238 lines
8.1 KiB
Plaintext
238 lines
8.1 KiB
Plaintext
MSM Bus Devices
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The bus devices (fabrics/NoCs) are the interconnects between various
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components on chipsets. These devices form the backbone of the chip
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topology. Entire topology of the chipset is built using the
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device-tree data of these bus devices.
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To add the bus devices following properties are required:
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compatible: The bus devices need to be compatible with
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msm-bus-fabric
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cell-id: A 32 bit integer unique per bus per chipset. The IDs
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for buses are in multiples of 1024.
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label: Bus name
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qcom,fabclk-dual: Dual set (active/sleep) bus clock name
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qcom,fabclk-active: Active set bus clock name
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The following properties are optional as a bus might not support
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these features:
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qcom,ntieredslaves: Number of tiered slaves on the bus.
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qcom,qos-freq: QoS frequency (In Hz)
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qcom,hw-sel: A string which decides whether QoS data
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should be sent to RPM, set using BIMC or NoCs.
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It can be set to "RPM", "NoC" or "BIMC".
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qcom,rpm-en: A boolean flag indicating whether RPM transactions are
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supported for nodes of the bus.
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qcom,ahb: A boolean flag indicating whether the bus is ahb type.
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qcom,virt: A boolean property indicating this is a virtual bus.
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reg: Register space of the bus device. Not required in case
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the bus is virtual.
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The following properties are optional as collecting data via coresight might
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not be supported for every bus. The documentation for coresight properties
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can be found in:
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Documentation/devicetree/bindings/coresight/coresight.txt
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coreisght-id Unique integer identifier for the bus.
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coresight-name Unique descriptive name of the bus.
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coresight-nr-inports Number of input ports on the bus.
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coresight-outports List of output port numbers on the bus.
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coresight-child-list List of phandles pointing to the children of this
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component.
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coresight-child-ports List of input port numbers of the children.
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Any interconnect on the bus is represented as a child node.
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A child node can be of type: master, slave or a gateway.
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A gateway is an interconnect between buses and can be of both
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master and slave type.
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The following properties are available to characterize a child node.
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The properties can be chosen depending on the type of child node.
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cell-id: For a master the ID is between 0 - 512
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For a slave the ID is between 512 - 1024
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label: Name of the master/slave/gateway
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qcom,masterp: Hardware master port number(s)
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qcom,tier: The tier to which a master/slave belongs.
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Note that tiering might not be supported on
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all architectures.
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qcom,hw-sel: A string which decides whether QoS data should be sent
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to RPM, set using BIMC or NoCs.
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It can be set to "RPM", "NoC" or "BIMC".
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qcom,mode: Used for masters on NoC/BIMC. Indicates which of the
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four modes (Fixed/Limiter/Bypass/Regulator) the master
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belongs to.
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qcom,perm-mode: Permissible mode switches. Indicates which of the four
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modes are supported of the master node. Generally,
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modes are set at boot-up and not switched at run-time.
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qcom,qport: QoS port number. This can be different from the
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master-port number.
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qcom,ws: Window size (in Hz), used for NoC/BIMC masters to
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calculate saturation values.
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qcom,mas-hw-id: A unique hardware ID agreed upon by processors across
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the system. This ID is assigned to every master. It can
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be used to send master specific data from
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Apps/Modem/LPASS to RPM.
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qcom,slv-hw-id: A unique hardware ID agreed upon by processors across
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the system. This ID is assigned to every slave. It can
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be used to send slave specific data from
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Apps/Modem/LPASS to RPM.
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qcom,gateway: Flag indicating whether a particular node is a gateway.
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qcom,slavep: Hardware slave port number(s).
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qcom,buswidth: Width of the interconnect between a node and the bus.
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(In Bytes).
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qcom,prio-rd: Read priority for a BIMC bus master (Can be 0/1/2)
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qcom,prio-wr: Write priority for a BIMC bus master (Can be 0/1/2)
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qcom,prio0: Priority low signal for a NoC bus master
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(Can be 0/1/2).
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qcom,prio1: Priority high signal for a NoC bus master
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(Can be 0/1/2)
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qcom,dual-conf: Indicates whether a BIMC/NoC master can be configured
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in multiple modes at run-time. (Boolean)
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qcom,mode-thresh: Threshold mode for a BIMC/NoC master. Beyond a certain
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threshold frequency, a threshold mode can be used.
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(Can be Fixed/Limiter/Bypass/Regulator)
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qcom,bimc,bw: Bandwidth limit for a BIMC master using dual modes.
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This bandwidth is used to calculate Grant count and
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other parameters used in Limiter and Regular mode
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for static BKE configuration. It is defined in KBps.
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qcom,bimc,gp: Grant Period for configuring a master in limiter
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mode. This is an integer value in micro-seconds.
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qcom,bimc,thmp: Medium threshold percentage for BIMC masters.
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This percentage is used to calculate medium threshold
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value for BIMC Masters in Limiter mode for static
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configuration. This can be any integer value between
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1 and 100.
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qcom,thresh: Beyond this threshold frequency, the mode usage is
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switched from mode specified by property qcom,mode
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to the one specified by qcom,mode-thresh. In case the
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requested IB value falls below this threshold, the mode
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is switched back to qcom,mode. Frequency is specified in
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KBps.
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Example:
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msm-mmss-noc@fc478000 {
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compatible = "msm-bus-fabric";
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reg = <0xfc478000 0x00004000>;
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cell-id = <2048>;
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label = "msm_mmss_noc";
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qcom,fabclk-dual = "bus_clk";
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qcom,fabclk-active = "bus_a_clk";
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qcom,ntieredslaves = <0>;
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qcom,qos-freq = <4800>;
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qcom,hw-sel = "NoC";
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qcom,rpm-en;
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mas-gfx3d {
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cell-id = <26>;
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label = "mas-gfx3d";
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qcom,masterp = <2 3>;
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qcom,tier = <2>;
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qcom,hw-sel = "NoC";
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qcom,perm-mode = "Bypass";
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qcom,mode = "Bypass";
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qcom,ws = <10000>;
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qcom,qport = <2 3>;
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qcom,mas-hw-id = <6>;
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};
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mas-jpeg {
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cell-id = <62>;
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label = "mas-jpeg";
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qcom,masterp = <4>;
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qcom,tier = <2>;
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qcom,hw-sel = "NoC";
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qcom,perm-mode = "Bypass";
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qcom,mode = "Bypass";
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qcom,qport = <0>;
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qcom,ws = <10000>;
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qcom,mas-hw-id = <7>;
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};
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};
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msm-bimc@0xfc380000 {
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compatible = "msm-bus-fabric";
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reg = <0xfc380000 0x0006A000>;
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cell-id = <0>;
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label = "msm_bimc";
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qcom,fabclk-dual = "mem_clk";
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qcom,fabclk-active = "mem_a_clk";
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qcom,ntieredslaves = <0>;
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qcom,qos-freq = <19200>;
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qcom,hw-sel = "BIMC";
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qcom,rpm-en;
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coresight-id = <55>;
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coresight-name = "coresight-bimc";
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coresight-nr-inports = <0>;
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coresight-outports = <0>;
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coresight-child-list = <&funnel_in1>;
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coresight-child-ports = <3>;
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mas-ampss-m0 {
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cell-id = <1>;
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label = "mas-ampss-m0";
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qcom,masterp = <0>;
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qcom,tier = <2>;
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qcom,hw-sel = "BIMC";
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qcom,mode = "Limiter";
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qcom,qport = <0>;
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qcom,ws = <10000>;
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qcom,mas-hw-id = <0>;
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qcom,prio-rd = <0>;
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qcom,prio-wr = <0>;
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qcom,mode-thresh = "Fixed";
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qcom,thresh = <2000000>;
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qcom,dual-conf;
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qcom,bimc,bw = <300000>;
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qcom,bimc,gp = <5>;
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qcom,bimc,thmp = <50>;
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};
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};
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The bus scaling driver also provides the ability to configure
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bus performance parameters across the entire chip-set.
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Various clients use MSM scaling APIs to request bandwidth
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between multiple master-slave pairs. The bus driver then finds
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the optimal path between the master and the slave, and aggregates
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the bandwidth and clock requests for all master-slave pairs on
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that path, and programs hardware accordingly.
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The device-tree data required for bus-scaling can be embedded within
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the clients' device nodes. The clients can register with the bus driver
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using the following properties:
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- qcom,msm-bus,name: String representing the client-name
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- qcom,msm-bus,num-cases: Total number of usecases
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- qcom,msm-bus,active-only: Boolean context flag for requests in active or
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dual (active & sleep) contex
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- qcom,msm-bus,num-paths: Total number of master-slave pairs
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- qcom,msm-bus,vectors-KBps: Arrays of unsigned integers representing:
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master-id, slave-id, arbitrated bandwidth
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in KBps, instantaneous bandwidth in KBps
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Example:
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qcom,msm-bus,name = "client-name";
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qcom,msm-bus,num-cases = <3>;
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qcom,msm-bus,active-only;
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qcom,msm-bus,num-paths = <2>;
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qcom,msm-bus,vectors =
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<22 512 0 0>, <26 512 0 0>,
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<22 512 320000 3200000>, <26 512 3200000 3200000>,
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<22 512 160000 1600000>, <26 512 1600000 1600000>;
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