Re: [PATCH v6 03/10] arm_ffa: introduce Arm FF-A low-level driver

25 Oct 2022

On Tue, Oct 25, 2022 at 11:31:11AM +0200, Jens Wiklander wrote:
...
On Thu, Oct 13, 2022 at 11:38:50AM +0100, Abdellatif El Khlifi wrote:
...
Add the core driver 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.
32-bit version of the ABIs is supported and 64-bit version of FFA_RXTX_MAP
and FFA_MSG_SEND_DIRECT_{REQ, RESP}.
In u-boot FF-A design, FF-A is considered as a discoverable bus.
U-Boot
...
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:

partition_info_get
sync_send_receive
rxtx_unmap

Signed-off-by: Abdellatif El Khlifi abdellatif.elkhlifi@arm.com
Cc: Tom Rini trini@konsulko.com
Cc: Simon Glass sjg@chromium.org
Cc: Ilias Apalodimas ilias.apalodimas@linaro.org
Cc: Jens Wiklander jens.wiklander@linaro.org

Changelog:
v6:

drop use of EFI runtime support (We decided with Linaro to add this later)
drop discovery from initcalls (discovery will be on demand by FF-A users)
set the alignment of the RX/TX buffers to the larger translation granule size
move FF-A RX/TX buffers unmapping at ExitBootServices() to a separate commit
update the documentation and move it to doc/arch/arm64.ffa.rst

v4:

add doc/README.ffa.drv
moving the FF-A driver work to drivers/firmware/arm-ffa
use less #ifdefs in lib/efi_loader/efi_boottime.c and replace
#if defined by #if CONFIG_IS_ENABLED
improving error handling by mapping the FF-A errors to standard errors
and logs
replacing panics with an error log and returning an error code
improving features discovery in FFA_FEATURES by introducing
rxtx_min_pages private data field
add ffa_remove and ffa_unbind functions
improve how the driver behaves when bus discovery is done more than
once

v3:

align the interfaces of the u-boot FF-A driver with those in the linux
FF-A driver
remove the FF-A helper layer
make the u-boot FF-A driver independent from EFI
provide an optional config that enables copying the driver data to EFI
runtime section at ExitBootServices service
use 64-bit version of FFA_RXTX_MAP, FFA_MSG_SEND_DIRECT_{REQ, RESP}

v2:

make FF-A bus discoverable using device_{bind, probe} APIs
remove device tree support

v1:

introduce FF-A bus driver with device tree support

MAINTAINERS                               |    7 +
 doc/arch/arm64.ffa.rst                    |  207 ++++
 doc/arch/index.rst                        |    1 +
 drivers/Kconfig                           |    2 +
 drivers/Makefile                          |    1 +
 drivers/firmware/arm-ffa/Kconfig          |   30 +
 drivers/firmware/arm-ffa/Makefile         |    6 +
 drivers/firmware/arm-ffa/arm-ffa-uclass.c |   16 +
 drivers/firmware/arm-ffa/arm_ffa_prv.h    |  196 +++
 drivers/firmware/arm-ffa/core.c           | 1337 +++++++++++++++++++++
 include/arm_ffa.h                         |   93 ++
 include/dm/uclass-id.h                    |    4 +
 12 files changed, 1900 insertions(+)
 create mode 100644 doc/arch/arm64.ffa.rst
 create mode 100644 drivers/firmware/arm-ffa/Kconfig
 create mode 100644 drivers/firmware/arm-ffa/Makefile
 create mode 100644 drivers/firmware/arm-ffa/arm-ffa-uclass.c
 create mode 100644 drivers/firmware/arm-ffa/arm_ffa_prv.h
 create mode 100644 drivers/firmware/arm-ffa/core.c
 create mode 100644 include/arm_ffa.h

diff --git a/MAINTAINERS b/MAINTAINERS
index a26b36c7c2..496f47a516 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -248,6 +248,13 @@ F:	drivers/net/cortina_ni.h
 F:	drivers/net/phy/ca_phy.c
 F:	configs/cortina_presidio-asic-pnand_defconfig
+ARM FF-A
+M:	Abdellatif El Khlifi abdellatif.elkhlifi@arm.com
+S:	Maintained
+F:	doc/arch/arm64.ffa.rst
+F:	drivers/firmware/arm-ffa/
+F:	include/arm_ffa.h



ARM FREESCALE IMX
 M:	Stefano Babic sbabic@denx.de
 M:	Fabio Estevam festevam@gmail.com
diff --git a/doc/arch/arm64.ffa.rst b/doc/arch/arm64.ffa.rst
new file mode 100644
index 0000000000..e98d2cf2b3
--- /dev/null
+++ b/doc/arch/arm64.ffa.rst
@@ -0,0 +1,207 @@
+.. SPDX-License-Identifier: GPL-2.0+



+Arm FF-A Driver
+===============



+Summary
+-------



+FF-A stands for Firmware Framework for Arm A-profile processors.



+FF-A specifies interfaces that enable a pair of software sandboxes to
+communicate with each other. A sandbox aka partition could
+be a VM in the Normal or Secure world, an application in S-EL0, or a
+Trusted OS in S-EL1.



+This FF-A driver implements the interfaces to communicate with partitions in
+the Secure world aka Secure partitions (SPs).



+The driver specifically focuses on communicating with SPs that isolate portions
+of EFI runtime services that must run in a protected environment which is
+inaccessible by the Host OS or Hypervisor. Examples of such services are
+set/get variables.



+FF-A driver uses the SMC ABIs defined by the FF-A specification to:



+- Discover the presence of SPs of interest
+- Access an SP's service through communication protocols

e.g. EFI MM communication protocol


+FF-A and SMC specifications
+-------------------------------------------



+The current implementation of the driver relies on FF-A specification v1.0
+and uses SMC32 calling convention.



+At this stage we only need the FF-A v1.0 features.



+The driver has been tested with Optee OS which supports SMC32 for most of
s/Optee OS/OP-TEE/
...
+the SMC ABIs.



+For more details please refer to the FF-A v1.0 spec:
+https://documentation-service.arm.com/static/5fb7e8a6ca04df4095c1d65e?token=



+Hypervisors are supported if they are configured to trap SMC calls.



+The FF-A driver uses 64-bit registers as per SMCCCv1.2 specification.



+For more details please refer to the SMC Calling Convention v1.2 spec:
+https://documentation-service.arm.com/static/5f8edaeff86e16515cdbe4c6?token=



+Supported hardware
+--------------------------------



+Aarch64 plaforms



+Configuration
+----------------------



+CONFIG_ARM_FFA_TRANSPORT

Enables the FF-A bus driver. Turn this on if you want to use FF-A
communication.


+CONFIG_SANDBOX_FFA

Enables FF-A Sandbox driver. This emulates the FF-A ABIs handling under
Sandbox and provides functional tests for FF-A.


+FF-A ABIs under the hood
+---------------------------------------



+Invoking an FF-A ABI involves providing to the secure world/hypervisor the
+expected arguments from the ABI.



+The ABI arguments are stored in x0 to x7 registers. Then, an SMC instruction
+is executed.



+At the secure side level or hypervisor the ABI is handled at a higher exception
+level and the arguments are read and processed.



+The response is put back through x0 to x7 registers and control is given back
+to the U-boot FF-A driver (non-secure world).



+The driver reads the response and processes it accordingly.



+This methodology applies to all the FF-A ABIs in the driver.



+FF-A bus discovery in U-boot
U-Boot, please search and replace.
...
+-------------------------------------------



+When CONFIG_ARM_FFA_TRANSPORT is enabled, the FF-A bus is discovered on
+demand by the clients (users).



+Clients can discover the FF-A bus using ffa_bus_discover() API which triggers the
+discovery process.



+ffa_bus_discover() creates, binds and probes the arm_ffa device using
+device_{bind, probe} APIs.



+The discovery process consists in communicating with secure world (or hypervisor)
+and querying specific data.



+The discovery process takes place during the arm_ffa device probing which is
+handled by ffa_probe().



+The FF-A bus discovery is successful and the bus is ready for use when these
+operations succeed:



+- querying the FF-A framework version
+- querying from secure world the U-boot endpoint ID
+- querying from secure world the RX/TX mapping  features
+- mapping the RX/TX buffers
+- querying from secure world all the partitions information



+Discovery failure results in a probing failure and the arm_ffa device is
+destroyed.



+Requirements for clients
+-------------------------------------



+When using the FF-A bus with EFI, clients must:



+- Query SPs in EFI boot time mode using the service UUID.
+- Unmap RX/TX buffers before EFI runtime mode starts.



+The RX/TX buffers are only available at EFI boot time. Querying partitions is
+done at boot time and data is cached for future use.



+RX/TX buffers should be unmapped by the user before EFI runtime mode
+starts. The driver provides a bus operation for that: rxtx_unmap()



+If  RX/TX buffers created by U-boot are not unmapped and by
+consequence becoming available at EFI runtime, secure world will get confused
+about RX/TX buffers ownership (U-boot vs kernel).



+The bus driver layer
+------------------------------



+The driver comes on top of the SMCCC layer and is implemented in
+drivers/firmware/arm-ffa/core.c



+The driver provides the following features:



+- Support for the 32-bit version of the following ABIs:



+FFA_VERSION
+FFA_ID_GET
+FFA_FEATURES
+FFA_PARTITION_INFO_GET
+FFA_RXTX_UNMAP
+FFA_RX_RELEASE
+FFA_RUN
+FFA_ERROR
+FFA_SUCCESS
+FFA_INTERRUPT



+- Support for the 64-bit version of the following ABIs:



+FFA_RXTX_MAP
+FFA_MSG_SEND_DIRECT_REQ
+FFA_MSG_SEND_DIRECT_RESP



+- Processing the received data from the secure world/hypervisor and caching it



+- Hiding from upper layers the FF-A protocol and registers details. Upper

layers focus on exchanged data, the driver takes care of how to transport
that to the secure world/hypervisor using FF-A


+- The driver provides callbacks to be used by clients to access the FF-A bus:



+partition_info_get
+sync_send_receive
+rxtx_unmap



+- FF-A bus discovery makes sure FF-A framework is responsive and compatible

with the driver


+- FF-A bus can be compiled and used without EFI



+Using armffa command
+-----------------------------------



+armffa is a command showcasing how to use the FF-A driver and how to invoke
+its operations.



+This provides a guidance to the client developers on how to call the FF-A bus
+interfaces.



+Usage:



+armffa <sub-command> <arguments>



+sub-commands:


   getpart <partition UUID>



       lists the partition(s) info



   ping <partition ID>



       sends a data pattern to the specified partition



It may be worth mentioning that this is an implementation defined
command.
...


   devlist



       displays the arm_ffa device info




+Contributors
+------------


Abdellatif El Khlifi abdellatif.elkhlifi@arm.com



diff --git a/doc/arch/index.rst b/doc/arch/index.rst
index 792d9182c3..8d1ab0ad4e 100644
--- a/doc/arch/index.rst
+++ b/doc/arch/index.rst
@@ -8,6 +8,7 @@ Architecture-specific doc
arc
arm64


arm64.ffa
m68k
mips
nios2

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 8b6fead351..b06b1ae481 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -6,6 +6,8 @@ source "drivers/core/Kconfig"
source "drivers/adc/Kconfig"
+source "drivers/firmware/arm-ffa/Kconfig"



source "drivers/ata/Kconfig"
source "drivers/axi/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index 9d9f69a3c9..bf8d7b8cfc 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -111,6 +111,7 @@ obj-y += iommu/
 obj-y += smem/
 obj-y += thermal/
 obj-$(CONFIG_TEE) += tee/
+obj-$(CONFIG_ARM_FFA_TRANSPORT) += firmware/arm-ffa/
 obj-y += axi/
 obj-y += ufs/
 obj-$(CONFIG_W1) += w1/
diff --git a/drivers/firmware/arm-ffa/Kconfig b/drivers/firmware/arm-ffa/Kconfig
new file mode 100644
index 0000000000..f1427535f9
--- /dev/null
+++ b/drivers/firmware/arm-ffa/Kconfig
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0



+config ARM_FFA_TRANSPORT

bool "Enable Arm Firmware Framework for Armv8-A driver"
depends on DM && ARM64
select ARM_SMCCC
select LIB_UUID
select DEVRES
help
 The Firmware Framework for Arm A-profile processors (FF-A)


 describes interfaces (ABIs) that standardize communication


 between the Secure World and Normal World leveraging TrustZone


 technology.



 This driver is based on FF-A specification v1.0 and uses SMC32


 calling convention.



 FF-A specification:



 https://developer.arm.com/documentation/den0077/a/?lang=en



 In u-boot FF-A design, FF-A is considered as a discoverable bus.



U-Boot
...

 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.



 For more details about the FF-A driver, please refer to doc/README.ffa.drv



Not doc/arch/arm64.ffa.rst?
...



diff --git a/drivers/firmware/arm-ffa/Makefile b/drivers/firmware/arm-ffa/Makefile
new file mode 100644
index 0000000000..043a8915be
--- /dev/null
+++ b/drivers/firmware/arm-ffa/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# (C) Copyright 2022
+# Abdellatif El Khlifi, Arm Limited, abdellatif.elkhlifi@arm.com.



+obj-y += arm-ffa-uclass.o core.o
diff --git a/drivers/firmware/arm-ffa/arm-ffa-uclass.c b/drivers/firmware/arm-ffa/arm-ffa-uclass.c
new file mode 100644
index 0000000000..7d9695d289
--- /dev/null
+++ b/drivers/firmware/arm-ffa/arm-ffa-uclass.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*


(C) Copyright 2022 ARM Limited



Abdellatif El Khlifi abdellatif.elkhlifi@arm.com


*/


+#include <common.h>
+#include <dm.h>
+#include <asm/global_data.h>



+DECLARE_GLOBAL_DATA_PTR;



+UCLASS_DRIVER(ffa) = {

.name		= "ffa",
.id		= UCLASS_FFA,

+};
diff --git a/drivers/firmware/arm-ffa/arm_ffa_prv.h b/drivers/firmware/arm-ffa/arm_ffa_prv.h
new file mode 100644
index 0000000000..7bc90f7f66
--- /dev/null
+++ b/drivers/firmware/arm-ffa/arm_ffa_prv.h
@@ -0,0 +1,196 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*


(C) Copyright 2022 ARM Limited



Abdellatif El Khlifi abdellatif.elkhlifi@arm.com


*/


+#ifndef __ARM_FFA_PRV_H
+#define __ARM_FFA_PRV_H



+#include <arm_ffa.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/arm-smccc.h>



+/*


This header is private. It is exclusively used by the FF-A driver


*/


+/* FF-A core driver name */
+#define FFA_DRV_NAME "arm_ffa"



+/* 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*/

+};



+/* number of the errors supported by the FF-A specification */
+#define MAX_NUMBER_FFA_ERR 9



+/* 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)



+/* The FF-A SMC function definitions */



+typedef struct arm_smccc_1_2_regs ffa_value_t;
+typedef void (*invoke_ffa_fn_t)(ffa_value_t args, ffa_value_t *res);



+/*


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 */

+};



+/**


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 - structure hosting 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







Data structure hosting 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 {

u64 rxbuf; /* virtual address */
u64 txbuf; /* virtual address */
size_t rxtx_min_pages; /* minimum number of pages in each of the RX/TX buffers */

+};



+/**


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_partitions - descriptors for all secure partitions



@count:	The number of partitions descriptors



@descs	The partitions descriptors table







This data structure contains the partitions descriptors table


*/

+struct ffa_partitions {

u32 count;
struct ffa_partition_desc *descs; /* virtual address */

+};



+/**


struct ffa_prvdata - the driver private data structure







@dev:	The arm_ffa device under u-boot driver model



@ffa_ops:	The driver operations structure



@fwk_version:	FF-A framework version



@id:	u-boot endpoint ID



@partitions:	The partitions descriptors structure



@pair:	The RX/TX buffers pair



@invoke_ffa_fn:	The function executing the FF-A function







The driver data structure hosting all resident data.


*/

+struct ffa_prvdata {

struct udevice *dev;
struct ffa_bus_ops ffa_ops;
u32 fwk_version;
u16 id;
struct ffa_partitions partitions;
struct ffa_rxtxpair pair;
invoke_ffa_fn_t invoke_ffa_fn;

+};



+/**


ffa_device_get - create, bind and probe the arm_ffa device


*/

+int ffa_device_get(void);



+/**


ffa_bus_prvdata_get - bus driver private data getter


*/

+struct ffa_prvdata **ffa_bus_prvdata_get(void);



+#endif
diff --git a/drivers/firmware/arm-ffa/core.c b/drivers/firmware/arm-ffa/core.c
new file mode 100644
index 0000000000..324367d12b
--- /dev/null
+++ b/drivers/firmware/arm-ffa/core.c
@@ -0,0 +1,1337 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*


(C) Copyright 2022 ARM Limited



Abdellatif El Khlifi abdellatif.elkhlifi@arm.com


*/


+#include "arm_ffa_prv.h"
+#include <asm/global_data.h>
+#include <common.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/devres.h>
+#include <dm/root.h>
+#include <linux/errno.h>
+#include <linux/sizes.h>
+#include <log.h>
+#include <malloc.h>
+#include <string.h>
+#include <uuid.h>



+DECLARE_GLOBAL_DATA_PTR;



+/**


The device private data structure containing all the



data read from secure world


*/

+struct ffa_prvdata *ffa_priv_data;



+/* Error mapping declarations */



+int ffa_to_std_errmap[MAX_NUMBER_FFA_ERR] = {

0,
-EOPNOTSUPP,	/* NOT_SUPPORTED */
-EINVAL,	/* INVALID_PARAMETERS */
-ENOMEM,	/* NO_MEMORY */
-EBUSY,		/* BUSY */
-EINTR,		/* INTERRUPTED */
-EACCES,	/* DENIED */
-EAGAIN,	/* RETRY */
-ECANCELED,	/* ABORTED */

+};



+struct ffa_abi_errmap err_msg_map[FFA_ERRMAP_COUNT] = {

[FFA_ID_TO_ERRMAP_ID(FFA_VERSION)] = {
{


	"",



Shouldn't all these empty strings be NULL instead? Given that's that
what you check for in ffa_print_error_log() below.
You could save a few lines by using designated initializers for only the
used elements in err_str for each FF-A function ID.
...

	"NOT_SUPPORTED: A Firmware Framework implementation does not exist",


	"", /* INVALID_PARAMETERS */


	"", /* NO_MEMORY */


	"", /* BUSY */


	"", /* INTERRUPTED */


	"", /* DENIED */


	"", /* RETRY */


	"", /* ABORTED */


},


},
[FFA_ID_TO_ERRMAP_ID(FFA_ID_GET)] = {
{


	"",


	"NOT_SUPPORTED: This function is not implemented at this FF-A instance",


	"", /* INVALID_PARAMETERS */


	"", /* NO_MEMORY */


	"", /* BUSY */


	"", /* INTERRUPTED */


	"", /* DENIED */


	"", /* RETRY */


	"", /* ABORTED */


},


},
[FFA_ID_TO_ERRMAP_ID(FFA_FEATURES)] = {
{


	"",


	"NOT_SUPPORTED: FFA_RXTX_MAP is not implemented at this FF-A instance",


	"", /* INVALID_PARAMETERS */


	"", /* NO_MEMORY */


	"", /* BUSY */


	"", /* INTERRUPTED */


	"", /* DENIED */


	"", /* RETRY */


	"", /* ABORTED */


},


},
[FFA_ID_TO_ERRMAP_ID(FFA_PARTITION_INFO_GET)] = {
{


	"",


	"NOT_SUPPORTED: This function is not implemented at this FF-A instance",


	"INVALID_PARAMETERS: Unrecognized UUID",


	"NO_MEMORY: Results cannot fit in RX buffer of the caller",


	"BUSY: RX buffer of the caller is not free",


	"", /* INTERRUPTED */


	"DENIED: Callee is not in a state to handle this request",


	"", /* RETRY */


	"", /* ABORTED */


},


},
[FFA_ID_TO_ERRMAP_ID(FFA_RXTX_UNMAP)] = {
	{


	"",


	"NOT_SUPPORTED: FFA_RXTX_UNMAP is not implemented at this FF-A instance",


	"INVALID_PARAMETERS: No buffer pair registered on behalf of the caller",


	"", /* NO_MEMORY */


	"", /* BUSY */


	"", /* INTERRUPTED */


	"", /* DENIED */


	"", /* RETRY */


	"", /* ABORTED */


},


},
[FFA_ID_TO_ERRMAP_ID(FFA_RX_RELEASE)] = {
	{


	"",


	"NOT_SUPPORTED: FFA_RX_RELEASE is not implemented at this FF-A instance",


	"", /* INVALID_PARAMETERS */


	"", /* NO_MEMORY */


	"", /* BUSY */


	"", /* INTERRUPTED */


	"DENIED: Caller did not have ownership of the RX buffer",


	"", /* RETRY */


	"", /* ABORTED */


},


},
[FFA_ID_TO_ERRMAP_ID(FFA_RXTX_MAP)] = {
	{


	"",


	"NOT_SUPPORTED: This function is not implemented at this FF-A instance",


	"INVALID_PARAMETERS: Field(s) in input parameters incorrectly encoded",


	"NO_MEMORY: Not enough memory",


	"", /* BUSY */


	"", /* INTERRUPTED */


	"DENIED: Buffer pair already registered",


	"", /* RETRY */


	"", /* ABORTED */


},


},

+};



+/**


ffa_to_std_errno - convert FF-A error code to standard error code



@ffa_errno:	Error code returned by the FF-A ABI







This function maps the given FF-A error code as specified



by the spec to a u-boot standard error code.







Return:







The standard error code on success. . Otherwise, failure


*/

+int ffa_to_std_errno(int ffa_errno)
+{

int err_idx = -ffa_errno;

/* map the FF-A error code to the standard u-boot error code */
if (err_idx > 0 && err_idx < MAX_NUMBER_FFA_ERR)
return ffa_to_std_errmap[err_idx];


return -EINVAL;

+}



+/**


ffa_print_error_log - print the error log corresponding to the selected FF-A ABI



@ffa_id:	FF-A ABI ID



@ffa_errno:	Error code returned by the FF-A ABI







This function maps the FF-A error code to the error log relevant to the



selected FF-A ABI. Then the error log is printed.







Return:







0 on success. . Otherwise, failure


*/

+int ffa_print_error_log(u32 ffa_id, int ffa_errno)
+{

int err_idx = -ffa_errno, abi_idx = 0;

/* map the FF-A error code to the corresponding error log */

if (err_idx <= 0 || err_idx >= MAX_NUMBER_FFA_ERR)
return -EINVAL;



if (ffa_id < FFA_FIRST_ID || ffa_id > FFA_LAST_ID)
return -EINVAL;



abi_idx = FFA_ID_TO_ERRMAP_ID(ffa_id);
if (abi_idx < 0 || abi_idx >= FFA_ERRMAP_COUNT)
return -EINVAL;



if (!err_msg_map[abi_idx].err_str || !err_msg_map[abi_idx].err_str[err_idx])

err_str can't be NULL since it's an array in the struct ffa_abi_errmap.
...

return -EINVAL;



ffa_err("%s", err_msg_map[abi_idx].err_str[err_idx]);

return 0;

+}



+/*


Driver core functions


*/


+/**


ffa_remove_device - removes the arm_ffa device



@dev:	the device to be removed







This function makes sure the arm_ffa device is removed



No need to free the kmalloced data when the device is destroyed.



It's automatically done by devm management by



device_remove() -> device_free() -> devres_release_probe().







Return:







0 on success. Otherwise, failure


*/

+int ffa_remove_device(struct udevice *dev)
+{

int ret;

if (!dev) {
ffa_err("no udevice found");


return -ENODEV;


}

ret = device_remove(dev, DM_REMOVE_NORMAL);
if (ret) {
ffa_err("unable to remove. err:%d\n", ret);


return ret;


}

ffa_info("device removed and freed");

ret = device_unbind(dev);
if (ret) {
ffa_err("unable to unbind. err:%d\n", ret);


return ret;


}

ffa_info("device unbound");

return 0;

+}



+/**


ffa_device_get - create, bind and probe the arm_ffa device







This function makes sure the arm_ffa device is



created, bound to this driver, probed and ready to use.



Arm FF-A transport is implemented through a single u-boot



device managing the FF-A bus (arm_ffa).







Return:







0 on success. Otherwise, failure


*/

+int ffa_device_get(void)
+{

int ret;
struct udevice *dev = NULL;

ret = device_bind(dm_root(),
	  DM_DRIVER_GET(arm_ffa),


	  FFA_DRV_NAME,


	  NULL,


	  ofnode_null(),


	  &dev);



There's no need for separate lines for each argument, please fold up a bit.
...

if (ret)
return ret;



/* The FF-A bus discovery succeeds when probing is successful */
ret = device_probe(dev);
if (ret) {
ffa_err("arm_ffa device probing failed");


ffa_remove_device(dev);


return ret;


}

return 0;

+}



+/**


ffa_get_version - FFA_VERSION handler function







This function implements FFA_VERSION FF-A function



to get from the secure world the FF-A framework version







Return:







0 on success. Otherwise, failure


*/

+static int ffa_get_version(void)
+{

u16 major, minor;
ffa_value_t res = {0};
int ffa_errno;

ffa_priv_data->invoke_ffa_fn((ffa_value_t){
	.a0 = FFA_SMC_32(FFA_VERSION),


	.a1 = FFA_VERSION_1_0



It's generally preferred to have comma after the last initializer too.
It could also be worth comparing with the style (alignment and folding
up where possible) of the corresponding driver in the Linux kernel which
I find a bit easier to read. However, checkpatch seems happy enough so I
guess it's not a big deal.
I asked earlier why you're not supporting the latest version, 1.1, but
you never answered that.
Thanks for all the new comments. I'll address these in v7.
Regarding you older comments, I already replied here [1]. Please have a look.
[1]: https://lore.kernel.org/all/20221014102849.GA14576@e121910.cambridge.arm.com...
...
...

	}, &res);



ffa_errno = res.a0;
if (ffa_errno < 0) {
ffa_print_error_log(FFA_VERSION, ffa_errno);


return ffa_to_std_errno(ffa_errno);


}

major = GET_FFA_MAJOR_VERSION(res.a0);
minor = GET_FFA_MINOR_VERSION(res.a0);

ffa_info("FF-A driver %d.%d\nFF-A framework %d.%d",
 FFA_MAJOR_VERSION, FFA_MINOR_VERSION, major, minor);



if ((major == FFA_MAJOR_VERSION && minor >= FFA_MINOR_VERSION)) {
ffa_info("Versions are compatible ");



ffa_priv_data->fwk_version = res.a0;



return 0;


}

ffa_err("versions are incompatible\nExpected: %d.%d , Found: %d.%d\n",
FFA_MAJOR_VERSION, FFA_MINOR_VERSION, major, minor);



return -EPROTONOSUPPORT;

+}



+/**


ffa_get_endpoint_id - FFA_ID_GET handler function







This function implements FFA_ID_GET FF-A function



to get from the secure world u-boot endpoint ID







Return:







0 on success. Otherwise, failure


*/

+static int ffa_get_endpoint_id(void)
+{

ffa_value_t res = {0};
int ffa_errno;

ffa_priv_data->invoke_ffa_fn((ffa_value_t){
	.a0 = FFA_SMC_32(FFA_ID_GET)


	}, &res);



if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
ffa_priv_data->id = GET_SELF_ENDPOINT_ID((u32)res.a2);


ffa_info("endpoint ID is %u", ffa_priv_data->id);



return 0;


}

ffa_errno = res.a2;

ffa_print_error_log(FFA_ID_GET, ffa_errno);

return ffa_to_std_errno(ffa_errno);

+}



+/**


ffa_set_rxtx_buffers_pages_cnt - sets the minimum number of pages in each of the RX/TX buffers



@prop_field: properties field obtained from FFA_FEATURES ABI







This function sets the minimum number of pages



in each of the RX/TX buffers in the private data structure







Return:







buf_4k_pages points to the returned number of pages



0 on success. Otherwise, failure


*/

+static int ffa_set_rxtx_buffers_pages_cnt(u32 prop_field)
+{

if (!ffa_priv_data)
return -EINVAL;



switch (prop_field) {
case RXTX_4K:
ffa_priv_data->pair.rxtx_min_pages = 1;


break;


case RXTX_16K:
ffa_priv_data->pair.rxtx_min_pages = 4;


break;


case RXTX_64K:
ffa_priv_data->pair.rxtx_min_pages = 16;


break;


default:
ffa_err("RX/TX buffer size not supported");


return -EINVAL;


}

return 0;

+}



+/**


ffa_get_rxtx_map_features - FFA_FEATURES handler function with FFA_RXTX_MAP argument







This function implements FFA_FEATURES FF-A function



to retrieve the FFA_RXTX_MAP features







Return:







0 on success. Otherwise, failure


*/

+static int ffa_get_rxtx_map_features(void)
+{

ffa_value_t res = {0};
int ffa_errno;

ffa_priv_data->invoke_ffa_fn((ffa_value_t){
	.a0 = FFA_SMC_32(FFA_FEATURES),


	.a1 = FFA_SMC_64(FFA_RXTX_MAP)


	}, &res);



if (res.a0 == FFA_SMC_32(FFA_SUCCESS))
return ffa_set_rxtx_buffers_pages_cnt((u32)res.a2);



The cast isn't needed.
...


ffa_errno = res.a2;
ffa_print_error_log(FFA_FEATURES, ffa_errno);

return ffa_to_std_errno(ffa_errno);

+}



+/**


ffa_free_rxtx_buffers - frees the RX/TX buffers







This  function  frees the RX/TX buffers






*/

+static void ffa_free_rxtx_buffers(void)
+{

ffa_info("Freeing RX/TX buffers");

if (ffa_priv_data->pair.rxbuf) {
free((void *)ffa_priv_data->pair.rxbuf);


ffa_priv_data->pair.rxbuf = 0;


}

if (ffa_priv_data->pair.txbuf) {
free((void *)ffa_priv_data->pair.txbuf);


ffa_priv_data->pair.txbuf = 0;


}

+}



+/**


ffa_alloc_rxtx_buffers - allocates the RX/TX buffers







This function is used by ffa_map_rxtx_buffers to allocate



the RX/TX buffers before mapping them. The allocated memory is physically



contiguous since memalign ends up calling malloc which allocates



contiguous memory in u-boot.







Return:







0 on success. Otherwise, failure


*/

+static int ffa_alloc_rxtx_buffers(void)
+{

u64 bytes;

ffa_info("Using %lu 4KB page(s) for RX/TX buffers size",
 ffa_priv_data->pair.rxtx_min_pages);



bytes = ffa_priv_data->pair.rxtx_min_pages * SZ_4K;

/*
* The alignment of the RX and TX buffers must be equal


* to the larger translation granule size


*/



ffa_priv_data->pair.rxbuf = (u64)memalign(bytes, bytes);
if (!ffa_priv_data->pair.rxbuf) {
ffa_err("failure to allocate RX buffer");


return -ENOBUFS;


}

ffa_info("RX buffer at virtual address 0x%llx", ffa_priv_data->pair.rxbuf);

ffa_priv_data->pair.txbuf = (u64)memalign(bytes, bytes);
if (!ffa_priv_data->pair.txbuf) {
free((void *)ffa_priv_data->pair.rxbuf);


ffa_priv_data->pair.rxbuf = 0;


ffa_err("failure to allocate the TX buffer");


return -ENOBUFS;


}

ffa_info("TX buffer at virtual address 0x%llx", ffa_priv_data->pair.txbuf);

/*
* make sure the buffers are cleared before use


*/


memset((void *)ffa_priv_data->pair.rxbuf, 0, bytes);
memset((void *)ffa_priv_data->pair.txbuf, 0, bytes);

return 0;

+}



+/**


ffa_map_rxtx_buffers - FFA_RXTX_MAP handler function







This function implements FFA_RXTX_MAP FF-A function



to map the RX/TX buffers







Return:







0 on success. Otherwise, failure


*/

+static int ffa_map_rxtx_buffers(void)
+{

int ret;
ffa_value_t res = {0};
int ffa_errno;

ret = ffa_alloc_rxtx_buffers();
if (ret)
return ret;



/*
* we need to pass the physical addresses of the RX/TX buffers


* in u-boot physical/virtual mapping is 1:1


*no need to convert from virtual to physical



A space is missing after the '*'.
...

*/



ffa_priv_data->invoke_ffa_fn((ffa_value_t){
	.a0 = FFA_SMC_64(FFA_RXTX_MAP),


	.a1 = ffa_priv_data->pair.txbuf,


	.a2 = ffa_priv_data->pair.rxbuf,


	.a3 = ffa_priv_data->pair.rxtx_min_pages,


	}, &res);



if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
ffa_info("RX/TX buffers mapped");


return 0;


}

ffa_errno = res.a2;
ffa_print_error_log(FFA_RXTX_MAP, ffa_errno);

ffa_free_rxtx_buffers();

return ffa_to_std_errno(ffa_errno);

+}



+/**


ffa_unmap_rxtx_buffers - FFA_RXTX_UNMAP handler function







This function implements FFA_RXTX_UNMAP FF-A function



to unmap the RX/TX buffers







Return:







0 on success. Otherwise, failure


*/

+static int ffa_unmap_rxtx_buffers(void)
+{

ffa_value_t res = {0};
int ffa_errno;

ffa_priv_data->invoke_ffa_fn((ffa_value_t){
	.a0 = FFA_SMC_32(FFA_RXTX_UNMAP),


	.a1 = PREP_SELF_ENDPOINT_ID(ffa_priv_data->id)


	}, &res);



if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
ffa_free_rxtx_buffers();


return 0;


}

ffa_errno = res.a2;
ffa_print_error_log(FFA_RXTX_UNMAP, ffa_errno);

return ffa_to_std_errno(ffa_errno);

+}



+/**


ffa_release_rx_buffer - FFA_RX_RELEASE handler function







This function invokes FFA_RX_RELEASE FF-A function



to release the ownership of the RX buffer







Return:







0 on success. Otherwise, failure


*/

+static int ffa_release_rx_buffer(void)
+{

ffa_value_t res = {0};
int ffa_errno;

ffa_priv_data->invoke_ffa_fn((ffa_value_t){
	.a0 = FFA_SMC_32(FFA_RX_RELEASE)


	}, &res);



if (res.a0 == FFA_SMC_32(FFA_SUCCESS))
return 0;



ffa_errno = res.a2;
ffa_print_error_log(FFA_RX_RELEASE, ffa_errno);

return ffa_to_std_errno(ffa_errno);

+}



+/**


ffa_uuid_are_identical - checks whether two given UUIDs are identical



@uuid1: first UUID



@uuid2: second UUID







This function is used by ffa_read_partitions_info to search



for a UUID in the partitions descriptors table







Return:







1 when UUIDs match. Otherwise, 0


*/

+int ffa_uuid_are_identical(const struct ffa_partition_uuid *uuid1,

	   const struct ffa_partition_uuid *uuid2)



Would it make sense to use the bool type instead?
...
+{

if (!uuid1 || !uuid2)
return 0;



return !memcmp(uuid1, uuid2, sizeof(struct ffa_partition_uuid));

+}



+/**


ffa_read_partitions_info - reads the data queried by FFA_PARTITION_INFO_GET



					and saves it in the private structure





@count: The number of partitions queried



@part_uuid: Pointer to the partition(s) UUID







This function reads the partitions information



returned by the FFA_PARTITION_INFO_GET and saves it in the private



data structure.







Return:







The private data structure is updated with the partition(s) information



0 is returned on success. Otherwise, failure


*/

+static int ffa_read_partitions_info(u32 count, struct ffa_partition_uuid *part_uuid)
+{

if (!count) {
ffa_err("no partition detected");


return -ENODATA;


}

ffa_info("Reading partitions data from the RX buffer");

if (!part_uuid) {
/*


 * querying information of all partitions


 */


u64 buf_bytes;


u64 data_bytes;


u32 desc_idx;


struct ffa_partition_info *parts_info;



data_bytes = count * sizeof(struct ffa_partition_desc);



buf_bytes = ffa_priv_data->pair.rxtx_min_pages * SZ_4K;



if (data_bytes > buf_bytes) {


	ffa_err("partitions data size exceeds the RX buffer size:");


	ffa_err("    sizes in bytes: data %llu , RX buffer %llu ",


		data_bytes,


		buf_bytes);



	return -ENOMEM;


}



ffa_priv_data->partitions.descs = devm_kmalloc(ffa_priv_data->dev, data_bytes,


					       __GFP_ZERO);


if (!ffa_priv_data->partitions.descs) {


	ffa_err("cannot  allocate partitions data buffer");


	return -ENOMEM;


}



parts_info = (struct ffa_partition_info *)ffa_priv_data->pair.rxbuf;



for (desc_idx = 0 ; desc_idx < count ; desc_idx++) {


	ffa_priv_data->partitions.descs[desc_idx].info =


		parts_info[desc_idx];



	ffa_info("Partition ID %x : info cached",


		 ffa_priv_data->partitions.descs[desc_idx].info.id);


}



ffa_priv_data->partitions.count = count;



ffa_info("%d partition(s) found and cached", count);



} else {
u32 rx_desc_idx, cached_desc_idx;


struct ffa_partition_info *parts_info;


u8 desc_found;



parts_info = (struct ffa_partition_info *)ffa_priv_data->pair.rxbuf;



/*


 * search for the SP IDs read from the RX buffer


 * in the already cached SPs.


 * Update the UUID when ID found.


 */


for (rx_desc_idx = 0; rx_desc_idx < count ; rx_desc_idx++) {


	desc_found = 0;



	/*


	 * search the current ID in the cached partitions


	 */


	for (cached_desc_idx = 0;


	     cached_desc_idx < ffa_priv_data->partitions.count;


	     cached_desc_idx++) {


		/*


		 * save the UUID


		 */


		if (ffa_priv_data->partitions.descs[cached_desc_idx].info.id ==


		    parts_info[rx_desc_idx].id) {


			ffa_priv_data->partitions.descs[cached_desc_idx].sp_uuid =


				*part_uuid;



			desc_found = 1;


			break;


		}


	}



	if (!desc_found)


		return -ENODATA;


}


}

return  0;

+}



+/**


ffa_query_partitions_info - invokes FFA_PARTITION_INFO_GET and saves partitions data







@part_uuid: Pointer to the partition(s) UUID



@pcount: Pointer to the number of partitions variable filled when querying







This function executes the FFA_PARTITION_INFO_GET



to query the partitions data. Then, it calls ffa_read_partitions_info



to save the data in the private data structure.







After reading the data the RX buffer is released using ffa_release_rx_buffer







Return:







When part_uuid is NULL, all partitions data are retrieved from secure world



When part_uuid is non NULL, data for partitions matching the given UUID are



retrieved and the number of partitions is returned



0 is returned on success. Otherwise, failure


*/

+static int ffa_query_partitions_info(struct ffa_partition_uuid *part_uuid,

		     u32 *pcount)



+{

struct ffa_partition_uuid query_uuid = {0};
ffa_value_t res = {0};
int ffa_errno;

/*
* If a UUID is specified. Information for one or more


* partitions in the system is queried. Otherwise, information


* for all installed partitions is queried


*/



if (part_uuid) {
if (!pcount)


	return -EINVAL;



query_uuid = *part_uuid;


} else if (pcount) {
return -EINVAL;


}

ffa_priv_data->invoke_ffa_fn((ffa_value_t){
	.a0 = FFA_SMC_32(FFA_PARTITION_INFO_GET),


	.a1 = query_uuid.a1,


	.a2 = query_uuid.a2,


	.a3 = query_uuid.a3,


	.a4 = query_uuid.a4


	}, &res);



if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
int ret;



/*


 * res.a2 contains the count of partition information descriptors


 * populated in the RX buffer


 */


if (res.a2) {


	ret = ffa_read_partitions_info((u32)res.a2, part_uuid);


	if (ret) {


		ffa_err("failed to read partition(s) data , error (%d)", ret);


		ffa_release_rx_buffer();


		return -EINVAL;


	}


}



/*


 * return the SP count (when querying using a UUID)


 */


if (pcount)


	*pcount = (u32)res.a2;



/*


 * After calling FFA_PARTITION_INFO_GET the buffer ownership


 * is assigned to the consumer (u-boot). So, we need to give


 * the ownership back to the SPM or hypervisor


 */


ret = ffa_release_rx_buffer();



return ret;


}

ffa_errno = res.a2;
ffa_print_error_log(FFA_PARTITION_INFO_GET, ffa_errno);

return ffa_to_std_errno(ffa_errno);

+}



+/**


ffa_get_partitions_info - FFA_PARTITION_INFO_GET handler function







The passed arguments:



Mode 1: When getting from the driver the number of



secure partitions:



@uuid_str: pointer to the UUID string



@parts_size: pointer to the variable that contains the number of partitions



	 The variable will be set by the driver





@buffer: NULL







Mode 2: When requesting the driver to return the



partitions information:



@uuid_str: pointer to the UUID string



@parts_size: pointer to the size of the SPs information buffer in bytes



@buffer: pointer to SPs information buffer



(allocated by the client).





The buffer will be filled by the driver









This function queries the secure partition data from



the private data structure. If not found, it invokes 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 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().







When invoked through a client request, ffa_get_partitions_info should be



called twice. First call is to get from the driver the number of secure



partitions (SPs) associated to a particular UUID.



Then, the caller (client) allocates the buffer to host the SPs data and



issues a 2nd call. Then, the driver fills the SPs data in the pre-allocated



buffer.







To achieve the mechanism described above, ffa_get_partitions_info uses the



following functions:



ffa_read_partitions_info





ffa_query_partitions_info









Return:







@parts_size: When pointing to the number of partitions variable, the number is



set by the driver.



When pointing to the partitions information buffer size, the buffer will be



filled by the driver.







On success 0 is returned. Otherwise, failure


*/

+static int ffa_get_partitions_info(const char *uuid_str,

		   u32 *parts_size, struct ffa_partition_info *buffer)



+{

/*
* fill_data:


* 0: return the SP count


* 1: fill SP data and return it to the caller


* -1: undefined mode


*/


int fill_data = -1;
u32 desc_idx, client_desc_idx;
struct ffa_partition_uuid part_uuid = {0};
u32 client_desc_max_cnt;
u32 parts_found = 0;

if (!ffa_priv_data->partitions.count || !ffa_priv_data->partitions.descs) {
ffa_err("no partition installed");


return -EINVAL;


}

if (!uuid_str) {
ffa_err("no UUID provided");


return -EINVAL;


}

if (!parts_size) {
ffa_err("no size/count provided");


return -EINVAL;


}

if (be_uuid_str_to_le_bin(uuid_str, (unsigned char *)&part_uuid)) {
ffa_err("invalid UUID");


return -EINVAL;


}

if (!buffer) {
/* Mode 1: getting the number of secure partitions */



fill_data = 0;



ffa_info("Preparing for checking partitions count");



} else if ((*parts_size >= sizeof(struct ffa_partition_info)) &&
   !(*parts_size % sizeof(struct ffa_partition_info))) {


/* Mode 2: retrieving the partitions information */



fill_data = 1;



client_desc_idx = 0;



/*


 * number of empty descriptors preallocated by the caller


 */


client_desc_max_cnt = *parts_size / sizeof(struct ffa_partition_info);



ffa_info("Preparing for filling partitions info");



} else {
ffa_err("invalid function arguments provided");


return -EINVAL;


}

ffa_info("Searching partitions using the provided UUID");

/*
* search in the cached partitions


*/


for (desc_idx = 0;
    desc_idx < ffa_priv_data->partitions.count;


    desc_idx++) {


if (ffa_uuid_are_identical(&ffa_priv_data->partitions.descs[desc_idx].sp_uuid,


			   &part_uuid)) {


	ffa_info("Partition ID %x matches the provided UUID",


		 ffa_priv_data->partitions.descs[desc_idx].info.id);



	parts_found++;



	if (fill_data) {


		/*


		 * trying to fill the partition info in the input buffer


		 */



		if (client_desc_idx < client_desc_max_cnt) {


			buffer[client_desc_idx++] =


				ffa_priv_data->partitions.descs[desc_idx].info;


			continue;


		}



		ffa_err("failed to fill the current descriptor client buffer full");


		return -ENOBUFS;


	}


}


}

if (!parts_found) {
int ret;



ffa_info("No partition found. Querying framework ...");



ret = ffa_query_partitions_info(&part_uuid, &parts_found);



if (ret == 0) {


	if (!fill_data) {


		*parts_size = parts_found;



		ffa_info("Number of partition(s) found matching the UUID: %d",


			 parts_found);


	} else {


		/*


		 * If SPs data detected, they are already in the private data


		 * structure, retry searching SP data again to return them


		 *  to the caller


		 */


		if (parts_found)


			ret = ffa_get_partitions_info(uuid_str, parts_size, buffer);


		else


			ret = -ENODATA;


	}


}



return ret;


}

/* partition(s) found */
if (!fill_data)
*parts_size = parts_found;



return 0;

+}



+/**


ffa_cache_partitions_info - Queries and saves all secure partitions data







This function invokes FFA_PARTITION_INFO_GET FF-A



function to query from secure world all partitions information.







The FFA_PARTITION_INFO_GET call is issued with nil UUID as an argument.



All installed partitions information are returned. We cache them in the



resident private data structure and we keep the UUID field empty



(in FF-A 1.0 UUID is not provided by the partition descriptor)







This function is called at the device probing level.



ffa_cache_partitions_info uses ffa_query_partitions_info to get the data







Return:







0 on success. Otherwise, failure


*/

+static int ffa_cache_partitions_info(void)
+{

return ffa_query_partitions_info(NULL, NULL);

+}



+/**


ffa_msg_send_direct_req - FFA_MSG_SEND_DIRECT_{REQ,RESP} handler function



@dst_part_id: destination partition ID



@msg: pointer to the message data preallocated by the client (in/out)







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


*/

+static int ffa_msg_send_direct_req(u16 dst_part_id, struct ffa_send_direct_data *msg)
+{

ffa_value_t res = {0};
int ffa_errno;

if (!ffa_priv_data || !ffa_priv_data->invoke_ffa_fn)
return -EINVAL;



/* No partition installed */
if (!ffa_priv_data->partitions.count || !ffa_priv_data->partitions.descs)
return -ENODEV;



ffa_priv_data->invoke_ffa_fn((ffa_value_t){
	.a0 = FFA_SMC_64(FFA_MSG_SEND_DIRECT_REQ),


	.a1 = PREP_SELF_ENDPOINT_ID(ffa_priv_data->id) |


		PREP_PART_ENDPOINT_ID(dst_part_id),


	.a2 = 0,


	.a3 = msg->data0,


	.a4 = msg->data1,


	.a5 = msg->data2,


	.a6 = msg->data3,


	.a7 = msg->data4,


	}, &res);



while (res.a0 == FFA_SMC_32(FFA_INTERRUPT))
ffa_priv_data->invoke_ffa_fn((ffa_value_t){


	.a0 = FFA_SMC_32(FFA_RUN),


	.a1 = res.a1


	}, &res);



if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
/* Message sent with no response */


return 0;


}

if (res.a0 == FFA_SMC_64(FFA_MSG_SEND_DIRECT_RESP)) {
/*


 * Message sent with response


 * extract the return data


 */


msg->data0 = res.a3;


msg->data1 = res.a4;


msg->data2 = res.a5;


msg->data3 = res.a6;


msg->data4 = res.a7;



return 0;


}

ffa_errno = res.a2;
return ffa_to_std_errno(ffa_errno);

+}



+/**


__arm_ffa_fn_smc - 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 assembly function







Return: void


*/

+void __arm_ffa_fn_smc(ffa_value_t args, ffa_value_t *res)
+{

arm_smccc_1_2_smc(&args, res);

+}



+/**


ffa_set_smc_conduit - Set the SMC conduit







This function selects the SMC conduit by setting the driver invoke function



to SMC assembly function







Return:







0 on success. Otherwise, failure


*/

+static int ffa_set_smc_conduit(void)
+{

ffa_priv_data->invoke_ffa_fn = __arm_ffa_fn_smc;

if (!ffa_priv_data->invoke_ffa_fn) {
ffa_err("failure to set the invoke function");


return -EINVAL;


}

ffa_info("Conduit is SMC");

return 0;

+}



+/**


ffa_set_bus_ops - Set the bus driver operations







Setting the driver callbacks.






*/

+static void ffa_set_bus_ops(void)
+{

ffa_priv_data->ffa_ops.partition_info_get = ffa_get_partitions_info;
ffa_priv_data->ffa_ops.sync_send_receive = ffa_msg_send_direct_req;
ffa_priv_data->ffa_ops.rxtx_unmap = ffa_unmap_rxtx_buffers;

+}



+/**


ffa_alloc_prvdata - allocate the driver main data structure and sets the device



@dev:	the arm_ffa device







This function creates the main data structure embedding all the driver data.







Return:







0 on success. Otherwise, failure


*/

+static int ffa_alloc_prvdata(struct udevice *dev)
+{

if (!dev) {
ffa_err("no udevice found");


return -ENODEV;


}

/* The device is registered with the DM. Let's create the driver main data structure*/

ffa_priv_data = devm_kmalloc(dev, sizeof(struct ffa_prvdata), __GFP_ZERO);
if (!ffa_priv_data) {
ffa_err("can not allocate the driver main data structure");


return -ENOMEM;


}

ffa_priv_data->dev = dev;

return 0;

+}



+/**


ffa_probe - The driver probe function



@dev:	the arm_ffa device







Probing is done at boot time and triggered by the uclass device discovery.



At probe level the following actions are done:




setting the conduit






querying the FF-A framework version






querying from secure world the u-boot endpoint ID






querying from secure world the supported features of FFA_RXTX_MAP






mapping the RX/TX buffers






querying from secure world all the partitions information









All data queried from secure world is saved in the resident private data structure.







The probe will fail if either FF-A framework is not detected or the



FF-A requests are not behaving correctly. This ensures that the



driver is not installed and its operations are not exported to the clients.







Return:







0 on success. Otherwise, failure


*/

+static int ffa_probe(struct udevice *dev)
+{

int ret;

ret = ffa_alloc_prvdata(dev);
if (ret != 0)
return ret;



ffa_set_bus_ops();

ret = ffa_set_smc_conduit();
if (ret != 0)
return ret;



ret = ffa_get_version();
if (ret != 0)
return ret;



ret = ffa_get_endpoint_id();
if (ret != 0)
return ret;



ret = ffa_get_rxtx_map_features();
if (ret != 0)
return ret;



ret = ffa_map_rxtx_buffers();
if (ret != 0)
return ret;



ret = ffa_cache_partitions_info();

I've asked this before, but never got an answer:
Why are we saving all the found partitions in a cache? It seems that
FFA_PARTITION_INFO_GET could be called each time when needed instead
without any noticeable overhead. Or is the result cached for some other
reason?
I already replied here [1]. Please have a look.
[1]: https://lore.kernel.org/all/20221014102849.GA14576@e121910.cambridge.arm.com...
...
Cheers,
Jens
...

if (ret != 0) {
ffa_free_rxtx_buffers();


return ret;


}

return 0;

+}



+/**


ffa_remove - The driver remove function



@dev:	the arm_ffa device



When the device is about to be removed ,  unmap the RX/TX buffers and free the memory



Return:







0 on success.


*/

+static int ffa_remove(struct udevice *dev)
+{

ffa_info("removing the device");

ffa_unmap_rxtx_buffers();

if (ffa_priv_data->pair.rxbuf || ffa_priv_data->pair.txbuf)
ffa_free_rxtx_buffers();



return 0;

+}



+/**


ffa_unbind - The driver unbind function



@dev:	the arm_ffa device



After the device is removed and memory freed the device is unbound



Return:







0 on success.


*/

+static int ffa_unbind(struct udevice *dev)
+{

ffa_info("unbinding the device , private data already released");

ffa_priv_data = NULL;

return 0;

+}



+/**


ffa_bus_ops_get - bus driver operations getter







Return:



This function returns a pointer to the driver operations structure


*/

+const struct ffa_bus_ops *ffa_bus_ops_get(void)
+{

return &ffa_priv_data->ffa_ops;

+}



+/**


ffa_bus_prvdata_get - bus driver private data getter







Return:



This function returns a pointer to the main private data structure


*/

+struct ffa_prvdata **ffa_bus_prvdata_get(void)
+{

return &ffa_priv_data;

+}



+/**


ffa_bus_discover - discover FF-A bus and probe the arm_ffa device







This function makes sure the FF-A bus is discoverable.



When probing succeeds FF-A discovery is done. The arm_ffa device is ready to use.







When the bus was already discovered successfully the discovery will not run again.







Arm FF-A transport is implemented through arm_ffa u-boot device managing the FF-A



communication.



All FF-A clients should use the arm_ffa device to use the FF-A transport.







Return:







0 on success. Otherwise, failure


*/

+int ffa_bus_discover(void)
+{

int ret = 0;

if (!ffa_priv_data)
ret = ffa_device_get();



return ret;

+}



+/**


Declaring the arm_ffa driver under UCLASS_FFA


*/


+U_BOOT_DRIVER(arm_ffa) = {

.name		= FFA_DRV_NAME,
.id		= UCLASS_FFA,
.probe		= ffa_probe,
.remove		= ffa_remove,
.unbind		= ffa_unbind,

+};
diff --git a/include/arm_ffa.h b/include/arm_ffa.h
new file mode 100644
index 0000000000..d146e7b328
--- /dev/null
+++ b/include/arm_ffa.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*


(C) Copyright 2022 ARM Limited



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


*/


+/*


Macros for displaying logs


*/


+#define ffa_info(fmt, ...)  pr_info("[FFA] " fmt "\n", ##__VA_ARGS__)
+#define ffa_err(fmt, ...)  pr_err("[FFA] " fmt "\n", ##__VA_ARGS__)



+/*


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  __packed 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_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 __packed ffa_send_direct_data {

unsigned long data0; /* w3/x3 */
unsigned long data1; /* w4/x4 */
unsigned long data2; /* w5/x5 */
unsigned long data3; /* w6/x6 */
unsigned long data4; /* w7/x7 */

+};



+/**


struct ffa_bus_ops - The driver operations structure



@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)(const char *uuid_str,
		  u32 *parts_size, struct ffa_partition_info *buffer);


int (*sync_send_receive)(u16 dst_part_id, struct ffa_send_direct_data *msg);
int (*rxtx_unmap)(void);

+};



+/**


The device driver and the Uclass driver public functions


*/


+/**


ffa_bus_ops_get - driver operations getter


*/

+const struct ffa_bus_ops *ffa_bus_ops_get(void);



+/**


ffa_bus_discover - discover FF-A bus and probes the arm_ffa device


*/

+int ffa_bus_discover(void);



+#endif
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index a432e43871..5dd698b7a9 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -4,6 +4,9 @@


(C) Copyright 2012
Pavel Herrmann morpheus.ibis@gmail.com







(C) Copyright 2022 ARM Limited



Abdellatif El Khlifi abdellatif.elkhlifi@arm.com

*/

#ifndef _DM_UCLASS_ID_H
@@ -55,6 +58,7 @@ enum uclass_id {
   UCLASS_EFI_MEDIA,	/* Devices provided by UEFI firmware */
   UCLASS_ETH,		/* Ethernet device */
   UCLASS_ETH_PHY,		/* Ethernet PHY device */

UCLASS_FFA,		/* Arm Firmware Framework for Armv8-A */
UCLASS_FIRMWARE,	/* Firmware */
UCLASS_FUZZING_ENGINE,	/* Fuzzing engine */
UCLASS_FS_FIRMWARE_LOADER,		/* Generic loader */

-- 
2.17.1

    