Re: [PATCH V2 3/3] mmc: sdhci-msm: Use internal voltage control

[Veerabhadrarao Badiganti]

On 9/22/2018 1:39 AM, Evan Green wrote:
> On Wed, Sep 19, 2018 at 11:24 PM Veerabhadrarao Badiganti
> <vbadigan@xxxxxxxxxxxxxx> wrote:
> > From: Vijay Viswanath <vviswana@xxxxxxxxxxxxxx>
> >
> > Some sdhci-msm controllers require that voltage switching be done after
> > the HW is ready for it. The HW informs its readiness through power irq.
> > The voltage switching should happen only then.
> >
> > Use the quirk for internal voltage switching and then control the
> > voltage switching using power irq.
> >
> > Signed-off-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
> > Signed-off-by: Venkat Gopalakrishnan <venkatg@xxxxxxxxxxxxxx>
> > Signed-off-by: Vijay Viswanath <vviswana@xxxxxxxxxxxxxx>
> > Signed-off-by: Veerabhadrarao Badiganti <vbadigan@xxxxxxxxxxxxxx>
> > ---
> >   drivers/mmc/host/sdhci-msm.c | 211 +++++++++++++++++++++++++++++++++++++++++--
> >   1 file changed, 203 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> > index 3cc8bfe..486462d 100644
> > --- a/drivers/mmc/host/sdhci-msm.c
> > +++ b/drivers/mmc/host/sdhci-msm.c
> > @@ -43,7 +43,9 @@
> >   #define CORE_PWRCTL_IO_LOW     BIT(2)
> >   #define CORE_PWRCTL_IO_HIGH    BIT(3)
> >   #define CORE_PWRCTL_BUS_SUCCESS BIT(0)
> > +#define CORE_PWRCTL_BUS_FAIL    BIT(1)
> >   #define CORE_PWRCTL_IO_SUCCESS BIT(2)
> > +#define CORE_PWRCTL_IO_FAIL     BIT(3)
> >   #define REQ_BUS_OFF            BIT(0)
> >   #define REQ_BUS_ON             BIT(1)
> >   #define REQ_IO_LOW             BIT(2)
> > @@ -258,6 +260,10 @@ struct sdhci_msm_host {
> >          bool mci_removed;
> >          const struct sdhci_msm_variant_ops *var_ops;
> >          const struct sdhci_msm_offset *offset;
> > +       bool vmmc_load;
> > +       u32 vmmc_level[2];
> > +       bool vqmmc_load;
> > +       u32 vqmmc_level[2];
> >   };
> >
> >   static const struct sdhci_msm_offset *sdhci_priv_msm_offset(struct sdhci_host *host)
> > @@ -1211,6 +1217,74 @@ static void sdhci_msm_set_uhs_signaling(struct sdhci_host *host,
> >                  sdhci_msm_hs400(host, &mmc->ios);
> >   }
> >
> > +static int sdhci_msm_set_vmmc(struct sdhci_msm_host *msm_host,
> > +                             struct mmc_host *mmc, int level)
> > +{
> > +       int load = msm_host->vmmc_level[level];
> > +       int ret;
> > +
> > +       if (IS_ERR(mmc->supply.vmmc))
> > +               return 0;
> > +
> > +       if (msm_host->vmmc_load) {
> > +               ret = regulator_set_load(mmc->supply.vmmc, load);
> > +               if (ret)
> > +                       goto out;
> > +       }
> > +
> > +       ret = mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, mmc->ios.vdd);
> This is new, isn't it? Could you explain why this is needed?

This sets the regulator voltage to supplied value and
enables/disables the regulator.

> > +out:
> > +       if (ret)
> > +               pr_err("%s: vmmc set load/ocr failed: %d\n",
> > +                               mmc_hostname(mmc), ret);
> > +
> > +       return ret;
> > +}
> > +
> > +static int sdhci_msm_set_vqmmc(struct sdhci_msm_host *msm_host,
> > +                             struct mmc_host *mmc, int level)
> > +{
> > +       int load = msm_host->vqmmc_level[level];
> > +       int ret;
> > +       struct mmc_ios ios;
> > +
> > +       if (IS_ERR(mmc->supply.vqmmc))
> > +               return 0;
> > +
> > +       if (msm_host->vqmmc_load) {
> > +               ret = regulator_set_load(mmc->supply.vqmmc, load);
> > +               if (ret)
> > +                       goto out;
> > +       }
> > +
> > +       /*
> > +        * The IO voltage regulator maynot always support a voltage close to
> s/maynot/may not/
>
> > +        * vdd. Set IO voltage based on  capability of the regulator.
> remove extra space between on and capability.
>
> > +        */
> > +       if (level) {
> > +               if (msm_host->caps_0 & CORE_3_0V_SUPPORT)
> > +                       ios.signal_voltage = MMC_SIGNAL_VOLTAGE_330;
> > +               else if (msm_host->caps_0 & CORE_1_8V_SUPPORT)
> > +                       ios.signal_voltage = MMC_SIGNAL_VOLTAGE_180;
> > +               if (msm_host->caps_0 & CORE_VOLT_SUPPORT) {
> > +                       pr_debug("%s: %s: setting signal voltage: %d\n",
> > +                                       mmc_hostname(mmc), __func__,
> > +                                       ios.signal_voltage);
> > +                       ret = mmc_regulator_set_vqmmc(mmc, &ios);
> > +                       if (ret)
> > +                               goto out;
> > +               }
> > +               ret = regulator_enable(mmc->supply.vqmmc);
> > +       } else {
> > +               ret = regulator_disable(mmc->supply.vqmmc);
> > +       }
> > +out:
> > +       if (ret)
> > +               pr_err("%s: vqmmc failed: %d\n", mmc_hostname(mmc), ret);
> > +
> > +       return ret;
> > +}
> > +
> >   static inline void sdhci_msm_init_pwr_irq_wait(struct sdhci_msm_host *msm_host)
> >   {
> >          init_waitqueue_head(&msm_host->pwr_irq_wait);
> > @@ -1314,8 +1388,9 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
> >   {
> >          struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> >          struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> > +       struct mmc_host *mmc = host->mmc;
> >          u32 irq_status, irq_ack = 0;
> > -       int retry = 10;
> > +       int retry = 10, ret = 0;
> >          u32 pwr_state = 0, io_level = 0;
> >          u32 config;
> >          const struct sdhci_msm_offset *msm_offset = msm_host->offset;
> > @@ -1351,14 +1426,34 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
> >
> >          /* Handle BUS ON/OFF*/
> >          if (irq_status & CORE_PWRCTL_BUS_ON) {
> > -               pwr_state = REQ_BUS_ON;
> > -               io_level = REQ_IO_HIGH;
> > -               irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> > +               ret = sdhci_msm_set_vmmc(msm_host, mmc, 1);
> > +               if (!ret)
> > +                       ret = sdhci_msm_set_vqmmc(msm_host, mmc, 1);
> Should you put vmmc back to 0 if setting vqmmc to 1 fails?

Yeah, will set to back to 0.

> > +
> > +               if (!ret) {
> > +                       pwr_state = REQ_BUS_ON;
> > +                       io_level = REQ_IO_HIGH;
> > +                       irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> > +               } else {
> > +                       pr_err("%s: BUS_ON req failed(%d). irq_status: 0x%08x\n",
> > +                                       mmc_hostname(mmc), ret, irq_status);
> > +                       irq_ack |= CORE_PWRCTL_BUS_FAIL;
> > +               }
> >          }
> >          if (irq_status & CORE_PWRCTL_BUS_OFF) {
> > -               pwr_state = REQ_BUS_OFF;
> > -               io_level = REQ_IO_LOW;
> > -               irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> > +               ret = sdhci_msm_set_vmmc(msm_host, mmc, 0);
> > +               if (!ret)
> > +                       ret = sdhci_msm_set_vqmmc(msm_host, mmc, 0);
> > +
> > +               if (!ret) {
> > +                       pwr_state = REQ_BUS_OFF;
> > +                       io_level = REQ_IO_LOW;
> > +                       irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> > +               } else {
> > +                       pr_err("%s: BUS_ON req failed(%d). irq_status: 0x%08x\n",
> > +                                       mmc_hostname(mmc), ret, irq_status);
> > +                       irq_ack |= CORE_PWRCTL_BUS_FAIL;
> > +               }
> >          }
> >          /* Handle IO LOW/HIGH */
> >          if (irq_status & CORE_PWRCTL_IO_LOW) {
> > @@ -1370,6 +1465,15 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
> >                  irq_ack |= CORE_PWRCTL_IO_SUCCESS;
> >          }
> >
> > +       if (io_level && !IS_ERR(mmc->supply.vqmmc) && !pwr_state) {
> > +               ret = mmc_regulator_set_vqmmc(mmc, &mmc->ios);
> > +               if (ret)
> > +                       pr_err("%s: IO_level setting failed(%d). signal_voltage: %d, vdd: %d irq_status: 0x%08x\n",
> > +                                       mmc_hostname(mmc), ret,
> > +                                       mmc->ios.signal_voltage, mmc->ios.vdd,
> > +                                       irq_status);
> > +       }
> > +
> >          /*
> >           * The driver has to acknowledge the interrupt, switch voltages and
> >           * report back if it succeded or not to this register. The voltage
> > @@ -1605,6 +1709,91 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> >          pr_debug("%s: supported caps: 0x%08x\n", mmc_hostname(mmc), caps);
> >   }
> >
> > +static int sdhci_msm_register_vreg(struct sdhci_msm_host *msm_host)
> > +{
> > +       int ret = 0;
> > +
> > +       ret = mmc_regulator_get_supply(msm_host->mmc);
> > +       if (ret)
> > +               return ret;
> > +       if (device_property_read_u32_array(&msm_host->pdev->dev,
> > +                       "qcom,vmmc-current-level-microamp",
> > +                       msm_host->vmmc_level, 2) >= 0)
> > +               msm_host->vmmc_load = true;
> > +       if (device_property_read_u32_array(&msm_host->pdev->dev,
> > +                       "qcom,vqmmc-current-level-microamp",
> > +                       msm_host->vqmmc_level, 2) >= 0)
> > +               msm_host->vqmmc_load = true;
> > +
> > +       sdhci_msm_set_regulator_caps(msm_host);
> > +
> > +       return 0;
> > +
> > +}
> > +
> > +static int sdhci_msm_start_signal_voltage_switch(struct mmc_host *mmc,
> > +                                     struct mmc_ios *ios)
> > +{
> > +       struct sdhci_host *host = mmc_priv(mmc);
> > +       u16 ctrl;
> > +
> > +       /*
> > +        * Signal Voltage Switching is only applicable for Host Controllers
> > +        * v3.00 and above.
> > +        */
> > +       if (host->version < SDHCI_SPEC_300)
> > +               return 0;
> > +
> > +       ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> > +
> > +       switch (ios->signal_voltage) {
> > +       case MMC_SIGNAL_VOLTAGE_330:
> > +               if (!(host->flags & SDHCI_SIGNALING_330))
> > +                       return -EINVAL;
> > +               /* Set 1.8V Signal Enable in the Host Control2 register to 0 */
> > +               ctrl &= ~SDHCI_CTRL_VDD_180;
> > +               sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
> > +
> > +               /* 3.3V regulator output should be stable within 5 ms */
> > +               ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> > +               if (!(ctrl & SDHCI_CTRL_VDD_180))
> > +                       return 0;
> > +
> > +               pr_warn("%s: 3.3V regulator output did not became stable\n",
> > +                       mmc_hostname(mmc));
> > +
> > +               return -EAGAIN;
> > +       case MMC_SIGNAL_VOLTAGE_180:
> > +               if (!(host->flags & SDHCI_SIGNALING_180))
> > +                       return -EINVAL;
> > +
> > +               /*
> > +                * Enable 1.8V Signal Enable in the Host Control2
> > +                * register
> > +                */
> > +               ctrl |= SDHCI_CTRL_VDD_180;
> > +               sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
> > +
> > +               /* 1.8V regulator output should be stable within 5 ms */
> > +               ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> > +               if (ctrl & SDHCI_CTRL_VDD_180)
> > +                       return 0;
> > +
> > +               pr_warn("%s: 1.8V regulator output did not became stable\n",
> > +                       mmc_hostname(mmc));
> > +
> > +               return -EAGAIN;
> > +       case MMC_SIGNAL_VOLTAGE_120:
> > +               if (!(host->flags & SDHCI_SIGNALING_120))
> > +                       return -EINVAL;
> So the state of SDHCI_CTRL_VDD_180 doesn't matter when trying to set
> 1.2V? I tried looking at the SDHC spec, but it was similarly silent
> about 1.2V. So I guess it's fine?

Right.
But SDHCI_SIGNALING_120 gets set only if the the vqmmc regulator
supports 1.2v. On all msm platforms, the minimum voltage of vqmmc is 1.8v
only. So 1.2v is not supported on sdhci-msm platforms.

> > +               return 0;
> > +       default:
> > +               /* No signal voltage switch required */
> > +               return 0;
> > +       }
> > +
> > +}
> > +
> >   static const struct sdhci_msm_variant_ops mci_var_ops = {
> >          .msm_readl_relaxed = sdhci_msm_mci_variant_readl_relaxed,
> >          .msm_writel_relaxed = sdhci_msm_mci_variant_writel_relaxed,
> > @@ -1644,6 +1833,7 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> >          .set_uhs_signaling = sdhci_msm_set_uhs_signaling,
> >          .write_w = sdhci_msm_writew,
> >          .write_b = sdhci_msm_writeb,
> > +       .set_power = sdhci_set_power_noreg,
> >   };
> >
> >   static const struct sdhci_pltfm_data sdhci_msm_pdata = {
> > @@ -1818,6 +2008,10 @@ static int sdhci_msm_probe(struct platform_device *pdev)
> >                                  msm_offset->core_vendor_spec_capabilities0);
> >          }
> >
> > +       ret = sdhci_msm_register_vreg(msm_host);
> > +       if (ret)
> > +               goto clk_disable;
> > +
> >          /*
> >           * Power on reset state may trigger power irq if previous status of
> >           * PWRCTL was either BUS_ON or IO_HIGH_V. So before enabling pwr irq
> > @@ -1862,11 +2056,12 @@ static int sdhci_msm_probe(struct platform_device *pdev)
> >                                           MSM_MMC_AUTOSUSPEND_DELAY_MS);
> >          pm_runtime_use_autosuspend(&pdev->dev);
> >
> > +       host->mmc_host_ops.start_signal_voltage_switch =
> > +               sdhci_msm_start_signal_voltage_switch;
> >          host->mmc_host_ops.execute_tuning = sdhci_msm_execute_tuning;
> >          ret = sdhci_add_host(host);
> >          if (ret)
> >                  goto pm_runtime_disable;
> > -       sdhci_msm_set_regulator_caps(msm_host);
> >
> >          pm_runtime_mark_last_busy(&pdev->dev);
> >          pm_runtime_put_autosuspend(&pdev->dev);
> > --
> > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc., is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

Thanks,
Veeera