Hi Zhangfei,
[...]
> Hi, Arindam
>
> The uhs card works OK,
> However after use uhs card, the io voltage keeps 1.8v, and
> mmc_send_app_op_cond will return error, so no chance to go back to
> 3.3v.
> The result is hs card can not be detected after using uhs card.
> Also some hs card have timeout issue here when reading partition
> table, still not know it is local reason.
[...]
> > @@ -781,6 +808,11 @@ int mmc_attach_sd(struct mmc_host *host)
> > if (host->ocr_avail_sd)
> > host->ocr_avail = host->ocr_avail_sd;
> >
> > + /* Make sure we are at 3.3V signalling voltage */
> > + err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330);
> > + if (err)
> > + return err;
>
> The code here may have no chance to execute, since
> mmc_send_app_op_cond already failed if v_io is 1.8v for hs card.
> Could you move the voltage setting before mmc_send_app_op_cond.
Thanks once again for your sharp review. Yes, it makes sense to move mmc_set_signal_voltage() before mmc_send_app_op_cond(). Will do it.
[...]
> > @@ -1297,11 +1299,116 @@ out:
> > spin_unlock_irqrestore(&host->lock, flags);
> > }
> >
> > +static int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
> > + struct mmc_ios *ios)
> > +{
> > + struct sdhci_host *host;
> > + u8 pwr;
> > + u16 clk, ctrl;
> > + u32 present_state;
> > +
> > + host = mmc_priv(mmc);
> > +
> > + /*
> > + * Signal Voltage Switching is only applicable for Host
> Controllers
> > + * v3.00 and above.
> > + */
> > + if (host->version < SDHCI_SPEC_300)
> > + return 0;
> > +
> > + /*
> > + * We first check whether the request is to set signalling
> voltage
> > + * to 3.3V. If so, we change the voltage to 3.3V and return
> quickly.
> > + */
> > + ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> > + if ((ctrl & SDHCI_CTRL_VDD_180) &&
>
> The check here may fail, could you remove this check, for example
> ctrl=0x10 and no chance to 3.3v.
If ctrl=0x10, it would mean the signaling voltage is already at 3.3V, so why do we need to set it to 3.3V again?
Thanks,
Arindam
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