path: root/stack/btm/btm_pm.cc

/******************************************************************************
 *
 *  Copyright (C) 2000-2012 Broadcom Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

/*****************************************************************************
 *
 *  This file contains functions that manages ACL link modes.
 *  This includes operations such as active, hold,
 *  park and sniff modes.
 *
 *  This module contains both internal and external (API)
 *  functions. External (API) functions are distinguishable
 *  by their names beginning with uppercase BTM.
 *
 *****************************************************************************/

#define LOG_TAG "bt_btm_pm"

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "bt_common.h"
#include "bt_types.h"
#include "bt_utils.h"
#include "btm_api.h"
#include "btm_int.h"
#include "btu.h"
#include "hcidefs.h"
#include "hcimsgs.h"
#include "l2c_int.h"
#include "osi/include/log.h"
#include "osi/include/osi.h"

/*****************************************************************************/
/*      to handle different modes                                            */
/*****************************************************************************/
#define BTM_PM_STORED_MASK 0x80 /* set this mask if the command is stored */
#define BTM_PM_NUM_SET_MODES 3  /* only hold, sniff & park */

/* Usage:  (ptr_features[ offset ] & mask )?true:false */
/* offset to supported feature */
const uint8_t btm_pm_mode_off[BTM_PM_NUM_SET_MODES] = {0, 0, 1};
/* mask to supported feature */
const uint8_t btm_pm_mode_msk[BTM_PM_NUM_SET_MODES] = {0x40, 0x80, 0x01};

#define BTM_PM_GET_MD1 1
#define BTM_PM_GET_MD2 2
#define BTM_PM_GET_COMP 3

const uint8_t
    btm_pm_md_comp_matrix[BTM_PM_NUM_SET_MODES * BTM_PM_NUM_SET_MODES] = {
        BTM_PM_GET_COMP, BTM_PM_GET_MD2,  BTM_PM_GET_MD2,

        BTM_PM_GET_MD1,  BTM_PM_GET_COMP, BTM_PM_GET_MD1,

        BTM_PM_GET_MD1,  BTM_PM_GET_MD2,  BTM_PM_GET_COMP};

/* function prototype */
static int btm_pm_find_acl_ind(const RawAddress& remote_bda);
static tBTM_STATUS btm_pm_snd_md_req(uint8_t pm_id, int link_ind,
                                     tBTM_PM_PWR_MD* p_mode);
static const char* mode_to_string(tBTM_PM_MODE mode);

#if (BTM_PM_DEBUG == TRUE)
const char* btm_pm_state_str[] = {"pm_active_state", "pm_hold_state",
                                  "pm_sniff_state", "pm_park_state",
                                  "pm_pend_state"};

const char* btm_pm_event_str[] = {"pm_set_mode_event", "pm_hci_sts_event",
                                  "pm_mod_chg_event", "pm_update_event"};

const char* btm_pm_action_str[] = {"pm_set_mode_action", "pm_update_db_action",
                                   "pm_mod_chg_action", "pm_hci_sts_action",
                                   "pm_update_action"};
#endif  // BTM_PM_DEBUG

/*****************************************************************************/
/*                     P U B L I C  F U N C T I O N S                        */
/*****************************************************************************/
/*******************************************************************************
 *
 * Function         BTM_PmRegister
 *
 * Description      register or deregister with power manager
 *
 * Returns          BTM_SUCCESS if successful,
 *                  BTM_NO_RESOURCES if no room to hold registration
 *                  BTM_ILLEGAL_VALUE
 *
 ******************************************************************************/
tBTM_STATUS BTM_PmRegister(uint8_t mask, uint8_t* p_pm_id,
                           tBTM_PM_STATUS_CBACK* p_cb) {
  int xx;

  /* de-register */
  if (mask & BTM_PM_DEREG) {
    if (*p_pm_id >= BTM_MAX_PM_RECORDS) return BTM_ILLEGAL_VALUE;
    btm_cb.pm_reg_db[*p_pm_id].mask = BTM_PM_REC_NOT_USED;
    return BTM_SUCCESS;
  }

  for (xx = 0; xx < BTM_MAX_PM_RECORDS; xx++) {
    /* find an unused entry */
    if (btm_cb.pm_reg_db[xx].mask == BTM_PM_REC_NOT_USED) {
      /* if register for notification, should provide callback routine */
      if (mask & BTM_PM_REG_NOTIF) {
        if (p_cb == NULL) return BTM_ILLEGAL_VALUE;
        btm_cb.pm_reg_db[xx].cback = p_cb;
      }
      btm_cb.pm_reg_db[xx].mask = mask;
      *p_pm_id = xx;
      return BTM_SUCCESS;
    }
  }

  return BTM_NO_RESOURCES;
}

/*******************************************************************************
 *
 * Function         BTM_SetPowerMode
 *
 * Description      store the mode in control block or
 *                  alter ACL connection behavior.
 *
 * Returns          BTM_SUCCESS if successful,
 *                  BTM_UNKNOWN_ADDR if bd addr is not active or bad
 *
 ******************************************************************************/
tBTM_STATUS BTM_SetPowerMode(uint8_t pm_id, const RawAddress& remote_bda,
                             tBTM_PM_PWR_MD* p_mode) {
  uint8_t* p_features;
  uint8_t* p_rem_features;
  int ind, acl_ind;
  tBTM_PM_MCB* p_cb = NULL; /* per ACL link */
  tBTM_PM_MODE mode;
  int temp_pm_id;

  if (pm_id >= BTM_MAX_PM_RECORDS) pm_id = BTM_PM_SET_ONLY_ID;

  if (p_mode == NULL) return BTM_ILLEGAL_VALUE;

  VLOG(2) << __func__ << " pm_id " << pm_id << " BDA: " << remote_bda
          << " mode:0x" << std::hex << p_mode->mode;

  /* take out the force bit */
  mode = p_mode->mode & ~BTM_PM_MD_FORCE;

  acl_ind = btm_pm_find_acl_ind(remote_bda);
  if (acl_ind == MAX_L2CAP_LINKS) return (BTM_UNKNOWN_ADDR);

  p_cb = &(btm_cb.pm_mode_db[acl_ind]);

  if (mode != BTM_PM_MD_ACTIVE) {
    /* check if the requested mode is supported */
    ind = mode - BTM_PM_MD_HOLD; /* make it base 0 */
    p_features = BTM_ReadLocalFeatures();
    p_rem_features = BTM_ReadRemoteFeatures(remote_bda);
    if (ind < BTM_PM_NUM_SET_MODES &&
        (!(p_features[btm_pm_mode_off[ind]] & btm_pm_mode_msk[ind]) ||
        ((p_rem_features != NULL) &&
         (!(p_rem_features[btm_pm_mode_off[ind]] & btm_pm_mode_msk[ind])))))
      return BTM_MODE_UNSUPPORTED;
  }

  if (mode == p_cb->state) /* the requested mode is current mode */
  {
    /* already in the requested mode and the current interval has less latency
     * than the max */
    if ((mode == BTM_PM_MD_ACTIVE) ||
        ((p_mode->mode & BTM_PM_MD_FORCE) && (p_mode->max >= p_cb->interval) &&
         (p_mode->min <= p_cb->interval)) ||
        ((p_mode->mode & BTM_PM_MD_FORCE) == 0 &&
         (p_mode->max >= p_cb->interval))) {
      BTM_TRACE_DEBUG("BTM_SetPowerMode: mode:0x%x interval %d max:%d, min:%d",
                      p_mode->mode, p_cb->interval, p_mode->max, p_mode->min);
      return BTM_SUCCESS;
    }
  }

  temp_pm_id = pm_id;
  if (pm_id == BTM_PM_SET_ONLY_ID) temp_pm_id = BTM_MAX_PM_RECORDS;

  /* update mode database */
  if (((pm_id != BTM_PM_SET_ONLY_ID) &&
       (btm_cb.pm_reg_db[pm_id].mask & BTM_PM_REG_SET)) ||
      ((pm_id == BTM_PM_SET_ONLY_ID) &&
       (btm_cb.pm_pend_link != MAX_L2CAP_LINKS || p_cb->state == BTM_PM_STS_PENDING))) {
    BTM_TRACE_DEBUG("BTM_SetPowerMode: Saving cmd acl_ind %d temp_pm_id %d",
                    acl_ind, temp_pm_id);
    /* Make sure mask is set to BTM_PM_REG_SET */
    btm_cb.pm_reg_db[temp_pm_id].mask |= BTM_PM_REG_SET;
    memcpy((&p_cb->req_mode[temp_pm_id]), p_mode, sizeof(tBTM_PM_PWR_MD));
    p_cb->chg_ind = true;
  }

  BTM_TRACE_DEBUG("btm_pm state:0x%x, pm_pend_link: %d", p_cb->state,
                  btm_cb.pm_pend_link);
  /* if mode == hold or pending, return */
  if ((p_cb->state == BTM_PM_STS_HOLD) || (p_cb->state == BTM_PM_STS_PENDING) ||
      (btm_cb.pm_pend_link != MAX_L2CAP_LINKS)) /* command pending */
  {
    if (acl_ind != btm_cb.pm_pend_link) {
      /* set the stored mask */
      p_cb->state |= BTM_PM_STORED_MASK;
      BTM_TRACE_DEBUG("btm_pm state stored:%d", acl_ind);
    }
    return BTM_CMD_STORED;
  }

  return btm_pm_snd_md_req(pm_id, acl_ind, p_mode);
}

/*******************************************************************************
 *
 * Function         BTM_ReadPowerMode
 *
 * Description      This returns the current mode for a specific
 *                  ACL connection.
 *
 * Input Param      remote_bda - device address of desired ACL connection
 *
 * Output Param     p_mode - address where the current mode is copied into.
 *                          BTM_ACL_MODE_NORMAL
 *                          BTM_ACL_MODE_HOLD
 *                          BTM_ACL_MODE_SNIFF
 *                          BTM_ACL_MODE_PARK
 *                          (valid only if return code is BTM_SUCCESS)
 *
 * Returns          BTM_SUCCESS if successful,
 *                  BTM_UNKNOWN_ADDR if bd addr is not active or bad
 *
 ******************************************************************************/
tBTM_STATUS BTM_ReadPowerMode(const RawAddress& remote_bda,
                              tBTM_PM_MODE* p_mode) {
  int acl_ind;

  acl_ind = btm_pm_find_acl_ind(remote_bda);
  if (acl_ind == MAX_L2CAP_LINKS) return (BTM_UNKNOWN_ADDR);

  if (btm_cb.pm_mode_db[acl_ind].state & BTM_PM_STORED_MASK) {
      *p_mode = btm_cb.pm_mode_db[acl_ind].state & (~BTM_PM_STORED_MASK);
  } else {
      *p_mode = btm_cb.pm_mode_db[acl_ind].state;
  }
  BTM_TRACE_DEBUG("BTM_ReadPowerMode mode:0x%x,",*p_mode);
  return BTM_SUCCESS;
}

/*******************************************************************************
 *
 * Function         btm_read_power_mode_state
 *
 * Description      This returns the current pm state for a specific
 *                  ACL connection.
 *
 * Input Param      remote_bda - device address of desired ACL connection
 *
 * Output Param     pmState - address where the current pm state is copied.
 *                          BTM_PM_ST_ACTIVE
 *                          BTM_PM_ST_HOLD
 *                          BTM_PM_ST_SNIFF
 *                          BTM_PM_ST_PARK
 *                          BTM_PM_ST_PENDING
 *                          (valid only if return code is BTM_SUCCESS)
 *
 * Returns          BTM_SUCCESS if successful,
 *                  BTM_UNKNOWN_ADDR if bd addr is not active or bad
 *
 ******************************************************************************/
tBTM_STATUS btm_read_power_mode_state(const RawAddress& remote_bda,
                                      tBTM_PM_STATE* pmState) {
  int acl_ind = btm_pm_find_acl_ind(remote_bda);

  if (acl_ind == MAX_L2CAP_LINKS) return (BTM_UNKNOWN_ADDR);

  if (btm_cb.pm_mode_db[acl_ind].state & BTM_PM_STORED_MASK) {
      *pmState = btm_cb.pm_mode_db[acl_ind].state & (~BTM_PM_STORED_MASK);
  } else {
      *pmState = btm_cb.pm_mode_db[acl_ind].state;
  }
  BTM_TRACE_DEBUG("btm_read_power_mode_state pmstate:0x%x,",*pmState);

  return BTM_SUCCESS;
}

/*******************************************************************************
 *
 * Function         BTM_SetSsrParams
 *
 * Description      This sends the given SSR parameters for the given ACL
 *                  connection if it is in ACTIVE mode.
 *
 * Input Param      remote_bda - device address of desired ACL connection
 *                  max_lat    - maximum latency (in 0.625ms)(0-0xFFFE)
 *                  min_rmt_to - minimum remote timeout
 *                  min_loc_to - minimum local timeout
 *
 *
 * Returns          BTM_SUCCESS if the HCI command is issued successful,
 *                  BTM_UNKNOWN_ADDR if bd addr is not active or bad
 *                  BTM_CMD_STORED if the command is stored
 *
 ******************************************************************************/
tBTM_STATUS BTM_SetSsrParams(const RawAddress& remote_bda, uint16_t max_lat,
                             uint16_t min_rmt_to, uint16_t min_loc_to) {
#if (BTM_SSR_INCLUDED == TRUE)
  int acl_ind;
  tBTM_PM_MCB* p_cb;

  acl_ind = btm_pm_find_acl_ind(remote_bda);
  if (acl_ind == MAX_L2CAP_LINKS) return (BTM_UNKNOWN_ADDR);

  if (BTM_PM_STS_ACTIVE == btm_cb.pm_mode_db[acl_ind].state ||
      BTM_PM_STS_SNIFF == btm_cb.pm_mode_db[acl_ind].state) {
    btsnd_hcic_sniff_sub_rate(btm_cb.acl_db[acl_ind].hci_handle, max_lat,
                              min_rmt_to, min_loc_to);
    return BTM_SUCCESS;
  }
  p_cb = &btm_cb.pm_mode_db[acl_ind];
  p_cb->max_lat = max_lat;
  p_cb->min_rmt_to = min_rmt_to;
  p_cb->min_loc_to = min_loc_to;
  return BTM_CMD_STORED;
#else
  return BTM_ILLEGAL_ACTION;
#endif  // BTM_SSR_INCLUDED
}

/*******************************************************************************
 *
 * Function         btm_pm_reset
 *
 * Description      as a part of the BTM reset process.
 *
 * Returns          void
 *
 ******************************************************************************/
void btm_pm_reset(void) {
  int xx;
  tBTM_PM_STATUS_CBACK* cb = NULL;

  /* clear the pending request for application */
  if ((btm_cb.pm_pend_id < BTM_MAX_PM_RECORDS) &&
      (btm_cb.pm_reg_db[btm_cb.pm_pend_id].mask & BTM_PM_REG_NOTIF)) {
    cb = btm_cb.pm_reg_db[btm_cb.pm_pend_id].cback;
  }

  /* clear the register record */
  for (xx = 0; xx < BTM_MAX_PM_RECORDS; xx++) {
    btm_cb.pm_reg_db[xx].mask = BTM_PM_REC_NOT_USED;
  }

  if (cb != NULL && btm_cb.pm_pend_link < MAX_L2CAP_LINKS)
    (*cb)(btm_cb.acl_db[btm_cb.pm_pend_link].remote_addr, BTM_PM_STS_ERROR,
          BTM_DEV_RESET, 0);

  /* no command pending */
  btm_cb.pm_pend_link = MAX_L2CAP_LINKS;
}

/*******************************************************************************
 *
 * Function         btm_pm_sm_alloc
 *
 * Description      This function initializes the control block of an ACL link.
 *                  It is called when an ACL connection is created.
 *
 * Returns          void
 *
 ******************************************************************************/
void btm_pm_sm_alloc(uint8_t ind) {
  tBTM_PM_MCB* p_db = &btm_cb.pm_mode_db[ind]; /* per ACL link */
  memset(p_db, 0, sizeof(tBTM_PM_MCB));
  p_db->state = BTM_PM_ST_ACTIVE;
#if (BTM_PM_DEBUG == TRUE)
  BTM_TRACE_DEBUG("btm_pm_sm_alloc ind:%d st:%d", ind, p_db->state);
#endif  // BTM_PM_DEBUG
}

/*******************************************************************************
 *
 * Function         btm_pm_find_acl_ind
 *
 * Description      This function initializes the control block of an ACL link.
 *                  It is called when an ACL connection is created.
 *
 * Returns          void
 *
 ******************************************************************************/
static int btm_pm_find_acl_ind(const RawAddress& remote_bda) {
  tACL_CONN* p = &btm_cb.acl_db[0];
  uint8_t xx;

  for (xx = 0; xx < MAX_L2CAP_LINKS; xx++, p++) {
    if (p->in_use && p->remote_addr == remote_bda &&
        p->transport == BT_TRANSPORT_BR_EDR) {
#if (BTM_PM_DEBUG == TRUE)
      BTM_TRACE_DEBUG("btm_pm_find_acl_ind ind:%d, st:%d", xx,
                      btm_cb.pm_mode_db[xx].state);
#endif  // BTM_PM_DEBUG
      break;
    }
  }
  return xx;
}

/*******************************************************************************
 *
 * Function     btm_pm_compare_modes
 * Description  get the "more active" mode of the 2
 * Returns      void
 *
 ******************************************************************************/
static tBTM_PM_PWR_MD* btm_pm_compare_modes(tBTM_PM_PWR_MD* p_md1,
                                            tBTM_PM_PWR_MD* p_md2,
                                            tBTM_PM_PWR_MD* p_res) {
  uint8_t res;

  if (p_md1 == NULL) {
    memcpy(p_res, p_md2, sizeof(tBTM_PM_PWR_MD));
    p_res->mode &= ~BTM_PM_MD_FORCE;

    return p_md2;
  }

  if (p_md2->mode == BTM_PM_MD_ACTIVE || p_md1->mode == BTM_PM_MD_ACTIVE) {
    return NULL;
  }

  /* check if force bit is involved */
  if (p_md1->mode & BTM_PM_MD_FORCE) {
    memcpy(p_res, p_md1, sizeof(tBTM_PM_PWR_MD));
    p_res->mode &= ~BTM_PM_MD_FORCE;
    return p_res;
  }

  if (p_md2->mode & BTM_PM_MD_FORCE) {
    memcpy(p_res, p_md2, sizeof(tBTM_PM_PWR_MD));
    p_res->mode &= ~BTM_PM_MD_FORCE;
    return p_res;
  }

  res = (p_md1->mode - 1) * BTM_PM_NUM_SET_MODES + (p_md2->mode - 1);
  res = btm_pm_md_comp_matrix[res];
  switch (res) {
    case BTM_PM_GET_MD1:
      memcpy(p_res, p_md1, sizeof(tBTM_PM_PWR_MD));
      return p_md1;

    case BTM_PM_GET_MD2:
      memcpy(p_res, p_md2, sizeof(tBTM_PM_PWR_MD));
      return p_md2;

    case BTM_PM_GET_COMP:
      p_res->mode = p_md1->mode;
      /* min of the two */
      p_res->max = (p_md1->max < p_md2->max) ? (p_md1->max) : (p_md2->max);
      /* max of the two */
      p_res->min = (p_md1->min > p_md2->min) ? (p_md1->min) : (p_md2->min);

      /* the intersection is NULL */
      if (p_res->max < p_res->min) return NULL;

      if (p_res->mode == BTM_PM_MD_SNIFF) {
        /* max of the two */
        p_res->attempt = (p_md1->attempt > p_md2->attempt) ? (p_md1->attempt)
                                                           : (p_md2->attempt);
        p_res->timeout = (p_md1->timeout > p_md2->timeout) ? (p_md1->timeout)
                                                           : (p_md2->timeout);
      }
      return p_res;
  }
  return NULL;
}

/*******************************************************************************
 *
 * Function     btm_pm_get_set_mode
 * Description  get the resulting mode from the registered parties, then compare
 *              it with the requested mode, if the command is from an
 *              unregistered party.
 *
 * Returns      void
 *
 ******************************************************************************/
static tBTM_PM_MODE btm_pm_get_set_mode(uint8_t pm_id, tBTM_PM_MCB* p_cb,
                                        tBTM_PM_PWR_MD* p_mode,
                                        tBTM_PM_PWR_MD* p_res) {
  int xx, loop_max;
  tBTM_PM_PWR_MD* p_md = NULL;

  if (p_mode != NULL && p_mode->mode & BTM_PM_MD_FORCE) {
    memcpy(p_res, p_mode, sizeof(tBTM_PM_PWR_MD));
    p_res->mode &= ~BTM_PM_MD_FORCE;
    return p_res->mode;
  }

  if (!p_mode)
    loop_max = BTM_MAX_PM_RECORDS + 1;
  else
    loop_max = BTM_MAX_PM_RECORDS;

  for (xx = 0; xx < loop_max; xx++) {
    /* g through all the registered "set" parties */
    if (btm_cb.pm_reg_db[xx].mask & BTM_PM_REG_SET) {
      if (p_cb->req_mode[xx].mode == BTM_PM_MD_ACTIVE) {
        /* if at least one registered (SET) party says ACTIVE, stay active */
        return BTM_PM_MD_ACTIVE;
      } else {
        /* if registered parties give conflicting information, stay active */
        if ((btm_pm_compare_modes(p_md, &p_cb->req_mode[xx], p_res)) == NULL)
          return BTM_PM_MD_ACTIVE;
        p_md = p_res;
      }
    }
  }

  /* if the resulting mode is NULL(nobody registers SET), use the requested mode
   */
  if (p_md == NULL) {
    if (p_mode)
      memcpy(p_res , p_mode, sizeof(tBTM_PM_PWR_MD));
    else /* p_mode is NULL when btm_pm_snd_md_req is called from
            btm_pm_proc_mode_change */
      return BTM_PM_MD_ACTIVE;
  } else {
    /* if the command is from unregistered party,
       compare the resulting mode from registered party*/
    if ((pm_id == BTM_PM_SET_ONLY_ID) &&
        ((btm_pm_compare_modes(p_mode, p_md, p_res)) == NULL))
      return BTM_PM_MD_ACTIVE;
  }

  return p_res->mode;
}

/*******************************************************************************
 *
 * Function     btm_pm_snd_md_req
 * Description  get the resulting mode and send the resuest to host controller
 * Returns      tBTM_STATUS
 *, bool    *p_chg_ind
 ******************************************************************************/
static tBTM_STATUS btm_pm_snd_md_req(uint8_t pm_id, int link_ind,
                                     tBTM_PM_PWR_MD* p_mode) {
  tBTM_PM_PWR_MD md_res;
  tBTM_PM_MODE mode;
  tBTM_PM_MCB* p_cb = &btm_cb.pm_mode_db[link_ind];
  bool chg_ind = false;
  memset(&md_res, 0, sizeof(tBTM_PM_PWR_MD));
  mode = btm_pm_get_set_mode(pm_id, p_cb, p_mode, &md_res);
  md_res.mode = mode;

#if (BTM_PM_DEBUG == TRUE)
  BTM_TRACE_DEBUG("btm_pm_snd_md_req link_ind:%d, mode: %d", link_ind, mode);
#endif  // BTM_PM_DEBUG

  if (p_cb->state == mode) {
    /* already in the resulting mode */
    if ((mode == BTM_PM_MD_ACTIVE) ||
        ((md_res.max >= p_cb->interval) && (md_res.min <= p_cb->interval))) {
      BTM_TRACE_DEBUG("btm_pm_snd_md_req p_cb->chg_ind:%d, mode: %d", p_cb->chg_ind, mode);
      p_cb->chg_ind = chg_ind;
      return BTM_CMD_STORED;
    }
    /* Otherwise, needs to wake, then sleep */
    chg_ind = true;
  }
  p_cb->chg_ind = chg_ind;

  /* cannot go directly from current mode to resulting mode. */
  if (mode != BTM_PM_MD_ACTIVE && p_cb->state != BTM_PM_MD_ACTIVE)
    p_cb->chg_ind = true; /* needs to wake, then sleep */

  if (p_cb->chg_ind == true) /* needs to wake first */
    md_res.mode = BTM_PM_MD_ACTIVE;
#if (BTM_SSR_INCLUDED == TRUE)
  else if (BTM_PM_MD_SNIFF == md_res.mode && p_cb->max_lat) {
    btsnd_hcic_sniff_sub_rate(btm_cb.acl_db[link_ind].hci_handle, p_cb->max_lat,
                              p_cb->min_rmt_to, p_cb->min_loc_to);
    p_cb->max_lat = 0;
  }
#endif  // BTM_SSR_INCLUDED
  /* Default is failure */
  btm_cb.pm_pend_link = MAX_L2CAP_LINKS;

  /* send the appropriate HCI command */
  btm_cb.pm_pend_id = pm_id;

#if (BTM_PM_DEBUG == TRUE)
  BTM_TRACE_DEBUG("btm_pm_snd_md_req state:0x%x, link_ind: %d", p_cb->state,
                  link_ind);
#endif  // BTM_PM_DEBUG

  BTM_TRACE_DEBUG("%s switching from %s to %s.", __func__,
                  mode_to_string(p_cb->state), mode_to_string(md_res.mode));
  switch (md_res.mode) {
    case BTM_PM_MD_ACTIVE:
      switch (p_cb->state) {
        case BTM_PM_MD_SNIFF:
          btsnd_hcic_exit_sniff_mode(btm_cb.acl_db[link_ind].hci_handle);
          btm_cb.pm_pend_link = link_ind;
          break;
        case BTM_PM_MD_PARK:
          btsnd_hcic_exit_park_mode(btm_cb.acl_db[link_ind].hci_handle);
          btm_cb.pm_pend_link = link_ind;
          break;
        default:
          /* Failure btm_cb.pm_pend_link = MAX_L2CAP_LINKS */
          break;
      }
      break;

    case BTM_PM_MD_HOLD:
      btsnd_hcic_hold_mode(btm_cb.acl_db[link_ind].hci_handle, md_res.max,
                           md_res.min);
      btm_cb.pm_pend_link = link_ind;
      break;

    case BTM_PM_MD_SNIFF:
      btsnd_hcic_sniff_mode(btm_cb.acl_db[link_ind].hci_handle, md_res.max,
                            md_res.min, md_res.attempt, md_res.timeout);
      btm_cb.pm_pend_link = link_ind;
      break;

    case BTM_PM_MD_PARK:
      btsnd_hcic_park_mode(btm_cb.acl_db[link_ind].hci_handle, md_res.max,
                           md_res.min);
      btm_cb.pm_pend_link = link_ind;
      break;
    default:
      /* Failure btm_cb.pm_pend_link = MAX_L2CAP_LINKS */
      break;
  }

  if (btm_cb.pm_pend_link == MAX_L2CAP_LINKS) {
/* the command was not sent */
#if (BTM_PM_DEBUG == TRUE)
    BTM_TRACE_DEBUG("pm_pend_link: %d", btm_cb.pm_pend_link);
#endif  // BTM_PM_DEBUG
    return (BTM_NO_RESOURCES);
  }

  return BTM_CMD_STARTED;
}

/*******************************************************************************
 *
 * Function         btm_pm_check_stored
 *
 * Description      This function is called when an HCI command status event
 *                  occurs to check if there's any PM command issued while
 *                  waiting for HCI command status.
 *
 * Returns          none.
 *
 ******************************************************************************/
static void btm_pm_check_stored(void) {
  int xx;
  for (xx = 0; xx < MAX_L2CAP_LINKS; xx++) {
    if (btm_cb.pm_mode_db[xx].state & BTM_PM_STORED_MASK) {
      btm_cb.pm_mode_db[xx].state &= ~BTM_PM_STORED_MASK;
      BTM_TRACE_DEBUG("btm_pm_check_stored :%d", xx);
      btm_pm_snd_md_req(BTM_PM_SET_ONLY_ID, xx, NULL);
      break;
    }
  }
}

/*******************************************************************************
 *
 * Function         btm_pm_proc_cmd_status
 *
 * Description      This function is called when an HCI command status event
 *                  occurs for power manager related commands.
 *
 * Input Parms      status - status of the event (HCI_SUCCESS if no errors)
 *
 * Returns          none.
 *
 ******************************************************************************/
void btm_pm_proc_cmd_status(uint8_t status) {
  tBTM_PM_MCB* p_cb;
  tBTM_PM_STATUS pm_status;
  tACL_CONN* p;
  tL2C_LCB* p_lcb;

  if (btm_cb.pm_pend_link >= MAX_L2CAP_LINKS) return;

  p_cb = &btm_cb.pm_mode_db[btm_cb.pm_pend_link];
  p = &btm_cb.acl_db[btm_cb.pm_pend_link];

  if (status == HCI_SUCCESS) {
    p_cb->state = BTM_PM_ST_PENDING;
    pm_status = BTM_PM_STS_PENDING;
#if (BTM_PM_DEBUG == TRUE)
    BTM_TRACE_DEBUG("btm_pm_proc_cmd_status new state:0x%x", p_cb->state);
#endif   // BTM_PM_DEBUG
  } else /* the command was not successfull. Stay in the same state */
  {
    pm_status = BTM_PM_STS_ERROR;
    p_lcb = l2cu_find_lcb_by_bd_addr(p->remote_addr, BT_TRANSPORT_BR_EDR);
    if (p_lcb != NULL) {
      if ((p_cb->state == BTM_PM_ST_ACTIVE) || (p_cb->state == BTM_PM_ST_SNIFF)) {
        /* There might be any pending packets due to SNIFF or PENDING state */
        /* Trigger L2C to start transmission of the pending packets. */
        BTM_TRACE_DEBUG(
            "btm mode change command failed; check l2c_link for outgoing packets");
        l2c_link_check_send_pkts(p_lcb, NULL, NULL);
      }
    }
  }

  /* notify the caller is appropriate */
  if ((btm_cb.pm_pend_id < BTM_MAX_PM_RECORDS) &&
      (btm_cb.pm_reg_db[btm_cb.pm_pend_id].mask & BTM_PM_REG_NOTIF)) {
    (*btm_cb.pm_reg_db[btm_cb.pm_pend_id].cback)(
        btm_cb.acl_db[btm_cb.pm_pend_link].remote_addr, pm_status, 0, status);
  }

/* no pending cmd now */
#if (BTM_PM_DEBUG == TRUE)
  BTM_TRACE_DEBUG(
      "btm_pm_proc_cmd_status state:0x%x, pm_pend_link: %d(new: %d)",
      p_cb->state, btm_cb.pm_pend_link, MAX_L2CAP_LINKS);
#endif  // BTM_PM_DEBUG
  btm_cb.pm_pend_link = MAX_L2CAP_LINKS;

  btm_pm_check_stored();
}

/*******************************************************************************
 *
 * Function         btm_process_mode_change
 *
 * Description      This function is called when an HCI mode change event
 *                  occurs.
 *
 * Input Parms      hci_status - status of the event (HCI_SUCCESS if no errors)
 *                  hci_handle - connection handle associated with the change
 *                  mode - HCI_MODE_ACTIVE, HCI_MODE_HOLD, HCI_MODE_SNIFF, or
 *                         HCI_MODE_PARK
 *                  interval - number of baseband slots (meaning depends on
 *                                                       mode)
 *
 * Returns          none.
 *
 ******************************************************************************/
void btm_pm_proc_mode_change(uint8_t hci_status, uint16_t hci_handle,
                             uint8_t mode, uint16_t interval) {
  tACL_CONN* p;
  tBTM_PM_MCB* p_cb = NULL;
  int xx, yy, zz;
  tBTM_PM_STATE old_state;
  tL2C_LCB* p_lcb;

  /* get the index to acl_db */
  xx = btm_handle_to_acl_index(hci_handle);
  if (xx >= MAX_L2CAP_LINKS) return;

  p = &btm_cb.acl_db[xx];

  /* update control block */
  p_cb = &(btm_cb.pm_mode_db[xx]);
  old_state = p_cb->state;
  p_cb->state = mode;
  p_cb->interval = interval;

  BTM_TRACE_DEBUG("%s switched from %s to %s.", __func__,
                  mode_to_string(old_state), mode_to_string(p_cb->state));

  p_lcb = l2cu_find_lcb_by_bd_addr(p->remote_addr, BT_TRANSPORT_BR_EDR);
  if (p_lcb != NULL) {
    if ((p_cb->state == BTM_PM_ST_ACTIVE) || (p_cb->state == BTM_PM_ST_SNIFF)) {
      /* There might be any pending packets due to SNIFF or PENDING state */
      /* Trigger L2C to start transmission of the pending packets. */
      BTM_TRACE_DEBUG(
          "btm mode change to active; check l2c_link for outgoing packets");
      l2c_link_check_send_pkts(p_lcb, NULL, NULL);
    }
  }

  /* notify registered parties */
  for (yy = 0; yy <= BTM_MAX_PM_RECORDS; yy++) {
    /* set req_mode  HOLD mode->ACTIVE */
    if ((mode == BTM_PM_MD_ACTIVE) &&
        (p_cb->req_mode[yy].mode == BTM_PM_MD_HOLD))
      p_cb->req_mode[yy].mode = BTM_PM_MD_ACTIVE;
  }

  /* new request has been made. - post a message to BTU task */
  if (old_state & BTM_PM_STORED_MASK) {
#if (BTM_PM_DEBUG == TRUE)
    BTM_TRACE_DEBUG("btm_pm_proc_mode_change: Sending stored req:%d", xx);
#endif  // BTM_PM_DEBUG
    btm_pm_snd_md_req(BTM_PM_SET_ONLY_ID, xx, NULL);
  } else {
    for (zz = 0; zz < MAX_L2CAP_LINKS; zz++) {
      if (btm_cb.pm_mode_db[zz].chg_ind == true) {
#if (BTM_PM_DEBUG == TRUE)
        BTM_TRACE_DEBUG("btm_pm_proc_mode_change: Sending PM req :%d", zz);
#endif  // BTM_PM_DEBUG
        btm_pm_snd_md_req(BTM_PM_SET_ONLY_ID, zz, NULL);
        break;
      }
    }
  }

  /* notify registered parties */
  for (yy = 0; yy < BTM_MAX_PM_RECORDS; yy++) {
    if (btm_cb.pm_reg_db[yy].mask & BTM_PM_REG_NOTIF) {
      (*btm_cb.pm_reg_db[yy].cback)(p->remote_addr, mode, interval, hci_status);
    }
  }
#if (BTM_SCO_INCLUDED == TRUE)
  /*check if sco disconnect  is waiting for the mode change */
  btm_sco_disc_chk_pend_for_modechange(hci_handle);
#endif

  /* If mode change was because of an active role switch or change link key */
  btm_cont_rswitch(p, btm_find_dev(p->remote_addr), hci_status);
}

/*******************************************************************************
 *
 * Function         btm_pm_proc_ssr_evt
 *
 * Description      This function is called when an HCI sniff subrating event
 *                  occurs.
 *
 * Returns          none.
 *
 ******************************************************************************/
#if (BTM_SSR_INCLUDED == TRUE)
void btm_pm_proc_ssr_evt(uint8_t* p, UNUSED_ATTR uint16_t evt_len) {
  uint8_t status;
  uint16_t handle;
  uint16_t max_rx_lat;
  int xx, yy;
  tBTM_PM_MCB* p_cb;
  tACL_CONN* p_acl = NULL;
  uint16_t use_ssr = true;

  STREAM_TO_UINT8(status, p);

  STREAM_TO_UINT16(handle, p);
  /* get the index to acl_db */
  xx = btm_handle_to_acl_index(handle);
  if (xx >= MAX_L2CAP_LINKS) return;

  p += 2;
  STREAM_TO_UINT16(max_rx_lat, p);
  p_cb = &(btm_cb.pm_mode_db[xx]);

  p_acl = &btm_cb.acl_db[xx];
  if (p_cb->interval == max_rx_lat) {
    /* using legacy sniff */
    use_ssr = false;
  }

  /* notify registered parties */
  for (yy = 0; yy < BTM_MAX_PM_RECORDS; yy++) {
    if (btm_cb.pm_reg_db[yy].mask & BTM_PM_REG_NOTIF) {
      if (p_acl) {
        (*btm_cb.pm_reg_db[yy].cback)(p_acl->remote_addr, BTM_PM_STS_SSR,
                                      use_ssr, status);
      }
    }
  }
}
#endif  // BTM_SSR_INCLUDED

/*******************************************************************************
 *
 * Function         btm_pm_is_mode_pend_link
 *
 * Description      This function is called to check if mode change pending on this acl
 *
 * Returns          true, if mode change pending
 *
 ******************************************************************************/
bool btm_pm_is_mode_pend_link(uint16_t hci_handle) {
  int acl_index;

  acl_index = btm_handle_to_acl_index(hci_handle);

  BTM_TRACE_DEBUG("btm_pm_is_mode_pend_link btm_cb.pm_pend_link:%d,acl_index:%d",
                   btm_cb.pm_pend_link, acl_index);

  if (acl_index >= MAX_L2CAP_LINKS) {
    return false;
  } else if (btm_cb.pm_pend_link == acl_index) {
    return true;
  } else {
    return false;
  }
}

/*******************************************************************************
 *
 * Function         btm_pm_device_in_active_or_sniff_mode
 *
 * Description      This function is called to check if in active or sniff mode
 *
 * Returns          true, if in active or sniff mode
 *
 ******************************************************************************/
bool btm_pm_device_in_active_or_sniff_mode(void) {
  /* The active state is the highest state-includes connected device and sniff
   * mode*/

  /* Covers active and sniff modes */
  if (BTM_GetNumAclLinks() > 0) {
    BTM_TRACE_DEBUG("%s - ACL links: %d", __func__, BTM_GetNumAclLinks());
    return true;
  }

  /* Check BLE states */
  if (btm_ble_get_conn_st() != BLE_CONN_IDLE) {
    BTM_TRACE_DEBUG("%s - BLE state: %x", __func__, btm_ble_get_conn_st());
    return true;
  }

  return false;
}

/*******************************************************************************
 *
 * Function         btm_pm_device_in_scan_state
 *
 * Description      This function is called to check if in paging, inquiry or
 *                  connecting mode
 *
 * Returns          true, if in paging, inquiry or connecting mode
 *
 ******************************************************************************/
bool btm_pm_device_in_scan_state(void) {
  /* Scan state-paging, inquiry, and trying to connect */

  /* Check for paging */
  if (btm_cb.is_paging || (!fixed_queue_is_empty(btm_cb.page_queue)) ||
      BTM_BL_PAGING_STARTED == btm_cb.busy_level) {
    BTM_TRACE_DEBUG("btm_pm_device_in_scan_state- paging");
    return true;
  }

  /* Check for inquiry */
  if ((btm_cb.btm_inq_vars.inq_active &
       (BTM_BR_INQ_ACTIVE_MASK | BTM_BLE_INQ_ACTIVE_MASK)) != 0) {
    BTM_TRACE_DEBUG("btm_pm_device_in_scan_state- Inq active");
    return true;
  }

  return false;
}

/*******************************************************************************
 *
 * Function         BTM_PM_ReadControllerState
 *
 * Description      This function is called to obtain the controller state
 *
 * Returns          Controller State-BTM_CONTRL_ACTIVE, BTM_CONTRL_SCAN, and
 *                  BTM_CONTRL_IDLE
 *
 ******************************************************************************/
tBTM_CONTRL_STATE BTM_PM_ReadControllerState(void) {
  if (true == btm_pm_device_in_active_or_sniff_mode())
    return BTM_CONTRL_ACTIVE;
  else if (true == btm_pm_device_in_scan_state())
    return BTM_CONTRL_SCAN;
  else
    return BTM_CONTRL_IDLE;
}

static const char* mode_to_string(tBTM_PM_MODE mode) {
  switch (mode) {
    case BTM_PM_MD_ACTIVE:
      return "ACTIVE";
    case BTM_PM_MD_SNIFF:
      return "SNIFF";
    case BTM_PM_MD_PARK:
      return "PARK";
    case BTM_PM_MD_HOLD:
      return "HOLD";
    default:
      return "UNKNOWN";
  }
}