arm_ffa: introduce Arm FF-A support

Add Arm FF-A support implementing Arm Firmware Framework for Armv8-A v1.0

The Firmware Framework for Arm A-profile processors (FF-A v1.0) [1]
describes interfaces (ABIs) that standardize communication
between the Secure World and Normal World leveraging TrustZone
technology.

This driver uses 64-bit registers as per SMCCCv1.2 spec and comes
on top of the SMCCC layer. The driver provides the FF-A ABIs needed for
querying the FF-A framework from the secure world.

The driver uses SMC32 calling convention which means using the first
32-bit data of the Xn registers.

All supported ABIs come with their 32-bit version except FFA_RXTX_MAP
which has 64-bit version supported.

Both 32-bit and 64-bit direct messaging are supported which allows both
32-bit and 64-bit clients to use the FF-A bus.

FF-A is a discoverable bus and similar to architecture features.
FF-A bus is discovered using ARM_SMCCC_FEATURES mechanism performed
by the PSCI driver.

Clients are able to probe then use the FF-A bus by calling the DM class
searching APIs (e.g: uclass_first_device).

The Secure World is considered as one entity to communicate with
using the FF-A bus. FF-A communication is handled by one device and
one instance (the bus). This FF-A driver takes care of all the
interactions between Normal world and Secure World.

The driver exports its operations to be used by upper layers.

Exported operations:

- ffa_partition_info_get
- ffa_sync_send_receive
- ffa_rxtx_unmap

Generic FF-A methods are implemented in the Uclass (arm-ffa-uclass.c).
Arm specific methods are implemented in the Arm driver (arm-ffa.c).

For more details please refer to the driver documentation [2].

[1]: https://developer.arm.com/documentation/den0077/latest/
[2]: doc/arch/arm64.ffa.rst

Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>

3 files changed, 465 insertions, 0 deletions

diff --git a/include/arm_ffa.h b/include/arm_ffa.h
new file mode 100644
index 0000000000..db9b1be995
--- /dev/null
+++ b/include/arm_ffa.h
@@ -0,0 +1,213 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office@arm.com>
+ *
+ * Authors:
+ *   Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+ */
+
+#ifndef __ARM_FFA_H
+#define __ARM_FFA_H
+
+#include <linux/printk.h>
+
+/*
+ * This header is public. It can be used by clients to access
+ * data structures and definitions they need
+ */
+
+/*
+ * struct ffa_partition_info - Partition information descriptor
+ * @id:	Partition ID
+ * @exec_ctxt:	Execution context count
+ * @properties:	Partition properties
+ *
+ * Data structure containing information about partitions instantiated in the system
+ * This structure is filled with the data queried by FFA_PARTITION_INFO_GET
+ */
+struct ffa_partition_info {
+	u16 id;
+	u16 exec_ctxt;
+/* partition supports receipt of direct requests */
+#define FFA_PARTITION_DIRECT_RECV	BIT(0)
+/* partition can send direct requests. */
+#define FFA_PARTITION_DIRECT_SEND	BIT(1)
+/* partition can send and receive indirect messages. */
+#define FFA_PARTITION_INDIRECT_MSG	BIT(2)
+	u32 properties;
+};
+
+/*
+ * struct ffa_partition_uuid - 16 bytes UUID transmitted by FFA_PARTITION_INFO_GET
+ * @a1-4:	32-bit words access to the UUID data
+ *
+ */
+struct ffa_partition_uuid {
+	u32 a1; /* w1 */
+	u32 a2; /* w2 */
+	u32 a3; /* w3 */
+	u32 a4; /* w4 */
+};
+
+/**
+ * struct ffa_partition_desc - the secure partition descriptor
+ * @info:	partition information
+ * @sp_uuid:	the secure partition UUID
+ *
+ * Each partition has its descriptor containing the partitions information and the UUID
+ */
+struct ffa_partition_desc {
+	struct ffa_partition_info info;
+	struct ffa_partition_uuid sp_uuid;
+};
+
+/*
+ * struct ffa_send_direct_data - Data structure hosting the data
+ *                                       used by FFA_MSG_SEND_DIRECT_{REQ,RESP}
+ * @data0-4:	Data read/written from/to x3-x7 registers
+ *
+ * Data structure containing the data to be sent by FFA_MSG_SEND_DIRECT_REQ
+ * or read from FFA_MSG_SEND_DIRECT_RESP
+ */
+
+/* For use with FFA_MSG_SEND_DIRECT_{REQ,RESP} which pass data via registers */
+struct ffa_send_direct_data {
+	ulong data0; /* w3/x3 */
+	ulong data1; /* w4/x4 */
+	ulong data2; /* w5/x5 */
+	ulong data3; /* w6/x6 */
+	ulong data4; /* w7/x7 */
+};
+
+struct udevice;
+
+/**
+ * struct ffa_bus_ops - Operations for FF-A
+ * @partition_info_get:	callback for the FFA_PARTITION_INFO_GET
+ * @sync_send_receive:	callback for the FFA_MSG_SEND_DIRECT_REQ
+ * @rxtx_unmap:	callback for the FFA_RXTX_UNMAP
+ *
+ * The data structure providing all the operations supported by the driver.
+ * This structure is EFI runtime resident.
+ */
+struct ffa_bus_ops {
+	int (*partition_info_get)(struct udevice *dev, const char *uuid_str,
+				  u32 *sp_count, struct ffa_partition_desc **sp_descs);
+	int (*sync_send_receive)(struct udevice *dev, u16 dst_part_id,
+				 struct ffa_send_direct_data *msg,
+				 bool is_smc64);
+	int (*rxtx_unmap)(struct udevice *dev);
+};
+
+#define ffa_get_ops(dev)        ((struct ffa_bus_ops *)(dev)->driver->ops)
+
+/**
+ * ffa_rxtx_unmap() - FFA_RXTX_UNMAP driver operation
+ * Please see ffa_unmap_rxtx_buffers_hdlr() description for more details.
+ */
+int ffa_rxtx_unmap(struct udevice *dev);
+
+/**
+ * ffa_unmap_rxtx_buffers_hdlr() - FFA_RXTX_UNMAP handler function
+ * @dev: The arm_ffa bus device
+ *
+ * This function implements FFA_RXTX_UNMAP FF-A function
+ * to unmap the RX/TX buffers
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int ffa_unmap_rxtx_buffers_hdlr(struct udevice *dev);
+
+/**
+ * ffa_sync_send_receive() - FFA_MSG_SEND_DIRECT_{REQ,RESP} driver operation
+ * Please see ffa_msg_send_direct_req_hdlr() description for more details.
+ */
+int ffa_sync_send_receive(struct udevice *dev, u16 dst_part_id,
+			  struct ffa_send_direct_data *msg, bool is_smc64);
+
+/**
+ * ffa_msg_send_direct_req_hdlr() - FFA_MSG_SEND_DIRECT_{REQ,RESP} handler function
+ * @dev: The arm_ffa bus device
+ * @dst_part_id: destination partition ID
+ * @msg: pointer to the message data preallocated by the client (in/out)
+ * @is_smc64: select 64-bit or 32-bit FF-A ABI
+ *
+ * This function implements FFA_MSG_SEND_DIRECT_{REQ,RESP}
+ * FF-A functions.
+ *
+ * FFA_MSG_SEND_DIRECT_REQ is used to send the data to the secure partition.
+ * The response from the secure partition is handled by reading the
+ * FFA_MSG_SEND_DIRECT_RESP arguments.
+ *
+ * The maximum size of the data that can be exchanged is 40 bytes which is
+ * sizeof(struct ffa_send_direct_data) as defined by the FF-A specification 1.0
+ * in the section relevant to FFA_MSG_SEND_DIRECT_{REQ,RESP}
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int ffa_msg_send_direct_req_hdlr(struct udevice *dev, u16 dst_part_id,
+				 struct ffa_send_direct_data *msg, bool is_smc64);
+
+/**
+ * ffa_partition_info_get() - FFA_PARTITION_INFO_GET driver operation
+ * Please see ffa_get_partitions_info_hdlr() description for more details.
+ */
+int ffa_partition_info_get(struct udevice *dev, const char *uuid_str,
+			   u32 *sp_count, struct ffa_partition_desc **sp_descs);
+
+/**
+ * ffa_get_partitions_info_hdlr() - FFA_PARTITION_INFO_GET handler function
+ *	@uuid_str: pointer to the UUID string
+ *	@sp_count: address of the variable containing the number of partitions matching the UUID
+ *			 The variable is set by the driver
+ *	@sp_descs: address of the descriptors of the partitions matching the UUID
+ *			 The address is set by the driver
+ *
+ * Return the number of partitions and their descriptors matching the UUID
+ *
+ * Query the secure partition data from uc_priv.
+ * If not found, invoke FFA_PARTITION_INFO_GET
+ * FF-A function to query the partition information from secure world.
+ *
+ * A client of the FF-A driver should know the UUID of the service it wants to
+ * access. It should use the UUID to request the FF-A driver to provide the
+ * partition(s) information of the service. The FF-A driver uses
+ * PARTITION_INFO_GET to obtain this information. This is implemented through
+ * ffa_get_partitions_info_hdlr() function.
+ * A new FFA_PARTITION_INFO_GET call is issued (first one performed through
+ * ffa_cache_partitions_info) allowing to retrieve the partition(s) information.
+ * They are not saved (already done). We only update the UUID in the cached area.
+ * This assumes that partitions data does not change in the secure world.
+ * Otherwise u-boot will have an outdated partition data. The benefit of caching
+ * the information in the FF-A driver is to accommodate discovery after
+ * ExitBootServices().
+ *
+ * Return:
+ *
+ * @sp_count: the number of partitions
+ * @sp_descs: address of the partitions descriptors
+ *
+ * On success 0 is returned. Otherwise, failure
+ */
+int ffa_get_partitions_info_hdlr(struct udevice *dev, const char *uuid_str,
+				 u32 *sp_count, struct ffa_partition_desc **sp_descs);
+
+struct ffa_priv;
+
+/**
+ * ffa_set_smc_conduit() - Set the SMC conduit
+ * @dev: The FF-A bus device
+ *
+ * Selects the SMC conduit by setting the FF-A ABI invoke function.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int ffa_set_smc_conduit(struct udevice *dev);
+
+#endif
diff --git a/include/arm_ffa_priv.h b/include/arm_ffa_priv.h
new file mode 100644
index 0000000000..d564c33c64
--- /dev/null
+++ b/include/arm_ffa_priv.h
@@ -0,0 +1,246 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office@arm.com>
+ *
+ * Authors:
+ *   Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+ */
+
+#ifndef __ARM_FFA_PRV_H
+#define __ARM_FFA_PRV_H
+
+#include <mapmem.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+
+/* This header is exclusively used by the FF-A Uclass and FF-A driver(s) */
+
+/* Arm FF-A driver name */
+#define FFA_DRV_NAME "arm_ffa"
+
+/* The FF-A SMC function definitions */
+
+#if CONFIG_IS_ENABLED(SANDBOX)
+
+/* Providing Arm SMCCC declarations to sandbox */
+
+/**
+ * struct sandbox_smccc_1_2_regs - emulated SMC call arguments or results
+ * @a0-a17 argument values from registers 0 to 17
+ */
+struct sandbox_smccc_1_2_regs {
+	ulong a0;
+	ulong a1;
+	ulong a2;
+	ulong a3;
+	ulong a4;
+	ulong a5;
+	ulong a6;
+	ulong a7;
+	ulong a8;
+	ulong a9;
+	ulong a10;
+	ulong a11;
+	ulong a12;
+	ulong a13;
+	ulong a14;
+	ulong a15;
+	ulong a16;
+	ulong a17;
+};
+
+typedef struct sandbox_smccc_1_2_regs ffa_value_t;
+
+#define ARM_SMCCC_FAST_CALL		1UL
+#define ARM_SMCCC_OWNER_STANDARD	4
+#define ARM_SMCCC_SMC_32		0
+#define ARM_SMCCC_SMC_64		1
+#define ARM_SMCCC_TYPE_SHIFT		31
+#define ARM_SMCCC_CALL_CONV_SHIFT	30
+#define ARM_SMCCC_OWNER_MASK		0x3f
+#define ARM_SMCCC_OWNER_SHIFT		24
+#define ARM_SMCCC_FUNC_MASK		0xffff
+
+#define ARM_SMCCC_CALL_VAL(type, calling_convention, owner, func_num) \
+	(((type) << ARM_SMCCC_TYPE_SHIFT) | \
+	((calling_convention) << ARM_SMCCC_CALL_CONV_SHIFT) | \
+	(((owner) & ARM_SMCCC_OWNER_MASK) << ARM_SMCCC_OWNER_SHIFT) | \
+	((func_num) & ARM_SMCCC_FUNC_MASK))
+
+#else
+/* CONFIG_ARM64 */
+#include <linux/arm-smccc.h>
+typedef struct arm_smccc_1_2_regs ffa_value_t;
+#endif
+
+/* Defining the function pointer type for the function executing the FF-A ABIs */
+typedef void (*invoke_ffa_fn_t)(ffa_value_t args, ffa_value_t *res);
+
+/* FF-A driver version definitions */
+
+#define MAJOR_VERSION_MASK		GENMASK(30, 16)
+#define MINOR_VERSION_MASK		GENMASK(15, 0)
+#define GET_FFA_MAJOR_VERSION(x)		\
+				((u16)(FIELD_GET(MAJOR_VERSION_MASK, (x))))
+#define GET_FFA_MINOR_VERSION(x)		\
+				((u16)(FIELD_GET(MINOR_VERSION_MASK, (x))))
+#define PACK_VERSION_INFO(major, minor)			\
+	(FIELD_PREP(MAJOR_VERSION_MASK, (major)) |	\
+	 FIELD_PREP(MINOR_VERSION_MASK, (minor)))
+
+#define FFA_MAJOR_VERSION		(1)
+#define FFA_MINOR_VERSION		(0)
+#define FFA_VERSION_1_0		\
+			PACK_VERSION_INFO(FFA_MAJOR_VERSION, FFA_MINOR_VERSION)
+
+/* Endpoint ID mask (u-boot endpoint ID) */
+
+#define GET_SELF_ENDPOINT_ID_MASK		GENMASK(15, 0)
+#define GET_SELF_ENDPOINT_ID(x)		\
+			((u16)(FIELD_GET(GET_SELF_ENDPOINT_ID_MASK, (x))))
+
+#define PREP_SELF_ENDPOINT_ID_MASK		GENMASK(31, 16)
+#define PREP_SELF_ENDPOINT_ID(x)		\
+			(FIELD_PREP(PREP_SELF_ENDPOINT_ID_MASK, (x)))
+
+/* Partition endpoint ID mask  (partition with which u-boot communicates with) */
+
+#define PREP_PART_ENDPOINT_ID_MASK		GENMASK(15, 0)
+#define PREP_PART_ENDPOINT_ID(x)		\
+			(FIELD_PREP(PREP_PART_ENDPOINT_ID_MASK, (x)))
+
+/* Definitions of the Arm FF-A interfaces supported by the Arm FF-A driver */
+
+#define FFA_SMC(calling_convention, func_num)				\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, (calling_convention),	\
+			   ARM_SMCCC_OWNER_STANDARD, (func_num))
+
+#define FFA_SMC_32(func_num)				FFA_SMC(ARM_SMCCC_SMC_32, (func_num))
+#define FFA_SMC_64(func_num)				FFA_SMC(ARM_SMCCC_SMC_64, (func_num))
+
+enum ffa_abis {
+	FFA_ERROR                 = 0x60,
+	FFA_SUCCESS               = 0x61,
+	FFA_INTERRUPT             = 0x62,
+	FFA_VERSION               = 0x63,
+	FFA_FEATURES              = 0x64,
+	FFA_RX_RELEASE            = 0x65,
+	FFA_RXTX_MAP              = 0x66,
+	FFA_RXTX_UNMAP            = 0x67,
+	FFA_PARTITION_INFO_GET    = 0x68,
+	FFA_ID_GET                = 0x69,
+	FFA_RUN                   = 0x6d,
+	FFA_MSG_SEND_DIRECT_REQ   = 0x6f,
+	FFA_MSG_SEND_DIRECT_RESP  = 0x70,
+
+	/* To be updated when adding new FFA IDs */
+	FFA_FIRST_ID              = FFA_ERROR, /* Lowest number ID */
+	FFA_LAST_ID               = FFA_MSG_SEND_DIRECT_RESP, /* Highest number ID */
+};
+
+enum ffa_abi_errcode {
+	NOT_SUPPORTED = 1,
+	INVALID_PARAMETERS,
+	NO_MEMORY,
+	BUSY,
+	INTERRUPTED,
+	DENIED,
+	RETRY,
+	ABORTED,
+	MAX_NUMBER_FFA_ERR
+};
+
+extern int ffa_to_std_errmap[MAX_NUMBER_FFA_ERR];
+
+/* Container structure and helper macros to map between an FF-A error and relevant error log */
+struct ffa_abi_errmap {
+	char *err_str[MAX_NUMBER_FFA_ERR];
+};
+
+#define FFA_ERRMAP_COUNT (FFA_LAST_ID - FFA_FIRST_ID + 1)
+#define FFA_ID_TO_ERRMAP_ID(ffa_id) ((ffa_id) - FFA_FIRST_ID)
+
+/**
+ * enum ffa_rxtx_buf_sizes - minimum sizes supported
+ * for the RX/TX buffers
+ */
+enum ffa_rxtx_buf_sizes {
+	RXTX_4K,
+	RXTX_64K,
+	RXTX_16K
+};
+
+/**
+ * struct ffa_rxtxpair - Hosts the RX/TX buffers virtual addresses
+ * @rxbuf:	virtual address of the RX buffer
+ * @txbuf:	virtual address of the TX buffer
+ * @rxtx_min_pages:	RX/TX buffers minimum size in pages
+ *
+ * Hosts the virtual addresses of the mapped RX/TX buffers
+ * These addresses are used by the FF-A functions that use the RX/TX buffers
+ */
+struct ffa_rxtxpair {
+	void *rxbuf; /* Virtual address returned by memalign */
+	void *txbuf; /* Virtual address returned by memalign */
+	size_t rxtx_min_pages; /* Minimum number of pages in each of the RX/TX buffers */
+};
+
+struct ffa_partition_desc;
+
+/**
+ * struct ffa_partitions - descriptors for all secure partitions
+ * @count:	The number of partitions descriptors
+ * @descs	The partitions descriptors table
+ *
+ * Contains the partitions descriptors table
+ */
+struct ffa_partitions {
+	u32 count;
+	struct ffa_partition_desc *descs; /* Virtual address */
+};
+
+/**
+ * struct ffa_priv - the driver private data structure
+ *
+ * @fwk_version:	FF-A framework version
+ * @emul:	FF-A sandbox emulator
+ * @id:	u-boot endpoint ID
+ * @partitions:	The partitions descriptors structure
+ * @pair:	The RX/TX buffers pair
+ *
+ * The device private data structure containing all the
+ * data read from secure world.
+ */
+struct ffa_priv {
+	u32 fwk_version;
+	struct udevice *emul;
+	u16 id;
+	struct ffa_partitions partitions;
+	struct ffa_rxtxpair pair;
+};
+
+/**
+ * ffa_get_version_hdlr() - FFA_VERSION handler function
+ * @dev: The FF-A bus device
+ *
+ * Implement FFA_VERSION FF-A function
+ * to get from the secure world the FF-A framework version
+ * FFA_VERSION is used to discover the FF-A framework.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int ffa_get_version_hdlr(struct udevice *dev);
+
+/**
+ * invoke_ffa_fn() - SMC wrapper
+ * @args: FF-A ABI arguments to be copied to Xn registers
+ * @res: FF-A ABI return data to be copied from Xn registers
+ *
+ * Calls low level SMC implementation.
+ * This function should be implemented by the user driver.
+ */
+void invoke_ffa_fn(ffa_value_t args, ffa_value_t *res);
+
+#endif
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 307ad6931c..3c6af2e3d2 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -4,6 +4,11 @@
  *
  * (C) Copyright 2012
  * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office@arm.com>
+ *
+ * Authors:
+ *   Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
  */
 
 #ifndef _DM_UCLASS_ID_H
@@ -57,6 +62,7 @@ enum uclass_id {
 	UCLASS_ETH,		/* Ethernet device */
 	UCLASS_ETH_PHY,		/* Ethernet PHY device */
 	UCLASS_EXTCON,		/* External Connector Class */
+	UCLASS_FFA,		/* Arm Firmware Framework for Armv8-A */
 	UCLASS_FIRMWARE,	/* Firmware */
 	UCLASS_FPGA,		/* FPGA device */
 	UCLASS_FUZZING_ENGINE,	/* Fuzzing engine */