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path: root/drivers/mmc/host/cqhci-crypto.c
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Diffstat (limited to 'drivers/mmc/host/cqhci-crypto.c')
-rw-r--r--drivers/mmc/host/cqhci-crypto.c243
1 files changed, 243 insertions, 0 deletions
diff --git a/drivers/mmc/host/cqhci-crypto.c b/drivers/mmc/host/cqhci-crypto.c
new file mode 100644
index 0000000000..d5f4b6972f
--- /dev/null
+++ b/drivers/mmc/host/cqhci-crypto.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CQHCI crypto engine (inline encryption) support
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <linux/blk-crypto.h>
+#include <linux/blk-crypto-profile.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_crypto_profile(struct blk_crypto_profile *profile)
+{
+ struct mmc_host *mmc =
+ container_of(profile, struct mmc_host, crypto_profile);
+
+ 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_crypto_profile *profile,
+ const struct blk_crypto_key *key,
+ unsigned int slot)
+
+{
+ struct cqhci_host *cq_host = cqhci_host_from_crypto_profile(profile);
+ 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_crypto_profile *profile,
+ const struct blk_crypto_key *key,
+ unsigned int slot)
+{
+ struct cqhci_host *cq_host = cqhci_host_from_crypto_profile(profile);
+
+ 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_crypto_ll_ops cqhci_crypto_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 blk_crypto_profile, 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_crypto_profile *profile = &mmc->crypto_profile;
+ 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_crypto_profile_init(dev, profile, num_keyslots);
+ if (err)
+ goto out;
+
+ profile->ll_ops = cqhci_crypto_ops;
+ profile->dev = dev;
+
+ /* Unfortunately, CQHCI crypto only supports 32 DUN bits. */
+ profile->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;
+ profile->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;
+}