drivers/mmc/host/cqhci-crypto.c - linux - Git at Google

 // 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 int 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;

 	if (cq_host->ops->program_key)
 		return cq_host->ops->program_key(cq_host, cfg, slot);

 	/* 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]));
 	return 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 = {};
 	int err;

 	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);
 	}

 	err = cqhci_crypto_program_key(cq_host, &cfg, slot);

 	memzero_explicit(&cfg, sizeof(cfg));
 	return err;
 }

 static int 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 = {};

 	return 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);

 	return cqhci_crypto_clear_keyslot(cq_host, slot);
 }

 /*
  * 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;

 	ksm->features = BLK_CRYPTO_FEATURE_STANDARD_KEYS;

 	/*
 	 * 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;
 }
	// 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 int 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;

	if (cq_host->ops->program_key)
	return cq_host->ops->program_key(cq_host, cfg, slot);

	/* 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]));
	return 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 = {};
	int err;

	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);
	}

	err = cqhci_crypto_program_key(cq_host, &cfg, slot);

	memzero_explicit(&cfg, sizeof(cfg));
	return err;
	}

	static int 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 = {};

	return 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);

	return cqhci_crypto_clear_keyslot(cq_host, slot);
	}

	/*
	* 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;

	ksm->features = BLK_CRYPTO_FEATURE_STANDARD_KEYS;

	/*
	* 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;
	}