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

[Eric Biggers <ebiggers@kernel.org>]

On Sun, Oct 06, 2024 at 07:25:29PM +0530, 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);
> +	}

This should be a simple flag, not an indirect function call which is
inefficient.

It could be a bit in mmc_host_ops, though based on the existing code maybe a new
bit in MMC_CAP2_* would be more appropriate.

- Eric