mmc: cqhci: add support for inline encryption

Add support for eMMC inline encryption using the blk-crypto framework
(Documentation/block/inline-encryption.rst).

eMMC inline encryption support is specified by the upcoming JEDEC eMMC
v5.2 specification.  It is only specified for the CQ interface, not the
non-CQ interface.  Although the eMMC v5.2 specification hasn't been
officially released yet, the crypto support was already agreed on
several years ago, and it was already implemented by at least two major
hardware vendors.  Lots of hardware in the field already supports and
uses it, e.g. Snapdragon 630 to give one example.

eMMC inline encryption support is very similar to the UFS inline
encryption support which was standardized in the UFS v2.1 specification
and was already upstreamed.  The only major difference is that eMMC
limits data unit numbers to 32 bits, unlike UFS's 64 bits.

Like we did with UFS, make the crypto support opt-in by individual
drivers; don't enable it automatically whenever the hardware declares
crypto support.  This is necessary because in every case we've seen,
some extra vendor-specific logic is needed to use the crypto support.
Co-developed-by: NSatya Tangirala <satyat@google.com>
Signed-off-by: NSatya Tangirala <satyat@google.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NSatya Tangirala <satyat@google.com>
Reviewed-and-tested-by: NPeng Zhou <peng.zhou@mediatek.com>
Signed-off-by: NEric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20210125183810.198008-5-ebiggers@kernel.orgSigned-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/Makefile

@@ -103,6 +103,7 @@ obj-$(CONFIG_MMC_SDHCI_OMAP)		+= sdhci-omap.o
 obj-$(CONFIG_MMC_SDHCI_SPRD)		+= sdhci-sprd.o
 obj-$(CONFIG_MMC_CQHCI)			+= cqhci.o
 cqhci-y					+= cqhci-core.o
+cqhci-$(CONFIG_MMC_CRYPTO)		+= cqhci-crypto.o
 obj-$(CONFIG_MMC_HSQ)			+= mmc_hsq.o
 
 ifeq ($(CONFIG_CB710_DEBUG),y)

drivers/mmc/host/cqhci-core.c

@@ -18,6 +18,7 @@
 #include <linux/mmc/card.h>
 
 #include "cqhci.h"
+#include "cqhci-crypto.h"
 
 #define DCMD_SLOT 31
 #define NUM_SLOTS 32
@@ -258,6 +259,9 @@ static void __cqhci_enable(struct cqhci_host *cq_host)
 	if (cq_host->caps & CQHCI_TASK_DESC_SZ_128)
 		cqcfg |= CQHCI_TASK_DESC_SZ;
 
+	if (mmc->caps2 & MMC_CAP2_CRYPTO)
+		cqcfg |= CQHCI_CRYPTO_GENERAL_ENABLE;
+
 	cqhci_writel(cq_host, cqcfg, CQHCI_CFG);
 
 	cqhci_writel(cq_host, lower_32_bits(cq_host->desc_dma_base),
@@ -430,7 +434,7 @@ static void cqhci_prep_task_desc(struct mmc_request *mrq,
 	task_desc[0] = cpu_to_le64(desc0);
 
 	if (cq_host->caps & CQHCI_TASK_DESC_SZ_128) {
-		u64 desc1 = 0;
+		u64 desc1 = cqhci_crypto_prep_task_desc(mrq);
 
 		task_desc[1] = cpu_to_le64(desc1);
 
@@ -681,6 +685,7 @@ static void cqhci_error_irq(struct mmc_host *mmc, u32 status, int cmd_error,
 	struct cqhci_host *cq_host = mmc->cqe_private;
 	struct cqhci_slot *slot;
 	u32 terri;
+	u32 tdpe;
 	int tag;
 
 	spin_lock(&cq_host->lock);
@@ -719,6 +724,30 @@ static void cqhci_error_irq(struct mmc_host *mmc, u32 status, int cmd_error,
 		}
 	}
 
+	/*
+	 * Handle ICCE ("Invalid Crypto Configuration Error").  This should
+	 * never happen, since the block layer ensures that all crypto-enabled
+	 * I/O requests have a valid keyslot before they reach the driver.
+	 *
+	 * Note that GCE ("General Crypto Error") is different; it already got
+	 * handled above by checking TERRI.
+	 */
+	if (status & CQHCI_IS_ICCE) {
+		tdpe = cqhci_readl(cq_host, CQHCI_TDPE);
+		WARN_ONCE(1,
+			  "%s: cqhci: invalid crypto configuration error. IRQ status: 0x%08x TDPE: 0x%08x\n",
+			  mmc_hostname(mmc), status, tdpe);
+		while (tdpe != 0) {
+			tag = __ffs(tdpe);
+			tdpe &= ~(1 << tag);
+			slot = &cq_host->slot[tag];
+			if (!slot->mrq)
+				continue;
+			slot->flags = cqhci_error_flags(data_error, cmd_error);
+			cqhci_recovery_needed(mmc, slot->mrq, true);
+		}
+	}
+
 	if (!cq_host->recovery_halt) {
 		/*
 		 * The only way to guarantee forward progress is to mark at
@@ -784,7 +813,8 @@ irqreturn_t cqhci_irq(struct mmc_host *mmc, u32 intmask, int cmd_error,
 
 	pr_debug("%s: cqhci: IRQ status: 0x%08x\n", mmc_hostname(mmc), status);
 
-	if ((status & CQHCI_IS_RED) || cmd_error || data_error)
+	if ((status & (CQHCI_IS_RED | CQHCI_IS_GCE | CQHCI_IS_ICCE)) ||
+	    cmd_error || data_error)
 		cqhci_error_irq(mmc, status, cmd_error, data_error);
 
 	if (status & CQHCI_IS_TCC) {
@@ -1151,6 +1181,13 @@ int cqhci_init(struct cqhci_host *cq_host, struct mmc_host *mmc,
 		goto out_err;
 	}
 
+	err = cqhci_crypto_init(cq_host);
+	if (err) {
+		pr_err("%s: CQHCI crypto initialization failed\n",
+		       mmc_hostname(mmc));
+		goto out_err;
+	}
+
 	spin_lock_init(&cq_host->lock);
 
 	init_completion(&cq_host->halt_comp);

drivers/mmc/host/cqhci-crypto.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CQHCI crypto engine (inline encryption) support
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <linux/blk-crypto.h>
+#include <linux/keyslot-manager.h>
+#include <linux/mmc/host.h>
+
+#include "cqhci-crypto.h"
+
+/* Map from blk-crypto modes to CQHCI crypto algorithm IDs and key sizes */
+static const struct cqhci_crypto_alg_entry {
+	enum cqhci_crypto_alg alg;
+	enum cqhci_crypto_key_size key_size;
+} cqhci_crypto_algs[BLK_ENCRYPTION_MODE_MAX] = {
+	[BLK_ENCRYPTION_MODE_AES_256_XTS] = {
+		.alg = CQHCI_CRYPTO_ALG_AES_XTS,
+		.key_size = CQHCI_CRYPTO_KEY_SIZE_256,
+	},
+};
+
+static inline struct cqhci_host *
+cqhci_host_from_ksm(struct blk_keyslot_manager *ksm)
+{
+	struct mmc_host *mmc = container_of(ksm, struct mmc_host, ksm);
+
+	return mmc->cqe_private;
+}
+
+static void cqhci_crypto_program_key(struct cqhci_host *cq_host,
+				     const union cqhci_crypto_cfg_entry *cfg,
+				     int slot)
+{
+	u32 slot_offset = cq_host->crypto_cfg_register + slot * sizeof(*cfg);
+	int i;
+
+	/* Clear CFGE */
+	cqhci_writel(cq_host, 0, slot_offset + 16 * sizeof(cfg->reg_val[0]));
+
+	/* Write the key */
+	for (i = 0; i < 16; i++) {
+		cqhci_writel(cq_host, le32_to_cpu(cfg->reg_val[i]),
+			     slot_offset + i * sizeof(cfg->reg_val[0]));
+	}
+	/* Write dword 17 */
+	cqhci_writel(cq_host, le32_to_cpu(cfg->reg_val[17]),
+		     slot_offset + 17 * sizeof(cfg->reg_val[0]));
+	/* Write dword 16, which includes the new value of CFGE */
+	cqhci_writel(cq_host, le32_to_cpu(cfg->reg_val[16]),
+		     slot_offset + 16 * sizeof(cfg->reg_val[0]));
+}
+
+static int cqhci_crypto_keyslot_program(struct blk_keyslot_manager *ksm,
+					const struct blk_crypto_key *key,
+					unsigned int slot)
+
+{
+	struct cqhci_host *cq_host = cqhci_host_from_ksm(ksm);
+	const union cqhci_crypto_cap_entry *ccap_array =
+		cq_host->crypto_cap_array;
+	const struct cqhci_crypto_alg_entry *alg =
+			&cqhci_crypto_algs[key->crypto_cfg.crypto_mode];
+	u8 data_unit_mask = key->crypto_cfg.data_unit_size / 512;
+	int i;
+	int cap_idx = -1;
+	union cqhci_crypto_cfg_entry cfg = {};
+
+	BUILD_BUG_ON(CQHCI_CRYPTO_KEY_SIZE_INVALID != 0);
+	for (i = 0; i < cq_host->crypto_capabilities.num_crypto_cap; i++) {
+		if (ccap_array[i].algorithm_id == alg->alg &&
+		    ccap_array[i].key_size == alg->key_size &&
+		    (ccap_array[i].sdus_mask & data_unit_mask)) {
+			cap_idx = i;
+			break;
+		}
+	}
+	if (WARN_ON(cap_idx < 0))
+		return -EOPNOTSUPP;
+
+	cfg.data_unit_size = data_unit_mask;
+	cfg.crypto_cap_idx = cap_idx;
+	cfg.config_enable = CQHCI_CRYPTO_CONFIGURATION_ENABLE;
+
+	if (ccap_array[cap_idx].algorithm_id == CQHCI_CRYPTO_ALG_AES_XTS) {
+		/* In XTS mode, the blk_crypto_key's size is already doubled */
+		memcpy(cfg.crypto_key, key->raw, key->size/2);
+		memcpy(cfg.crypto_key + CQHCI_CRYPTO_KEY_MAX_SIZE/2,
+		       key->raw + key->size/2, key->size/2);
+	} else {
+		memcpy(cfg.crypto_key, key->raw, key->size);
+	}
+
+	cqhci_crypto_program_key(cq_host, &cfg, slot);
+
+	memzero_explicit(&cfg, sizeof(cfg));
+	return 0;
+}
+
+static void cqhci_crypto_clear_keyslot(struct cqhci_host *cq_host, int slot)
+{
+	/*
+	 * Clear the crypto cfg on the device. Clearing CFGE
+	 * might not be sufficient, so just clear the entire cfg.
+	 */
+	union cqhci_crypto_cfg_entry cfg = {};
+
+	cqhci_crypto_program_key(cq_host, &cfg, slot);
+}
+
+static int cqhci_crypto_keyslot_evict(struct blk_keyslot_manager *ksm,
+				      const struct blk_crypto_key *key,
+				      unsigned int slot)
+{
+	struct cqhci_host *cq_host = cqhci_host_from_ksm(ksm);
+
+	cqhci_crypto_clear_keyslot(cq_host, slot);
+	return 0;
+}
+
+/*
+ * The keyslot management operations for CQHCI crypto.
+ *
+ * Note that the block layer ensures that these are never called while the host
+ * controller is runtime-suspended.  However, the CQE won't necessarily be
+ * "enabled" when these are called, i.e. CQHCI_ENABLE might not be set in the
+ * CQHCI_CFG register.  But the hardware allows that.
+ */
+static const struct blk_ksm_ll_ops cqhci_ksm_ops = {
+	.keyslot_program	= cqhci_crypto_keyslot_program,
+	.keyslot_evict		= cqhci_crypto_keyslot_evict,
+};
+
+static enum blk_crypto_mode_num
+cqhci_find_blk_crypto_mode(union cqhci_crypto_cap_entry cap)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(cqhci_crypto_algs); i++) {
+		BUILD_BUG_ON(CQHCI_CRYPTO_KEY_SIZE_INVALID != 0);
+		if (cqhci_crypto_algs[i].alg == cap.algorithm_id &&
+		    cqhci_crypto_algs[i].key_size == cap.key_size)
+			return i;
+	}
+	return BLK_ENCRYPTION_MODE_INVALID;
+}
+
+/**
+ * cqhci_crypto_init - initialize CQHCI crypto support
+ * @cq_host: a cqhci host
+ *
+ * If the driver previously set MMC_CAP2_CRYPTO and the CQE declares
+ * CQHCI_CAP_CS, initialize the crypto support.  This involves reading the
+ * crypto capability registers, initializing the keyslot manager, clearing all
+ * keyslots, and enabling 128-bit task descriptors.
+ *
+ * Return: 0 if crypto was initialized or isn't supported; whether
+ *	   MMC_CAP2_CRYPTO remains set indicates which one of those cases it is.
+ *	   Also can return a negative errno value on unexpected error.
+ */
+int cqhci_crypto_init(struct cqhci_host *cq_host)
+{
+	struct mmc_host *mmc = cq_host->mmc;
+	struct device *dev = mmc_dev(mmc);
+	struct blk_keyslot_manager *ksm = &mmc->ksm;
+	unsigned int num_keyslots;
+	unsigned int cap_idx;
+	enum blk_crypto_mode_num blk_mode_num;
+	unsigned int slot;
+	int err = 0;
+
+	if (!(mmc->caps2 & MMC_CAP2_CRYPTO) ||
+	    !(cqhci_readl(cq_host, CQHCI_CAP) & CQHCI_CAP_CS))
+		goto out;
+
+	cq_host->crypto_capabilities.reg_val =
+			cpu_to_le32(cqhci_readl(cq_host, CQHCI_CCAP));
+
+	cq_host->crypto_cfg_register =
+		(u32)cq_host->crypto_capabilities.config_array_ptr * 0x100;
+
+	cq_host->crypto_cap_array =
+		devm_kcalloc(dev, cq_host->crypto_capabilities.num_crypto_cap,
+			     sizeof(cq_host->crypto_cap_array[0]), GFP_KERNEL);
+	if (!cq_host->crypto_cap_array) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * CCAP.CFGC is off by one, so the actual number of crypto
+	 * configurations (a.k.a. keyslots) is CCAP.CFGC + 1.
+	 */
+	num_keyslots = cq_host->crypto_capabilities.config_count + 1;
+
+	err = devm_blk_ksm_init(dev, ksm, num_keyslots);
+	if (err)
+		goto out;
+
+	ksm->ksm_ll_ops = cqhci_ksm_ops;
+	ksm->dev = dev;
+
+	/* Unfortunately, CQHCI crypto only supports 32 DUN bits. */
+	ksm->max_dun_bytes_supported = 4;
+
+	/*
+	 * Cache all the crypto capabilities and advertise the supported crypto
+	 * modes and data unit sizes to the block layer.
+	 */
+	for (cap_idx = 0; cap_idx < cq_host->crypto_capabilities.num_crypto_cap;
+	     cap_idx++) {
+		cq_host->crypto_cap_array[cap_idx].reg_val =
+			cpu_to_le32(cqhci_readl(cq_host,
+						CQHCI_CRYPTOCAP +
+						cap_idx * sizeof(__le32)));
+		blk_mode_num = cqhci_find_blk_crypto_mode(
+					cq_host->crypto_cap_array[cap_idx]);
+		if (blk_mode_num == BLK_ENCRYPTION_MODE_INVALID)
+			continue;
+		ksm->crypto_modes_supported[blk_mode_num] |=
+			cq_host->crypto_cap_array[cap_idx].sdus_mask * 512;
+	}
+
+	/* Clear all the keyslots so that we start in a known state. */
+	for (slot = 0; slot < num_keyslots; slot++)
+		cqhci_crypto_clear_keyslot(cq_host, slot);
+
+	/* CQHCI crypto requires the use of 128-bit task descriptors. */
+	cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
+
+	return 0;
+
+out:
+	mmc->caps2 &= ~MMC_CAP2_CRYPTO;
+	return err;
+}

drivers/mmc/host/cqhci-crypto.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * CQHCI crypto engine (inline encryption) support
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#ifndef LINUX_MMC_CQHCI_CRYPTO_H
+#define LINUX_MMC_CQHCI_CRYPTO_H
+
+#include <linux/mmc/host.h>
+
+#include "cqhci.h"
+
+#ifdef CONFIG_MMC_CRYPTO
+
+int cqhci_crypto_init(struct cqhci_host *host);
+
+/*
+ * Returns the crypto bits that should be set in bits 64-127 of the
+ * task descriptor.
+ */
+static inline u64 cqhci_crypto_prep_task_desc(struct mmc_request *mrq)
+{
+	if (!mrq->crypto_enabled)
+		return 0;
+
+	return CQHCI_CRYPTO_ENABLE_BIT |
+	       CQHCI_CRYPTO_KEYSLOT(mrq->crypto_key_slot) |
+	       mrq->data_unit_num;
+}
+
+#else /* CONFIG_MMC_CRYPTO */
+
+static inline int cqhci_crypto_init(struct cqhci_host *host)
+{
+	return 0;
+}
+
+static inline u64 cqhci_crypto_prep_task_desc(struct mmc_request *mrq)
+{
+	return 0;
+}
+
+#endif /* !CONFIG_MMC_CRYPTO */
+
+#endif /* LINUX_MMC_CQHCI_CRYPTO_H */

drivers/mmc/host/cqhci.h

@@ -22,10 +22,13 @@
 
 /* capabilities */
 #define CQHCI_CAP			0x04
+#define CQHCI_CAP_CS			0x10000000 /* Crypto Support */
+
 /* configuration */
 #define CQHCI_CFG			0x08
 #define CQHCI_DCMD			0x00001000
 #define CQHCI_TASK_DESC_SZ		0x00000100
+#define CQHCI_CRYPTO_GENERAL_ENABLE	0x00000002
 #define CQHCI_ENABLE			0x00000001
 
 /* control */
@@ -39,8 +42,11 @@
 #define CQHCI_IS_TCC			BIT(1)
 #define CQHCI_IS_RED			BIT(2)
 #define CQHCI_IS_TCL			BIT(3)
+#define CQHCI_IS_GCE			BIT(4) /* General Crypto Error */
+#define CQHCI_IS_ICCE			BIT(5) /* Invalid Crypto Config Error */
 
-#define CQHCI_IS_MASK (CQHCI_IS_TCC | CQHCI_IS_RED)
+#define CQHCI_IS_MASK (CQHCI_IS_TCC | CQHCI_IS_RED | \
+		       CQHCI_IS_GCE | CQHCI_IS_ICCE)
 
 /* interrupt status enable */
 #define CQHCI_ISTE			0x14
@@ -78,6 +84,9 @@
 /* task clear */
 #define CQHCI_TCLR			0x38
 
+/* task descriptor processing error */
+#define CQHCI_TDPE			0x3c
+
 /* send status config 1 */
 #define CQHCI_SSC1			0x40
 #define CQHCI_SSC1_CBC_MASK		GENMASK(19, 16)
@@ -107,6 +116,10 @@
 /* command response argument */
 #define CQHCI_CRA			0x5C
 
+/* crypto capabilities */
+#define CQHCI_CCAP			0x100
+#define CQHCI_CRYPTOCAP			0x104
+
 #define CQHCI_INT_ALL			0xF
 #define CQHCI_IC_DEFAULT_ICCTH		31
 #define CQHCI_IC_DEFAULT_ICTOVAL	1
@@ -133,11 +146,70 @@
 #define CQHCI_CMD_TIMING(x)		(((x) & 1) << 22)
 #define CQHCI_RESP_TYPE(x)		(((x) & 0x3) << 23)
 
+/* crypto task descriptor fields (for bits 64-127 of task descriptor) */
+#define CQHCI_CRYPTO_ENABLE_BIT		(1ULL << 47)
+#define CQHCI_CRYPTO_KEYSLOT(x)		((u64)(x) << 32)
+
 /* transfer descriptor fields */
 #define CQHCI_DAT_LENGTH(x)		(((x) & 0xFFFF) << 16)
 #define CQHCI_DAT_ADDR_LO(x)		(((x) & 0xFFFFFFFF) << 32)
 #define CQHCI_DAT_ADDR_HI(x)		(((x) & 0xFFFFFFFF) << 0)
 
+/* CCAP - Crypto Capability 100h */
+union cqhci_crypto_capabilities {
+	__le32 reg_val;
+	struct {
+		u8 num_crypto_cap;
+		u8 config_count;
+		u8 reserved;
+		u8 config_array_ptr;
+	};
+};
+
+enum cqhci_crypto_key_size {
+	CQHCI_CRYPTO_KEY_SIZE_INVALID	= 0,
+	CQHCI_CRYPTO_KEY_SIZE_128	= 1,
+	CQHCI_CRYPTO_KEY_SIZE_192	= 2,
+	CQHCI_CRYPTO_KEY_SIZE_256	= 3,
+	CQHCI_CRYPTO_KEY_SIZE_512	= 4,
+};
+
+enum cqhci_crypto_alg {
+	CQHCI_CRYPTO_ALG_AES_XTS		= 0,
+	CQHCI_CRYPTO_ALG_BITLOCKER_AES_CBC	= 1,
+	CQHCI_CRYPTO_ALG_AES_ECB		= 2,
+	CQHCI_CRYPTO_ALG_ESSIV_AES_CBC		= 3,
+};
+
+/* x-CRYPTOCAP - Crypto Capability X */
+union cqhci_crypto_cap_entry {
+	__le32 reg_val;
+	struct {
+		u8 algorithm_id;
+		u8 sdus_mask; /* Supported data unit size mask */
+		u8 key_size;
+		u8 reserved;
+	};
+};
+
+#define CQHCI_CRYPTO_CONFIGURATION_ENABLE (1 << 7)
+#define CQHCI_CRYPTO_KEY_MAX_SIZE 64
+/* x-CRYPTOCFG - Crypto Configuration X */
+union cqhci_crypto_cfg_entry {
+	__le32 reg_val[32];
+	struct {
+		u8 crypto_key[CQHCI_CRYPTO_KEY_MAX_SIZE];
+		u8 data_unit_size;
+		u8 crypto_cap_idx;
+		u8 reserved_1;
+		u8 config_enable;
+		u8 reserved_multi_host;
+		u8 reserved_2;
+		u8 vsb[2];
+		u8 reserved_3[56];
+	};
+};
+
 struct cqhci_host_ops;
 struct mmc_host;
 struct mmc_request;
@@ -196,6 +268,12 @@ struct cqhci_host {
 	struct completion halt_comp;
 	wait_queue_head_t wait_queue;
 	struct cqhci_slot *slot;
+
+#ifdef CONFIG_MMC_CRYPTO
+	union cqhci_crypto_capabilities crypto_capabilities;
+	union cqhci_crypto_cap_entry *crypto_cap_array;
+	u32 crypto_cfg_register;
+#endif
 };
 
 struct cqhci_host_ops {