Merge branch '2023-08-08-introuce-Arm-FF-A-support'

To quote the author:
Adding support for Arm FF-A v1.0 (Arm Firmware Framework for Armv8-A) [A].

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

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.

   => dm tree

    Class     Index  Probed  Driver                Name
   -----------------------------------------------------------
   ...
    firmware      0  [ + ]   psci                      |-- psci
    ffa                   0  [   ]   arm_ffa               |   `-- arm_ffa
   ...

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

This implementation of the specification provides support for Aarch64.

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

    - Discover the presence of secure partitions (SPs) of interest
    - Access an SP's service through communication protocols
      (e.g: EFI MM communication protocol)

The FF-A support provides the following features:

    - Being generic by design and can be used by any Arm 64-bit platform
    - FF-A support can be compiled and used without EFI
    - Support for SMCCCv1.2 x0-x17 registers
    - Support for SMC32 calling convention
    - Support for 32-bit and 64-bit FF-A direct messaging
    - Support for FF-A MM communication (compatible with EFI boot time)
    - Enabling FF-A and MM communication in Corstone1000 platform as a use case
    - A Uclass driver providing generic FF-A methods.
    - An Arm FF-A device driver providing Arm-specific methods and reusing the Uclass methods.
    - A sandbox emulator for Arm FF-A, emulates the FF-A side of the Secure World and provides
      FF-A ABIs inspection methods.
    - An FF-A sandbox device driver for FF-A communication with the emulated Secure World.
      The driver leverages the FF-A Uclass to establish FF-A communication.
    - Sandbox FF-A test cases.
    - A new command called armffa is provided as an example of how to access the
      FF-A bus

For more details about the FF-A support please refer to [B] and refer to [C] for
how to use the armffa command.

Please find at [D] an example of the expected boot logs when enabling
FF-A support for a platform. In this example the platform is
Corstone1000. But it can be any Arm 64-bit platform.

More details:

[A]: https://developer.arm.com/documentation/den0077/latest/
[B]: doc/arch/arm64.ffa.rst
[C]: doc/usage/cmd/armffa.rst
[D]: example of boot logs when enabling FF-A

1 files changed, 45 insertions, 0 deletions

diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index e1d09884a1c..f44e9e8f930 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -1,6 +1,10 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2015, Linaro Limited
+ * Copyright 2022-2023 Arm Limited and/or its affiliates <[email protected]>
+ *
+ * Authors:
+ *   Abdellatif El Khlifi <[email protected]>
  */
 #ifndef __LINUX_ARM_SMCCC_H
 #define __LINUX_ARM_SMCCC_H
@@ -70,6 +74,47 @@ struct arm_smccc_res {
 	unsigned long a3;
 };
 
+#ifdef CONFIG_ARM64
+/**
+ * struct arm_smccc_1_2_regs - Arguments for or Results from SMC call
+ * @a0-a17 argument values from registers 0 to 17
+ */
+struct arm_smccc_1_2_regs {
+	unsigned long a0;
+	unsigned long a1;
+	unsigned long a2;
+	unsigned long a3;
+	unsigned long a4;
+	unsigned long a5;
+	unsigned long a6;
+	unsigned long a7;
+	unsigned long a8;
+	unsigned long a9;
+	unsigned long a10;
+	unsigned long a11;
+	unsigned long a12;
+	unsigned long a13;
+	unsigned long a14;
+	unsigned long a15;
+	unsigned long a16;
+	unsigned long a17;
+};
+
+/**
+ * arm_smccc_1_2_smc() - make SMC calls
+ * @args: arguments passed via struct arm_smccc_1_2_regs
+ * @res: result values via struct arm_smccc_1_2_regs
+ *
+ * This function is used to make SMC calls following SMC Calling Convention
+ * v1.2 or above. The content of the supplied param are copied from the
+ * structure to registers prior to the SMC instruction. The return values
+ * are updated with the content from registers on return from the SMC
+ * instruction.
+ */
+asmlinkage void arm_smccc_1_2_smc(const struct arm_smccc_1_2_regs *args,
+				  struct arm_smccc_1_2_regs *res);
+#endif
+
 /**
  * struct arm_smccc_quirk - Contains quirk information
  * @id: quirk identification