Re: Warnings for invalid VDD (sdhci-s3c)

[Ludovic Desroches]

On Thu, Mar 24, 2016 at 09:45:56PM +0800, Jisheng Zhang wrote:
> On Thu, 24 Mar 2016 15:21:47 +0200
> Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> 
> > On 24/03/16 15:11, Adrian Hunter wrote:
> > > On 24/03/16 10:42, Krzysztof Kozlowski wrote:  
> > >> On 24.03.2016 17:24, Jisheng Zhang wrote:  
> > >>> Hi,
> > >>>
> > >>> On Thu, 24 Mar 2016 17:09:27 +0900 Jaehoon Chung wrote:
> > >>>  
> > >>>> Hi,
> > >>>>
> > >>>> On 03/24/2016 04:58 PM, Jisheng Zhang wrote:  
> > >>>>> Hi,
> > >>>>>
> > >>>>> On Thu, 24 Mar 2016 16:28:56 +0900 Krzysztof Kozlowski wrote:
> > >>>>>     
> > >>>>>> Hi,
> > >>>>>>
> > >>>>>> After 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD via
> > >>>>>> external regulator") On Trats2 board I see warnings for invalid VDD
> > >>>>>> value (2.8V):
> > >>>>>>
> > >>>>>> [    3.119656] ------------[ cut here ]------------
> > >>>>>> [    3.119666] WARNING: CPU: 3 PID: 90 at
> > >>>>>> ../drivers/mmc/host/sdhci.c:1234 sdhci_do_set_ios+0x4cc/0x5e0
> > >>>>>> [    3.119669] mmc0: Invalid vdd 0x10    
> > >>>>>
> > >>>>> Per my understanding, the wrong vdd indicates a wrong ocr, what's the voltage of
> > >>>>> this host's vmmc regulator?    
> > >>>>
> > >>>> As i know, it's fixed-voltage with gpio on trats2. It's 2.8V.
> > >>>> I didn't check this entirely..need to check ocr value.
> > >>>>  
> > >>>
> > >>> I may know the reason. the vmmc is 2.8v, then mmc_regulator_get_supply() convert
> > >>> the value to a ocr as 0x10. The key here is that the 2.8v is invalid in SDHCI
> > >>> case and isn't accepted by current sdhci driver.  
> > >>
> > >> Yeah, I already wrote that. It is the part of the warning and my email.
> > >> Our regulator is fixed at 2.8 which is 0x10. :)
> > >>  
> > >>> I dunno the elegant solution to handle this case, let's wait for sdhci maintainers
> > >>> idea.  
> > >>
> > >> Hmm...  
> > > 
> > > I haven't tested it, but what about this:  
> > 
> > And now with checkpatch complaints fixed:
> > 
> > From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> > Date: Thu, 24 Mar 2016 14:29:24 +0200
> > Subject: [PATCH V2] mmc: sdhci: Fix regression setting power on Trats2 board
> > 
> > Several commits relating to setting power have been introducing
> > problems by putting driver-specific rules into generic SDHCI code.
> > 
> > Fix by adding a 'set_power' callback and restoring the default
> > behaviour prior to commit 918f4cbd4340 ("mmc: sdhci: restore
> > behavior when setting VDD via external regulator").  The desired
> > behaviour of that commit is gotten by having sdhci-pxav3 provide
> > its own set_power callback.
> > 
> > Reported-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
> > Fixes: 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD...)
> > Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> 
> Reviewed-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
> Tested-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
> 
> The only problem is atmel's sdhc host also need similar own .set_power
> Ludovic knows details.

It doesn't introduce regression on my side since I have removed
regulators from my device tree. If I introduce then back, I'll need my
own set_power callback.

I am not in favour of this patch only because I have the feeling that
sdhci_set_power_reg() is not conform to the specification.

Tested-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>

> 
> Thanks,
> Jisheng
> 
> > Cc: stable@xxxxxxxxxxxxxxx # v4.5+
> > ---
> >  drivers/mmc/host/sdhci-pxav3.c | 17 +++++++++++++++++
> >  drivers/mmc/host/sdhci.c       | 38 ++++++++++++++++++++++++++++++--------
> >  drivers/mmc/host/sdhci.h       |  4 ++++
> >  3 files changed, 51 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
> > index f5edf9d3a18a..673d1e8446a5 100644
> > --- a/drivers/mmc/host/sdhci-pxav3.c
> > +++ b/drivers/mmc/host/sdhci-pxav3.c
> > @@ -307,8 +307,25 @@ static void pxav3_set_uhs_signaling(struct sdhci_host *host, unsigned int uhs)
> >  		__func__, uhs, ctrl_2);
> >  }
> >  
> > +static void pxav3_set_power(struct sdhci_host *host, unsigned char mode,
> > +			    unsigned short vdd)
> > +{
> > +	struct mmc_host *mmc = host->mmc;
> > +	u8 pwr = host->pwr;
> > +
> > +	sdhci_set_power(host, mode, vdd);
> > +
> > +	if (host->pwr == pwr)
> > +		return;
> > +
> > +	spin_unlock_irq(&host->lock);
> > +	mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
> > +	spin_lock_irq(&host->lock);
> > +}
> > +
> >  static const struct sdhci_ops pxav3_sdhci_ops = {
> >  	.set_clock = sdhci_set_clock,
> > +	.set_power = pxav3_set_power,
> >  	.platform_send_init_74_clocks = pxav3_gen_init_74_clocks,
> >  	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
> >  	.set_bus_width = sdhci_set_bus_width,
> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> > index add9fdfd1d8f..282257222121 100644
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -1269,10 +1269,24 @@ clock_set:
> >  }
> >  EXPORT_SYMBOL_GPL(sdhci_set_clock);
> >  
> > -static void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> > -			    unsigned short vdd)
> > +static void sdhci_set_power_reg(struct sdhci_host *host, unsigned char mode,
> > +				unsigned short vdd)
> >  {
> >  	struct mmc_host *mmc = host->mmc;
> > +
> > +	spin_unlock_irq(&host->lock);
> > +	mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
> > +	spin_lock_irq(&host->lock);
> > +
> > +	if (mode != MMC_POWER_OFF)
> > +		sdhci_writeb(host, SDHCI_POWER_ON, SDHCI_POWER_CONTROL);
> > +	else
> > +		sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
> > +}
> > +
> > +void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> > +		     unsigned short vdd)
> > +{
> >  	u8 pwr = 0;
> >  
> >  	if (mode != MMC_POWER_OFF) {
> > @@ -1335,12 +1349,20 @@ static void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> >  		if (host->quirks & SDHCI_QUIRK_DELAY_AFTER_POWER)
> >  			mdelay(10);
> >  	}
> > +}
> > +EXPORT_SYMBOL_GPL(sdhci_set_power);
> >  
> > -	if (!IS_ERR(mmc->supply.vmmc)) {
> > -		spin_unlock_irq(&host->lock);
> > -		mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
> > -		spin_lock_irq(&host->lock);
> > -	}
> > +static void __sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> > +			      unsigned short vdd)
> > +{
> > +	struct mmc_host *mmc = host->mmc;
> > +
> > +	if (host->ops->set_power)
> > +		host->ops->set_power(host, mode, vdd);
> > +	else if (!IS_ERR(mmc->supply.vmmc))
> > +		sdhci_set_power_reg(host, mode, vdd);
> > +	else
> > +		sdhci_set_power(host, mode, vdd);
> >  }
> >  
> >  /*****************************************************************************\
> > @@ -1490,7 +1512,7 @@ static void sdhci_do_set_ios(struct sdhci_host *host, struct mmc_ios *ios)
> >  		}
> >  	}
> >  
> > -	sdhci_set_power(host, ios->power_mode, ios->vdd);
> > +	__sdhci_set_power(host, ios->power_mode, ios->vdd);
> >  
> >  	if (host->ops->platform_send_init_74_clocks)
> >  		host->ops->platform_send_init_74_clocks(host, ios->power_mode);
> > diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> > index 0115e9907bf8..033d72b5bbd5 100644
> > --- a/drivers/mmc/host/sdhci.h
> > +++ b/drivers/mmc/host/sdhci.h
> > @@ -529,6 +529,8 @@ struct sdhci_ops {
> >  #endif
> >  
> >  	void	(*set_clock)(struct sdhci_host *host, unsigned int clock);
> > +	void	(*set_power)(struct sdhci_host *host, unsigned char mode,
> > +			     unsigned short vdd);
> >  
> >  	int		(*enable_dma)(struct sdhci_host *host);
> >  	unsigned int	(*get_max_clock)(struct sdhci_host *host);
> > @@ -660,6 +662,8 @@ static inline bool sdhci_sdio_irq_enabled(struct sdhci_host *host)
> >  }
> >  
> >  void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
> > +void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> > +		     unsigned short vdd);
> >  void sdhci_set_bus_width(struct sdhci_host *host, int width);
> >  void sdhci_reset(struct sdhci_host *host, u8 mask);
> >  void sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned timing);
>