Merge branch '2023-07-24-introduce-FF-A-suppport'

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.

[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, 252 insertions, 5 deletions

diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c
index dfef18435df..5137b871eae 100644
--- a/lib/efi_loader/efi_variable_tee.c
+++ b/lib/efi_loader/efi_variable_tee.c
@@ -4,17 +4,34 @@
  *
  *  Copyright (C) 2019 Linaro Ltd. <sughosh.ganu@linaro.org>
  *  Copyright (C) 2019 Linaro Ltd. <ilias.apalodimas@linaro.org>
+ *  Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office@arm.com>
+ *
+ *  Authors:
+ *    Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
  */
 
 #include <common.h>
+#include <arm_ffa.h>
+#include <cpu_func.h>
+#include <dm.h>
 #include <efi.h>
 #include <efi_api.h>
 #include <efi_loader.h>
 #include <efi_variable.h>
-#include <tee.h>
 #include <malloc.h>
+#include <mapmem.h>
 #include <mm_communication.h>
+#include <tee.h>
+
+/* MM return codes */
+#define MM_SUCCESS (0)
+#define MM_NOT_SUPPORTED (-1)
+#define MM_INVALID_PARAMETER (-2)
+#define MM_DENIED (-3)
+#define MM_NO_MEMORY (-5)
 
+static const char *mm_sp_svc_uuid = MM_SP_UUID;
+static u16 mm_sp_id;
 extern struct efi_var_file __efi_runtime_data *efi_var_buf;
 static efi_uintn_t max_buffer_size;	/* comm + var + func + data */
 static efi_uintn_t max_payload_size;	/* func + data */
@@ -145,16 +162,241 @@ static efi_status_t optee_mm_communicate(void *comm_buf, ulong dsize)
 }
 
 /**
- * mm_communicate() - Adjust the cmonnucation buffer to StandAlonneMM and send
+ * ffa_notify_mm_sp() - Announce there is data in the shared buffer
+ *
+ * Notify the MM partition in the trusted world that
+ * data is available in the shared buffer.
+ * This is a blocking call during which trusted world has exclusive access
+ * to the MM shared buffer.
+ *
+ * Return:
+ *
+ * 0 on success
+ */
+static int ffa_notify_mm_sp(void)
+{
+	struct ffa_send_direct_data msg = {0};
+	int ret;
+	int sp_event_ret;
+	struct udevice *dev;
+
+	ret = uclass_first_device_err(UCLASS_FFA, &dev);
+	if (ret) {
+		log_err("EFI: Cannot find FF-A bus device, notify MM SP failure\n");
+		return ret;
+	}
+
+	msg.data0 = CONFIG_FFA_SHARED_MM_BUF_OFFSET; /* x3 */
+
+	ret = ffa_sync_send_receive(dev, mm_sp_id, &msg, 1);
+	if (ret)
+		return ret;
+
+	sp_event_ret = msg.data0; /* x3 */
+
+	switch (sp_event_ret) {
+	case MM_SUCCESS:
+		ret = 0;
+		break;
+	case MM_NOT_SUPPORTED:
+		ret = -EINVAL;
+		break;
+	case MM_INVALID_PARAMETER:
+		ret = -EPERM;
+		break;
+	case MM_DENIED:
+		ret = -EACCES;
+		break;
+	case MM_NO_MEMORY:
+		ret = -EBUSY;
+		break;
+	default:
+		ret = -EACCES;
+	}
+
+	return ret;
+}
+
+/**
+ * ffa_discover_mm_sp_id() - Query the MM partition ID
+ *
+ * Use the FF-A driver to get the MM partition ID.
+ * If multiple partitions are found, use the first one.
+ * This is a boot time function.
+ *
+ * Return:
+ *
+ * 0 on success
+ */
+static int ffa_discover_mm_sp_id(void)
+{
+	u32 count = 0;
+	int ret;
+	struct ffa_partition_desc *descs;
+	struct udevice *dev;
+
+	ret = uclass_first_device_err(UCLASS_FFA, &dev);
+	if (ret) {
+		log_err("EFI: Cannot find FF-A bus device, MM SP discovery failure\n");
+		return ret;
+	}
+
+	/* Ask the driver to fill the buffer with the SPs info */
+	ret = ffa_partition_info_get(dev, mm_sp_svc_uuid, &count, &descs);
+	if (ret) {
+		log_err("EFI: Failure in querying SPs info (%d), MM SP discovery failure\n", ret);
+		return ret;
+	}
+
+	/* MM SPs found , use the first one */
+
+	mm_sp_id = descs[0].info.id;
+
+	log_info("EFI: MM partition ID 0x%x\n", mm_sp_id);
+
+	return 0;
+}
+
+/**
+ * ffa_mm_communicate() - Exchange EFI services data with  the MM partition using FF-A
+ * @comm_buf:		locally allocated communication buffer used for rx/tx
+ * @dsize:				communication buffer size
+ *
+ * Issue a door bell event to notify the MM partition (SP) running in OP-TEE
+ * that there is data to read from the shared buffer.
+ * Communication with the MM SP is performed using FF-A transport.
+ * On the event, MM SP can read the data from the buffer and
+ * update the MM shared buffer with response data.
+ * The response data is copied back to the communication buffer.
+ *
+ * Return:
+ *
+ * EFI status code
+ */
+static efi_status_t ffa_mm_communicate(void *comm_buf, ulong comm_buf_size)
+{
+	ulong tx_data_size;
+	int ffa_ret;
+	efi_status_t efi_ret;
+	struct efi_mm_communicate_header *mm_hdr;
+	void *virt_shared_buf;
+
+	if (!comm_buf)
+		return EFI_INVALID_PARAMETER;
+
+	/* Discover MM partition ID at boot time */
+	if (!mm_sp_id && ffa_discover_mm_sp_id()) {
+		log_err("EFI: Failure to discover MM SP ID at boot time, FF-A MM comms failure\n");
+		return EFI_UNSUPPORTED;
+	}
+
+	mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
+	tx_data_size = mm_hdr->message_len + sizeof(efi_guid_t) + sizeof(size_t);
+
+	if (comm_buf_size != tx_data_size || tx_data_size > CONFIG_FFA_SHARED_MM_BUF_SIZE)
+		return EFI_INVALID_PARAMETER;
+
+	/* Copy the data to the shared buffer */
+
+	virt_shared_buf = map_sysmem((phys_addr_t)CONFIG_FFA_SHARED_MM_BUF_ADDR, 0);
+	memcpy(virt_shared_buf, comm_buf, tx_data_size);
+
+	/*
+	 * The secure world might have cache disabled for
+	 * the device region used for shared buffer (which is the case for Optee).
+	 * In this case, the secure world reads the data from DRAM.
+	 * Let's flush the cache so the DRAM is updated with the latest data.
+	 */
+#ifdef CONFIG_ARM64
+	invalidate_dcache_all();
+#endif
+
+	/* Announce there is data in the shared buffer */
+
+	ffa_ret = ffa_notify_mm_sp();
+
+	switch (ffa_ret) {
+	case 0: {
+		ulong rx_data_size;
+		/* Copy the MM SP response from the shared buffer to the communication buffer */
+		rx_data_size = ((struct efi_mm_communicate_header *)virt_shared_buf)->message_len +
+			sizeof(efi_guid_t) +
+			sizeof(size_t);
+
+		if (rx_data_size > comm_buf_size) {
+			efi_ret = EFI_OUT_OF_RESOURCES;
+			break;
+		}
+
+		memcpy(comm_buf, virt_shared_buf, rx_data_size);
+		efi_ret = EFI_SUCCESS;
+		break;
+	}
+	case -EINVAL:
+		efi_ret = EFI_DEVICE_ERROR;
+		break;
+	case -EPERM:
+		efi_ret = EFI_INVALID_PARAMETER;
+		break;
+	case -EACCES:
+		efi_ret = EFI_ACCESS_DENIED;
+		break;
+	case -EBUSY:
+		efi_ret = EFI_OUT_OF_RESOURCES;
+		break;
+	default:
+		efi_ret = EFI_ACCESS_DENIED;
+	}
+
+	unmap_sysmem(virt_shared_buf);
+	return efi_ret;
+}
+
+/**
+ * get_mm_comms() - detect the available MM transport
+ *
+ * Make sure the FF-A bus is probed successfully
+ * which means FF-A communication with secure world works and ready
+ * for use.
+ *
+ * If FF-A bus is not ready, use OPTEE comms.
+ *
+ * Return:
+ *
+ * MM_COMMS_FFA or MM_COMMS_OPTEE
+ */
+static enum mm_comms_select get_mm_comms(void)
+{
+	struct udevice *dev;
+	int ret;
+
+	ret = uclass_first_device_err(UCLASS_FFA, &dev);
+	if (ret) {
+		log_err("EFI: Cannot find FF-A bus device, trying Optee comms\n");
+		return MM_COMMS_OPTEE;
+	}
+
+	return MM_COMMS_FFA;
+}
+
+/**
+ * mm_communicate() - Adjust the communication buffer to the MM SP and send
  * it to OP-TEE
  *
- * @comm_buf:		locally allocted communcation buffer
+ * @comm_buf:		locally allocated communication buffer
  * @dsize:		buffer size
+ *
+ * The SP (also called partition) can be any MM SP such as  StandAlonneMM or smm-gateway.
+ * The comm_buf format is the same for both partitions.
+ * When using the u-boot OP-TEE driver, StandAlonneMM is supported.
+ * When using the u-boot FF-A  driver, any MM SP is supported.
+ *
  * Return:		status code
  */
 static efi_status_t mm_communicate(u8 *comm_buf, efi_uintn_t dsize)
 {
 	efi_status_t ret;
+	enum mm_comms_select mm_comms;
 	struct efi_mm_communicate_header *mm_hdr;
 	struct smm_variable_communicate_header *var_hdr;
 
@@ -162,7 +404,12 @@ static efi_status_t mm_communicate(u8 *comm_buf, efi_uintn_t dsize)
 	mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
 	var_hdr = (struct smm_variable_communicate_header *)mm_hdr->data;
 
-	ret = optee_mm_communicate(comm_buf, dsize);
+	mm_comms = get_mm_comms();
+	if (mm_comms == MM_COMMS_FFA)
+		ret = ffa_mm_communicate(comm_buf, dsize);
+	else
+		ret = optee_mm_communicate(comm_buf, dsize);
+
 	if (ret != EFI_SUCCESS) {
 		log_err("%s failed!\n", __func__);
 		return ret;
@@ -697,7 +944,7 @@ void efi_variables_boot_exit_notify(void)
 		ret = EFI_NOT_FOUND;
 
 	if (ret != EFI_SUCCESS)
-		log_err("Unable to notify StMM for ExitBootServices\n");
+		log_err("Unable to notify the MM partition for ExitBootServices\n");
 	free(comm_buf);
 
 	/*