Re: [PATCH 3/4] mmc: core: make hw_reset generic

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

On 24/10/14 15:46, Johan Rudholm wrote:
> Move the (e)MMC specific hw_reset code from core.c into mmc.c and call
> it from the new bus_ops member power_reset. This also lets us add code

power_reset is not a good name because it does not necessarily have
anything to do with power.  I am not sure why you don't stick with
hw_reset.

> for reseting SD cards as well.
> 
> Rename the mmc_hw_reset* functions into mmc_reset*, since what they
> now actually do depends on the device type (and it may be something else
> than doing a hw_reset).

I don't follow your reasoning about the rename.  Cycling the power is
a kind of hardware reset isn't it.

> 
> Signed-off-by: Johan Rudholm <johanru@axis.com>
> ---
>  drivers/mmc/card/block.c    |    2 +-
>  drivers/mmc/card/mmc_test.c |    5 +---
>  drivers/mmc/core/core.c     |   58 +++++++++---------------------------------
>  drivers/mmc/core/core.h     |    4 +++
>  drivers/mmc/core/mmc.c      |   40 +++++++++++++++++++++++++++++
>  include/linux/mmc/core.h    |    5 +--
>  6 files changed, 61 insertions(+), 53 deletions(-)
> 
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 452782b..8c4fa46 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -1001,7 +1001,7 @@ static int mmc_blk_reset(struct mmc_blk_data *md, struct mmc_host *host,
>  		return -EEXIST;
>  
>  	md->reset_done |= type;
> -	err = mmc_hw_reset(host);
> +	err = mmc_reset(host);
>  	/* Ensure we switch back to the correct partition */
>  	if (err != -EOPNOTSUPP) {
>  		struct mmc_blk_data *main_md = mmc_get_drvdata(host->card);
> diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c
> index 0c0fc52..599c683 100644
> --- a/drivers/mmc/card/mmc_test.c
> +++ b/drivers/mmc/card/mmc_test.c
> @@ -2339,7 +2339,7 @@ static int mmc_test_hw_reset(struct mmc_test_card *test)
>  	struct mmc_host *host = card->host;
>  	int err;
>  
> -	err = mmc_hw_reset_check(host);
> +	err = mmc_reset_check(host);
>  	if (!err)
>  		return RESULT_OK;
>  
> @@ -2349,9 +2349,6 @@ static int mmc_test_hw_reset(struct mmc_test_card *test)
>  	if (err != -EOPNOTSUPP)
>  		return err;
>  
> -	if (!mmc_can_reset(card))
> -		return RESULT_UNSUP_CARD;
> -
>  	return RESULT_UNSUP_HOST;
>  }
>  
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index d56e222..486cda8 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2232,65 +2232,33 @@ static void mmc_hw_reset_for_init(struct mmc_host *host)
>  	mmc_host_clk_release(host);
>  }
>  
> -int mmc_can_reset(struct mmc_card *card)
> +/* Reset card in a bus-specific way */
> +static int mmc_do_reset(struct mmc_host *host, int check)
>  {
> -	u8 rst_n_function;
> -
> -	if (!mmc_card_mmc(card))
> -		return 0;
> -	rst_n_function = card->ext_csd.rst_n_function;
> -	if ((rst_n_function & EXT_CSD_RST_N_EN_MASK) != EXT_CSD_RST_N_ENABLED)
> -		return 0;
> -	return 1;
> -}
> -EXPORT_SYMBOL(mmc_can_reset);
> -
> -static int mmc_do_hw_reset(struct mmc_host *host, int check)
> -{
> -	struct mmc_card *card = host->card;
> -
> -	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
> -		return -EOPNOTSUPP;
> -
> -	if (!card)
> -		return -EINVAL;
> +	int ret;
>  
> -	if (!mmc_can_reset(card))
> +	if (!host->bus_ops || !host->bus_ops->power_reset ||
> +			host->bus_ops->power_reset(host, MMC_POWER_RESET_TEST))
>  		return -EOPNOTSUPP;
>  
> -	mmc_host_clk_hold(host);
> -	mmc_set_clock(host, host->f_init);
> -
> -	host->ops->hw_reset(host);
> -
> -	/* If the reset has happened, then a status command will fail */
> -	if (check) {
> -		u32 status;
> -
> -		if (!mmc_send_status(card, &status)) {
> -			mmc_host_clk_release(host);
> -			return -ENOSYS;
> -		}
> -	}
> -
> -	mmc_power_up(host, card->ocr);
> +	ret = host->bus_ops->power_reset(host, check);
>  
> -	mmc_host_clk_release(host);
> +	pr_warning("%s: tried to reset card (%d)\n", mmc_hostname(host), ret);
>  
>  	return host->bus_ops->power_restore(host);
>  }
>  
> -int mmc_hw_reset(struct mmc_host *host)
> +int mmc_reset(struct mmc_host *host)
>  {
> -	return mmc_do_hw_reset(host, 0);
> +	return mmc_do_reset(host, MMC_POWER_RESET_RESET);
>  }
> -EXPORT_SYMBOL(mmc_hw_reset);
> +EXPORT_SYMBOL(mmc_reset);
>  
> -int mmc_hw_reset_check(struct mmc_host *host)
> +int mmc_reset_check(struct mmc_host *host)
>  {
> -	return mmc_do_hw_reset(host, 1);
> +	return mmc_do_reset(host, MMC_POWER_RESET_CHECK);
>  }
> -EXPORT_SYMBOL(mmc_hw_reset_check);
> +EXPORT_SYMBOL(mmc_reset_check);
>  
>  static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
>  {
> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> index 443a584..6a0420b 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -25,6 +25,10 @@ struct mmc_bus_ops {
>  	int (*runtime_resume)(struct mmc_host *);
>  	int (*power_save)(struct mmc_host *);
>  	int (*power_restore)(struct mmc_host *);
> +	int (*power_reset)(struct mmc_host *, int);
> +#define MMC_POWER_RESET_RESET	0
> +#define MMC_POWER_RESET_TEST	1
> +#define MMC_POWER_RESET_CHECK	2
>  	int (*alive)(struct mmc_host *);
>  	int (*shutdown)(struct mmc_host *);
>  };
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 793c6f7..ac5192c 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1762,6 +1762,45 @@ static int mmc_runtime_resume(struct mmc_host *host)
>  	return 0;
>  }
>  
> +static int mmc_power_reset(struct mmc_host *host, int test)
> +{
> +	struct mmc_card *card = host->card;
> +	u8 rst_n_function;
> +
> +	if (!card)
> +		return -EINVAL;
> +
> +	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
> +		return -EOPNOTSUPP;
> +
> +	rst_n_function = card->ext_csd.rst_n_function;
> +	if ((rst_n_function & EXT_CSD_RST_N_EN_MASK) != EXT_CSD_RST_N_ENABLED)
> +		return -EOPNOTSUPP;
> +
> +	if (test == MMC_POWER_RESET_TEST)
> +		return 0;
> +
> +	mmc_host_clk_hold(host);
> +	mmc_set_clock(host, host->f_init);
> +
> +	host->ops->hw_reset(host);
> +
> +	if (test == MMC_POWER_RESET_CHECK) {
> +		u32 status;
> +
> +		if (!mmc_send_status(card, &status)) {
> +			mmc_host_clk_release(host);
> +			return -ENOSYS;
> +		}
> +	}
> +
> +	mmc_power_up(host, card->ocr);
> +
> +	mmc_host_clk_release(host);
> +
> +	return 0;
> +}
> +
>  static int mmc_power_restore(struct mmc_host *host)
>  {
>  	int ret;
> @@ -1781,6 +1820,7 @@ static const struct mmc_bus_ops mmc_ops = {
>  	.runtime_suspend = mmc_runtime_suspend,
>  	.runtime_resume = mmc_runtime_resume,
>  	.power_restore = mmc_power_restore,
> +	.power_reset = mmc_power_reset,
>  	.alive = mmc_alive,
>  	.shutdown = mmc_shutdown,
>  };
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index f206e29..4f7a76e 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -180,9 +180,8 @@ extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
>  extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);
>  extern int mmc_set_blockcount(struct mmc_card *card, unsigned int blockcount,
>  			      bool is_rel_write);
> -extern int mmc_hw_reset(struct mmc_host *host);
> -extern int mmc_hw_reset_check(struct mmc_host *host);
> -extern int mmc_can_reset(struct mmc_card *card);
> +extern int mmc_reset(struct mmc_host *host);
> +extern int mmc_reset_check(struct mmc_host *host);
>  
>  extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);
>  extern unsigned int mmc_align_data_size(struct mmc_card *, unsigned int);
>