boards: qemu_cortex_r5: Add board documentation

This commit adds the board documentation to the qemu_cortex_r5
platform.

Signed-off-by: Stephanos Ioannidis <[email protected]>

boards/arm/qemu_cortex_r5/doc/index.rst

@@ -0,0 +1,111 @@
+.. _qemu_cortex_r5:
+
+ARM Cortex-R5 Emulation (QEMU)
+##############################
+
+Overview
+********
+
+This board configuration will use QEMU to emulate the Xilinx Zynq UltraScale+
+(ZynqMP) platform.
+
+.. figure:: qemu_cortex_r5.png
+   :width: 600px
+   :align: center
+   :alt: Qemu
+
+   Qemu (Credit: qemu.org)
+
+This configuration provides support for an ARM Cortex-R5 CPU and these devices:
+
+* ARM PL-390 Generic Interrupt Controller
+* Xilinx Zynq TTC (Cadence TTC)
+* Xilinx Zynq UART
+
+.. note::
+   This board configuration makes no claims about its suitability for use
+   with an actual ZCU102 hardware system, or any other hardware system.
+
+Hardware
+********
+Supported Features
+==================
+
+The following hardware features are supported:
+
++--------------+------------+----------------------+
+| Interface    | Controller | Driver/Component     |
++==============+============+======================+
+| GIC          | on-chip    | generic interrupt    |
+|              |            | controller           |
++--------------+------------+----------------------+
+| TTC          | on-chip    | system timer         |
++--------------+------------+----------------------+
+| UART         | on-chip    | serial port          |
++--------------+------------+----------------------+
+
+The kernel currently does not support other hardware features on this platform.
+
+Devices
+========
+System Timer
+------------
+
+This board configuration uses a system timer tick frequency of 1000 Hz.
+
+Serial Port
+-----------
+
+This board configuration uses a single serial communication channel with the
+on-chip UART0.
+
+Known Problems or Limitations
+==============================
+
+The following platform features are unsupported:
+
+* Dual-redundant Core Lock-step (DCLS) execution is not emulated.
+* Xilinx Zynq TTC driver does not support tickless mode operation.
+
+Programming and Debugging
+*************************
+
+Use this configuration to run basic Zephyr applications and kernel tests in the
+QEMU emulated environment, for example, with the :ref:`synchronization_sample`:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/synchronization
+   :host-os: unix
+   :board: qemu_cortex_r5
+   :goals: run
+
+This will build an image with the synchronization sample app, boot it using
+QEMU, and display the following console output:
+
+.. code-block:: console
+
+        *** Booting Zephyr OS build v2.2.0  ***
+        threadA: Hello World from qemu_cortex_r5!
+        threadB: Hello World from qemu_cortex_r5!
+        threadA: Hello World from qemu_cortex_r5!
+        threadB: Hello World from qemu_cortex_r5!
+        threadA: Hello World from qemu_cortex_r5!
+        threadB: Hello World from qemu_cortex_r5!
+        threadA: Hello World from qemu_cortex_r5!
+        threadB: Hello World from qemu_cortex_r5!
+        threadA: Hello World from qemu_cortex_r5!
+        threadB: Hello World from qemu_cortex_r5!
+
+Exit QEMU by pressing :kbd:`CTRL+A` :kbd:`x`.
+
+Debugging
+=========
+
+Refer to the detailed overview about :ref:`application_debugging`.
+
+References
+**********
+
+1. ARMv7-A and ARMv7-R Architecture Reference Manual (ARM DDI 0406C ID051414)
+2. Cortex-R5 and Cortex-R5F Technical Reference Manual (ARM DDI 0460C ID021511)
+3. Zynq UltraScale+ Device Technical Reference Manual (UG1085)