[U-Boot] [PATCH 21/22] mmc: Change mode when switching to a boot partition

[Jaehoon Chung]

On 05/13/2017 03:16 AM, Jean-Jacques Hiblot wrote:
> Boot partitions do not support HS200. Changing to a lower performance mode
> is required to access them.
> mmc_select_mode_and_width() and sd_select_mode_and_width() are modified to
> make it easier to call them outside of the initialization context.

This patch should be important to support the HS200 mode on u-boot..
So i need to test this..more detail..

> 
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot at ti.com>
> ---
>  drivers/mmc/mmc.c | 66 +++++++++++++++++++++++++++++++++++++++++--------------
>  include/mmc.h     |  1 +
>  2 files changed, 50 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
> index 074d286..c7dda64 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -32,6 +32,7 @@ static const unsigned int sd_au_size[] = {
>  static int mmc_set_signal_voltage(struct mmc *mmc, uint signal_voltage);
>  static void mmc_power_cycle(struct mmc *mmc);
>  static int mmc_card_busy(struct mmc *mmc);
> +static int mmc_select_mode_and_width(struct mmc *mmc, uint card_caps);
>  
>  #if CONFIG_IS_ENABLED(MMC_TINY)
>  static struct mmc mmc_static;
> @@ -788,10 +789,38 @@ static int mmc_set_capacity(struct mmc *mmc, int part_num)
>  	return 0;
>  }
>  
> +static int mmc_boot_part_access_chk(struct mmc *mmc, unsigned int part_num)
> +{
> +	int forbiden = 0;

forbiden? typo?

> +	bool change = false;
> +
> +	if (part_num & PART_ACCESS_MASK)
> +		forbiden = MMC_CAP(MMC_HS_200);
> +
> +	if (MMC_CAP(mmc->selected_mode) & forbiden) {
> +		debug("selected mode (%s) is forbiden for part %d\n",
> +		      mmc_mode_name(mmc->selected_mode), part_num);
> +		change = true;
> +	} else if (mmc->selected_mode != mmc->best_mode) {
> +		debug("selected mode is not optimal\n");
> +		change = true;
> +	}
> +
> +	if (change)
> +		return mmc_select_mode_and_width(mmc,
> +						 mmc->card_caps & ~forbiden);
> +
> +	return 0;
> +}
> +
>  int mmc_switch_part(struct mmc *mmc, unsigned int part_num)
>  {
>  	int ret;
>  
> +	ret = mmc_boot_part_access_chk(mmc, part_num);
> +	if (ret)
> +		return ret;
> +
>  	ret = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_PART_CONF,
>  			 (mmc->part_config & ~PART_ACCESS_MASK)
>  			 | (part_num & PART_ACCESS_MASK));
> @@ -1438,7 +1467,7 @@ static const struct mode_width_tuning sd_modes_by_pref[] = {
>  	     mwt++) \
>  		if (caps & MMC_CAP(mwt->mode))
>  
> -static int sd_select_mode_and_width(struct mmc *mmc)
> +static int sd_select_mode_and_width(struct mmc *mmc, uint card_caps)
>  {
>  	int err;
>  	uint widths[] = {MMC_MODE_4BIT, MMC_MODE_1BIT};
> @@ -1447,11 +1476,8 @@ static int sd_select_mode_and_width(struct mmc *mmc)
>  	uint caps;
>  
>  
> -	err = sd_get_capabilities(mmc);
> -	if (err)
> -		return err;
>  	/* Restrict card's capabilities by what the host can do */
> -	caps = mmc->card_caps & (mmc->cfg->host_caps | MMC_MODE_1BIT);
> +	caps = card_caps & (mmc->cfg->host_caps | MMC_MODE_1BIT);
>  
>  	if (!uhs_en)
>  		caps &= ~UHS_CAPS;
> @@ -1582,18 +1608,14 @@ static const struct ext_csd_bus_width {
>  	    ecbv++) \
>  		if ((ddr == ecbv->is_ddr) && (caps & ecbv->cap))
>  
> -static int mmc_select_mode_and_width(struct mmc *mmc)
> +static int mmc_select_mode_and_width(struct mmc *mmc, uint card_caps)
>  {
>  	int err;
>  	const struct mode_width_tuning *mwt;
>  	const struct ext_csd_bus_width *ecbw;
>  
> -	err = mmc_get_capabilities(mmc);
> -	if (err)
> -		return err;
> -
>  	/* Restrict card's capabilities by what the host can do */
> -	mmc->card_caps &= (mmc->cfg->host_caps | MMC_MODE_1BIT);
> +	card_caps &= (mmc->cfg->host_caps | MMC_MODE_1BIT);
>  
>  	/* Only version 4 of MMC supports wider bus widths */
>  	if (mmc->version < MMC_VERSION_4)
> @@ -1605,8 +1627,10 @@ static int mmc_select_mode_and_width(struct mmc *mmc)
>  		return -ENOTSUPP;
>  	}
>  
> -	for_each_mmc_mode_by_pref(mmc->card_caps, mwt) {
> -		for_each_supported_width(mmc->card_caps & mwt->widths,
> +	mmc_set_clock(mmc, mmc->legacy_speed, false);
> +
> +	for_each_mmc_mode_by_pref(card_caps, mwt) {
> +		for_each_supported_width(card_caps & mwt->widths,
>  					 mmc_is_mode_ddr(mwt->mode), ecbw) {
>  			debug("trying mode %s width %d (at %d MHz)\n",
>  			      mmc_mode_name(mwt->mode),
> @@ -1999,14 +2023,22 @@ static int mmc_startup(struct mmc *mmc)
>  	if (err)
>  		return err;
>  
> -	if (IS_SD(mmc))
> -		err = sd_select_mode_and_width(mmc);
> -	else
> -		err = mmc_select_mode_and_width(mmc);
> +	if (IS_SD(mmc)) {
> +		err = sd_get_capabilities(mmc);
> +		if (err)
> +			return err;
> +		err = sd_select_mode_and_width(mmc, mmc->card_caps);
> +	} else {
> +		err = mmc_get_capabilities(mmc);
> +		if (err)
> +			return err;
> +		mmc_select_mode_and_width(mmc, mmc->card_caps);
> +	}
>  
>  	if (err)
>  		return err;
>  
> +	mmc->best_mode = mmc->selected_mode;
>  
>  	/* Fix the block length for DDR mode */
>  	if (mmc->ddr_mode) {
> diff --git a/include/mmc.h b/include/mmc.h
> index 775c47e..921a7ff 100644
> --- a/include/mmc.h
> +++ b/include/mmc.h
> @@ -573,6 +573,7 @@ struct mmc {
>  #endif
>  	u8 *ext_csd;
>  	enum bus_mode selected_mode;
> +	enum bus_mode best_mode;
>  };
>  
>  struct mmc_hwpart_conf {
>