[PATCH 1/8] mmc: add basic support for inline encryption

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

In preparation for adding CQHCI crypto engine (inline encryption)
support, add the code required to make mmc_core and mmc_block aware of
inline encryption.  Specifically:

- Add a capability flag MMC_CAP2_CRYPTO to struct mmc_host.  Drivers
  will set this if the host and driver support inline encryption.

- Embed a blk_keyslot_manager in struct mmc_host.  Drivers will
  initialize this if the host and driver support inline encryption.
  mmc_block registers this keyslot manager with the request_queue of any
  MMC card attached to the host.  mmc_core destroys this keyslot manager
  when freeing the mmc_host.

- Make mmc_block copy the crypto keyslot and crypto data unit number
  from struct request to struct mmc_request, so that drivers will have
  access to them.

- If the MMC host is reset, reprogram all the keyslots to ensure that
  the software state stays in sync with the hardware state.

Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 drivers/mmc/core/Kconfig  |  8 ++++++
 drivers/mmc/core/Makefile |  1 +
 drivers/mmc/core/block.c  |  3 +++
 drivers/mmc/core/core.c   |  3 +++
 drivers/mmc/core/crypto.c | 54 +++++++++++++++++++++++++++++++++++++++
 drivers/mmc/core/crypto.h | 46 +++++++++++++++++++++++++++++++++
 drivers/mmc/core/host.c   |  2 ++
 drivers/mmc/core/queue.c  |  3 +++
 include/linux/mmc/core.h  |  6 +++++
 include/linux/mmc/host.h  |  7 +++++
 10 files changed, 133 insertions(+)
 create mode 100644 drivers/mmc/core/crypto.c
 create mode 100644 drivers/mmc/core/crypto.h

diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
index c12fe13e4b147..ae8b69aee6190 100644
--- a/drivers/mmc/core/Kconfig
+++ b/drivers/mmc/core/Kconfig
@@ -81,3 +81,11 @@ config MMC_TEST
 	  This driver is only of interest to those developing or
 	  testing a host driver. Most people should say N here.
 
+config MMC_CRYPTO
+	bool "MMC Crypto Engine Support"
+	depends on BLK_INLINE_ENCRYPTION
+	help
+	  Enable Crypto Engine Support in MMC.
+	  Enabling this makes it possible for the kernel to use the crypto
+	  capabilities of the MMC device (if present) to perform crypto
+	  operations on data being transferred to/from the device.
diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
index 95ffe008ebdf8..6a907736cd7a5 100644
--- a/drivers/mmc/core/Makefile
+++ b/drivers/mmc/core/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_MMC_BLOCK)		+= mmc_block.o
 mmc_block-objs			:= block.o queue.o
 obj-$(CONFIG_MMC_TEST)		+= mmc_test.o
 obj-$(CONFIG_SDIO_UART)		+= sdio_uart.o
+mmc_core-$(CONFIG_MMC_CRYPTO)	+= crypto.o
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 8d3df0be0355c..eaf2f10743260 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -51,6 +51,7 @@
 #include "block.h"
 #include "core.h"
 #include "card.h"
+#include "crypto.h"
 #include "host.h"
 #include "bus.h"
 #include "mmc_ops.h"
@@ -1247,6 +1248,8 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
 
 	memset(brq, 0, sizeof(struct mmc_blk_request));
 
+	mmc_crypto_prepare_req(mqrq);
+
 	brq->mrq.data = &brq->data;
 	brq->mrq.tag = req->tag;
 
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index d42037f0f10d7..275de270232b3 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -37,6 +37,7 @@
 
 #include "core.h"
 #include "card.h"
+#include "crypto.h"
 #include "bus.h"
 #include "host.h"
 #include "sdio_bus.h"
@@ -992,6 +993,8 @@ void mmc_set_initial_state(struct mmc_host *host)
 		host->ops->hs400_enhanced_strobe(host, &host->ios);
 
 	mmc_set_ios(host);
+
+	mmc_crypto_set_initial_state(host);
 }
 
 /**
diff --git a/drivers/mmc/core/crypto.c b/drivers/mmc/core/crypto.c
new file mode 100644
index 0000000000000..4f47eb4740db0
--- /dev/null
+++ b/drivers/mmc/core/crypto.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MMC crypto engine (inline encryption) support
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <linux/blk-crypto.h>
+#include <linux/mmc/host.h>
+
+#include "core.h"
+#include "crypto.h"
+#include "queue.h"
+
+void mmc_crypto_set_initial_state(struct mmc_host *host)
+{
+	/* Reset might clear all keys, so reprogram all the keys. */
+	if (host->caps2 & MMC_CAP2_CRYPTO)
+		blk_ksm_reprogram_all_keys(&host->ksm);
+}
+
+void mmc_crypto_free_host(struct mmc_host *host)
+{
+	if (host->caps2 & MMC_CAP2_CRYPTO)
+		blk_ksm_destroy(&host->ksm);
+}
+
+void mmc_crypto_setup_queue(struct request_queue *q, struct mmc_host *host)
+{
+	if (host->caps2 & MMC_CAP2_CRYPTO)
+		blk_ksm_register(&host->ksm, q);
+}
+EXPORT_SYMBOL_GPL(mmc_crypto_setup_queue);
+
+void mmc_crypto_prepare_req(struct mmc_queue_req *mqrq)
+{
+	struct request *req = mmc_queue_req_to_req(mqrq);
+	struct mmc_request *mrq = &mqrq->brq.mrq;
+
+	if (!req->crypt_keyslot)
+		return;
+
+	mrq->crypto_enabled = true;
+	mrq->crypto_key_slot = blk_ksm_get_slot_idx(req->crypt_keyslot);
+
+	/*
+	 * For now we assume that all MMC drivers set max_dun_bytes_supported=4,
+	 * which is the limit for CQHCI crypto.  So all DUNs should be 32-bit.
+	 */
+	WARN_ON_ONCE(req->crypt_ctx->bc_dun[0] > U32_MAX);
+
+	mrq->data_unit_num = req->crypt_ctx->bc_dun[0];
+}
+EXPORT_SYMBOL_GPL(mmc_crypto_prepare_req);
diff --git a/drivers/mmc/core/crypto.h b/drivers/mmc/core/crypto.h
new file mode 100644
index 0000000000000..4780639b832f4
--- /dev/null
+++ b/drivers/mmc/core/crypto.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * MMC crypto engine (inline encryption) support
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#ifndef _MMC_CORE_CRYPTO_H
+#define _MMC_CORE_CRYPTO_H
+
+struct mmc_host;
+struct mmc_queue_req;
+struct request_queue;
+
+#ifdef CONFIG_MMC_CRYPTO
+
+void mmc_crypto_set_initial_state(struct mmc_host *host);
+
+void mmc_crypto_free_host(struct mmc_host *host);
+
+void mmc_crypto_setup_queue(struct request_queue *q, struct mmc_host *host);
+
+void mmc_crypto_prepare_req(struct mmc_queue_req *mqrq);
+
+#else /* CONFIG_MMC_CRYPTO */
+
+static inline void mmc_crypto_set_initial_state(struct mmc_host *host)
+{
+}
+
+static inline void mmc_crypto_free_host(struct mmc_host *host)
+{
+}
+
+static inline void mmc_crypto_setup_queue(struct request_queue *q,
+					  struct mmc_host *host)
+{
+}
+
+static inline void mmc_crypto_prepare_req(struct mmc_queue_req *mqrq)
+{
+}
+
+#endif /* !CONFIG_MMC_CRYPTO */
+
+#endif /* _MMC_CORE_CRYPTO_H */
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 96b2ca1f1b06d..d962b9ca0e37a 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -25,6 +25,7 @@
 #include <linux/mmc/slot-gpio.h>
 
 #include "core.h"
+#include "crypto.h"
 #include "host.h"
 #include "slot-gpio.h"
 #include "pwrseq.h"
@@ -532,6 +533,7 @@ EXPORT_SYMBOL(mmc_remove_host);
  */
 void mmc_free_host(struct mmc_host *host)
 {
+	mmc_crypto_free_host(host);
 	mmc_pwrseq_free(host);
 	put_device(&host->class_dev);
 }
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index de7cb0369c308..d96db852bb91a 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -19,6 +19,7 @@
 #include "block.h"
 #include "core.h"
 #include "card.h"
+#include "crypto.h"
 #include "host.h"
 
 #define MMC_DMA_MAP_MERGE_SEGMENTS	512
@@ -405,6 +406,8 @@ static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
 	mutex_init(&mq->complete_lock);
 
 	init_waitqueue_head(&mq->wait);
+
+	mmc_crypto_setup_queue(mq->queue, host);
 }
 
 static inline bool mmc_merge_capable(struct mmc_host *host)
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 29aa507116261..ab19245e99451 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -162,6 +162,12 @@ struct mmc_request {
 	bool			cap_cmd_during_tfr;
 
 	int			tag;
+
+#ifdef CONFIG_MMC_CRYPTO
+	bool			crypto_enabled;
+	int			crypto_key_slot;
+	u32			data_unit_num;
+#endif
 };
 
 struct mmc_card;
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index c079b932330f2..550460bf1b37c 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -15,6 +15,7 @@
 #include <linux/mmc/card.h>
 #include <linux/mmc/pm.h>
 #include <linux/dma-direction.h>
+#include <linux/keyslot-manager.h>
 
 struct mmc_ios {
 	unsigned int	clock;			/* clock rate */
@@ -377,6 +378,7 @@ struct mmc_host {
 #define MMC_CAP2_CQE_DCMD	(1 << 24)	/* CQE can issue a direct command */
 #define MMC_CAP2_AVOID_3_3V	(1 << 25)	/* Host must negotiate down from 3.3V */
 #define MMC_CAP2_MERGE_CAPABLE	(1 << 26)	/* Host can merge a segment over the segment size */
+#define MMC_CAP2_CRYPTO		(1 << 27)	/* Host supports inline encryption */
 
 	int			fixed_drv_type;	/* fixed driver type for non-removable media */
 
@@ -471,6 +473,11 @@ struct mmc_host {
 	bool			cqe_enabled;
 	bool			cqe_on;
 
+	/* Inline encryption support */
+#ifdef CONFIG_MMC_CRYPTO
+	struct blk_keyslot_manager ksm;
+#endif
+
 	/* Host Software Queue support */
 	bool			hsq_enabled;
 
-- 
2.29.2