1 files changed, 242 insertions, 0 deletions
diff --git a/drivers/mmc/host/cqhci-crypto.c b/drivers/mmc/host/cqhci-crypto.c
new file mode 100644
index 000000000000..6419cfbb4ab7
--- /dev/null
+++ b/drivers/mmc/host/cqhci-crypto.c
@@ -0,0 +1,242 @@
+// 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;
+
+	/*
+	 * 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;
+}