drivers/net/wireless/brcm80211/brcmfmac/btcoex.c - kernel/bruno - Git at Google

 /*
  * Copyright (c) 2013 Broadcom Corporation
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 #include <linux/slab.h>
 #include <linux/netdevice.h>
 #include <net/cfg80211.h>

 #include <brcmu_wifi.h>
 #include <brcmu_utils.h>
 #include <defs.h>
 #include "core.h"
 #include "debug.h"
 #include "fwil.h"
 #include "fwil_types.h"
 #include "btcoex.h"
 #include "p2p.h"
 #include "cfg80211.h"

 /* T1 start SCO/eSCO priority suppression */
 #define BRCMF_BTCOEX_OPPR_WIN_TIME   2000

 /* BT registers values during DHCP */
 #define BRCMF_BT_DHCP_REG50 0x8022
 #define BRCMF_BT_DHCP_REG51 0
 #define BRCMF_BT_DHCP_REG64 0
 #define BRCMF_BT_DHCP_REG65 0
 #define BRCMF_BT_DHCP_REG71 0
 #define BRCMF_BT_DHCP_REG66 0x2710
 #define BRCMF_BT_DHCP_REG41 0x33
 #define BRCMF_BT_DHCP_REG68 0x190

 /* number of samples for SCO detection */
 #define BRCMF_BT_SCO_SAMPLES 12

 /**
 * enum brcmf_btcoex_state - BT coex DHCP state machine states
 * @BRCMF_BT_DHCP_IDLE: DCHP is idle
 * @BRCMF_BT_DHCP_START: DHCP started, wait before
 *	boosting wifi priority
 * @BRCMF_BT_DHCP_OPPR_WIN: graceful DHCP opportunity ended,
 *	boost wifi priority
 * @BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT: wifi priority boost end,
 *	restore defaults
 */
 enum brcmf_btcoex_state {
 	BRCMF_BT_DHCP_IDLE,
 	BRCMF_BT_DHCP_START,
 	BRCMF_BT_DHCP_OPPR_WIN,
 	BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT
 };

 /**
  * struct brcmf_btcoex_info - BT coex related information
  * @vif: interface for which request was done.
  * @timer: timer for DHCP state machine
  * @timeout: configured timeout.
  * @timer_on:  DHCP timer active
  * @dhcp_done: DHCP finished before T1/T2 timer expiration
  * @bt_state: DHCP state machine state
  * @work: DHCP state machine work
  * @cfg: driver private data for cfg80211 interface
  * @reg66: saved value of btc_params 66
  * @reg41: saved value of btc_params 41
  * @reg68: saved value of btc_params 68
  * @saved_regs_part1: flag indicating regs 66,41,68
  *	have been saved
  * @reg51: saved value of btc_params 51
  * @reg64: saved value of btc_params 64
  * @reg65: saved value of btc_params 65
  * @reg71: saved value of btc_params 71
  * @saved_regs_part1: flag indicating regs 50,51,64,65,71
  *	have been saved
  */
 struct brcmf_btcoex_info {
 	struct brcmf_cfg80211_vif *vif;
 	struct timer_list timer;
 	u16 timeout;
 	bool timer_on;
 	bool dhcp_done;
 	enum brcmf_btcoex_state bt_state;
 	struct work_struct work;
 	struct brcmf_cfg80211_info *cfg;
 	u32 reg66;
 	u32 reg41;
 	u32 reg68;
 	bool saved_regs_part1;
 	u32 reg50;
 	u32 reg51;
 	u32 reg64;
 	u32 reg65;
 	u32 reg71;
 	bool saved_regs_part2;
 };

 /**
  * brcmf_btcoex_params_write() - write btc_params firmware variable
  * @ifp: interface
  * @addr: btc_params register number
  * @data: data to write
  */
 static s32 brcmf_btcoex_params_write(struct brcmf_if *ifp, u32 addr, u32 data)
 {
 	struct {
 		__le32 addr;
 		__le32 data;
 	} reg_write;

 	reg_write.addr = cpu_to_le32(addr);
 	reg_write.data = cpu_to_le32(data);
 	return brcmf_fil_iovar_data_set(ifp, "btc_params",
 					&reg_write, sizeof(reg_write));
 }

 /**
  * brcmf_btcoex_params_read() - read btc_params firmware variable
  * @ifp: interface
  * @addr: btc_params register number
  * @data: read data
  */
 static s32 brcmf_btcoex_params_read(struct brcmf_if *ifp, u32 addr, u32 *data)
 {
 	*data = addr;

 	return brcmf_fil_iovar_int_get(ifp, "btc_params", data);
 }

 /**
  * brcmf_btcoex_boost_wifi() - control BT SCO/eSCO parameters
  * @btci: BT coex info
  * @trump_sco:
  *	true - set SCO/eSCO parameters for compatibility
  *		during DHCP window
  *	false - restore saved parameter values
  *
  * Enhanced BT COEX settings for eSCO compatibility during DHCP window
  */
 static void brcmf_btcoex_boost_wifi(struct brcmf_btcoex_info *btci,
 				    bool trump_sco)
 {
 	struct brcmf_if *ifp = brcmf_get_ifp(btci->cfg->pub, 0);

 	if (trump_sco && !btci->saved_regs_part2) {
 		/* this should reduce eSCO agressive
 		 * retransmit w/o breaking it
 		 */

 		/* save current */
 		brcmf_dbg(INFO, "new SCO/eSCO coex algo {save & override}\n");
 		brcmf_btcoex_params_read(ifp, 50, &btci->reg50);
 		brcmf_btcoex_params_read(ifp, 51, &btci->reg51);
 		brcmf_btcoex_params_read(ifp, 64, &btci->reg64);
 		brcmf_btcoex_params_read(ifp, 65, &btci->reg65);
 		brcmf_btcoex_params_read(ifp, 71, &btci->reg71);

 		btci->saved_regs_part2 = true;
 		brcmf_dbg(INFO,
 			  "saved bt_params[50,51,64,65,71]: 0x%x 0x%x 0x%x 0x%x 0x%x\n",
 			  btci->reg50, btci->reg51, btci->reg64,
 			  btci->reg65, btci->reg71);

 		/* pacify the eSco   */
 		brcmf_btcoex_params_write(ifp, 50, BRCMF_BT_DHCP_REG50);
 		brcmf_btcoex_params_write(ifp, 51, BRCMF_BT_DHCP_REG51);
 		brcmf_btcoex_params_write(ifp, 64, BRCMF_BT_DHCP_REG64);
 		brcmf_btcoex_params_write(ifp, 65, BRCMF_BT_DHCP_REG65);
 		brcmf_btcoex_params_write(ifp, 71, BRCMF_BT_DHCP_REG71);

 	} else if (btci->saved_regs_part2) {
 		/* restore previously saved bt params */
 		brcmf_dbg(INFO, "Do new SCO/eSCO coex algo {restore}\n");
 		brcmf_btcoex_params_write(ifp, 50, btci->reg50);
 		brcmf_btcoex_params_write(ifp, 51, btci->reg51);
 		brcmf_btcoex_params_write(ifp, 64, btci->reg64);
 		brcmf_btcoex_params_write(ifp, 65, btci->reg65);
 		brcmf_btcoex_params_write(ifp, 71, btci->reg71);

 		brcmf_dbg(INFO,
 			  "restored bt_params[50,51,64,65,71]: 0x%x 0x%x 0x%x 0x%x 0x%x\n",
 			  btci->reg50, btci->reg51, btci->reg64,
 			  btci->reg65, btci->reg71);

 		btci->saved_regs_part2 = false;
 	} else {
 		brcmf_dbg(INFO, "attempted to restore not saved BTCOEX params\n");
 	}
 }

 /**
  * brcmf_btcoex_is_sco_active() - check if SCO/eSCO is active
  * @ifp: interface
  *
  * return: true if SCO/eSCO session is active
  */
 static bool brcmf_btcoex_is_sco_active(struct brcmf_if *ifp)
 {
 	int ioc_res = 0;
 	bool res = false;
 	int sco_id_cnt = 0;
 	u32 param27;
 	int i;

 	for (i = 0; i < BRCMF_BT_SCO_SAMPLES; i++) {
 		ioc_res = brcmf_btcoex_params_read(ifp, 27, &param27);

 		if (ioc_res < 0) {
 			brcmf_err("ioc read btc params error\n");
 			break;
 		}

 		brcmf_dbg(INFO, "sample[%d], btc_params 27:%x\n", i, param27);

 		if ((param27 & 0x6) == 2) { /* count both sco & esco  */
 			sco_id_cnt++;
 		}

 		if (sco_id_cnt > 2) {
 			brcmf_dbg(INFO,
 				  "sco/esco detected, pkt id_cnt:%d samples:%d\n",
 				  sco_id_cnt, i);
 			res = true;
 			break;
 		}
 	}
 	brcmf_dbg(TRACE, "exit: result=%d\n", res);
 	return res;
 }

 /**
  * btcmf_btcoex_save_part1() - save first step parameters.
  */
 static void btcmf_btcoex_save_part1(struct brcmf_btcoex_info *btci)
 {
 	struct brcmf_if *ifp = btci->vif->ifp;

 	if (!btci->saved_regs_part1) {
 		/* Retrieve and save original reg value */
 		brcmf_btcoex_params_read(ifp, 66, &btci->reg66);
 		brcmf_btcoex_params_read(ifp, 41, &btci->reg41);
 		brcmf_btcoex_params_read(ifp, 68, &btci->reg68);
 		btci->saved_regs_part1 = true;
 		brcmf_dbg(INFO,
 			  "saved btc_params regs (66,41,68) 0x%x 0x%x 0x%x\n",
 			  btci->reg66, btci->reg41,
 			  btci->reg68);
 	}
 }

 /**
  * brcmf_btcoex_restore_part1() - restore first step parameters.
  */
 static void brcmf_btcoex_restore_part1(struct brcmf_btcoex_info *btci)
 {
 	struct brcmf_if *ifp;

 	if (btci->saved_regs_part1) {
 		btci->saved_regs_part1 = false;
 		ifp = btci->vif->ifp;
 		brcmf_btcoex_params_write(ifp, 66, btci->reg66);
 		brcmf_btcoex_params_write(ifp, 41, btci->reg41);
 		brcmf_btcoex_params_write(ifp, 68, btci->reg68);
 		brcmf_dbg(INFO,
 			  "restored btc_params regs {66,41,68} 0x%x 0x%x 0x%x\n",
 			  btci->reg66, btci->reg41,
 			  btci->reg68);
 	}
 }

 /**
  * brcmf_btcoex_timerfunc() - BT coex timer callback
  */
 static void brcmf_btcoex_timerfunc(ulong data)
 {
 	struct brcmf_btcoex_info *bt_local = (struct brcmf_btcoex_info *)data;
 	brcmf_dbg(TRACE, "enter\n");

 	bt_local->timer_on = false;
 	schedule_work(&bt_local->work);
 }

 /**
  * brcmf_btcoex_handler() - BT coex state machine work handler
  * @work: work
  */
 static void brcmf_btcoex_handler(struct work_struct *work)
 {
 	struct brcmf_btcoex_info *btci;
 	btci = container_of(work, struct brcmf_btcoex_info, work);
 	if (btci->timer_on) {
 		btci->timer_on = false;
 		del_timer_sync(&btci->timer);
 	}

 	switch (btci->bt_state) {
 	case BRCMF_BT_DHCP_START:
 		/* DHCP started provide OPPORTUNITY window
 		   to get DHCP address
 		*/
 		brcmf_dbg(INFO, "DHCP started\n");
 		btci->bt_state = BRCMF_BT_DHCP_OPPR_WIN;
 		if (btci->timeout < BRCMF_BTCOEX_OPPR_WIN_TIME) {
 			mod_timer(&btci->timer, btci->timer.expires);
 		} else {
 			btci->timeout -= BRCMF_BTCOEX_OPPR_WIN_TIME;
 			mod_timer(&btci->timer,
 				  jiffies +
 				  msecs_to_jiffies(BRCMF_BTCOEX_OPPR_WIN_TIME));
 		}
 		btci->timer_on = true;
 		break;

 	case BRCMF_BT_DHCP_OPPR_WIN:
 		if (btci->dhcp_done) {
 			brcmf_dbg(INFO, "DHCP done before T1 expiration\n");
 			goto idle;
 		}

 		/* DHCP is not over yet, start lowering BT priority */
 		brcmf_dbg(INFO, "DHCP T1:%d expired\n",
 			  BRCMF_BTCOEX_OPPR_WIN_TIME);
 		brcmf_btcoex_boost_wifi(btci, true);

 		btci->bt_state = BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT;
 		mod_timer(&btci->timer,
 			  jiffies + msecs_to_jiffies(btci->timeout));
 		btci->timer_on = true;
 		break;

 	case BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT:
 		if (btci->dhcp_done)
 			brcmf_dbg(INFO, "DHCP done before T2 expiration\n");
 		else
 			brcmf_dbg(INFO, "DHCP T2:%d expired\n",
 				  BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT);

 		goto idle;

 	default:
 		brcmf_err("invalid state=%d !!!\n", btci->bt_state);
 		goto idle;
 	}

 	return;

 idle:
 	btci->bt_state = BRCMF_BT_DHCP_IDLE;
 	btci->timer_on = false;
 	brcmf_btcoex_boost_wifi(btci, false);
 	cfg80211_crit_proto_stopped(&btci->vif->wdev, GFP_KERNEL);
 	brcmf_btcoex_restore_part1(btci);
 	btci->vif = NULL;
 }

 /**
  * brcmf_btcoex_attach() - initialize BT coex data
  * @cfg: driver private cfg80211 data
  *
  * return: 0 on success
  */
 int brcmf_btcoex_attach(struct brcmf_cfg80211_info *cfg)
 {
 	struct brcmf_btcoex_info *btci = NULL;
 	brcmf_dbg(TRACE, "enter\n");

 	btci = kmalloc(sizeof(struct brcmf_btcoex_info), GFP_KERNEL);
 	if (!btci)
 		return -ENOMEM;

 	btci->bt_state = BRCMF_BT_DHCP_IDLE;

 	/* Set up timer for BT  */
 	btci->timer_on = false;
 	btci->timeout = BRCMF_BTCOEX_OPPR_WIN_TIME;
 	init_timer(&btci->timer);
 	btci->timer.data = (ulong)btci;
 	btci->timer.function = brcmf_btcoex_timerfunc;
 	btci->cfg = cfg;
 	btci->saved_regs_part1 = false;
 	btci->saved_regs_part2 = false;

 	INIT_WORK(&btci->work, brcmf_btcoex_handler);

 	cfg->btcoex = btci;
 	return 0;
 }

 /**
  * brcmf_btcoex_detach - clean BT coex data
  * @cfg: driver private cfg80211 data
  */
 void brcmf_btcoex_detach(struct brcmf_cfg80211_info *cfg)
 {
 	brcmf_dbg(TRACE, "enter\n");

 	if (!cfg->btcoex)
 		return;

 	if (cfg->btcoex->timer_on) {
 		cfg->btcoex->timer_on = false;
 		del_timer_sync(&cfg->btcoex->timer);
 	}

 	cancel_work_sync(&cfg->btcoex->work);

 	brcmf_btcoex_boost_wifi(cfg->btcoex, false);
 	brcmf_btcoex_restore_part1(cfg->btcoex);

 	kfree(cfg->btcoex);
 	cfg->btcoex = NULL;
 }

 static void brcmf_btcoex_dhcp_start(struct brcmf_btcoex_info *btci)
 {
 	struct brcmf_if *ifp = btci->vif->ifp;

 	btcmf_btcoex_save_part1(btci);
 	/* set new regs values */
 	brcmf_btcoex_params_write(ifp, 66, BRCMF_BT_DHCP_REG66);
 	brcmf_btcoex_params_write(ifp, 41, BRCMF_BT_DHCP_REG41);
 	brcmf_btcoex_params_write(ifp, 68, BRCMF_BT_DHCP_REG68);
 	btci->dhcp_done = false;
 	btci->bt_state = BRCMF_BT_DHCP_START;
 	schedule_work(&btci->work);
 	brcmf_dbg(TRACE, "enable BT DHCP Timer\n");
 }

 static void brcmf_btcoex_dhcp_end(struct brcmf_btcoex_info *btci)
 {
 	/* Stop any bt timer because DHCP session is done */
 	btci->dhcp_done = true;
 	if (btci->timer_on) {
 		brcmf_dbg(INFO, "disable BT DHCP Timer\n");
 		btci->timer_on = false;
 		del_timer_sync(&btci->timer);

 		/* schedule worker if transition to IDLE is needed */
 		if (btci->bt_state != BRCMF_BT_DHCP_IDLE) {
 			brcmf_dbg(INFO, "bt_state:%d\n",
 				  btci->bt_state);
 			schedule_work(&btci->work);
 		}
 	} else {
 		/* Restore original values */
 		brcmf_btcoex_restore_part1(btci);
 	}
 }

 /**
  * brcmf_btcoex_set_mode - set BT coex mode
  * @cfg: driver private cfg80211 data
  * @mode: Wifi-Bluetooth coexistence mode
  *
  * return: 0 on success
  */
 int brcmf_btcoex_set_mode(struct brcmf_cfg80211_vif *vif,
 			  enum brcmf_btcoex_mode mode, u16 duration)
 {
 	struct brcmf_cfg80211_info *cfg = wiphy_priv(vif->wdev.wiphy);
 	struct brcmf_btcoex_info *btci = cfg->btcoex;
 	struct brcmf_if *ifp = brcmf_get_ifp(cfg->pub, 0);

 	switch (mode) {
 	case BRCMF_BTCOEX_DISABLED:
 		brcmf_dbg(INFO, "DHCP session starts\n");
 		if (btci->bt_state != BRCMF_BT_DHCP_IDLE)
 			return -EBUSY;
 		/* Start BT timer only for SCO connection */
 		if (brcmf_btcoex_is_sco_active(ifp)) {
 			btci->timeout = duration;
 			btci->vif = vif;
 			brcmf_btcoex_dhcp_start(btci);
 		}
 		break;

 	case BRCMF_BTCOEX_ENABLED:
 		brcmf_dbg(INFO, "DHCP session ends\n");
 		if (btci->bt_state != BRCMF_BT_DHCP_IDLE &&
 		    vif == btci->vif) {
 			brcmf_btcoex_dhcp_end(btci);
 		}
 		break;
 	default:
 		brcmf_dbg(INFO, "Unknown mode, ignored\n");
 	}
 	return 0;
 }
	/*
	* Copyright (c) 2013 Broadcom Corporation
	*
	* Permission to use, copy, modify, and/or distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
	* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
	* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
	* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	*/
	#include <linux/slab.h>
	#include <linux/netdevice.h>
	#include <net/cfg80211.h>

	#include <brcmu_wifi.h>
	#include <brcmu_utils.h>
	#include <defs.h>
	#include "core.h"
	#include "debug.h"
	#include "fwil.h"
	#include "fwil_types.h"
	#include "btcoex.h"
	#include "p2p.h"
	#include "cfg80211.h"

	/* T1 start SCO/eSCO priority suppression */
	#define BRCMF_BTCOEX_OPPR_WIN_TIME 2000

	/* BT registers values during DHCP */
	#define BRCMF_BT_DHCP_REG50 0x8022
	#define BRCMF_BT_DHCP_REG51 0
	#define BRCMF_BT_DHCP_REG64 0
	#define BRCMF_BT_DHCP_REG65 0
	#define BRCMF_BT_DHCP_REG71 0
	#define BRCMF_BT_DHCP_REG66 0x2710
	#define BRCMF_BT_DHCP_REG41 0x33
	#define BRCMF_BT_DHCP_REG68 0x190

	/* number of samples for SCO detection */
	#define BRCMF_BT_SCO_SAMPLES 12

	/**
	* enum brcmf_btcoex_state - BT coex DHCP state machine states
	* @BRCMF_BT_DHCP_IDLE: DCHP is idle
	* @BRCMF_BT_DHCP_START: DHCP started, wait before
	* boosting wifi priority
	* @BRCMF_BT_DHCP_OPPR_WIN: graceful DHCP opportunity ended,
	* boost wifi priority
	* @BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT: wifi priority boost end,
	* restore defaults
	*/
	enum brcmf_btcoex_state {
	BRCMF_BT_DHCP_IDLE,
	BRCMF_BT_DHCP_START,
	BRCMF_BT_DHCP_OPPR_WIN,
	BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT
	};

	/**
	* struct brcmf_btcoex_info - BT coex related information
	* @vif: interface for which request was done.
	* @timer: timer for DHCP state machine
	* @timeout: configured timeout.
	* @timer_on: DHCP timer active
	* @dhcp_done: DHCP finished before T1/T2 timer expiration
	* @bt_state: DHCP state machine state
	* @work: DHCP state machine work
	* @cfg: driver private data for cfg80211 interface
	* @reg66: saved value of btc_params 66
	* @reg41: saved value of btc_params 41
	* @reg68: saved value of btc_params 68
	* @saved_regs_part1: flag indicating regs 66,41,68
	* have been saved
	* @reg51: saved value of btc_params 51
	* @reg64: saved value of btc_params 64
	* @reg65: saved value of btc_params 65
	* @reg71: saved value of btc_params 71
	* @saved_regs_part1: flag indicating regs 50,51,64,65,71
	* have been saved
	*/
	struct brcmf_btcoex_info {
	struct brcmf_cfg80211_vif *vif;
	struct timer_list timer;
	u16 timeout;
	bool timer_on;
	bool dhcp_done;
	enum brcmf_btcoex_state bt_state;
	struct work_struct work;
	struct brcmf_cfg80211_info *cfg;
	u32 reg66;
	u32 reg41;
	u32 reg68;
	bool saved_regs_part1;
	u32 reg50;
	u32 reg51;
	u32 reg64;
	u32 reg65;
	u32 reg71;
	bool saved_regs_part2;
	};

	/**
	* brcmf_btcoex_params_write() - write btc_params firmware variable
	* @ifp: interface
	* @addr: btc_params register number
	* @data: data to write
	*/
	static s32 brcmf_btcoex_params_write(struct brcmf_if *ifp, u32 addr, u32 data)
	{
	struct {
	__le32 addr;
	__le32 data;
	} reg_write;

	reg_write.addr = cpu_to_le32(addr);
	reg_write.data = cpu_to_le32(data);
	return brcmf_fil_iovar_data_set(ifp, "btc_params",
	&reg_write, sizeof(reg_write));
	}

	/**
	* brcmf_btcoex_params_read() - read btc_params firmware variable
	* @ifp: interface
	* @addr: btc_params register number
	* @data: read data
	*/
	static s32 brcmf_btcoex_params_read(struct brcmf_if ifp, u32 addr, u32 data)
	{
	*data = addr;

	return brcmf_fil_iovar_int_get(ifp, "btc_params", data);
	}

	/**
	* brcmf_btcoex_boost_wifi() - control BT SCO/eSCO parameters
	* @btci: BT coex info
	* @trump_sco:
	* true - set SCO/eSCO parameters for compatibility
	* during DHCP window
	* false - restore saved parameter values
	*
	* Enhanced BT COEX settings for eSCO compatibility during DHCP window
	*/
	static void brcmf_btcoex_boost_wifi(struct brcmf_btcoex_info *btci,
	bool trump_sco)
	{
	struct brcmf_if *ifp = brcmf_get_ifp(btci->cfg->pub, 0);

	if (trump_sco && !btci->saved_regs_part2) {
	/* this should reduce eSCO agressive
	* retransmit w/o breaking it
	*/

	/* save current */
	brcmf_dbg(INFO, "new SCO/eSCO coex algo {save & override}\n");
	brcmf_btcoex_params_read(ifp, 50, &btci->reg50);
	brcmf_btcoex_params_read(ifp, 51, &btci->reg51);
	brcmf_btcoex_params_read(ifp, 64, &btci->reg64);
	brcmf_btcoex_params_read(ifp, 65, &btci->reg65);
	brcmf_btcoex_params_read(ifp, 71, &btci->reg71);

	btci->saved_regs_part2 = true;
	brcmf_dbg(INFO,
	"saved bt_params[50,51,64,65,71]: 0x%x 0x%x 0x%x 0x%x 0x%x\n",
	btci->reg50, btci->reg51, btci->reg64,
	btci->reg65, btci->reg71);

	/* pacify the eSco */
	brcmf_btcoex_params_write(ifp, 50, BRCMF_BT_DHCP_REG50);
	brcmf_btcoex_params_write(ifp, 51, BRCMF_BT_DHCP_REG51);
	brcmf_btcoex_params_write(ifp, 64, BRCMF_BT_DHCP_REG64);
	brcmf_btcoex_params_write(ifp, 65, BRCMF_BT_DHCP_REG65);
	brcmf_btcoex_params_write(ifp, 71, BRCMF_BT_DHCP_REG71);

	} else if (btci->saved_regs_part2) {
	/* restore previously saved bt params */
	brcmf_dbg(INFO, "Do new SCO/eSCO coex algo {restore}\n");
	brcmf_btcoex_params_write(ifp, 50, btci->reg50);
	brcmf_btcoex_params_write(ifp, 51, btci->reg51);
	brcmf_btcoex_params_write(ifp, 64, btci->reg64);
	brcmf_btcoex_params_write(ifp, 65, btci->reg65);
	brcmf_btcoex_params_write(ifp, 71, btci->reg71);

	brcmf_dbg(INFO,
	"restored bt_params[50,51,64,65,71]: 0x%x 0x%x 0x%x 0x%x 0x%x\n",
	btci->reg50, btci->reg51, btci->reg64,
	btci->reg65, btci->reg71);

	btci->saved_regs_part2 = false;
	} else {
	brcmf_dbg(INFO, "attempted to restore not saved BTCOEX params\n");
	}
	}

	/**
	* brcmf_btcoex_is_sco_active() - check if SCO/eSCO is active
	* @ifp: interface
	*
	* return: true if SCO/eSCO session is active
	*/
	static bool brcmf_btcoex_is_sco_active(struct brcmf_if *ifp)
	{
	int ioc_res = 0;
	bool res = false;
	int sco_id_cnt = 0;
	u32 param27;
	int i;

	for (i = 0; i < BRCMF_BT_SCO_SAMPLES; i++) {
	ioc_res = brcmf_btcoex_params_read(ifp, 27, &param27);

	if (ioc_res < 0) {
	brcmf_err("ioc read btc params error\n");
	break;
	}

	brcmf_dbg(INFO, "sample[%d], btc_params 27:%x\n", i, param27);

	if ((param27 & 0x6) == 2) { /* count both sco & esco */
	sco_id_cnt++;
	}

	if (sco_id_cnt > 2) {
	brcmf_dbg(INFO,
	"sco/esco detected, pkt id_cnt:%d samples:%d\n",
	sco_id_cnt, i);
	res = true;
	break;
	}
	}
	brcmf_dbg(TRACE, "exit: result=%d\n", res);
	return res;
	}

	/**
	* btcmf_btcoex_save_part1() - save first step parameters.
	*/
	static void btcmf_btcoex_save_part1(struct brcmf_btcoex_info *btci)
	{
	struct brcmf_if *ifp = btci->vif->ifp;

	if (!btci->saved_regs_part1) {
	/* Retrieve and save original reg value */
	brcmf_btcoex_params_read(ifp, 66, &btci->reg66);
	brcmf_btcoex_params_read(ifp, 41, &btci->reg41);
	brcmf_btcoex_params_read(ifp, 68, &btci->reg68);
	btci->saved_regs_part1 = true;
	brcmf_dbg(INFO,
	"saved btc_params regs (66,41,68) 0x%x 0x%x 0x%x\n",
	btci->reg66, btci->reg41,
	btci->reg68);
	}
	}

	/**
	* brcmf_btcoex_restore_part1() - restore first step parameters.
	*/
	static void brcmf_btcoex_restore_part1(struct brcmf_btcoex_info *btci)
	{
	struct brcmf_if *ifp;

	if (btci->saved_regs_part1) {
	btci->saved_regs_part1 = false;
	ifp = btci->vif->ifp;
	brcmf_btcoex_params_write(ifp, 66, btci->reg66);
	brcmf_btcoex_params_write(ifp, 41, btci->reg41);
	brcmf_btcoex_params_write(ifp, 68, btci->reg68);
	brcmf_dbg(INFO,
	"restored btc_params regs {66,41,68} 0x%x 0x%x 0x%x\n",
	btci->reg66, btci->reg41,
	btci->reg68);
	}
	}

	/**
	* brcmf_btcoex_timerfunc() - BT coex timer callback
	*/
	static void brcmf_btcoex_timerfunc(ulong data)
	{
	struct brcmf_btcoex_info bt_local = (struct brcmf_btcoex_info )data;
	brcmf_dbg(TRACE, "enter\n");

	bt_local->timer_on = false;
	schedule_work(&bt_local->work);
	}

	/**
	* brcmf_btcoex_handler() - BT coex state machine work handler
	* @work: work
	*/
	static void brcmf_btcoex_handler(struct work_struct *work)
	{
	struct brcmf_btcoex_info *btci;
	btci = container_of(work, struct brcmf_btcoex_info, work);
	if (btci->timer_on) {
	btci->timer_on = false;
	del_timer_sync(&btci->timer);
	}

	switch (btci->bt_state) {
	case BRCMF_BT_DHCP_START:
	/* DHCP started provide OPPORTUNITY window
	to get DHCP address
	*/
	brcmf_dbg(INFO, "DHCP started\n");
	btci->bt_state = BRCMF_BT_DHCP_OPPR_WIN;
	if (btci->timeout < BRCMF_BTCOEX_OPPR_WIN_TIME) {
	mod_timer(&btci->timer, btci->timer.expires);
	} else {
	btci->timeout -= BRCMF_BTCOEX_OPPR_WIN_TIME;
	mod_timer(&btci->timer,
	jiffies +
	msecs_to_jiffies(BRCMF_BTCOEX_OPPR_WIN_TIME));
	}
	btci->timer_on = true;
	break;

	case BRCMF_BT_DHCP_OPPR_WIN:
	if (btci->dhcp_done) {
	brcmf_dbg(INFO, "DHCP done before T1 expiration\n");
	goto idle;
	}

	/* DHCP is not over yet, start lowering BT priority */
	brcmf_dbg(INFO, "DHCP T1:%d expired\n",
	BRCMF_BTCOEX_OPPR_WIN_TIME);
	brcmf_btcoex_boost_wifi(btci, true);

	btci->bt_state = BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT;
	mod_timer(&btci->timer,
	jiffies + msecs_to_jiffies(btci->timeout));
	btci->timer_on = true;
	break;

	case BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT:
	if (btci->dhcp_done)
	brcmf_dbg(INFO, "DHCP done before T2 expiration\n");
	else
	brcmf_dbg(INFO, "DHCP T2:%d expired\n",
	BRCMF_BT_DHCP_FLAG_FORCE_TIMEOUT);

	goto idle;

	default:
	brcmf_err("invalid state=%d !!!\n", btci->bt_state);
	goto idle;
	}

	return;

	idle:
	btci->bt_state = BRCMF_BT_DHCP_IDLE;
	btci->timer_on = false;
	brcmf_btcoex_boost_wifi(btci, false);
	cfg80211_crit_proto_stopped(&btci->vif->wdev, GFP_KERNEL);
	brcmf_btcoex_restore_part1(btci);
	btci->vif = NULL;
	}

	/**
	* brcmf_btcoex_attach() - initialize BT coex data
	* @cfg: driver private cfg80211 data
	*
	* return: 0 on success
	*/
	int brcmf_btcoex_attach(struct brcmf_cfg80211_info *cfg)
	{
	struct brcmf_btcoex_info *btci = NULL;
	brcmf_dbg(TRACE, "enter\n");

	btci = kmalloc(sizeof(struct brcmf_btcoex_info), GFP_KERNEL);
	if (!btci)
	return -ENOMEM;

	btci->bt_state = BRCMF_BT_DHCP_IDLE;

	/* Set up timer for BT */
	btci->timer_on = false;
	btci->timeout = BRCMF_BTCOEX_OPPR_WIN_TIME;
	init_timer(&btci->timer);
	btci->timer.data = (ulong)btci;
	btci->timer.function = brcmf_btcoex_timerfunc;
	btci->cfg = cfg;
	btci->saved_regs_part1 = false;
	btci->saved_regs_part2 = false;

	INIT_WORK(&btci->work, brcmf_btcoex_handler);

	cfg->btcoex = btci;
	return 0;
	}

	/**
	* brcmf_btcoex_detach - clean BT coex data
	* @cfg: driver private cfg80211 data
	*/
	void brcmf_btcoex_detach(struct brcmf_cfg80211_info *cfg)
	{
	brcmf_dbg(TRACE, "enter\n");

	if (!cfg->btcoex)
	return;

	if (cfg->btcoex->timer_on) {
	cfg->btcoex->timer_on = false;
	del_timer_sync(&cfg->btcoex->timer);
	}

	cancel_work_sync(&cfg->btcoex->work);

	brcmf_btcoex_boost_wifi(cfg->btcoex, false);
	brcmf_btcoex_restore_part1(cfg->btcoex);

	kfree(cfg->btcoex);
	cfg->btcoex = NULL;
	}

	static void brcmf_btcoex_dhcp_start(struct brcmf_btcoex_info *btci)
	{
	struct brcmf_if *ifp = btci->vif->ifp;

	btcmf_btcoex_save_part1(btci);
	/* set new regs values */
	brcmf_btcoex_params_write(ifp, 66, BRCMF_BT_DHCP_REG66);
	brcmf_btcoex_params_write(ifp, 41, BRCMF_BT_DHCP_REG41);
	brcmf_btcoex_params_write(ifp, 68, BRCMF_BT_DHCP_REG68);
	btci->dhcp_done = false;
	btci->bt_state = BRCMF_BT_DHCP_START;
	schedule_work(&btci->work);
	brcmf_dbg(TRACE, "enable BT DHCP Timer\n");
	}

	static void brcmf_btcoex_dhcp_end(struct brcmf_btcoex_info *btci)
	{
	/* Stop any bt timer because DHCP session is done */
	btci->dhcp_done = true;
	if (btci->timer_on) {
	brcmf_dbg(INFO, "disable BT DHCP Timer\n");
	btci->timer_on = false;
	del_timer_sync(&btci->timer);

	/* schedule worker if transition to IDLE is needed */
	if (btci->bt_state != BRCMF_BT_DHCP_IDLE) {
	brcmf_dbg(INFO, "bt_state:%d\n",
	btci->bt_state);
	schedule_work(&btci->work);
	}
	} else {
	/* Restore original values */
	brcmf_btcoex_restore_part1(btci);
	}
	}

	/**
	* brcmf_btcoex_set_mode - set BT coex mode
	* @cfg: driver private cfg80211 data
	* @mode: Wifi-Bluetooth coexistence mode
	*
	* return: 0 on success
	*/
	int brcmf_btcoex_set_mode(struct brcmf_cfg80211_vif *vif,
	enum brcmf_btcoex_mode mode, u16 duration)
	{
	struct brcmf_cfg80211_info *cfg = wiphy_priv(vif->wdev.wiphy);
	struct brcmf_btcoex_info *btci = cfg->btcoex;
	struct brcmf_if *ifp = brcmf_get_ifp(cfg->pub, 0);

	switch (mode) {
	case BRCMF_BTCOEX_DISABLED:
	brcmf_dbg(INFO, "DHCP session starts\n");
	if (btci->bt_state != BRCMF_BT_DHCP_IDLE)
	return -EBUSY;
	/* Start BT timer only for SCO connection */
	if (brcmf_btcoex_is_sco_active(ifp)) {
	btci->timeout = duration;
	btci->vif = vif;
	brcmf_btcoex_dhcp_start(btci);
	}
	break;

	case BRCMF_BTCOEX_ENABLED:
	brcmf_dbg(INFO, "DHCP session ends\n");
	if (btci->bt_state != BRCMF_BT_DHCP_IDLE &&
	vif == btci->vif) {
	brcmf_btcoex_dhcp_end(btci);
	}
	break;
	default:
	brcmf_dbg(INFO, "Unknown mode, ignored\n");
	}
	return 0;
	}