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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/devicetree/bindings/arm/fw-cfg.txt | |
parent | Initial commit. (diff) | |
download | linux-upstream/5.10.209.tar.xz linux-upstream/5.10.209.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/devicetree/bindings/arm/fw-cfg.txt')
-rw-r--r-- | Documentation/devicetree/bindings/arm/fw-cfg.txt | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/arm/fw-cfg.txt b/Documentation/devicetree/bindings/arm/fw-cfg.txt new file mode 100644 index 000000000..fd54e1db2 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/fw-cfg.txt @@ -0,0 +1,38 @@ +* QEMU Firmware Configuration bindings for ARM + +QEMU's arm-softmmu and aarch64-softmmu emulation / virtualization targets +provide the following Firmware Configuration interface on the "virt" machine +type: + +- A write-only, 16-bit wide selector (or control) register, +- a read-write, 64-bit wide data register. + +QEMU exposes the control and data register to ARM guests as memory mapped +registers; their location is communicated to the guest's UEFI firmware in the +DTB that QEMU places at the bottom of the guest's DRAM. + +The authoritative guest-side hardware interface documentation to the fw_cfg +device can be found in "docs/specs/fw_cfg.txt" in the QEMU source tree. + + +Required properties: + +- compatible: "qemu,fw-cfg-mmio". + +- reg: the MMIO region used by the device. + * Bytes 0x0 to 0x7 cover the data register. + * Bytes 0x8 to 0x9 cover the selector register. + * Further registers may be appended to the region in case of future interface + revisions / feature bits. + +Example: + +/ { + #size-cells = <0x2>; + #address-cells = <0x2>; + + fw-cfg@9020000 { + compatible = "qemu,fw-cfg-mmio"; + reg = <0x0 0x9020000 0x0 0xa>; + }; +}; |