platform_device *pdev)
> >
> >         msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
> >
> > +       ret = sdhci_msm_gcc_reset(&pdev->dev, host);
> > +       if (ret)
> > +               goto pltfm_free;
> > +
> >         /* Setup SDCC bus voter clock. */
> >         msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
> >         if (!IS_ERR(msm_host->bus_clk)) {
> > --
> > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> > of Code Aurora Forum, hosted by The Linux Foundation
> >