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+Mandatory modifications
+-----------------------
+
+File : platform_def.h [mandatory]
+`````````````````````````````````
+
+Each platform must ensure that a header file of this name is in the system
+include path with the following constants defined. This may require updating the
+list of ``PLAT_INCLUDES`` in the ``platform.mk`` file. In the ARM FVP port, this
+file is found in ``plat/arm/board/fvp/include/platform_def.h``.
+
+-  **#define : PLATFORM_LINKER_FORMAT**
+
+   Defines the linker format used by the platform, for example
+   `elf64-littleaarch64` used by the FVP.
+
+-  **#define : PLATFORM_LINKER_ARCH**
+
+   Defines the processor architecture for the linker by the platform, for
+   example `aarch64` used by the FVP.
+
+-  **#define : PLATFORM_STACK_SIZE**
+
+   Defines the stack memory available to each CPU. This constant is used by
+   ``plat/common/aarch64/platform_mp_stack.S``.
+
+-  **#define : PLATFORM_CLUSTER_COUNT**
+
+   Defines the total number of clusters implemented by the platform in the
+   system.
+
+-  **#define : PLATFORM_CORE_COUNT**
+
+   Defines the total number of CPUs implemented by the platform across all
+   clusters in the system.
+
+-  **#define : PLATFORM_NUM_AFFS**
+
+   Defines the total number of nodes in the affinity hierarchy at all affinity
+   levels used by the platform.
+
+-  **#define : PLATFORM_MAX_AFFLVL**
+
+   Defines the maximum number of affinity levels in the system that the platform
+   implements.  ARMv8-A has support for 4 affinity levels. It is likely that
+   hardware will implement fewer affinity levels. For example, the Base AEM FVP
+   implements two clusters with a configurable number of CPUs.  It reports the
+   maximum affinity level as 1.
+
+-  **#define : PLAT_MAX_SPI_OFFSET_ID**
+
+   Defines the offset of the last Shared Peripheral Interrupt supported by the
+   TF-A Tests on this platform. SPI numbers are mapped onto GIC interrupt IDs,
+   starting from interrupt ID 32. In other words, this offset ID corresponds to
+   the last SPI number, to which 32 must be added to get the corresponding last
+   GIC IRQ ID.
+
+   E.g. If ``PLAT_MAX_SPI_OFFSET_ID`` is 10, this means that IRQ #42 is the last
+   SPI.
+
+-  **#define : PLAT_LOCAL_PSTATE_WIDTH**
+
+   Defines the bit-field width of the local state in State-ID field of the
+   power-state parameter. This macro will be used to compose the State-ID field
+   given the local power state at different affinity levels.
+
+-  **#define : PLAT_MAX_PWR_STATES_PER_LVL**
+
+   Defines the maximum number of power states at a power domain level for the
+   platform. This macro will be used by the ``PSCI_STAT_COUNT/RESIDENCY`` tests
+   to determine the size of the array to allocate for storing the statistics.
+
+-  **#define : TFTF_BASE**
+
+   Defines the base address of the TFTF binary in DRAM. Used by the linker
+   script to link the image at the right address. Must be aligned on a page-size
+   boundary.
+
+-  **#define : IRQ_PCPU_NS_TIMER**
+
+   Defines the IRQ ID of the per-CPU Non-Secure timer of the platform.
+
+-  **#define : IRQ_CNTPSIRQ1**
+
+   Defines the IRQ ID of the System timer of the platform.
+
+-  **#define : TFTF_NVM_OFFSET**
+
+   The TFTF needs some Non-Volatile Memory to store persistent data. This
+   defines the offset from the beginning of this memory that the TFTF can use.
+
+-  **#define : TFTF_NVM_SIZE**
+
+   Defines the size of the Non-Volatile Memory allocated for TFTF usage.
+
+If the platform port uses the ARM Watchdog Module (`SP805`_) peripheral, the
+following constant needs to be defined:
+
+-  **#define : SP805_WDOG_BASE**
+
+   Defines the base address of the `SP805`_ watchdog peripheral.
+
+If the platform port uses the IO storage framework, the following constants
+must also be defined:
+
+-  **#define : MAX_IO_DEVICES**
+
+   Defines the maximum number of registered IO devices. Attempting to register
+   more devices than this value using ``io_register_device()`` will fail with
+   ``IO_RESOURCES_EXHAUSTED``.
+
+-  **#define : MAX_IO_HANDLES**
+
+   Defines the maximum number of open IO handles. Attempting to open more IO
+   entities than this value using ``io_open()`` will fail with
+   ``IO_RESOURCES_EXHAUSTED``.
+
+If the platform port uses the VExpress NOR flash driver (see
+``drivers/io/vexpress_nor/``), the following constants must also be defined:
+
+-  **#define : NOR_FLASH_BLOCK_SIZE**
+
+   Defines the largest block size as seen by the software while writing to NOR
+   flash.
+
+Function : tftf_plat_arch_setup() [mandatory]
+`````````````````````````````````````````````
+::
+
+    Argument : void
+    Return   : void
+
+This function performs any platform-specific and architectural setup that the
+platform requires.
+
+In both the ARM FVP and Juno ports, this function configures and enables the
+MMU.
+
+Function : tftf_early_platform_setup() [mandatory]
+``````````````````````````````````````````````````
+
+::
+
+    Argument : void
+    Return   : void
+
+This function executes with the MMU and data caches disabled. It is only called
+by the primary CPU. It is used to perform platform-specific actions very early
+in the boot.
+
+In both the ARM FVP and Juno ports, this function configures the console.
+
+Function : tftf_platform_setup() [mandatory]
+````````````````````````````````````````````
+
+::
+
+    Argument : void
+    Return   : void
+
+This function executes with the MMU and data caches enabled. It is responsible
+for performing any remaining platform-specific setup that can occur after the
+MMU and data cache have been enabled.
+
+This function is also responsible for initializing the storage abstraction layer
+used to access non-volatile memory for permanent storage of test results. It
+also initialises the GIC and detects the platform topology using
+platform-specific means.
+
+Function : plat_get_nvm_handle() [mandatory]
+````````````````````````````````````````````
+
+::
+
+    Argument : uintptr_t *
+    Return   : void
+
+It is needed if the platform port uses IO storage framework. This function is
+responsible for getting the pointer to the initialised non-volatile memory
+entity.
+
+Function : tftf_plat_get_pwr_domain_tree_desc() [mandatory]
+```````````````````````````````````````````````````````````
+
+::
+
+    Argument : void
+    Return   : const unsigned char *
+
+This function returns the platform topology description array in a suitable
+format as expected by TFTF. The size of the array is expected to be
+``PLATFORM_NUM_AFFS - PLATFORM_CORE_COUNT + 1``. The format used to describe
+this array is :
+
+1.  The first entry in the array specifies the number of power domains at the
+    highest power level implemented in the platform. This caters for platforms
+    where the power domain tree does not have a single root node e.g. the FVP
+    which has two cluster power domains at the highest level (that is, 1).
+
+2.  Each subsequent entry corresponds to a power domain and contains the number
+    of power domains that are its direct children.
+
+The array format is the same as the one used by Trusted Firmware-A and more
+details of its description can be found in the Trusted Firmware-A documentation:
+`docs/psci-pd-tree.rst`_.
+
+Function : tftf_plat_get_mpidr() [mandatory]
+````````````````````````````````````````````
+
+::
+
+    Argument : unsigned int
+    Return   : uint64_t
+
+This function converts a given `core_pos` into a valid MPIDR if the CPU is
+present in the platform. The `core_pos` is a unique number less than the
+``PLATFORM_CORE_COUNT`` returned by ``platform_get_core_pos()`` for a given
+CPU. This API is used by the topology framework in TFTF to query the presence of
+a CPU and, if present, returns the corresponding MPIDR for it. If the CPU
+referred to by the `core_pos` is absent, then this function returns
+``INVALID_MPID``.
+
+Function : plat_get_state_prop() [mandatory]
+````````````````````````````````````````````
+
+::
+
+    Argument : unsigned int
+    Return   : const plat_state_prop_t *
+
+This functions returns the ``plat_state_prop_t`` array for all the valid low
+power states from platform for a specified affinity level and returns ``NULL``
+for an invalid affinity level. The array is expected to be NULL-terminated.
+This function is expected to be used by tests that need to compose the power
+state parameter for use in ``PSCI_CPU_SUSPEND`` API or ``PSCI_STAT/RESIDENCY``
+API.
+
+Function : plat_fwu_io_setup() [mandatory]
+``````````````````````````````````````````
+
+::
+
+    Argument : void
+    Return   : void
+
+This function initializes the IO system used by the firmware update.
+
+Function : plat_arm_gic_init() [mandatory]
+``````````````````````````````````````````
+
+::
+
+    Argument : void
+    Return   : void
+
+This function initializes the ARM Generic Interrupt Controller (GIC).
+
+Function : platform_get_core_pos() [mandatory]
+``````````````````````````````````````````````
+
+::
+
+    Argument : u_register_t
+    Return   : unsigned int
+
+This function returns a linear core ID from a MPID.
+
+Function : plat_crash_console_init() [mandatory]
+````````````````````````````````````````````````
+
+::
+
+    Argument : void
+    Return   : int
+
+This function initializes a platform-specific console for crash reporting.
+
+Function : plat_crash_console_putc() [mandatory]
+````````````````````````````````````````````````
+
+::
+
+    Argument : int
+    Return   : int
+
+This function prints a character on the platform-specific crash console.
+
+Function : plat_crash_console_flush() [mandatory]
+`````````````````````````````````````````````````
+
+::
+
+    Argument : void
+    Return   : int
+
+This function waits until all the characters of the platform-specific crash
+console have been actually printed.
+
+--------------
+
+*Copyright (c) 2019, Arm Limited. All rights reserved.*
+
+.. _SP805: https://static.docs.arm.com/ddi0270/b/DDI0270.pdf
+.. _docs/psci-pd-tree.rst: https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/about/docs/psci-pd-tree.rst