MSM平台RPM

Software Component Block Diagram

RPM（Resource Power Manager）是高通MSM平台另外加的一块芯片，虽然与AP芯片打包在一起，但其是一个独立的ARM Core。之所以加这个东西，就是要控制整个电源相关的shared resources，比如ldo，clock。负责与SMP,MPM交互进入睡眠或者唤醒整个系统。 
以下是高通文档中对各个功能模块的说明。 
这里写图片描述

  • Kernel – DALSys-based lightweight kernel
  • RPM handler – RPM handler abstracts the RPM message protocol away 
    from other software
  • Drivers – Drivers for each of the resources supported by the RPM will 
    register with RPM handler to request notification when requests are 
    received for the resource which the driver controls
  • NPA – A driver may use the Node Power Architecture (NPA) to represent 
    resources controlled by the driver
  • Clock driver – RPM clock driver directly handles aggregating requests 
    from each of the masters for any of the systemwide clock resources 
    controlled by the RPM
  • Bus arbitration driver – RPM bus arbiter driver takes bus arbiter settings 
    as requests from the different masters in the system and aggregates them 
    to represent the frequency-independent system settings
  • PMIC – RPM PMIC driver directly aggregates requests from each of the 
    masters for any of the systemwide PMIC resources controlled by the RPM
  • Watch Dog driver – Watch Dog driver is a fail-safe for incorrect or stuck 
    code
  • MPM driver – Used to program the MPM hardware block during 
    systemwide sleep
  • RPM message driver – RPM message protocol driver abstracts the RPM 
    message protocol away from other subsystem software

Messaging Masters

与RPM通过shared memory region交互进行dynamic and static resource/power management的可以有很多种。 
这个可以查看smd_type.h中的smd_channel_type。但目前看只有AP,MODEM,RIVA,TZ与RPM有交互，这个可以看message_ram_malloc()函数中的设置。 
其实也可以间接从rpm_config.c文件中的SystempData temp_config_data这个变量中看出来到底有几个部分是与RPM进行交互的。

RPM Initialization

在main.c文件中会逐个调用init_fcns[]变量中的函数进行初始化。当然也包括上面的资源的初始化。

const init_fcn init_fcns[] =
{
  populate_image_header,
  npa_init,

#if (!defined(MSM8909_STUBS) )
  railway_init_v2,
#endif
  PlatformInfo_Init, /* pm_init is using PlatformInfo APIs */
  pm_init,//LDO等资源的注册
  acc_init,

#if (!defined(MSM8909_STUBS) )
  railway_init_early_proxy_votes,
 #endif
  // xpu_init, /* cookie set here also indicates to SBL that railway is ready */
  (init_fcn)Clock_Init, //Clock资源的注册
  __init_stack_chk_guard,
  ddr_init,
  smem_init,
  init_smdl,
  version_init,     /* Needs to be after smem_init */
  rpmserver_init,
  rpm_server_init_done,
  railway_init_proxies_and_pins,

#if (!defined(MSM8909_STUBS) )
  rbcpr_init,
#endif  
  svs_init,
  vmpm_init,
  sleep_init,

#if (!defined(MSM8909_STUBS) )
  QDSSInit,
 #endif
  exceptions_enable,
  swevent_qdss_init,
  icb_init,

#if (!defined(MSM8909_STUBS) )
  debug_init,
  system_db_init,
  zqcal_task_init,
#endif
  rpm_settling_timer_init,
  gpio_toggle_init,
  rpm_set_changer_common_init,
}
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  1. pm_init ： LDO等资源的注册，然后接收rpm_message。接收rpm_message的部分高通代码没有给，所以看不到，但从rpm log来看，是有接收处理并反馈的过程的。
107.764902: rpm_message_received (master: "APSS") (message id: 723)
107.764908: rpm_svs (mode: RPM_SVS_FAST) (reason: imminent processing)
107.764924: rpm_svs (mode: RPM_SVS_FAST) (reason: imminent processing)
107.764939: rpm_process_request (master: "APSS") (resource type: ldoa) (id: 14)
107.764942: rpm_xlate_request (resource type: ldoa) (resource id: 14)
107.764946: rpm_apply_request (resource type: ldoa) (resource id: 14)
107.765033: rpm_send_message_response (master: "APSS")
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ldoa对应的resource type为RPM_LDO_A_REQ。这个在pm_rom_device_init()里的pm_rpm_ldo_register_resources(RPM_LDO_A_REQ, num_of_ldoa); 这里被注册，所以看进去最后xlate和apply最终都会被pm_rpm_ldo_translation()和pm_rpm_ldo_apply进行处理。pm_rpm_ldo_tranlation()读取kvp内容，pm_rpm_ldo_apply最终把request的内容设置上去。
kernel端在msm-pm8916-rpm-regulator.dtsi文件中定如下ldo内容

2. (init_fcn)Clock_Init：Clock资源的注册，这个过程和上面的也差不多 
3. rpmserver_init：启动接收message的进程

比如要设置LDO3的电压和电流，kvp的内容如下：

{
     “req0” : {
         {“rsrc” : “ldo0”}
         {“id” : 3}
         {“set” : 0}
         {“data” : {
             {“uv” : 1100000}
             {“mA00” : 130}
         }
         }
     }
}
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RPM log里边显示是APSS，这个在kernel里边也是有设置的，在msm-pm8916-rpm-regulator.dtsi里的

    rpm-regulator-ldoa14 {
        compatible = "qcom,rpm-smd-regulator-resource";
        qcom,resource-name = "ldoa";
        qcom,resource-id = <14>;
        qcom,regulator-type = <0>;
        qcom,hpm-min-load = <5000>;
        status = "disabled";

        regulator-l14 {
            compatible = "qcom,rpm-smd-regulator";
            regulator-name = "8916_l14";
            qcom,set = <3>;
            status = "disabled";
        };
    };
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MSM的retulator相关的驱动会读取这个，如果有需要发请求的话，会根据这个dtsi的内容，组织kvp，然后通过rpm_request通道发过去。 
rpm_request通道在rpm里边打开的地方是在rpm_handler.cpp里边的Hander::init()函数

void Handler::init()
{
    smdlPort_ = smdl_open("rpm_requests",
                          rpm->ees[ee_].edge,
                          SMDL_OPEN_FLAGS_MODE_PACKET,
                          rpm->ees[ee_].smd_fifo_sz,
                          (smdl_callback_t)rpm_smd_handler,
                          this);
}
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在对应的kernel端也有打开，可以参考msm8916.dtsi文件里边的设置。

        rpm_bus: qcom,rpm-smd {
                compatible = "qcom,rpm-smd";
                rpm-channel-name = "rpm_requests";
                rpm-channel-type = <15>; /* SMD_APPS_RPM */
        };
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以下是注册资源的函数和资源的类型： 
所有的资源都通过rpm_register_resource()函数注册。这些资源包括clock, ldo等。具体可以看下面的类型定义。

typedef enum
{
    RPM_TEST_REQ               = 0x74736574, // 'test' in little endiant
    RPM_CLOCK_0_REQ            = 0x306b6c63, // 'clk0' in little endian; misc clocks [CXO, QDSS, dcvs.ena]
    RPM_CLOCK_1_REQ            = 0x316b6c63, // 'clk1' in little endian; bus clocks [pcnoc, snoc, sysmmnoc]
    RPM_CLOCK_2_REQ            = 0x326b6c63, // 'clk2' in little endian; memory clocks [bimc]
    RPM_CLOCK_QPIC_REQ         = 0x63697071, // 'qpic' in little endian; clock [qpic]
    RPM_BUS_SLAVE_REQ          = 0x766c7362, // 'bslv' in little endian
    RPM_BUS_MASTER_REQ         = 0x73616d62, // 'bmas' in little endian
    RPM_BUS_SPDM_CLK_REQ       = 0x63707362, // 'bspc' in little endian
    RPM_BUS_MASTER_LATENCY_REQ = 0x74616c62, // 'blat' in little endian
    RPM_SMPS_A_REQ             = 0x61706D73, // 'smpa' in little endian
    RPM_LDO_A_REQ              = 0x616F646C, // 'ldoa'  in little endian
    RPM_NCP_A_REQ              = 0x6170636E, // 'ncpa'  in little endian
    RPM_VS_A_REQ               = 0x617376,   // 'vsa'   in little endian
    RPM_CLK_BUFFER_A_REQ       = 0x616B6C63, // 'clka' in little endian
    RPM_BOOST_A_REQ            = 0x61747362, // 'bsta' in little endian
    RPM_SMPS_B_REQ             = 0x62706D73, // 'smpb' in little endian
    RPM_LDO_B_REQ              = 0x626F646C, // 'ldob'  in little endian
    RPM_NCP_B_REQ              = 0x6270636E, // 'ncpb'  in little endian
    RPM_VS_B_REQ               = 0x627376,   // 'vsb'   in little endian
    RPM_CLK_BUFFER_B_REQ       = 0x626B6C63, // 'clk' in little endian
    RPM_BOOST_B_REQ            = 0x62747362, // 'bstb' in little endian
    RPM_SWEVENT_REQ            = 0x76657773, // 'swev' in little endian
    RPM_OCMEM_POWER_REQ        = 0x706d636f, // 憃cmp?in little endian
    RPM_RBCPR_REQ              = 0x727063,   // 'cpr'in little endian
    RPM_GPIO_TOGGLE_REQ        = 0x6F697067, // 'gpio' in little endian:[gpio0,gpio1,gpio2]
} rpm_resource_type;
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RPM Resouce Registration

  1. rpm_register_resource()：
Gpio_toggle.c (x:j3_ctc
hlos
pm_proccorepower
pmcommon):    rpm_register_resource(RPM_GPIO_TOGGLE_REQ, 3, sizeof(gpio_toggle_inrep), gpio_toggle_xlate, gpio_toggle_apply, 0);

Icb_rpm_spdm_req.c (x:j3_ctc
hlos
pm_proccoreusesicbsrccommon):  rpm_register_resource( RPM_BUS_SPDM_CLK_REQ,

Ocmem_resource.c (x:j3_ctc
hlos
pm_proccorepowerocmemsrc):    rpm_register_resource(RPM_OCMEM_POWER_REQ, 3, sizeof(rpm_ocmem_vote_int_rep), rpm_ocmem_xlate, rpm_ocmem_apply, 0);

Pm_rpm_boost_trans_apply.c (x:j3_ctc
hlos
pm_proccoresystemdriverspmic
pasrc
pm):            rpm_register_resource(resourceType, num_npa_resources + 1 , sizeof(pm_npa_boost_int_rep), pm_rpm_boost_translation, pm_rpm_boost_apply, (void *)boost_data);
Pm_rpm_clk_buffer_trans_apply.c (x:j3_ctc
hlos
pm_proccoresystemdriverspmic
pasrc
pm):         rpm_register_resource(resourceType, num_npa_resources + 1, 

Pm_rpm_ldo_trans_apply.c (x:j3_ctc
hlos
pm_proccoresystemdriverspmic
pasrc
pm):            rpm_register_resource(resourceType, num_npa_resources + 1, sizeof(pm_npa_ldo_int_rep), pm_rpm_ldo_translation, pm_rpm_ldo_apply, (void *)ldo_data);

Pm_rpm_smps_trans_apply.c (x:j3_ctc
hlos
pm_proccoresystemdriverspmic
pasrc
pm):            rpm_register_resource(resourceType, num_npa_resources + 1, sizeof(pm_npa_smps_int_rep), pm_rpm_smps_translation, pm_rpm_smps_apply, (void *)smps_data);

Pm_rpm_vs_trans_apply.c (x:j3_ctc
hlos
pm_proccoresystemdriverspmic
pasrc
pm):            rpm_register_resource(resourceType, num_npa_resources + 1, sizeof(pm_npa_vs_int_rep), pm_rpm_vs_translation, pm_rpm_vs_apply, (void *)vs_data);        

Rpmserver.cpp (x:j3_ctc
hlos
pm_proccorepower
pmserver):void rpm_register_resource

Rpmserver.h (x:j3_ctc
hlos
pm_proccoreapipower):void rpm_register_resource

Rpm_npa.cpp (x:j3_ctc
hlos
pm_proccorepower
pmserver):    rpm_register_resource(resource, num_npa_resources, sizeof(npa_request_data_t), rpm_npa_xlate, rpm_npa_apply, adapter);

Rpm_npa.cpp (x:j3_ctc
hlos
pm_proccorepower
pmserver):    rpm_register_resource(resource, num_npa_resources, sizeof(npa_request_data_t), rpm_npa_xlate, rpm_npa_apply, adapter);

Rpm_test_resource.cpp (x:j3_ctc
hlos
pm_proccorepower
pmserver):    rpm_register_resource(RPM_TEST_REQ, 1, 4, rpm_test_xlate, rpm_test_apply, 0);

Swevent.c (x:j3_ctc
hlos
pm_proccorepower
pmcommon):    rpm_register_resource(RPM_SWEVENT_REQ, 1, sizeof(swevent_inrep), rpm_swevent_xlate, rpm_trace_control, 0);
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所有的资源都是通过rpm_register_resource函数注册。可以看到像RPM_BUS_SPDM_CLK_REQ，RPM_GPIO_TOGGLE_REQ都是通过这个接口直接注册的。

  1. NPA相关也是通过rpm_register_resource注册，但是用了NPA的driver去实际注册资源和使用资源。 
    NPA相关的两个注册接口是：rpm_create_npa_adapter()，rpm_create_npa_settling_adapter()。 
    可以看到这两个就注册了三个CLOCK相关的资源，
---- rpm_create_npa_adapter Matches (8 in 5 files) ----
ClockRPM.c :  clk0_adapter = rpm_create_npa_adapter(RPM_CLOCK_0_REQ, 3); // Misc clocks: [CXO, QDSS, dcvs.ena]
ClockRPM.c :  clk1_adapter = rpm_create_npa_adapter(RPM_CLOCK_1_REQ, 2); // Bus clocks: [pcnoc, snoc]
Rpmserver.h :rpm_npa_adapter rpm_create_npa_adapter(rpm_resource_type resource, unsigned num_npa_resources);
Rpm_npa.cpp :rpm_npa_adapter rpm_create_npa_adapter(rpm_resource_type resource, unsigned num_npa_resources)

---- rpm_create_npa_settling_adapter Matches (5 in 5 files) ----
ClockRPM.c :  clk2_adapter = rpm_create_npa_settling_adapter(RPM_CLOCK_2_REQ, 1); // Memory clocks: [bimc ]
Rpmserver.h :rpm_npa_adapter rpm_create_npa_settling_adapter(rpm_resource_type resource, unsigned num_npa_resources);
Rpm_npa.cpp :rpm_npa_adapter rpm_create_npa_settling_adapter(rpm_resource_type resource, unsigned num_npa_resources)
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NPA client的创建函数是:npa_create_sync_client() 
NPA clien request的函数是:npa_issue_required_request() 
NPA client创建并request这个资源，必须要适用像下面这样的npa node。这个可以直接像下面这样定义。然后再使用。步骤如下：

1.定义npa node definition

    static npa_resource_definition sleep_uber_resource[] = 
    { 
      {
        "/sleep/uber",        /* Name */
        "on/off",             /* Units */
        0x7,                  /* Max State */
        &npa_or_plugin,       /* Plugin */
        NPA_RESOURCE_DEFAULT, /* Attributes */
        NULL,                 /* User Data */
      }
    };

    npa_node_definition sleep_uber_node = 
    { 
      "/node/sleep/uber", /* name */
      sleep_uber_driver,  /* driver_fcn */
      NPA_NODE_DEFAULT,   /* attributes */
      NULL,               /* data */
      0, NULL,            /* dependency count, dependency list */
      NPA_ARRAY(sleep_uber_resource)
    };
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2.npa_define_node(&sleep_uber_node, initial_state, NULL)，调用这个函数初始化这个NPA node 
3.创建Client

  uber_node_handle = npa_create_sync_client("/sleep/uber",
                                            "sleep",
                                            NPA_CLIENT_REQUIRED);
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4.npa_issue_required_request(uber_node_handle, request) ： request

RPM Resource handle

当子系统通过share memory发送请求给RPM。RPM负责处理这些请求并设置。RPM处理请求的流程如下： 
SMD IRQ ->smd_isr()->rpm_smd_handler() [在Handler::init函数中注册的，rpm_request channel的SMD处理函数]->Handler::queue()->schedule_me()->Handler::execute_until()->Handler::processMessage()->resource_ee_request()->发到每个资源注册xlate然后再调用apply等

下面以高通控制DDR频率(BIMC)的过程为例，看一下kernel这边怎么发送请求给RPM的。 
device tree设置如下：

    cpubw: qcom,cpubw@0 {
        reg = <0 4>;
        compatible = "qcom,devbw";
        governor = "cpufreq";
        qcom,src-dst-ports = <1 512>;
        qcom,active-only;
        qcom,bw-tbl = //这个频率表对应RPM中BIMC频率表，不过删掉了50MHz和9.6MHz。
            /*  73 9.60 MHz */
            /* 381  50MHz */
            <  762 /* 100 MHz */>,
            < 1525 /* 200 MHz */>,
            < 3051 /* 400 MHz */>,
            < 4066 /* 533 MHz */>;
    };
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对应的kernel代码在devfeq_devbw.c文件。根据算法算出当前应该设定的ddr总线频率之后，最后通过以下顺序发消息给RPM。这里暂时不讨论按什么规则选择需要的频率的，只看按什么路径发频率给RPM的。 
set_bw()->msm_bus_scale_client_update_request()->update_request_adhoc()[msm_bus_arb_adhoc.c]->update_path()->msm_bus_commit_data()->flush_bw_data()->send_rpm_msg()->msm_rpm_send_message()

System Sleep Overview

RPM除了对Clock和LDO等资源的管理之外，还管理整个系统睡眠。 
这里写图片描述

可以看到睡眠并不是通过shared memory发送消息给RPM的，而是子系统通过设置对应的SPM，SPM触发RPM相应的中断来完成的。 
kernel这边设置spm的模式的设置如下：

enum {
    MSM_SPM_MODE_DISABLED,
    MSM_SPM_MODE_CLOCK_GATING,
    MSM_SPM_MODE_RETENTION,
    MSM_SPM_MODE_GDHS,
    MSM_SPM_MODE_POWER_COLLAPSE,//设置成这个状态之后，对应的SPM应该就会触发RPM的对应的shutdown中断
    MSM_SPM_MODE_NR
};
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rpm中，与哪几个子系统传递接收message，然后和哪几个子系统的SPM进行交互，交互的中断号是多少的设置如下：

static SystemData temp_config_data =
{
    .num_ees = 4, // 4 EE's, [apps, modem, pronto, tz]
    .ees    = (EEData[] ) {
        [0] = {
            .edge      = SMD_APPS_RPM,
            .smd_fifo_sz = 1024,
            .ee_buflen = 256,
            .priority  = 4,
            .wakeupInt = (1 << 5) | (1 << 7),
            .spm       = {
                             .numCores = 1,
                             .bringupInts  = (unsigned[]) {  15 },
                             .bringupAcks  = (unsigned[]) {  20 },
                             .shutdownInts = (unsigned[]) {  14 },//这个应该是SPM睡眠的中断号
                             .shutdownAcks = (unsigned[]) {   4 },
                         },
        },
        [1] = {
            .edge      = SMD_MODEM_RPM,
            .smd_fifo_sz = 1024,
            .ee_buflen = 1024,
            .priority  = 2,
            .wakeupInt = (1 << 13) | (1 << 15),
            .spm       = {
                             .numCores = 1,
                             .bringupInts  = (unsigned[]) { 25 },
                             .bringupAcks  = (unsigned[]) { 22 },
                             .shutdownInts = (unsigned[]) { 24 },
                             .shutdownAcks = (unsigned[]) {  6 },
                         },
        },
        [2] = {
            .edge      = SMD_RIVA_RPM,
            .smd_fifo_sz = 1024,
            .ee_buflen = 256,
            .priority  = 1,
            .wakeupInt = (1 << 17) | (1 << 19),
            .spm       = {
                             .numCores = 1,
                             .bringupInts  = (unsigned[]) { 31 },
                             .bringupAcks  = (unsigned[]) { 23 },
                             .shutdownInts = (unsigned[]) { 30 },
                             .shutdownAcks = (unsigned[]) {  7 },
                         },
        },
        [3] = {
            .edge      = SMD_RPM_TZ,
            .smd_fifo_sz = 1024,
            .ee_buflen = 256,
            .priority  = 5,
            .wakeupInt = 0,
            .spm       = {
                             .numCores = 0,
                             .bringupInts  = (unsigned[]) { 31 },
                             .bringupAcks  = (unsigned[]) { 23 },
                             .shutdownInts = (unsigned[]) { 30 },
                             .shutdownAcks = (unsigned[]) {  7 },
                         },
        },
    },
    .supported_classes   = SUPPORTED_CLASSES,
    .supported_resources = SUPPORTED_RESOURCES,
    .classes             = (ResourceClassData[SUPPORTED_CLASSES]) { 0 },
    .resources           = (ResourceData[SUPPORTED_RESOURCES])    { 0 },
    .resource_seeds      = (int16_t[SUPPORTED_RESOURCES])         { 0 },
}
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但还不知道这些中断号到底怎么来的，，中断的个数都是1个，，这个怎么来的也还是不知~ 
这些内容在rpm_spm_init中会读取，然后设置中断。shutdownISR对应的中断处理函数为rpm_spm_shutdown_high_isr。 
这个中断函数会调用rpm_spm_state_machine()处理RPM状态机，进入或者阻止进入睡眠模式等。

void rpm_spm_state_machine(unsigned ee, rpm_spm_entry_reason reason)
{
    INTLOCK();

    bool        changed_state = false;
    EEData     *ee_state      = &(rpm->ees[ee]);
    SetChanger *changer       = ee_state->changer;

    do
    {
        switch(ee_state->subsystem_status)
        {
            case SPM_AWAKE:
                changed_state = FALSE;

                if(0 == ee_state->num_active_cores) 
                {//等待所有的core都进入睡眠！！之后才能走到GOITONG TO SLEEP状态！！
                    SPM_CHANGE_STATE(SPM_GOING_TO_SLEEP);
                }
                else
                {
                    // We're awake, so make sure we keep up with any incoming bringup reqs.
                    rpm_acknowledge_spm_handshakes(ee);
                }
                break;

            case SPM_GOING_TO_SLEEP:
                if(changed_state)
                {
                    // check for scheduled wakeup
                    uint64_t deadline = 0;

                    if(! rpm_get_wakeup_deadline(ee, deadline))
                    {
                      deadline = 0;
                    }
                    changer->setWakeTime (deadline);
                    // enqueue immediate set transition to sleep
                    changer->enqueue(RPM_SLEEP_SET, 0);
                }
                changed_state = FALSE;

                // When we've finished selecting the sleep set, we're officially asleep.
                if((SPM_TRANSITION_COMPLETE == reason) && (RPM_SLEEP_SET == changer->currentSet()))
                {
                  SPM_CHANGE_STATE(SPM_SLEEPING);
                }
                // However, we might get a wakeup request before we've made it all the way to sleep.
                if(SPM_BRINGUP_REQ == reason)
                {
                    // Set the preempt flag; this will force the set change to recycle if
                    // it's currently running.  It will notice the processor has woken up
                    // and stop performing its work.
                    theSchedule().preempt();
                }
                break;

            case SPM_SLEEPING:
                if(changed_state)
                {
                    // check for scheduled wakeup
                    uint64_t deadline = changer->getWakeTime ();

                    // enqueue scheduled wakeup request
                    changer->enqueue(RPM_ACTIVE_SET, deadline);
                }
                changed_state = FALSE;

                if(ee_state->num_active_cores > 0)
                {
                    SPM_CHANGE_STATE(SPM_WAKING_UP);
                }
                break;

            case SPM_WAKING_UP:
                if(changed_state)
                {
                    // work our way back to the active set
                    if(RPM_SLEEP_SET == changer->currentSet() || changer->inTransition())
                    {
                        changer->enqueue(RPM_ACTIVE_SET, 0);
                    }
                }
                changed_state = FALSE;

                // check for completion
                if(RPM_ACTIVE_SET == changer->currentSet() && !changer->inTransition())
                {
                  SPM_CHANGE_STATE(SPM_AWAKE);
                }
                break;
        }
    } while(changed_state);

    INTFREE();
}
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最终会跑到SetChanger::enqueue()里。

RPM与MPM的交互

这里写图片描述

RPM 状态读取

rpm的状态读取，在/d/rpm_stats里边可以读到AP这边设置的几个APSS,MPSS,PRONTO等几个对应的RPM状态。 
读的内容当然也是从rpm_request这个shared memory里边读的。相应的设置在msm8916-pm.dts文件里边有。

    qcom,rpm-stats@29dba0 {
        compatible = "qcom,rpm-stats";
        reg = <0x29dba0 0x1000>;
        reg-names = "phys_addr_base";
        qcom,sleep-stats-version = <2>;
    };
    qcom,rpm-master-stats@60150 {
        compatible = "qcom,rpm-master-stats";
        reg = <0x60150 0x2030>;
        qcom,masters = "APSS", "MPSS", "PRONTO";
        qcom,master-stats-version = <2>;
        qcom,master-offset = <4096>;
    };
    qcom,rpm-rbcpr-stats@0x29daa0  {
        compatible = "qcom,rpmrbcpr-stats";
        reg = <0x29daa0 0x1a0000>;
        qcom,start-offset = <0x190010>;
    };
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原文地址：https://www.cnblogs.com/liang123/p/6325251.html