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

[Adrian Hunter <adrian.hunter@intel.com>]

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);