| Message ID | 20230531171834.236569-1-marcin.juszkiewicz@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] docs: sbsa: document board to firmware interface | expand |
On Wed, 31 May 2023 at 18:18, Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org> wrote: > > We plan to add more hardware information into DeviceTree to limit amount > of hardcoded values in firmware. > > Signed-off-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org> I'm going to apply this to target-arm.next with this squashed in to fix a few grammar/format nits and add some text from the comment in the source file about the platform version part. diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst index c5b3342b52f..f571fe645e7 100644 --- a/docs/system/arm/sbsa.rst +++ b/docs/system/arm/sbsa.rst @@ -28,19 +28,29 @@ The ``sbsa-ref`` board supports: Board to firmware interface """"""""""""""""""""""""""" -``sbsa-ref`` is a static system that reports a very minimal DeviceTree to the + +``sbsa-ref`` is a static system that reports a very minimal devicetree to the firmware for non-discoverable information about system components. This includes both internal hardware and parts affected by the qemu command line -(i.e. cpus and memory). As a result it must have a firmware specifically built +(i.e. CPUs and memory). As a result it must have a firmware specifically built to expect a certain hardware layout (as you would in a real machine). DeviceTree information -''''''''''''''''''''''' +'''''''''''''''''''''' -Provided DeviceTree is not intended to be a complete compliant DT. Only -minimal subset is provided: +The devicetree provided by the board model to the firmware is not intended +to be a complete compliant DT. It currently reports: - - cpus + - CPUs - memory - platform version - GIC addresses + +The platform version is only for informing platform firmware about +what kind of ``sbsa-ref`` board it is running on. It is neither +a QEMU versioned machine type nor a reflection of the level of the +SBSA/SystemReady SR support provided. + +The ``machine-version-major`` value is updated when changes breaking +fw compatibility are introduced. The ``machine-version-minor`` value +is updated when features are added that don't break fw compatibility. thanks -- PMM
W dniu 19.06.2023 o 14:41, Peter Maydell pisze: > I'm going to apply this to target-arm.next with this squashed in > to fix a few grammar/format nits and add some text from the comment > in the source file about the platform version part. Thanks. My English grammar sucks so I am glad that you looked and improved that text.
diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst index 016776aed8..c5b3342b52 100644 --- a/docs/system/arm/sbsa.rst +++ b/docs/system/arm/sbsa.rst @@ -6,12 +6,7 @@ any real hardware the ``sbsa-ref`` board intends to look like real hardware. The `Server Base System Architecture <https://developer.arm.com/documentation/den0029/latest>`_ defines a minimum base line of hardware support and importantly how the firmware -reports that to any operating system. It is a static system that -reports a very minimal DT to the firmware for non-discoverable -information about components affected by the qemu command line (i.e. -cpus and memory). As a result it must have a firmware specifically -built to expect a certain hardware layout (as you would in a real -machine). +reports that to any operating system. It is intended to be a machine for developing firmware and testing standards compliance with operating systems. @@ -19,7 +14,7 @@ standards compliance with operating systems. Supported devices """"""""""""""""" -The sbsa-ref board supports: +The ``sbsa-ref`` board supports: - A configurable number of AArch64 CPUs - GIC version 3 @@ -30,3 +25,22 @@ The sbsa-ref board supports: - Bochs display adapter on PCIe bus - A generic SBSA watchdog device + +Board to firmware interface +""""""""""""""""""""""""""" +``sbsa-ref`` is a static system that reports a very minimal DeviceTree to the +firmware for non-discoverable information about system components. This +includes both internal hardware and parts affected by the qemu command line +(i.e. cpus and memory). As a result it must have a firmware specifically built +to expect a certain hardware layout (as you would in a real machine). + +DeviceTree information +''''''''''''''''''''''' + +Provided DeviceTree is not intended to be a complete compliant DT. Only +minimal subset is provided: + + - cpus + - memory + - platform version + - GIC addresses
We plan to add more hardware information into DeviceTree to limit amount of hardcoded values in firmware. Signed-off-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org> --- docs/system/arm/sbsa.rst | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-)