Rtwo/kernel/motorola/sm8550-devicetrees/bindings/dma/qcom_gpi.txt
2025-09-30 19:22:48 -05:00

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Qualcomm Technologies Inc GPI DMA controller
MSM GPI DMA controller provides DMA capabilities for
peripheral buses such as I2C, UART, and SPI.
==============
Node Structure
==============
Main node properties:
- #dma-cells
Usage: required
Value type: <u32>
Definition: Number of parameters client will provide. Must be set to 5.
1st parameter: channel index, 0 for TX, 1 for RX
2nd parameter: serial engine index
3rd parameter: bus protocol, 1 for SPI, 2 for UART, 3 for I2C
4th parameter: channel ring length in transfer ring elements
5th parameter: event processing priority, set to 0 for lowest latency
- compatible
Usage: required
Value type: <string>
Definition: "qcom,gpi-dma"
- reg
Usage: required
Value type: Array of <u32>
Definition: register address space location and size
- reg-name
Usage: required
Value type: <string>
Definition: register space name, must be "gpi-top"
- interrupts
Usage: required
Value type: Array of <u32>
Definition: Array of tuples which describe interrupt line for each GPII
instance.
- qcom,max-num-gpii
Usage: required
Value type: <u32>
Definition: Total number of GPII instances available for this controller.
- qcom,gpii-mask
Usage: required
Value type: <u32>
Definition: Bitmap of supported GPII instances in hlos.
- qcom,ev-factor
Usage: required
Value type: <u32>
Definition: Event ring transfer size compare to channel transfer ring. Event
ring length = ev-factor * transfer ring size
- iommus
Usage: required
Value type: <phandle u32 u32>
Definition: phandle for apps smmu controller and SID, and mask
for the controller. For more detail please check binding
documentation arm,smmu.txt
Optional property:
- qcom,gpi-ee-offset
Usage: optional
Value type: u64
Definition: Specifies the gsi ee register offset for the QUP.
- qcom,iommu-dma-addr-pool
Usage: optional
Value type: tuple of <address size>.
Definition: Indicates the range of addresses that the dma layer will use.
- qcom,le-vm
Usage: optional
Value type: boolean
Definition: flag to support I2C functionality in trusted VM.
- qcom,static-gpii-mask
Usage: optional
Value type: boolean
Definition: GPII number statically assigned to TUI LA touch se.
========
Example:
========
gpi_dma0: qcom,gpi-dma@0x800000 {
#dma-cells = <5>;
compatible = "qcom,gpi-dma";
reg = <0x800000 0x60000>;
reg-names = "gpi-top";
interrupts = <0 244 0>, <0 245 0>, <0 246 0>, <0 247 0>,
<0 248 0>, <0 249 0>, <0 250 0>, <0 251 0>,
<0 252 0>, <0 253 0>, <0 254 0>, <0 255 0>,
<0 256 0>;
qcom,max-num-gpii = <13>;
qcom,gpii-mask = <0xfa>;
qcom,ev-factor = <2>;
iommus = <&apps_smmu 0x0016 0x0>;
qcom,iommu-dma-addr-pool = <0x40000000 0xc0000000>;
status = "ok";
};