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// 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;
}
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