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

[Neeraj Soni]

On 5/29/2026 3:49 PM, Jie Gan wrote:
> 
> 
> On 5/29/2026 5:26 PM, Neeraj Soni wrote:
>> From: Debraj Mukhopadhyay <quic_dmukhopa@xxxxxxxxxxx>
>>
>> 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@xxxxxxxxxxx>
>> Co-developed-by: Ram Prakash Gupta <quic_rampraka@xxxxxxxxxxx>
>> Signed-off-by: Ram Prakash Gupta <quic_rampraka@xxxxxxxxxxx>
>> Co-developed-by: Sarthak Garg <quic_sartgarg@xxxxxxxxxxx>
>> Signed-off-by: Sarthak Garg <quic_sartgarg@xxxxxxxxxxx>
>> Signed-off-by: Debraj Mukhopadhyay <quic_dmukhopa@xxxxxxxxxxx>
>> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>> Link: https://lore.kernel.org/r/20260116121004.1829223-1-neeraj.soni@xxxxxxxxxxxxxxxx
>> Signed-off-by: Neeraj Soni <neeraj.soni@xxxxxxxxxxxxxxxx>
>> ---
>>   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.
> 
Yes for cold boot this is true and Crypto reprogram is not needed. This patch addreses the use cases like
runtime suspend resume, deep sleep / Quick boot (DS/QB) and suspend to disk (aka hibernation) use cases
where the runtime context is preserved either in dynamic memory (DS/QB) or in secondry memory (hibernation).
This is tested internally on SAR1250P chipset for hibernation and DS/QB.
 
> 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 */
> 

Regards
Neeraj