Re: [PATCH RESEND v4] mmc: Avoid reprogram all keys to Inline Crypto Engine for MMC runtime suspend resume

[Jie Gan <jie.gan@oss.qualcomm.com>]

On 5/29/2026 5:26 PM, Neeraj Soni wrote:
> From: Debraj Mukhopadhyay <quic_dmukhopa@quicinc.com>
> 
> Crypto reprogram all keys is called for each MMC runtime
> suspend/resume in current upstream design. If this is implemented
> as a non-interruptible call to TEE for security, the cpu core is
> blocked for execution while this call executes although the crypto
> engine already has the keys. For example, glitches in audio/video
> streaming applications have been observed due to this. Add the flag
> MMC_CAP2_CRYPTO_NO_REPROG as part of host->caps2 to control reprogramming
> keys to crypto engine for socs which dont 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>
> Co-developed-by: Sarthak Garg <quic_sartgarg@quicinc.com>
> Signed-off-by: Sarthak Garg <quic_sartgarg@quicinc.com>
> Signed-off-by: Debraj Mukhopadhyay <quic_dmukhopa@quicinc.com>
> Acked-by: Adrian Hunter <adrian.hunter@intel.com>
> Link: https://lore.kernel.org/r/20260116121004.1829223-1-neeraj.soni@oss.qualcomm.com
> Signed-off-by: Neeraj Soni <neeraj.soni@oss.qualcomm.com>
> ---
>   drivers/mmc/core/crypto.c    | 2 +-
>   drivers/mmc/host/sdhci-msm.c | 6 ++++++
>   include/linux/mmc/host.h     | 5 +----
>   3 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mmc/core/crypto.c b/drivers/mmc/core/crypto.c
> index fec4fbf16a5b..a5a90bfc634e 100644
> --- a/drivers/mmc/core/crypto.c
> +++ b/drivers/mmc/core/crypto.c
> @@ -15,7 +15,7 @@
>   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)
> +	if ((host->caps2 & MMC_CAP2_CRYPTO) && !(host->caps2 & MMC_CAP2_CRYPTO_NO_REPROG))
>   		blk_crypto_reprogram_all_keys(&host->crypto_profile);
>   }
>   
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 4e5edbf2fc9b..2ccb63dde9c1 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -1949,6 +1949,7 @@ static int sdhci_msm_ice_init(struct sdhci_msm_host *msm_host,
>   	}
>   
>   	mmc->caps2 |= MMC_CAP2_CRYPTO;
> +	mmc->caps2 |= MMC_CAP2_CRYPTO_NO_REPROG;
>   	return 0;
>   }
>   
> @@ -2526,6 +2527,11 @@ static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
>   	usleep_range(200, 210);
>   	reset_control_put(reset);
>   
> +#ifdef CONFIG_MMC_CRYPTO
> +	if (host->mmc->caps2 & MMC_CAP2_CRYPTO)

Always false at this point. The first set of the host->mmc->caps2 is 
later in the sdhci_msm_cqe_add_host.

Thanks,
Jie

> +		blk_crypto_reprogram_all_keys(&host->mmc->crypto_profile);
> +#endif
> +
>   	return ret;
>   }
>   
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index e0e2c265e5d1..2fd76f966e24 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -457,12 +457,9 @@ struct mmc_host {
>   #define MMC_CAP2_CQE_DCMD	(1 << 24)	/* CQE can issue a direct command */
>   #define MMC_CAP2_AVOID_3_3V	(1 << 25)	/* Host must negotiate down from 3.3V */
>   #define MMC_CAP2_MERGE_CAPABLE	(1 << 26)	/* Host can merge a segment over the segment size */
> -#ifdef CONFIG_MMC_CRYPTO
>   #define MMC_CAP2_CRYPTO		(1 << 27)	/* Host supports inline encryption */
> -#else
> -#define MMC_CAP2_CRYPTO		0
> -#endif
>   #define MMC_CAP2_ALT_GPT_TEGRA	(1 << 28)	/* Host with eMMC that has GPT entry at a non-standard location */
> +#define MMC_CAP2_CRYPTO_NO_REPROG (1 << 29)	/* Host handles inline crypto key reprogramming */
>   
>   	bool			uhs2_sd_tran;	/* UHS-II flag for SD_TRAN state */
>   	bool			uhs2_app_cmd;	/* UHS-II flag for APP command */