69 lines
2.0 KiB
Plaintext
69 lines
2.0 KiB
Plaintext
MSM device bandwidth device
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devbw is a device that represents a MSM device's BW requirements from its
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master port(s) to a different device's slave port(s) in a MSM SoC. This
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device is typically used to vote for BW requirements from a device's (Eg:
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CPU, GPU) master port(s) to the slave (Eg: DDR) port(s).
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Required properties:
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- compatible: Must be "qcom,devbw"
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- qcom,src-dst-ports: A list of tuples where each tuple consists of a bus
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master port number and a bus slave port number.
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- operating-points-v2: A phandle to the OPP v2 table that holds meaningful
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instantaneous bandwidth values (in MB/s) that can be
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requested from the device master port to the slave port.
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The list of values depend on the supported bus/slave
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frequencies and the bus width.
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Optional properties:
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- qcom,active-only: Indicates that the bandwidth votes need to be
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enforced only when the CPU subsystem is active.
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- governor: Initial governor to use for the device.
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Default: "performance"
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- qcom,ddr-type: Optional property indicates ddr type which can support
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different frequencies for a given target.
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Example:
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bw_opp_table: bw-opp-table {
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compatible = "operating-points-v2";
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opp-75 {
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opp-hz = /bits/ 64 < 572 >; /* 75 MHz */
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};
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opp-150 {
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opp-hz = /bits/ 64 < 1144 >; /* 150 MHz */
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};
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opp-200 {
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opp-hz = /bits/ 64 < 1525 >; /* 200 MHz */
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};
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opp-307 {
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opp-hz = /bits/ 64 < 2342 >; /* 307 MHz */
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};
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opp-460 {
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opp-hz = /bits/ 64 < 3509 >; /* 460 MHz */
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};
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opp-614 {
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opp-hz = /bits/ 64 < 4684 >; /* 614 MHz */
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};
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opp-800 {
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opp-hz = /bits/ 64 < 6103 >; /* 800 MHz */
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};
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opp-931 {
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opp-hz = /bits/ 64 < 7102 >; /* 931 MHz */
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};
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};
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qcom,cpubw {
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compatible = "qcom,devbw";
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qcom,src-dst-ports = <1 512>, <2 512>;
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qcom,active-only;
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operating-points-v2 = <&bw_opp_table>;
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ddr3-opp {
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operating-points-v2 = <&ddr3_bw_opp_table>;
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qcom,ddr-type = <DDR_TYPE_LPDDR3>;
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};
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ddr4-opp {
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operating-points-v2 = <&ddr4_bw_opp_table>;
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qcom,ddr-type = <DDR_TYPE_LPDDR4X>;
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};
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};
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