drivers/gpu/drm/amd/display/dc/dce/dce_abm.c - linux - Git at Google

 /*
  * Copyright 2012-16 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  *
  * Authors: AMD
  *
  */

 #include <linux/slab.h>

 #include "dce_abm.h"
 #include "dm_services.h"
 #include "reg_helper.h"
 #include "fixed31_32.h"
 #include "dc.h"

 #include "atom.h"


 #define TO_DCE_ABM(abm)\
 	container_of(abm, struct dce_abm, base)

 #define REG(reg) \
 	(abm_dce->regs->reg)

 #undef FN
 #define FN(reg_name, field_name) \
 	abm_dce->abm_shift->field_name, abm_dce->abm_mask->field_name

 #define DC_LOGGER \
 	abm->ctx->logger
 #define CTX \
 	abm_dce->base.ctx

 #define MCP_ABM_LEVEL_SET 0x65
 #define MCP_ABM_PIPE_SET 0x66
 #define MCP_BL_SET 0x67

 #define MCP_DISABLE_ABM_IMMEDIATELY 255

 static bool dce_abm_set_pipe(struct abm *abm, uint32_t controller_id)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
 	uint32_t rampingBoundary = 0xFFFF;

 	if (abm->dmcu_is_running == false)
 		return true;

 	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0,
 			1, 80000);

 	/* set ramping boundary */
 	REG_WRITE(MASTER_COMM_DATA_REG1, rampingBoundary);

 	/* setDMCUParam_Pipe */
 	REG_UPDATE_2(MASTER_COMM_CMD_REG,
 			MASTER_COMM_CMD_REG_BYTE0, MCP_ABM_PIPE_SET,
 			MASTER_COMM_CMD_REG_BYTE1, controller_id);

 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);

 	return true;
 }

 static unsigned int calculate_16_bit_backlight_from_pwm(struct dce_abm *abm_dce)
 {
 	uint64_t current_backlight;
 	uint32_t round_result;
 	uint32_t pwm_period_cntl, bl_period, bl_int_count;
 	uint32_t bl_pwm_cntl, bl_pwm, fractional_duty_cycle_en;
 	uint32_t bl_period_mask, bl_pwm_mask;

 	pwm_period_cntl = REG_READ(BL_PWM_PERIOD_CNTL);
 	REG_GET(BL_PWM_PERIOD_CNTL, BL_PWM_PERIOD, &bl_period);
 	REG_GET(BL_PWM_PERIOD_CNTL, BL_PWM_PERIOD_BITCNT, &bl_int_count);

 	bl_pwm_cntl = REG_READ(BL_PWM_CNTL);
 	REG_GET(BL_PWM_CNTL, BL_ACTIVE_INT_FRAC_CNT, (uint32_t *)(&bl_pwm));
 	REG_GET(BL_PWM_CNTL, BL_PWM_FRACTIONAL_EN, &fractional_duty_cycle_en);

 	if (bl_int_count == 0)
 		bl_int_count = 16;

 	bl_period_mask = (1 << bl_int_count) - 1;
 	bl_period &= bl_period_mask;

 	bl_pwm_mask = bl_period_mask << (16 - bl_int_count);

 	if (fractional_duty_cycle_en == 0)
 		bl_pwm &= bl_pwm_mask;
 	else
 		bl_pwm &= 0xFFFF;

 	current_backlight = bl_pwm << (1 + bl_int_count);

 	if (bl_period == 0)
 		bl_period = 0xFFFF;

 	current_backlight = div_u64(current_backlight, bl_period);
 	current_backlight = (current_backlight + 1) >> 1;

 	current_backlight = (uint64_t)(current_backlight) * bl_period;

 	round_result = (uint32_t)(current_backlight & 0xFFFFFFFF);

 	round_result = (round_result >> (bl_int_count-1)) & 1;

 	current_backlight >>= bl_int_count;
 	current_backlight += round_result;

 	return (uint32_t)(current_backlight);
 }

 static void driver_set_backlight_level(struct dce_abm *abm_dce,
 		uint32_t backlight_pwm_u16_16)
 {
 	uint32_t backlight_16bit;
 	uint32_t masked_pwm_period;
 	uint8_t bit_count;
 	uint64_t active_duty_cycle;
 	uint32_t pwm_period_bitcnt;

 	/*
 	 * 1. Find  16 bit backlight active duty cycle, where 0 <= backlight
 	 * active duty cycle <= backlight period
 	 */

 	/* 1.1 Apply bitmask for backlight period value based on value of BITCNT
 	 */
 	REG_GET_2(BL_PWM_PERIOD_CNTL,
 			BL_PWM_PERIOD_BITCNT, &pwm_period_bitcnt,
 			BL_PWM_PERIOD, &masked_pwm_period);

 	if (pwm_period_bitcnt == 0)
 		bit_count = 16;
 	else
 		bit_count = pwm_period_bitcnt;

 	/* e.g. maskedPwmPeriod = 0x24 when bitCount is 6 */
 	masked_pwm_period = masked_pwm_period & ((1 << bit_count) - 1);

 	/* 1.2 Calculate integer active duty cycle required upper 16 bits
 	 * contain integer component, lower 16 bits contain fractional component
 	 * of active duty cycle e.g. 0x21BDC0 = 0xEFF0 * 0x24
 	 */
 	active_duty_cycle = backlight_pwm_u16_16 * masked_pwm_period;

 	/* 1.3 Calculate 16 bit active duty cycle from integer and fractional
 	 * components shift by bitCount then mask 16 bits and add rounding bit
 	 * from MSB of fraction e.g. 0x86F7 = ((0x21BDC0 >> 6) & 0xFFF) + 0
 	 */
 	backlight_16bit = active_duty_cycle >> bit_count;
 	backlight_16bit &= 0xFFFF;
 	backlight_16bit += (active_duty_cycle >> (bit_count - 1)) & 0x1;

 	/*
 	 * 2. Program register with updated value
 	 */

 	/* 2.1 Lock group 2 backlight registers */

 	REG_UPDATE_2(BL_PWM_GRP1_REG_LOCK,
 			BL_PWM_GRP1_IGNORE_MASTER_LOCK_EN, 1,
 			BL_PWM_GRP1_REG_LOCK, 1);

 	// 2.2 Write new active duty cycle
 	REG_UPDATE(BL_PWM_CNTL, BL_ACTIVE_INT_FRAC_CNT, backlight_16bit);

 	/* 2.3 Unlock group 2 backlight registers */
 	REG_UPDATE(BL_PWM_GRP1_REG_LOCK,
 			BL_PWM_GRP1_REG_LOCK, 0);

 	/* 3 Wait for pending bit to be cleared */
 	REG_WAIT(BL_PWM_GRP1_REG_LOCK,
 			BL_PWM_GRP1_REG_UPDATE_PENDING, 0,
 			1, 10000);
 }

 static void dmcu_set_backlight_level(
 	struct dce_abm *abm_dce,
 	uint32_t backlight_pwm_u16_16,
 	uint32_t frame_ramp,
 	uint32_t controller_id)
 {
 	unsigned int backlight_8_bit = 0;
 	uint32_t s2;

 	if (backlight_pwm_u16_16 & 0x10000)
 		// Check for max backlight condition
 		backlight_8_bit = 0xFF;
 	else
 		// Take MSB of fractional part since backlight is not max
 		backlight_8_bit = (backlight_pwm_u16_16 >> 8) & 0xFF;

 	dce_abm_set_pipe(&abm_dce->base, controller_id);

 	/* waitDMCUReadyForCmd */
 	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT,
 			0, 1, 80000);

 	/* setDMCUParam_BL */
 	REG_UPDATE(BL1_PWM_USER_LEVEL, BL1_PWM_USER_LEVEL, backlight_pwm_u16_16);

 	/* write ramp */
 	if (controller_id == 0)
 		frame_ramp = 0;
 	REG_WRITE(MASTER_COMM_DATA_REG1, frame_ramp);

 	/* setDMCUParam_Cmd */
 	REG_UPDATE(MASTER_COMM_CMD_REG, MASTER_COMM_CMD_REG_BYTE0, MCP_BL_SET);

 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);

 	/* UpdateRequestedBacklightLevel */
 	s2 = REG_READ(BIOS_SCRATCH_2);

 	s2 &= ~ATOM_S2_CURRENT_BL_LEVEL_MASK;
 	backlight_8_bit &= (ATOM_S2_CURRENT_BL_LEVEL_MASK >>
 				ATOM_S2_CURRENT_BL_LEVEL_SHIFT);
 	s2 |= (backlight_8_bit << ATOM_S2_CURRENT_BL_LEVEL_SHIFT);

 	REG_WRITE(BIOS_SCRATCH_2, s2);
 }

 static void dce_abm_init(struct abm *abm)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
 	unsigned int backlight = calculate_16_bit_backlight_from_pwm(abm_dce);

 	REG_WRITE(DC_ABM1_HG_SAMPLE_RATE, 0x103);
 	REG_WRITE(DC_ABM1_HG_SAMPLE_RATE, 0x101);
 	REG_WRITE(DC_ABM1_LS_SAMPLE_RATE, 0x103);
 	REG_WRITE(DC_ABM1_LS_SAMPLE_RATE, 0x101);
 	REG_WRITE(BL1_PWM_BL_UPDATE_SAMPLE_RATE, 0x101);

 	REG_SET_3(DC_ABM1_HG_MISC_CTRL, 0,
 			ABM1_HG_NUM_OF_BINS_SEL, 0,
 			ABM1_HG_VMAX_SEL, 1,
 			ABM1_HG_BIN_BITWIDTH_SIZE_SEL, 0);

 	REG_SET_3(DC_ABM1_IPCSC_COEFF_SEL, 0,
 			ABM1_IPCSC_COEFF_SEL_R, 2,
 			ABM1_IPCSC_COEFF_SEL_G, 4,
 			ABM1_IPCSC_COEFF_SEL_B, 2);

 	REG_UPDATE(BL1_PWM_CURRENT_ABM_LEVEL,
 			BL1_PWM_CURRENT_ABM_LEVEL, backlight);

 	REG_UPDATE(BL1_PWM_TARGET_ABM_LEVEL,
 			BL1_PWM_TARGET_ABM_LEVEL, backlight);

 	REG_UPDATE(BL1_PWM_USER_LEVEL,
 			BL1_PWM_USER_LEVEL, backlight);

 	REG_UPDATE_2(DC_ABM1_LS_MIN_MAX_PIXEL_VALUE_THRES,
 			ABM1_LS_MIN_PIXEL_VALUE_THRES, 0,
 			ABM1_LS_MAX_PIXEL_VALUE_THRES, 1000);

 	REG_SET_3(DC_ABM1_HGLS_REG_READ_PROGRESS, 0,
 			ABM1_HG_REG_READ_MISSED_FRAME_CLEAR, 1,
 			ABM1_LS_REG_READ_MISSED_FRAME_CLEAR, 1,
 			ABM1_BL_REG_READ_MISSED_FRAME_CLEAR, 1);
 }

 static unsigned int dce_abm_get_current_backlight(struct abm *abm)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
 	unsigned int backlight = REG_READ(BL1_PWM_CURRENT_ABM_LEVEL);

 	/* return backlight in hardware format which is unsigned 17 bits, with
 	 * 1 bit integer and 16 bit fractional
 	 */
 	return backlight;
 }

 static unsigned int dce_abm_get_target_backlight(struct abm *abm)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
 	unsigned int backlight = REG_READ(BL1_PWM_TARGET_ABM_LEVEL);

 	/* return backlight in hardware format which is unsigned 17 bits, with
 	 * 1 bit integer and 16 bit fractional
 	 */
 	return backlight;
 }

 static bool dce_abm_set_level(struct abm *abm, uint32_t level)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(abm);

 	if (abm->dmcu_is_running == false)
 		return true;

 	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0,
 			1, 80000);

 	/* setDMCUParam_ABMLevel */
 	REG_UPDATE_2(MASTER_COMM_CMD_REG,
 			MASTER_COMM_CMD_REG_BYTE0, MCP_ABM_LEVEL_SET,
 			MASTER_COMM_CMD_REG_BYTE2, level);

 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);

 	return true;
 }

 static bool dce_abm_immediate_disable(struct abm *abm)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(abm);

 	if (abm->dmcu_is_running == false)
 		return true;

 	dce_abm_set_pipe(abm, MCP_DISABLE_ABM_IMMEDIATELY);

 	abm->stored_backlight_registers.BL_PWM_CNTL =
 		REG_READ(BL_PWM_CNTL);
 	abm->stored_backlight_registers.BL_PWM_CNTL2 =
 		REG_READ(BL_PWM_CNTL2);
 	abm->stored_backlight_registers.BL_PWM_PERIOD_CNTL =
 		REG_READ(BL_PWM_PERIOD_CNTL);

 	REG_GET(LVTMA_PWRSEQ_REF_DIV, BL_PWM_REF_DIV,
 		&abm->stored_backlight_registers.LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV);
 	return true;
 }

 static bool dce_abm_init_backlight(struct abm *abm)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
 	uint32_t value;

 	/* It must not be 0, so we have to restore them
 	 * Bios bug w/a - period resets to zero,
 	 * restoring to cache values which is always correct
 	 */
 	REG_GET(BL_PWM_CNTL, BL_ACTIVE_INT_FRAC_CNT, &value);
 	if (value == 0 || value == 1) {
 		if (abm->stored_backlight_registers.BL_PWM_CNTL != 0) {
 			REG_WRITE(BL_PWM_CNTL,
 				abm->stored_backlight_registers.BL_PWM_CNTL);
 			REG_WRITE(BL_PWM_CNTL2,
 				abm->stored_backlight_registers.BL_PWM_CNTL2);
 			REG_WRITE(BL_PWM_PERIOD_CNTL,
 				abm->stored_backlight_registers.BL_PWM_PERIOD_CNTL);
 			REG_UPDATE(LVTMA_PWRSEQ_REF_DIV,
 				BL_PWM_REF_DIV,
 				abm->stored_backlight_registers.
 				LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV);
 		} else {
 			/* TODO: Note: This should not really happen since VBIOS
 			 * should have initialized PWM registers on boot.
 			 */
 			REG_WRITE(BL_PWM_CNTL, 0xC000FA00);
 			REG_WRITE(BL_PWM_PERIOD_CNTL, 0x000C0FA0);
 		}
 	} else {
 		abm->stored_backlight_registers.BL_PWM_CNTL =
 				REG_READ(BL_PWM_CNTL);
 		abm->stored_backlight_registers.BL_PWM_CNTL2 =
 				REG_READ(BL_PWM_CNTL2);
 		abm->stored_backlight_registers.BL_PWM_PERIOD_CNTL =
 				REG_READ(BL_PWM_PERIOD_CNTL);

 		REG_GET(LVTMA_PWRSEQ_REF_DIV, BL_PWM_REF_DIV,
 				&abm->stored_backlight_registers.
 				LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV);
 	}

 	/* Have driver take backlight control
 	 * TakeBacklightControl(true)
 	 */
 	value = REG_READ(BIOS_SCRATCH_2);
 	value |= ATOM_S2_VRI_BRIGHT_ENABLE;
 	REG_WRITE(BIOS_SCRATCH_2, value);

 	/* Enable the backlight output */
 	REG_UPDATE(BL_PWM_CNTL, BL_PWM_EN, 1);

 	/* Unlock group 2 backlight registers */
 	REG_UPDATE(BL_PWM_GRP1_REG_LOCK,
 			BL_PWM_GRP1_REG_LOCK, 0);

 	return true;
 }

 static bool dce_abm_set_backlight_level_pwm(
 		struct abm *abm,
 		unsigned int backlight_pwm_u16_16,
 		unsigned int frame_ramp,
 		unsigned int controller_id,
 		bool use_smooth_brightness)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(abm);

 	DC_LOG_BACKLIGHT("New Backlight level: %d (0x%X)\n",
 			backlight_pwm_u16_16, backlight_pwm_u16_16);

 	/* If DMCU is in reset state, DMCU is uninitialized */
 	if (use_smooth_brightness)
 		dmcu_set_backlight_level(abm_dce,
 				backlight_pwm_u16_16,
 				frame_ramp,
 				controller_id);
 	else
 		driver_set_backlight_level(abm_dce, backlight_pwm_u16_16);

 	return true;
 }

 static const struct abm_funcs dce_funcs = {
 	.abm_init = dce_abm_init,
 	.set_abm_level = dce_abm_set_level,
 	.init_backlight = dce_abm_init_backlight,
 	.set_pipe = dce_abm_set_pipe,
 	.set_backlight_level_pwm = dce_abm_set_backlight_level_pwm,
 	.get_current_backlight = dce_abm_get_current_backlight,
 	.get_target_backlight = dce_abm_get_target_backlight,
 	.set_abm_immediate_disable = dce_abm_immediate_disable
 };

 static void dce_abm_construct(
 	struct dce_abm *abm_dce,
 	struct dc_context *ctx,
 	const struct dce_abm_registers *regs,
 	const struct dce_abm_shift *abm_shift,
 	const struct dce_abm_mask *abm_mask)
 {
 	struct abm *base = &abm_dce->base;

 	base->ctx = ctx;
 	base->funcs = &dce_funcs;
 	base->stored_backlight_registers.BL_PWM_CNTL = 0;
 	base->stored_backlight_registers.BL_PWM_CNTL2 = 0;
 	base->stored_backlight_registers.BL_PWM_PERIOD_CNTL = 0;
 	base->stored_backlight_registers.LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV = 0;
 	base->dmcu_is_running = false;

 	abm_dce->regs = regs;
 	abm_dce->abm_shift = abm_shift;
 	abm_dce->abm_mask = abm_mask;
 }

 struct abm *dce_abm_create(
 	struct dc_context *ctx,
 	const struct dce_abm_registers *regs,
 	const struct dce_abm_shift *abm_shift,
 	const struct dce_abm_mask *abm_mask)
 {
 	struct dce_abm *abm_dce = kzalloc(sizeof(*abm_dce), GFP_KERNEL);

 	if (abm_dce == NULL) {
 		BREAK_TO_DEBUGGER();
 		return NULL;
 	}

 	dce_abm_construct(abm_dce, ctx, regs, abm_shift, abm_mask);

 	abm_dce->base.funcs = &dce_funcs;

 	return &abm_dce->base;
 }

 void dce_abm_destroy(struct abm **abm)
 {
 	struct dce_abm *abm_dce = TO_DCE_ABM(*abm);

 	if (abm_dce->base.dmcu_is_running == true)
 		abm_dce->base.funcs->set_abm_immediate_disable(*abm);

 	kfree(abm_dce);
 	*abm = NULL;
 }
	/*
	* Copyright 2012-16 Advanced Micro Devices, Inc.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*
	* Authors: AMD
	*
	*/

	#include <linux/slab.h>

	#include "dce_abm.h"
	#include "dm_services.h"
	#include "reg_helper.h"
	#include "fixed31_32.h"
	#include "dc.h"

	#include "atom.h"


	#define TO_DCE_ABM(abm)\
	container_of(abm, struct dce_abm, base)

	#define REG(reg) \
	(abm_dce->regs->reg)

	#undef FN
	#define FN(reg_name, field_name) \
	abm_dce->abm_shift->field_name, abm_dce->abm_mask->field_name

	#define DC_LOGGER \
	abm->ctx->logger
	#define CTX \
	abm_dce->base.ctx

	#define MCP_ABM_LEVEL_SET 0x65
	#define MCP_ABM_PIPE_SET 0x66
	#define MCP_BL_SET 0x67

	#define MCP_DISABLE_ABM_IMMEDIATELY 255

	static bool dce_abm_set_pipe(struct abm *abm, uint32_t controller_id)
	{
	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
	uint32_t rampingBoundary = 0xFFFF;

	if (abm->dmcu_is_running == false)
	return true;

	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0,
	1, 80000);

	/* set ramping boundary */
	REG_WRITE(MASTER_COMM_DATA_REG1, rampingBoundary);

	/* setDMCUParam_Pipe */
	REG_UPDATE_2(MASTER_COMM_CMD_REG,
	MASTER_COMM_CMD_REG_BYTE0, MCP_ABM_PIPE_SET,
	MASTER_COMM_CMD_REG_BYTE1, controller_id);

	/* notifyDMCUMsg */
	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);

	return true;
	}

	static unsigned int calculate_16_bit_backlight_from_pwm(struct dce_abm *abm_dce)
	{
	uint64_t current_backlight;
	uint32_t round_result;
	uint32_t pwm_period_cntl, bl_period, bl_int_count;
	uint32_t bl_pwm_cntl, bl_pwm, fractional_duty_cycle_en;
	uint32_t bl_period_mask, bl_pwm_mask;

	pwm_period_cntl = REG_READ(BL_PWM_PERIOD_CNTL);
	REG_GET(BL_PWM_PERIOD_CNTL, BL_PWM_PERIOD, &bl_period);
	REG_GET(BL_PWM_PERIOD_CNTL, BL_PWM_PERIOD_BITCNT, &bl_int_count);

	bl_pwm_cntl = REG_READ(BL_PWM_CNTL);
	REG_GET(BL_PWM_CNTL, BL_ACTIVE_INT_FRAC_CNT, (uint32_t *)(&bl_pwm));
	REG_GET(BL_PWM_CNTL, BL_PWM_FRACTIONAL_EN, &fractional_duty_cycle_en);

	if (bl_int_count == 0)
	bl_int_count = 16;

	bl_period_mask = (1 << bl_int_count) - 1;
	bl_period &= bl_period_mask;

	bl_pwm_mask = bl_period_mask << (16 - bl_int_count);

	if (fractional_duty_cycle_en == 0)
	bl_pwm &= bl_pwm_mask;
	else
	bl_pwm &= 0xFFFF;

	current_backlight = bl_pwm << (1 + bl_int_count);

	if (bl_period == 0)
	bl_period = 0xFFFF;

	current_backlight = div_u64(current_backlight, bl_period);
	current_backlight = (current_backlight + 1) >> 1;

	current_backlight = (uint64_t)(current_backlight) * bl_period;

	round_result = (uint32_t)(current_backlight & 0xFFFFFFFF);

	round_result = (round_result >> (bl_int_count-1)) & 1;

	current_backlight >>= bl_int_count;
	current_backlight += round_result;

	return (uint32_t)(current_backlight);
	}

	static void driver_set_backlight_level(struct dce_abm *abm_dce,
	uint32_t backlight_pwm_u16_16)
	{
	uint32_t backlight_16bit;
	uint32_t masked_pwm_period;
	uint8_t bit_count;
	uint64_t active_duty_cycle;
	uint32_t pwm_period_bitcnt;

	/*
	* 1. Find 16 bit backlight active duty cycle, where 0 <= backlight
	* active duty cycle <= backlight period
	*/

	/* 1.1 Apply bitmask for backlight period value based on value of BITCNT
	*/
	REG_GET_2(BL_PWM_PERIOD_CNTL,
	BL_PWM_PERIOD_BITCNT, &pwm_period_bitcnt,
	BL_PWM_PERIOD, &masked_pwm_period);

	if (pwm_period_bitcnt == 0)
	bit_count = 16;
	else
	bit_count = pwm_period_bitcnt;

	/* e.g. maskedPwmPeriod = 0x24 when bitCount is 6 */
	masked_pwm_period = masked_pwm_period & ((1 << bit_count) - 1);

	/* 1.2 Calculate integer active duty cycle required upper 16 bits
	* contain integer component, lower 16 bits contain fractional component
	* of active duty cycle e.g. 0x21BDC0 = 0xEFF0 * 0x24
	*/
	active_duty_cycle = backlight_pwm_u16_16 * masked_pwm_period;

	/* 1.3 Calculate 16 bit active duty cycle from integer and fractional
	* components shift by bitCount then mask 16 bits and add rounding bit
	* from MSB of fraction e.g. 0x86F7 = ((0x21BDC0 >> 6) & 0xFFF) + 0
	*/
	backlight_16bit = active_duty_cycle >> bit_count;
	backlight_16bit &= 0xFFFF;
	backlight_16bit += (active_duty_cycle >> (bit_count - 1)) & 0x1;

	/*
	* 2. Program register with updated value
	*/

	/* 2.1 Lock group 2 backlight registers */

	REG_UPDATE_2(BL_PWM_GRP1_REG_LOCK,
	BL_PWM_GRP1_IGNORE_MASTER_LOCK_EN, 1,
	BL_PWM_GRP1_REG_LOCK, 1);

	// 2.2 Write new active duty cycle
	REG_UPDATE(BL_PWM_CNTL, BL_ACTIVE_INT_FRAC_CNT, backlight_16bit);

	/* 2.3 Unlock group 2 backlight registers */
	REG_UPDATE(BL_PWM_GRP1_REG_LOCK,
	BL_PWM_GRP1_REG_LOCK, 0);

	/* 3 Wait for pending bit to be cleared */
	REG_WAIT(BL_PWM_GRP1_REG_LOCK,
	BL_PWM_GRP1_REG_UPDATE_PENDING, 0,
	1, 10000);
	}

	static void dmcu_set_backlight_level(
	struct dce_abm *abm_dce,
	uint32_t backlight_pwm_u16_16,
	uint32_t frame_ramp,
	uint32_t controller_id)
	{
	unsigned int backlight_8_bit = 0;
	uint32_t s2;

	if (backlight_pwm_u16_16 & 0x10000)
	// Check for max backlight condition
	backlight_8_bit = 0xFF;
	else
	// Take MSB of fractional part since backlight is not max
	backlight_8_bit = (backlight_pwm_u16_16 >> 8) & 0xFF;

	dce_abm_set_pipe(&abm_dce->base, controller_id);

	/* waitDMCUReadyForCmd */
	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT,
	0, 1, 80000);

	/* setDMCUParam_BL */
	REG_UPDATE(BL1_PWM_USER_LEVEL, BL1_PWM_USER_LEVEL, backlight_pwm_u16_16);

	/* write ramp */
	if (controller_id == 0)
	frame_ramp = 0;
	REG_WRITE(MASTER_COMM_DATA_REG1, frame_ramp);

	/* setDMCUParam_Cmd */
	REG_UPDATE(MASTER_COMM_CMD_REG, MASTER_COMM_CMD_REG_BYTE0, MCP_BL_SET);

	/* notifyDMCUMsg */
	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);

	/* UpdateRequestedBacklightLevel */
	s2 = REG_READ(BIOS_SCRATCH_2);

	s2 &= ~ATOM_S2_CURRENT_BL_LEVEL_MASK;
	backlight_8_bit &= (ATOM_S2_CURRENT_BL_LEVEL_MASK >>
	ATOM_S2_CURRENT_BL_LEVEL_SHIFT);
	s2 \|= (backlight_8_bit << ATOM_S2_CURRENT_BL_LEVEL_SHIFT);

	REG_WRITE(BIOS_SCRATCH_2, s2);
	}

	static void dce_abm_init(struct abm *abm)
	{
	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
	unsigned int backlight = calculate_16_bit_backlight_from_pwm(abm_dce);

	REG_WRITE(DC_ABM1_HG_SAMPLE_RATE, 0x103);
	REG_WRITE(DC_ABM1_HG_SAMPLE_RATE, 0x101);
	REG_WRITE(DC_ABM1_LS_SAMPLE_RATE, 0x103);
	REG_WRITE(DC_ABM1_LS_SAMPLE_RATE, 0x101);
	REG_WRITE(BL1_PWM_BL_UPDATE_SAMPLE_RATE, 0x101);

	REG_SET_3(DC_ABM1_HG_MISC_CTRL, 0,
	ABM1_HG_NUM_OF_BINS_SEL, 0,
	ABM1_HG_VMAX_SEL, 1,
	ABM1_HG_BIN_BITWIDTH_SIZE_SEL, 0);

	REG_SET_3(DC_ABM1_IPCSC_COEFF_SEL, 0,
	ABM1_IPCSC_COEFF_SEL_R, 2,
	ABM1_IPCSC_COEFF_SEL_G, 4,
	ABM1_IPCSC_COEFF_SEL_B, 2);

	REG_UPDATE(BL1_PWM_CURRENT_ABM_LEVEL,
	BL1_PWM_CURRENT_ABM_LEVEL, backlight);

	REG_UPDATE(BL1_PWM_TARGET_ABM_LEVEL,
	BL1_PWM_TARGET_ABM_LEVEL, backlight);

	REG_UPDATE(BL1_PWM_USER_LEVEL,
	BL1_PWM_USER_LEVEL, backlight);

	REG_UPDATE_2(DC_ABM1_LS_MIN_MAX_PIXEL_VALUE_THRES,
	ABM1_LS_MIN_PIXEL_VALUE_THRES, 0,
	ABM1_LS_MAX_PIXEL_VALUE_THRES, 1000);

	REG_SET_3(DC_ABM1_HGLS_REG_READ_PROGRESS, 0,
	ABM1_HG_REG_READ_MISSED_FRAME_CLEAR, 1,
	ABM1_LS_REG_READ_MISSED_FRAME_CLEAR, 1,
	ABM1_BL_REG_READ_MISSED_FRAME_CLEAR, 1);
	}

	static unsigned int dce_abm_get_current_backlight(struct abm *abm)
	{
	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
	unsigned int backlight = REG_READ(BL1_PWM_CURRENT_ABM_LEVEL);

	/* return backlight in hardware format which is unsigned 17 bits, with
	* 1 bit integer and 16 bit fractional
	*/
	return backlight;
	}

	static unsigned int dce_abm_get_target_backlight(struct abm *abm)
	{
	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
	unsigned int backlight = REG_READ(BL1_PWM_TARGET_ABM_LEVEL);

	/* return backlight in hardware format which is unsigned 17 bits, with
	* 1 bit integer and 16 bit fractional
	*/
	return backlight;
	}

	static bool dce_abm_set_level(struct abm *abm, uint32_t level)
	{
	struct dce_abm *abm_dce = TO_DCE_ABM(abm);

	if (abm->dmcu_is_running == false)
	return true;

	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0,
	1, 80000);

	/* setDMCUParam_ABMLevel */
	REG_UPDATE_2(MASTER_COMM_CMD_REG,
	MASTER_COMM_CMD_REG_BYTE0, MCP_ABM_LEVEL_SET,
	MASTER_COMM_CMD_REG_BYTE2, level);

	/* notifyDMCUMsg */
	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);

	return true;
	}

	static bool dce_abm_immediate_disable(struct abm *abm)
	{
	struct dce_abm *abm_dce = TO_DCE_ABM(abm);

	if (abm->dmcu_is_running == false)
	return true;

	dce_abm_set_pipe(abm, MCP_DISABLE_ABM_IMMEDIATELY);

	abm->stored_backlight_registers.BL_PWM_CNTL =
	REG_READ(BL_PWM_CNTL);
	abm->stored_backlight_registers.BL_PWM_CNTL2 =
	REG_READ(BL_PWM_CNTL2);
	abm->stored_backlight_registers.BL_PWM_PERIOD_CNTL =
	REG_READ(BL_PWM_PERIOD_CNTL);

	REG_GET(LVTMA_PWRSEQ_REF_DIV, BL_PWM_REF_DIV,
	&abm->stored_backlight_registers.LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV);
	return true;
	}

	static bool dce_abm_init_backlight(struct abm *abm)
	{
	struct dce_abm *abm_dce = TO_DCE_ABM(abm);
	uint32_t value;

	/* It must not be 0, so we have to restore them
	* Bios bug w/a - period resets to zero,
	* restoring to cache values which is always correct
	*/
	REG_GET(BL_PWM_CNTL, BL_ACTIVE_INT_FRAC_CNT, &value);
	if (value == 0 \|\| value == 1) {
	if (abm->stored_backlight_registers.BL_PWM_CNTL != 0) {
	REG_WRITE(BL_PWM_CNTL,
	abm->stored_backlight_registers.BL_PWM_CNTL);
	REG_WRITE(BL_PWM_CNTL2,
	abm->stored_backlight_registers.BL_PWM_CNTL2);
	REG_WRITE(BL_PWM_PERIOD_CNTL,
	abm->stored_backlight_registers.BL_PWM_PERIOD_CNTL);
	REG_UPDATE(LVTMA_PWRSEQ_REF_DIV,
	BL_PWM_REF_DIV,
	abm->stored_backlight_registers.
	LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV);
	} else {
	/* TODO: Note: This should not really happen since VBIOS
	* should have initialized PWM registers on boot.
	*/
	REG_WRITE(BL_PWM_CNTL, 0xC000FA00);
	REG_WRITE(BL_PWM_PERIOD_CNTL, 0x000C0FA0);
	}
	} else {
	abm->stored_backlight_registers.BL_PWM_CNTL =
	REG_READ(BL_PWM_CNTL);
	abm->stored_backlight_registers.BL_PWM_CNTL2 =
	REG_READ(BL_PWM_CNTL2);
	abm->stored_backlight_registers.BL_PWM_PERIOD_CNTL =
	REG_READ(BL_PWM_PERIOD_CNTL);

	REG_GET(LVTMA_PWRSEQ_REF_DIV, BL_PWM_REF_DIV,
	&abm->stored_backlight_registers.
	LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV);
	}

	/* Have driver take backlight control
	* TakeBacklightControl(true)
	*/
	value = REG_READ(BIOS_SCRATCH_2);
	value \|= ATOM_S2_VRI_BRIGHT_ENABLE;
	REG_WRITE(BIOS_SCRATCH_2, value);

	/* Enable the backlight output */
	REG_UPDATE(BL_PWM_CNTL, BL_PWM_EN, 1);

	/* Unlock group 2 backlight registers */
	REG_UPDATE(BL_PWM_GRP1_REG_LOCK,
	BL_PWM_GRP1_REG_LOCK, 0);

	return true;
	}

	static bool dce_abm_set_backlight_level_pwm(
	struct abm *abm,
	unsigned int backlight_pwm_u16_16,
	unsigned int frame_ramp,
	unsigned int controller_id,
	bool use_smooth_brightness)
	{
	struct dce_abm *abm_dce = TO_DCE_ABM(abm);

	DC_LOG_BACKLIGHT("New Backlight level: %d (0x%X)\n",
	backlight_pwm_u16_16, backlight_pwm_u16_16);

	/* If DMCU is in reset state, DMCU is uninitialized */
	if (use_smooth_brightness)
	dmcu_set_backlight_level(abm_dce,
	backlight_pwm_u16_16,
	frame_ramp,
	controller_id);
	else
	driver_set_backlight_level(abm_dce, backlight_pwm_u16_16);

	return true;
	}

	static const struct abm_funcs dce_funcs = {
	.abm_init = dce_abm_init,
	.set_abm_level = dce_abm_set_level,
	.init_backlight = dce_abm_init_backlight,
	.set_pipe = dce_abm_set_pipe,
	.set_backlight_level_pwm = dce_abm_set_backlight_level_pwm,
	.get_current_backlight = dce_abm_get_current_backlight,
	.get_target_backlight = dce_abm_get_target_backlight,
	.set_abm_immediate_disable = dce_abm_immediate_disable
	};

	static void dce_abm_construct(
	struct dce_abm *abm_dce,
	struct dc_context *ctx,
	const struct dce_abm_registers *regs,
	const struct dce_abm_shift *abm_shift,
	const struct dce_abm_mask *abm_mask)
	{
	struct abm *base = &abm_dce->base;

	base->ctx = ctx;
	base->funcs = &dce_funcs;
	base->stored_backlight_registers.BL_PWM_CNTL = 0;
	base->stored_backlight_registers.BL_PWM_CNTL2 = 0;
	base->stored_backlight_registers.BL_PWM_PERIOD_CNTL = 0;
	base->stored_backlight_registers.LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV = 0;
	base->dmcu_is_running = false;

	abm_dce->regs = regs;
	abm_dce->abm_shift = abm_shift;
	abm_dce->abm_mask = abm_mask;
	}

	struct abm *dce_abm_create(
	struct dc_context *ctx,
	const struct dce_abm_registers *regs,
	const struct dce_abm_shift *abm_shift,
	const struct dce_abm_mask *abm_mask)
	{
	struct dce_abm abm_dce = kzalloc(sizeof(abm_dce), GFP_KERNEL);

	if (abm_dce == NULL) {
	BREAK_TO_DEBUGGER();
	return NULL;
	}

	dce_abm_construct(abm_dce, ctx, regs, abm_shift, abm_mask);

	abm_dce->base.funcs = &dce_funcs;

	return &abm_dce->base;
	}

	void dce_abm_destroy(struct abm **abm)
	{
	struct dce_abm abm_dce = TO_DCE_ABM(abm);

	if (abm_dce->base.dmcu_is_running == true)
	abm_dce->base.funcs->set_abm_immediate_disable(*abm);

	kfree(abm_dce);
	*abm = NULL;
	}