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[PULL 29/33] docs: sbsa: document board to firmware interface
From: |
Peter Maydell |
Subject: |
[PULL 29/33] docs: sbsa: document board to firmware interface |
Date: |
Mon, 19 Jun 2023 15:29:10 +0100 |
From: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>
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>
Message-id: 20230531171834.236569-1-marcin.juszkiewicz@linaro.org
[PMM: fix format nits, add text about platform version fields from
a comment in the C source file]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
docs/system/arm/sbsa.rst | 38 +++++++++++++++++++++++++++++++-------
1 file changed, 31 insertions(+), 7 deletions(-)
diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
index 016776aed82..f571fe645e7 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 +25,32 @@ 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
+''''''''''''''''''''''
+
+The devicetree provided by the board model to the firmware is not intended
+to be a complete compliant DT. It currently reports:
+
+ - 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.
--
2.34.1
- [PULL 14/33] target/arm: Convert load/store-pair to decodetree, (continued)
- [PULL 14/33] target/arm: Convert load/store-pair to decodetree, Peter Maydell, 2023/06/19
- [PULL 16/33] target/arm: Convert LDR/STR with 12-bit immediate to decodetree, Peter Maydell, 2023/06/19
- [PULL 18/33] target/arm: Convert atomic memory ops to decodetree, Peter Maydell, 2023/06/19
- [PULL 25/33] hw/sd/allwinner-sdhost: Don't send non-boolean IRQ line levels, Peter Maydell, 2023/06/19
- [PULL 19/33] target/arm: Convert load (pointer auth) insns to decodetree, Peter Maydell, 2023/06/19
- [PULL 31/33] hw/misc/bcm2835_property: Use 'raspberrypi-fw-defs.h' definitions, Peter Maydell, 2023/06/19
- [PULL 22/33] target/arm: Convert load/store single structure to decodetree, Peter Maydell, 2023/06/19
- [PULL 23/33] target/arm: Convert load/store tags insns to decodetree, Peter Maydell, 2023/06/19
- [PULL 30/33] hw/arm/raspi: Import Linux raspi definitions as 'raspberrypi-fw-defs.h', Peter Maydell, 2023/06/19
- [PULL 28/33] imx_serial: set wake bit when we receive a data byte, Peter Maydell, 2023/06/19
- [PULL 29/33] docs: sbsa: document board to firmware interface,
Peter Maydell <=
- [PULL 33/33] hw/misc/bcm2835_property: Handle CORE_CLK_ID firmware property, Peter Maydell, 2023/06/19
- [PULL 17/33] target/arm: Convert LDR/STR reg+reg to decodetree, Peter Maydell, 2023/06/19
- [PULL 24/33] hw/intc/allwinner-a10-pic: Handle IRQ levels other than 0 or 1, Peter Maydell, 2023/06/19
- [PULL 20/33] target/arm: Convert LDAPR/STLR (imm) to decodetree, Peter Maydell, 2023/06/19
- [PULL 21/33] target/arm: Convert load/store (multiple structures) to decodetree, Peter Maydell, 2023/06/19
- [PULL 27/33] hw/arm/Kconfig: sbsa-ref uses Bochs display, Peter Maydell, 2023/06/19
- [PULL 26/33] hw/timer/nrf51_timer: Don't lose time when timer is queried in tight loop, Peter Maydell, 2023/06/19
- [PULL 32/33] hw/misc/bcm2835_property: Replace magic frequency values by definitions, Peter Maydell, 2023/06/19
- Re: [PULL 00/33] target-arm queue, Richard Henderson, 2023/06/19