linux-kernel - [PATCH v3] mmc: Avoid reprogram all keys to Inline Crypto Engine for MMC runtime suspend resume

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Message-ID: <20250718110217.1929526-1-quic_dmukhopa@quicinc.com>
Date: Fri, 18 Jul 2025 16:32:17 +0530
From: Debraj Mukhopadhyay <quic_dmukhopa@...cinc.com>
To: Eric Biggers <ebiggers@...nel.org>, Ulf Hansson <ulf.hansson@...aro.org>,
        Adrian Hunter <adrian.hunter@...el.com>
CC: <linux-mmc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <kernel@...cinc.com>,
        Neeraj Soni
	<quic_neersoni@...cinc.com>,
        Debraj Mukhopadhyay <quic_dmukhopa@...cinc.com>,
        Ram Prakash Gupta <quic_rampraka@...cinc.com>,
        Nitin Rawat
	<quic_nitirawa@...cinc.com>,
        Sachin Gupta <quic_sachgupt@...cinc.com>,
        Bhaskar Valaboju <quic_bhaskarv@...cinc.com>,
        Gaurav Kashyap
	<quic_gaurkash@...cinc.com>,
        Sarthak Garg <quic_sartgarg@...cinc.com>
Subject: [PATCH v3] mmc: Avoid reprogram all keys to Inline Crypto Engine for MMC runtime suspend resume

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@...cinc.com>
Co-developed-by: Ram Prakash Gupta <quic_rampraka@...cinc.com>
Signed-off-by: Ram Prakash Gupta <quic_rampraka@...cinc.com>
Co-developed-by: Sarthak Garg <quic_sartgarg@...cinc.com>
Signed-off-by: Sarthak Garg <quic_sartgarg@...cinc.com>
Signed-off-by: Debraj Mukhopadhyay <quic_dmukhopa@...cinc.com>

---

Changes in v3:
- Renamed MMC_CAP2_DONT_REPROGRAM to MMC_CAP2_CRYPTO_NO_REPROG
  in the commit message for clarity.
- Added parentheses around the condition: (host->caps2 & MMC_CAP2_CRYPTO)
  to improve readability and correctness.
- Updated the comment associated with MMC_CAP2_CRYPTO_NO_REPROG 
  to better reflect its purpose.
  
Changes in v2:
- Renamed MMC_CAP2_DONT_REPROGRAM to MMC_CAP2_CRYPTO_NO_REPROG for
  improved clarity.
- Defined MMC_CAP2_CRYPTO_NO_REPROG for MMC targets that do not support
  a Crypto Engine.
- Restricted the usage of struct crypto_profile to MMC devices that
  support a Crypto Engine.

Changes in v1:
- Addressed the comments from:
  https://lore.kernel.org/lkml/20241006135530.17363-3-
  quic_spuppala@...cinc.com/T/#m69c9ab538bd9efd54515646952d0d7d1d7c17690
- Avoided reprogram of keys for Qualcomm SOCs only.
- Ensured reprogram of all keys on host controller reset.

---

 drivers/mmc/core/crypto.c    | 2 +-
 drivers/mmc/host/sdhci-msm.c | 6 ++++++
 include/linux/mmc/host.h     | 5 +++++
 3 files changed, 12 insertions(+), 1 deletion(-)

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 66c0d1ba2a33..ee6783555f2e 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -1920,6 +1920,7 @@ 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;
 }
 
@@ -2497,6 +2498,11 @@ 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)
+		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 68f09a955a90..4a80da07cf39 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -459,6 +459,11 @@ struct mmc_host {
 #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 */
+#ifdef CONFIG_MMC_CRYPTO
+#define MMC_CAP2_CRYPTO_NO_REPROG	(1 << 29)	/* Host handles inline crypto key reprogramming */
+#else
+#define MMC_CAP2_CRYPTO_NO_REPROG	0
+#endif
 
 	bool			uhs2_sd_tran;	/* UHS-II flag for SD_TRAN state */
 	bool			uhs2_app_cmd;	/* UHS-II flag for APP command */
-- 
2.34.1