2020-11-04 19:52:54 +03:00
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Arm Server Base System Architecture Reference board (``sbsa-ref``)
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==================================================================
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2021-07-26 17:23:36 +03:00
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While the ``virt`` board is a generic board platform that doesn't match
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any real hardware the ``sbsa-ref`` board intends to look like real
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2020-11-04 19:52:54 +03:00
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hardware. The `Server Base System Architecture
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2021-04-28 16:13:16 +03:00
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<https://developer.arm.com/documentation/den0029/latest>`_ defines a
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2020-11-04 19:52:54 +03:00
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minimum base line of hardware support and importantly how the firmware
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2023-05-31 20:18:34 +03:00
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reports that to any operating system.
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2020-11-04 19:52:54 +03:00
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It is intended to be a machine for developing firmware and testing
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standards compliance with operating systems.
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Supported devices
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"""""""""""""""""
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2023-05-31 20:18:34 +03:00
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The ``sbsa-ref`` board supports:
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2020-11-04 19:52:54 +03:00
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- A configurable number of AArch64 CPUs
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- GIC version 3
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- System bus AHCI controller
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2023-07-04 16:08:47 +03:00
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- System bus XHCI controller
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2020-11-04 19:52:54 +03:00
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- CDROM and hard disc on AHCI bus
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- E1000E ethernet card on PCIe bus
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2023-05-24 14:33:07 +03:00
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- Bochs display adapter on PCIe bus
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2020-11-04 19:52:54 +03:00
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- A generic SBSA watchdog device
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2023-05-31 20:18:34 +03:00
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Board to firmware interface
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"""""""""""""""""""""""""""
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``sbsa-ref`` is a static system that reports a very minimal devicetree to the
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firmware for non-discoverable information about system components. This
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includes both internal hardware and parts affected by the qemu command line
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(i.e. CPUs and memory). As a result it must have a firmware specifically built
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to expect a certain hardware layout (as you would in a real machine).
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DeviceTree information
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''''''''''''''''''''''
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The devicetree provided by the board model to the firmware is not intended
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to be a complete compliant DT. It currently reports:
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- CPUs
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- memory
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- platform version
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- GIC addresses
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2023-06-19 20:09:13 +03:00
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Platform version
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''''''''''''''''
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2023-05-31 20:18:34 +03:00
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The platform version is only for informing platform firmware about
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what kind of ``sbsa-ref`` board it is running on. It is neither
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a QEMU versioned machine type nor a reflection of the level of the
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SBSA/SystemReady SR support provided.
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The ``machine-version-major`` value is updated when changes breaking
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fw compatibility are introduced. The ``machine-version-minor`` value
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is updated when features are added that don't break fw compatibility.
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2023-06-19 20:09:13 +03:00
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Platform version changes:
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0.0
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Devicetree holds information about CPUs, memory and platform version.
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0.1
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GIC information is present in devicetree.
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0.2
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GIC ITS information is present in devicetree.
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2023-07-04 16:08:47 +03:00
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0.3
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The USB controller is an XHCI device, not EHCI
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