Re: [PATCH RFC v3 1/2] mmc: core: Add vendor hook to control reprogram keys to Crypto Engine

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

On 6/10/24 16:55, Seshu Madhavi Puppala wrote:
> Add mmc_host_ops hook avoid_reprogram_allkeys to control
> reprogramming keys to Inline Crypto Engine by vendor as some
> vendors might not require this feature.
> 
> Signed-off-by: Seshu Madhavi Puppala <quic_spuppala@quicinc.com>
> Co-developed-by: Ram Prakash Gupta <quic_rampraka@quicinc.com>
> Signed-off-by: Ram Prakash Gupta <quic_rampraka@quicinc.com>
> ---
>  drivers/mmc/core/crypto.c | 8 +++++---
>  drivers/mmc/host/sdhci.c  | 6 ++++++
>  include/linux/mmc/host.h  | 7 +++++++
>  3 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/core/crypto.c b/drivers/mmc/core/crypto.c
> index fec4fbf16a5b..4168f7d135ff 100644
> --- a/drivers/mmc/core/crypto.c
> +++ b/drivers/mmc/core/crypto.c
> @@ -14,9 +14,11 @@
>  
>  void mmc_crypto_set_initial_state(struct mmc_host *host)
>  {
> -	/* Reset might clear all keys, so reprogram all the keys. */
> -	if (host->caps2 & MMC_CAP2_CRYPTO)
> -		blk_crypto_reprogram_all_keys(&host->crypto_profile);
> +	if (host->ops->avoid_reprogram_allkeys && !host->ops->avoid_reprogram_allkeys()) {
> +		/* Reset might clear all keys, so reprogram all the keys. */
> +		if (host->caps2 & MMC_CAP2_CRYPTO)
> +			blk_crypto_reprogram_all_keys(&host->crypto_profile);
> +	}

Probably nicer to put MMC_CAP2_CRYPTO check first, but also the logic
needs a tweak:

	/* Reset might clear all keys, so reprogram all the keys. */
	if (host->caps2 & MMC_CAP2_CRYPTO &&
	    (!host->ops->avoid_reprogram_allkeys ||
	     !host->ops->avoid_reprogram_allkeys()))
		blk_crypto_reprogram_all_keys(&host->crypto_profile);

>  }
>  
>  void mmc_crypto_setup_queue(struct request_queue *q, struct mmc_host *host)
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index fbf7a91bed35..cd663899c025 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2704,6 +2704,11 @@ int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
>  }
>  EXPORT_SYMBOL_GPL(sdhci_start_signal_voltage_switch);
>  
> +static bool sdhci_avoid_reprogram_allkeys(void)
> +{
> +	return false;
> +}
> +
>  static int sdhci_card_busy(struct mmc_host *mmc)
>  {
>  	struct sdhci_host *host = mmc_priv(mmc);
> @@ -3066,6 +3071,7 @@ static const struct mmc_host_ops sdhci_ops = {
>  	.execute_tuning			= sdhci_execute_tuning,
>  	.card_event			= sdhci_card_event,
>  	.card_busy	= sdhci_card_busy,
> +	.avoid_reprogram_allkeys	= sdhci_avoid_reprogram_allkeys,

There isn't any need for this

>  };
>  
>  /*****************************************************************************\
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 88c6a76042ee..c4109d17f177 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -218,6 +218,13 @@ struct mmc_host_ops {
>  
>  	/* Initialize an SD express card, mandatory for MMC_CAP2_SD_EXP. */
>  	int	(*init_sd_express)(struct mmc_host *host, struct mmc_ios *ios);
> +
> +	/*
> +	 * Optional callback to support controllers that dont require to
> +	 * reprogram all crypto keys on card suspend/resume.
> +	 */
> +	bool	(*avoid_reprogram_allkeys)(void);
> +
>  };
>  
>  struct mmc_cqe_ops {