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>

1 files changed, 213 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