diff mbox series

[V5,11/26] mmc: sdhci-uhs2: add reset function and uhs2_mode function

Message ID 20221019110647.11076-12-victor.shih@genesyslogic.com.tw
State New
Headers show
Series Add support UHS-II for GL9755 | expand

Commit Message

Victor Shih Oct. 19, 2022, 11:06 a.m. UTC
Sdhci_uhs2_reset() does a UHS-II specific reset operation.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
---
 drivers/mmc/host/sdhci-pci-core.c |  1 +
 drivers/mmc/host/sdhci-pci-gli.c  |  1 +
 drivers/mmc/host/sdhci-uhs2.c     | 68 +++++++++++++++++++++++++++++++
 drivers/mmc/host/sdhci-uhs2.h     |  3 ++
 drivers/mmc/host/sdhci.c          |  3 +-
 drivers/mmc/host/sdhci.h          | 14 +++++++
 6 files changed, 89 insertions(+), 1 deletion(-)

Comments

Adrian Hunter Nov. 1, 2022, 5:13 p.m. UTC | #1
On 19/10/22 14:06, Victor Shih wrote:
> Sdhci_uhs2_reset() does a UHS-II specific reset operation.
> 
> Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
> ---
>  drivers/mmc/host/sdhci-pci-core.c |  1 +
>  drivers/mmc/host/sdhci-pci-gli.c  |  1 +
>  drivers/mmc/host/sdhci-uhs2.c     | 68 +++++++++++++++++++++++++++++++
>  drivers/mmc/host/sdhci-uhs2.h     |  3 ++
>  drivers/mmc/host/sdhci.c          |  3 +-
>  drivers/mmc/host/sdhci.h          | 14 +++++++
>  6 files changed, 89 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> index 34ea1acbb3cc..cba5bba994b8 100644
> --- a/drivers/mmc/host/sdhci-pci-core.c
> +++ b/drivers/mmc/host/sdhci-pci-core.c
> @@ -1955,6 +1955,7 @@ static const struct sdhci_ops sdhci_pci_ops = {
>  	.reset		= sdhci_reset,
>  	.set_uhs_signaling = sdhci_set_uhs_signaling,
>  	.hw_reset		= sdhci_pci_hw_reset,
> +	.uhs2_reset		= sdhci_uhs2_reset,

AFAICT this isn't needed

>  };
>  
>  /*****************************************************************************\
> diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
> index 4d509f656188..607cf69f45d0 100644
> --- a/drivers/mmc/host/sdhci-pci-gli.c
> +++ b/drivers/mmc/host/sdhci-pci-gli.c
> @@ -1097,6 +1097,7 @@ static const struct sdhci_ops sdhci_gl9755_ops = {
>  	.reset			= sdhci_reset,
>  	.set_uhs_signaling	= sdhci_set_uhs_signaling,
>  	.voltage_switch		= sdhci_gli_voltage_switch,
> +	.uhs2_reset		= sdhci_uhs2_reset,
>  };
>  
>  const struct sdhci_pci_fixes sdhci_gl9755 = {
> diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> index 08905ed081fb..0e82f98d1967 100644
> --- a/drivers/mmc/host/sdhci-uhs2.c
> +++ b/drivers/mmc/host/sdhci-uhs2.c
> @@ -10,6 +10,7 @@
>   *  Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
>   */
>  
> +#include <linux/delay.h>
>  #include <linux/module.h>
>  
>  #include "sdhci.h"
> @@ -49,6 +50,73 @@ void sdhci_uhs2_dump_regs(struct sdhci_host *host)
>  }
>  EXPORT_SYMBOL_GPL(sdhci_uhs2_dump_regs);
>  
> +/*****************************************************************************\
> + *                                                                           *
> + * Low level functions                                                       *
> + *                                                                           *
> +\*****************************************************************************/
> +
> +bool sdhci_uhs2_mode(struct sdhci_host *host)
> +{
> +	if ((host->mmc->caps2 & MMC_CAP2_SD_UHS2) &&
> +	    (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> +		(host->version >= SDHCI_SPEC_400) &&
> +		(host->mmc->flags & MMC_UHS2_SUPPORT)))
> +		return true;
> +	else
> +		return false;

For now, let's just make this:

	return host->mmc->flags & MMC_UHS2_SUPPORT;

> +}
> +
> +/**
> + * sdhci_uhs2_reset - invoke SW reset
> + * @host: SDHCI host
> + * @mask: Control mask
> + *
> + * Invoke SW reset, depending on a bit in @mask and wait for completion.
> + */
> +void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask)
> +{
> +	unsigned long timeout;
> +	u32 val;
> +
> +	if (!(sdhci_uhs2_mode(host))) {

That isn't possible.

> +		/**
> +		 * u8  mask for legacy.
> +		 * u16 mask for uhs-2.
> +		 */
> +		u8 u8_mask;
> +
> +		u8_mask = (mask & 0xFF);
> +		sdhci_reset(host, u8_mask);

Probably should call host->ops->reset() but !sdhci_uhs2_mode(host)
isn't possible

> +
> +		return;
> +	}
> +
> +	sdhci_writew(host, mask, SDHCI_UHS2_SW_RESET);
> +
> +	if (mask & SDHCI_UHS2_SW_RESET_FULL) {
> +		host->clock = 0;
> +		/* Reset-all turns off SD Bus Power */
> +		if (host->quirks2 & SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON)
> +			sdhci_runtime_pm_bus_off(host);

We don't know what other drivers will opt for UHS-II
support, but I doubt this quirk will be used, so  let's
not support SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON for UHS-II

> +	}
> +
> +	/* Wait max 100 ms */
> +	timeout = 10000;

Isn't that 10ms

> +
> +	/* hw clears the bit when it's done */
> +	if (read_poll_timeout_atomic(sdhci_readw, val, !(val & mask), 10,
> +				     timeout, true, host, SDHCI_UHS2_SW_RESET)) {
> +		pr_err("%s: %s: Reset 0x%x never completed.\n",
> +					       __func__, mmc_hostname(host->mmc), (int)mask);
> +		pr_err("%s: clean reset bit\n",
> +					       mmc_hostname(host->mmc));
> +		sdhci_writeb(host, 0, SDHCI_UHS2_SW_RESET);
> +		return;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(sdhci_uhs2_reset);
> +
>  /*****************************************************************************\
>   *                                                                           *
>   * Driver init/exit                                                          *
> diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
> index afdb05d6056b..31776dcca5cf 100644
> --- a/drivers/mmc/host/sdhci-uhs2.h
> +++ b/drivers/mmc/host/sdhci-uhs2.h
> @@ -11,6 +11,7 @@
>  #define __SDHCI_UHS2_H
>  
>  #include <linux/bits.h>
> +#include <linux/iopoll.h>

Not needed in header.  Can just be in .c

>  
>  /*
>   * UHS-II Controller registers
> @@ -210,5 +211,7 @@
>  struct sdhci_host;
>  
>  void sdhci_uhs2_dump_regs(struct sdhci_host *host);
> +bool sdhci_uhs2_mode(struct sdhci_host *host);
> +void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
>  
>  #endif /* __SDHCI_UHS2_H */
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 2cdd183c8ada..bd017c59a020 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -194,13 +194,14 @@ static void sdhci_runtime_pm_bus_on(struct sdhci_host *host)
>  	pm_runtime_get_noresume(mmc_dev(host->mmc));
>  }
>  
> -static void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
> +void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
>  {
>  	if (!host->bus_on)
>  		return;
>  	host->bus_on = false;
>  	pm_runtime_put_noidle(mmc_dev(host->mmc));
>  }
> +EXPORT_SYMBOL_GPL(sdhci_runtime_pm_bus_off);

Let's not support SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON for UHS-II

>  
>  void sdhci_reset(struct sdhci_host *host, u8 mask)
>  {
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index bbed850241d4..28716105da61 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -715,6 +715,19 @@ struct sdhci_ops {
>  					     u8 power_mode);
>  	unsigned int    (*get_ro)(struct sdhci_host *host);
>  	void		(*reset)(struct sdhci_host *host, u8 mask);
> +	/**
> +	 * The sdhci_uhs2_reset callback is to implement for reset
> +	 * @host: SDHCI host
> +	 * @mask: Control mask
> +	 *
> +	 * Invoke reset, depending on a bit in @mask and wait for completion.
> +	 * SD mode				UHS-II mode
> +	 * SDHCI_RESET_ALL		SDHCI_UHS2_SW_RESET_FULL
> +	 * SDHCI_RESET_CMD		SDHCI_RESET_CMD
> +	 * SDHCI_RESET_DATA		SDHCI_UHS2_SW_RESET_SD
> +	 *
> +	 **/
> +	void (*uhs2_reset)(struct sdhci_host *host, u16 mask);

This is only being called from sdhci_uhs2.c so let's just call it
directly for now, instead of using a callback.

>  	int	(*platform_execute_tuning)(struct sdhci_host *host, u32 opcode);
>  	void	(*set_uhs_signaling)(struct sdhci_host *host, unsigned int uhs);
>  	void	(*hw_reset)(struct sdhci_host *host);
> @@ -837,6 +850,7 @@ static inline void sdhci_read_caps(struct sdhci_host *host)
>  	__sdhci_read_caps(host, NULL, NULL, NULL);
>  }
>  
> +void sdhci_runtime_pm_bus_off(struct sdhci_host *host);

Let's not support SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON for UHS-II

>  u16 sdhci_calc_clk(struct sdhci_host *host, unsigned int clock,
>  		   unsigned int *actual_clock);
>  void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
Victor Shih Dec. 13, 2022, 8:45 a.m. UTC | #2
Hi, Adrian

On Wed, Nov 2, 2022 at 1:13 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 19/10/22 14:06, Victor Shih wrote:
> > Sdhci_uhs2_reset() does a UHS-II specific reset operation.
> >
> > Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
> > ---
> >  drivers/mmc/host/sdhci-pci-core.c |  1 +
> >  drivers/mmc/host/sdhci-pci-gli.c  |  1 +
> >  drivers/mmc/host/sdhci-uhs2.c     | 68 +++++++++++++++++++++++++++++++
> >  drivers/mmc/host/sdhci-uhs2.h     |  3 ++
> >  drivers/mmc/host/sdhci.c          |  3 +-
> >  drivers/mmc/host/sdhci.h          | 14 +++++++
> >  6 files changed, 89 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> > index 34ea1acbb3cc..cba5bba994b8 100644
> > --- a/drivers/mmc/host/sdhci-pci-core.c
> > +++ b/drivers/mmc/host/sdhci-pci-core.c
> > @@ -1955,6 +1955,7 @@ static const struct sdhci_ops sdhci_pci_ops = {
> >       .reset          = sdhci_reset,
> >       .set_uhs_signaling = sdhci_set_uhs_signaling,
> >       .hw_reset               = sdhci_pci_hw_reset,
> > +     .uhs2_reset             = sdhci_uhs2_reset,
>
> AFAICT this isn't needed
>

I will update it in the patch#10 of the new [PATCH V6].

> >  };
> >
> >  /*****************************************************************************\
> > diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
> > index 4d509f656188..607cf69f45d0 100644
> > --- a/drivers/mmc/host/sdhci-pci-gli.c
> > +++ b/drivers/mmc/host/sdhci-pci-gli.c
> > @@ -1097,6 +1097,7 @@ static const struct sdhci_ops sdhci_gl9755_ops = {
> >       .reset                  = sdhci_reset,
> >       .set_uhs_signaling      = sdhci_set_uhs_signaling,
> >       .voltage_switch         = sdhci_gli_voltage_switch,
> > +     .uhs2_reset             = sdhci_uhs2_reset,
> >  };
> >
> >  const struct sdhci_pci_fixes sdhci_gl9755 = {
> > diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> > index 08905ed081fb..0e82f98d1967 100644
> > --- a/drivers/mmc/host/sdhci-uhs2.c
> > +++ b/drivers/mmc/host/sdhci-uhs2.c
> > @@ -10,6 +10,7 @@
> >   *  Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
> >   */
> >
> > +#include <linux/delay.h>
> >  #include <linux/module.h>
> >
> >  #include "sdhci.h"
> > @@ -49,6 +50,73 @@ void sdhci_uhs2_dump_regs(struct sdhci_host *host)
> >  }
> >  EXPORT_SYMBOL_GPL(sdhci_uhs2_dump_regs);
> >
> > +/*****************************************************************************\
> > + *                                                                           *
> > + * Low level functions                                                       *
> > + *                                                                           *
> > +\*****************************************************************************/
> > +
> > +bool sdhci_uhs2_mode(struct sdhci_host *host)
> > +{
> > +     if ((host->mmc->caps2 & MMC_CAP2_SD_UHS2) &&
> > +         (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> > +             (host->version >= SDHCI_SPEC_400) &&
> > +             (host->mmc->flags & MMC_UHS2_SUPPORT)))
> > +             return true;
> > +     else
> > +             return false;
>
> For now, let's just make this:
>
>         return host->mmc->flags & MMC_UHS2_SUPPORT;
>

I will update it in the patch#10 of the new [PATCH V6].

> > +}
> > +
> > +/**
> > + * sdhci_uhs2_reset - invoke SW reset
> > + * @host: SDHCI host
> > + * @mask: Control mask
> > + *
> > + * Invoke SW reset, depending on a bit in @mask and wait for completion.
> > + */
> > +void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask)
> > +{
> > +     unsigned long timeout;
> > +     u32 val;
> > +
> > +     if (!(sdhci_uhs2_mode(host))) {
>
> That isn't possible.
>

I will update it in the patch#10 of the new [PATCH V6].

> > +             /**
> > +              * u8  mask for legacy.
> > +              * u16 mask for uhs-2.
> > +              */
> > +             u8 u8_mask;
> > +
> > +             u8_mask = (mask & 0xFF);
> > +             sdhci_reset(host, u8_mask);
>
> Probably should call host->ops->reset() but !sdhci_uhs2_mode(host)
> isn't possible
>

I will update it in the patch#10 of the new [PATCH V6].

> > +
> > +             return;
> > +     }
> > +
> > +     sdhci_writew(host, mask, SDHCI_UHS2_SW_RESET);
> > +
> > +     if (mask & SDHCI_UHS2_SW_RESET_FULL) {
> > +             host->clock = 0;
> > +             /* Reset-all turns off SD Bus Power */
> > +             if (host->quirks2 & SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON)
> > +                     sdhci_runtime_pm_bus_off(host);
>
> We don't know what other drivers will opt for UHS-II
> support, but I doubt this quirk will be used, so  let's
> not support SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON for UHS-II
>

I will update it in the patch#10 of the new [PATCH V6].

> > +     }
> > +
> > +     /* Wait max 100 ms */
> > +     timeout = 10000;
>
> Isn't that 10ms
>

I will update it in the patch#10 of the new [PATCH V6].

> > +
> > +     /* hw clears the bit when it's done */
> > +     if (read_poll_timeout_atomic(sdhci_readw, val, !(val & mask), 10,
> > +                                  timeout, true, host, SDHCI_UHS2_SW_RESET)) {
> > +             pr_err("%s: %s: Reset 0x%x never completed.\n",
> > +                                            __func__, mmc_hostname(host->mmc), (int)mask);
> > +             pr_err("%s: clean reset bit\n",
> > +                                            mmc_hostname(host->mmc));
> > +             sdhci_writeb(host, 0, SDHCI_UHS2_SW_RESET);
> > +             return;
> > +     }
> > +}
> > +EXPORT_SYMBOL_GPL(sdhci_uhs2_reset);
> > +
> >  /*****************************************************************************\
> >   *                                                                           *
> >   * Driver init/exit                                                          *
> > diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
> > index afdb05d6056b..31776dcca5cf 100644
> > --- a/drivers/mmc/host/sdhci-uhs2.h
> > +++ b/drivers/mmc/host/sdhci-uhs2.h
> > @@ -11,6 +11,7 @@
> >  #define __SDHCI_UHS2_H
> >
> >  #include <linux/bits.h>
> > +#include <linux/iopoll.h>
>
> Not needed in header.  Can just be in .c
>

I will update it in the patch#10 of the new [PATCH V6].

> >
> >  /*
> >   * UHS-II Controller registers
> > @@ -210,5 +211,7 @@
> >  struct sdhci_host;
> >
> >  void sdhci_uhs2_dump_regs(struct sdhci_host *host);
> > +bool sdhci_uhs2_mode(struct sdhci_host *host);
> > +void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
> >
> >  #endif /* __SDHCI_UHS2_H */
> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> > index 2cdd183c8ada..bd017c59a020 100644
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -194,13 +194,14 @@ static void sdhci_runtime_pm_bus_on(struct sdhci_host *host)
> >       pm_runtime_get_noresume(mmc_dev(host->mmc));
> >  }
> >
> > -static void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
> > +void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
> >  {
> >       if (!host->bus_on)
> >               return;
> >       host->bus_on = false;
> >       pm_runtime_put_noidle(mmc_dev(host->mmc));
> >  }
> > +EXPORT_SYMBOL_GPL(sdhci_runtime_pm_bus_off);
>
> Let's not support SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON for UHS-II
>

I will update it in the patch#10 of the new [PATCH V6].

> >
> >  void sdhci_reset(struct sdhci_host *host, u8 mask)
> >  {
> > diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> > index bbed850241d4..28716105da61 100644
> > --- a/drivers/mmc/host/sdhci.h
> > +++ b/drivers/mmc/host/sdhci.h
> > @@ -715,6 +715,19 @@ struct sdhci_ops {
> >                                            u8 power_mode);
> >       unsigned int    (*get_ro)(struct sdhci_host *host);
> >       void            (*reset)(struct sdhci_host *host, u8 mask);
> > +     /**
> > +      * The sdhci_uhs2_reset callback is to implement for reset
> > +      * @host: SDHCI host
> > +      * @mask: Control mask
> > +      *
> > +      * Invoke reset, depending on a bit in @mask and wait for completion.
> > +      * SD mode                              UHS-II mode
> > +      * SDHCI_RESET_ALL              SDHCI_UHS2_SW_RESET_FULL
> > +      * SDHCI_RESET_CMD              SDHCI_RESET_CMD
> > +      * SDHCI_RESET_DATA             SDHCI_UHS2_SW_RESET_SD
> > +      *
> > +      **/
> > +     void (*uhs2_reset)(struct sdhci_host *host, u16 mask);
>
> This is only being called from sdhci_uhs2.c so let's just call it
> directly for now, instead of using a callback.
>

I will update it in the patch#10 of the new [PATCH V6].

> >       int     (*platform_execute_tuning)(struct sdhci_host *host, u32 opcode);
> >       void    (*set_uhs_signaling)(struct sdhci_host *host, unsigned int uhs);
> >       void    (*hw_reset)(struct sdhci_host *host);
> > @@ -837,6 +850,7 @@ static inline void sdhci_read_caps(struct sdhci_host *host)
> >       __sdhci_read_caps(host, NULL, NULL, NULL);
> >  }
> >
> > +void sdhci_runtime_pm_bus_off(struct sdhci_host *host);
>
> Let's not support SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON for UHS-II
>

I will update it in the patch#10 of the new [PATCH V6].

> >  u16 sdhci_calc_clk(struct sdhci_host *host, unsigned int clock,
> >                  unsigned int *actual_clock);
> >  void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
>

Thanks, Victor Shih
diff mbox series

Patch

diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
index 34ea1acbb3cc..cba5bba994b8 100644
--- a/drivers/mmc/host/sdhci-pci-core.c
+++ b/drivers/mmc/host/sdhci-pci-core.c
@@ -1955,6 +1955,7 @@  static const struct sdhci_ops sdhci_pci_ops = {
 	.reset		= sdhci_reset,
 	.set_uhs_signaling = sdhci_set_uhs_signaling,
 	.hw_reset		= sdhci_pci_hw_reset,
+	.uhs2_reset		= sdhci_uhs2_reset,
 };
 
 /*****************************************************************************\
diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
index 4d509f656188..607cf69f45d0 100644
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c
@@ -1097,6 +1097,7 @@  static const struct sdhci_ops sdhci_gl9755_ops = {
 	.reset			= sdhci_reset,
 	.set_uhs_signaling	= sdhci_set_uhs_signaling,
 	.voltage_switch		= sdhci_gli_voltage_switch,
+	.uhs2_reset		= sdhci_uhs2_reset,
 };
 
 const struct sdhci_pci_fixes sdhci_gl9755 = {
diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
index 08905ed081fb..0e82f98d1967 100644
--- a/drivers/mmc/host/sdhci-uhs2.c
+++ b/drivers/mmc/host/sdhci-uhs2.c
@@ -10,6 +10,7 @@ 
  *  Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
  */
 
+#include <linux/delay.h>
 #include <linux/module.h>
 
 #include "sdhci.h"
@@ -49,6 +50,73 @@  void sdhci_uhs2_dump_regs(struct sdhci_host *host)
 }
 EXPORT_SYMBOL_GPL(sdhci_uhs2_dump_regs);
 
+/*****************************************************************************\
+ *                                                                           *
+ * Low level functions                                                       *
+ *                                                                           *
+\*****************************************************************************/
+
+bool sdhci_uhs2_mode(struct sdhci_host *host)
+{
+	if ((host->mmc->caps2 & MMC_CAP2_SD_UHS2) &&
+	    (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
+		(host->version >= SDHCI_SPEC_400) &&
+		(host->mmc->flags & MMC_UHS2_SUPPORT)))
+		return true;
+	else
+		return false;
+}
+
+/**
+ * sdhci_uhs2_reset - invoke SW reset
+ * @host: SDHCI host
+ * @mask: Control mask
+ *
+ * Invoke SW reset, depending on a bit in @mask and wait for completion.
+ */
+void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask)
+{
+	unsigned long timeout;
+	u32 val;
+
+	if (!(sdhci_uhs2_mode(host))) {
+		/**
+		 * u8  mask for legacy.
+		 * u16 mask for uhs-2.
+		 */
+		u8 u8_mask;
+
+		u8_mask = (mask & 0xFF);
+		sdhci_reset(host, u8_mask);
+
+		return;
+	}
+
+	sdhci_writew(host, mask, SDHCI_UHS2_SW_RESET);
+
+	if (mask & SDHCI_UHS2_SW_RESET_FULL) {
+		host->clock = 0;
+		/* Reset-all turns off SD Bus Power */
+		if (host->quirks2 & SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON)
+			sdhci_runtime_pm_bus_off(host);
+	}
+
+	/* Wait max 100 ms */
+	timeout = 10000;
+
+	/* hw clears the bit when it's done */
+	if (read_poll_timeout_atomic(sdhci_readw, val, !(val & mask), 10,
+				     timeout, true, host, SDHCI_UHS2_SW_RESET)) {
+		pr_err("%s: %s: Reset 0x%x never completed.\n",
+					       __func__, mmc_hostname(host->mmc), (int)mask);
+		pr_err("%s: clean reset bit\n",
+					       mmc_hostname(host->mmc));
+		sdhci_writeb(host, 0, SDHCI_UHS2_SW_RESET);
+		return;
+	}
+}
+EXPORT_SYMBOL_GPL(sdhci_uhs2_reset);
+
 /*****************************************************************************\
  *                                                                           *
  * Driver init/exit                                                          *
diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
index afdb05d6056b..31776dcca5cf 100644
--- a/drivers/mmc/host/sdhci-uhs2.h
+++ b/drivers/mmc/host/sdhci-uhs2.h
@@ -11,6 +11,7 @@ 
 #define __SDHCI_UHS2_H
 
 #include <linux/bits.h>
+#include <linux/iopoll.h>
 
 /*
  * UHS-II Controller registers
@@ -210,5 +211,7 @@ 
 struct sdhci_host;
 
 void sdhci_uhs2_dump_regs(struct sdhci_host *host);
+bool sdhci_uhs2_mode(struct sdhci_host *host);
+void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
 
 #endif /* __SDHCI_UHS2_H */
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 2cdd183c8ada..bd017c59a020 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -194,13 +194,14 @@  static void sdhci_runtime_pm_bus_on(struct sdhci_host *host)
 	pm_runtime_get_noresume(mmc_dev(host->mmc));
 }
 
-static void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
+void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
 {
 	if (!host->bus_on)
 		return;
 	host->bus_on = false;
 	pm_runtime_put_noidle(mmc_dev(host->mmc));
 }
+EXPORT_SYMBOL_GPL(sdhci_runtime_pm_bus_off);
 
 void sdhci_reset(struct sdhci_host *host, u8 mask)
 {
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index bbed850241d4..28716105da61 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -715,6 +715,19 @@  struct sdhci_ops {
 					     u8 power_mode);
 	unsigned int    (*get_ro)(struct sdhci_host *host);
 	void		(*reset)(struct sdhci_host *host, u8 mask);
+	/**
+	 * The sdhci_uhs2_reset callback is to implement for reset
+	 * @host: SDHCI host
+	 * @mask: Control mask
+	 *
+	 * Invoke reset, depending on a bit in @mask and wait for completion.
+	 * SD mode				UHS-II mode
+	 * SDHCI_RESET_ALL		SDHCI_UHS2_SW_RESET_FULL
+	 * SDHCI_RESET_CMD		SDHCI_RESET_CMD
+	 * SDHCI_RESET_DATA		SDHCI_UHS2_SW_RESET_SD
+	 *
+	 **/
+	void (*uhs2_reset)(struct sdhci_host *host, u16 mask);
 	int	(*platform_execute_tuning)(struct sdhci_host *host, u32 opcode);
 	void	(*set_uhs_signaling)(struct sdhci_host *host, unsigned int uhs);
 	void	(*hw_reset)(struct sdhci_host *host);
@@ -837,6 +850,7 @@  static inline void sdhci_read_caps(struct sdhci_host *host)
 	__sdhci_read_caps(host, NULL, NULL, NULL);
 }
 
+void sdhci_runtime_pm_bus_off(struct sdhci_host *host);
 u16 sdhci_calc_clk(struct sdhci_host *host, unsigned int clock,
 		   unsigned int *actual_clock);
 void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);