drm/amd/display: Decouple aux from i2c

[Why]
Aux engine is created from i2caux layer. We want to remove this layer
and use the engine directly.

[How]
Decouple aux engine from i2caux. Move aux engine related code to dce folder and use
dc resource pool to manage the engine. And use the engine functions directly

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 942 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
new file mode 100644
index 000000000000..b28e2120767e
--- /dev/null
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
@@ -0,0 +1,942 @@
+/*
+ * Copyright 2012-15 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 "dm_services.h"
+#include "dce_aux.h"
+#include "dce/dce_11_0_sh_mask.h"
+
+#define CTX \
+	aux110->base.base.ctx
+#define REG(reg_name)\
+	(aux110->regs->reg_name)
+
+#define DC_LOGGER \
+	engine->base.ctx->logger
+
+#include "reg_helper.h"
+
+#define FROM_AUX_ENGINE(ptr) \
+	container_of((ptr), struct aux_engine_dce110, base)
+
+#define FROM_ENGINE(ptr) \
+	FROM_AUX_ENGINE(container_of((ptr), struct aux_engine, base))
+
+#define FROM_AUX_ENGINE_ENGINE(ptr) \
+	container_of((ptr), struct aux_engine, base)
+enum {
+	AUX_INVALID_REPLY_RETRY_COUNTER = 1,
+	AUX_TIMED_OUT_RETRY_COUNTER = 2,
+	AUX_DEFER_RETRY_COUNTER = 6
+};
+static void release_engine(
+	struct engine *engine)
+{
+	struct aux_engine_dce110 *aux110 = FROM_ENGINE(engine);
+
+	dal_ddc_close(engine->ddc);
+
+	engine->ddc = NULL;
+
+	REG_UPDATE(AUX_ARB_CONTROL, AUX_SW_DONE_USING_AUX_REG, 1);
+}
+
+#define SW_CAN_ACCESS_AUX 1
+#define DMCU_CAN_ACCESS_AUX 2
+
+static bool is_engine_available(
+	struct aux_engine *engine)
+{
+	struct aux_engine_dce110 *aux110 = FROM_AUX_ENGINE(engine);
+
+	uint32_t value = REG_READ(AUX_ARB_CONTROL);
+	uint32_t field = get_reg_field_value(
+			value,
+			AUX_ARB_CONTROL,
+			AUX_REG_RW_CNTL_STATUS);
+
+	return (field != DMCU_CAN_ACCESS_AUX);
+}
+static bool acquire_engine(
+	struct aux_engine *engine)
+{
+	struct aux_engine_dce110 *aux110 = FROM_AUX_ENGINE(engine);
+
+	uint32_t value = REG_READ(AUX_ARB_CONTROL);
+	uint32_t field = get_reg_field_value(
+			value,
+			AUX_ARB_CONTROL,
+			AUX_REG_RW_CNTL_STATUS);
+	if (field == DMCU_CAN_ACCESS_AUX)
+		return false;
+	/* enable AUX before request SW to access AUX */
+	value = REG_READ(AUX_CONTROL);
+	field = get_reg_field_value(value,
+				AUX_CONTROL,
+				AUX_EN);
+
+	if (field == 0) {
+		set_reg_field_value(
+				value,
+				1,
+				AUX_CONTROL,
+				AUX_EN);
+
+		if (REG(AUX_RESET_MASK)) {
+			/*DP_AUX block as part of the enable sequence*/
+			set_reg_field_value(
+				value,
+				1,
+				AUX_CONTROL,
+				AUX_RESET);
+		}
+
+		REG_WRITE(AUX_CONTROL, value);
+
+		if (REG(AUX_RESET_MASK)) {
+			/*poll HW to make sure reset it done*/
+
+			REG_WAIT(AUX_CONTROL, AUX_RESET_DONE, 1,
+					1, 11);
+
+			set_reg_field_value(
+				value,
+				0,
+				AUX_CONTROL,
+				AUX_RESET);
+
+			REG_WRITE(AUX_CONTROL, value);
+
+			REG_WAIT(AUX_CONTROL, AUX_RESET_DONE, 0,
+					1, 11);
+		}
+	} /*if (field)*/
+
+	/* request SW to access AUX */
+	REG_UPDATE(AUX_ARB_CONTROL, AUX_SW_USE_AUX_REG_REQ, 1);
+
+	value = REG_READ(AUX_ARB_CONTROL);
+	field = get_reg_field_value(
+			value,
+			AUX_ARB_CONTROL,
+			AUX_REG_RW_CNTL_STATUS);
+
+	return (field == SW_CAN_ACCESS_AUX);
+}
+
+#define COMPOSE_AUX_SW_DATA_16_20(command, address) \
+	((command) | ((0xF0000 & (address)) >> 16))
+
+#define COMPOSE_AUX_SW_DATA_8_15(address) \
+	((0xFF00 & (address)) >> 8)
+
+#define COMPOSE_AUX_SW_DATA_0_7(address) \
+	(0xFF & (address))
+
+static void submit_channel_request(
+	struct aux_engine *engine,
+	struct aux_request_transaction_data *request)
+{
+	struct aux_engine_dce110 *aux110 = FROM_AUX_ENGINE(engine);
+	uint32_t value;
+	uint32_t length;
+
+	bool is_write =
+		((request->type == AUX_TRANSACTION_TYPE_DP) &&
+		 (request->action == I2CAUX_TRANSACTION_ACTION_DP_WRITE)) ||
+		((request->type == AUX_TRANSACTION_TYPE_I2C) &&
+		((request->action == I2CAUX_TRANSACTION_ACTION_I2C_WRITE) ||
+		 (request->action == I2CAUX_TRANSACTION_ACTION_I2C_WRITE_MOT)));
+	if (REG(AUXN_IMPCAL)) {
+		/* clear_aux_error */
+		REG_UPDATE_SEQ(AUXN_IMPCAL, AUXN_CALOUT_ERROR_AK,
+				1,
+				0);
+
+		REG_UPDATE_SEQ(AUXP_IMPCAL, AUXP_CALOUT_ERROR_AK,
+				1,
+				0);
+
+		/* force_default_calibrate */
+		REG_UPDATE_1BY1_2(AUXN_IMPCAL,
+				AUXN_IMPCAL_ENABLE, 1,
+				AUXN_IMPCAL_OVERRIDE_ENABLE, 0);
+
+		/* bug? why AUXN update EN and OVERRIDE_EN 1 by 1 while AUX P toggles OVERRIDE? */
+
+		REG_UPDATE_SEQ(AUXP_IMPCAL, AUXP_IMPCAL_OVERRIDE_ENABLE,
+				1,
+				0);
+	}
+	/* set the delay and the number of bytes to write */
+
+	/* The length include
+	 * the 4 bit header and the 20 bit address
+	 * (that is 3 byte).
+	 * If the requested length is non zero this means
+	 * an addition byte specifying the length is required.
+	 */
+
+	length = request->length ? 4 : 3;
+	if (is_write)
+		length += request->length;
+
+	REG_UPDATE_2(AUX_SW_CONTROL,
+			AUX_SW_START_DELAY, request->delay,
+			AUX_SW_WR_BYTES, length);
+
+	/* program action and address and payload data (if 'is_write') */
+	value = REG_UPDATE_4(AUX_SW_DATA,
+			AUX_SW_INDEX, 0,
+			AUX_SW_DATA_RW, 0,
+			AUX_SW_AUTOINCREMENT_DISABLE, 1,
+			AUX_SW_DATA, COMPOSE_AUX_SW_DATA_16_20(request->action, request->address));
+
+	value = REG_SET_2(AUX_SW_DATA, value,
+			AUX_SW_AUTOINCREMENT_DISABLE, 0,
+			AUX_SW_DATA, COMPOSE_AUX_SW_DATA_8_15(request->address));
+
+	value = REG_SET(AUX_SW_DATA, value,
+			AUX_SW_DATA, COMPOSE_AUX_SW_DATA_0_7(request->address));
+
+	if (request->length) {
+		value = REG_SET(AUX_SW_DATA, value,
+				AUX_SW_DATA, request->length - 1);
+	}
+
+	if (is_write) {
+		/* Load the HW buffer with the Data to be sent.
+		 * This is relevant for write operation.
+		 * For read, the data recived data will be
+		 * processed in process_channel_reply().
+		 */
+		uint32_t i = 0;
+
+		while (i < request->length) {
+			value = REG_SET(AUX_SW_DATA, value,
+					AUX_SW_DATA, request->data[i]);
+
+			++i;
+		}
+	}
+
+	REG_UPDATE(AUX_INTERRUPT_CONTROL, AUX_SW_DONE_ACK, 1);
+	REG_WAIT(AUX_SW_STATUS, AUX_SW_DONE, 0,
+				10, aux110->timeout_period/10);
+	REG_UPDATE(AUX_SW_CONTROL, AUX_SW_GO, 1);
+}
+
+static int read_channel_reply(struct aux_engine *engine, uint32_t size,
+			      uint8_t *buffer, uint8_t *reply_result,
+			      uint32_t *sw_status)
+{
+	struct aux_engine_dce110 *aux110 = FROM_AUX_ENGINE(engine);
+	uint32_t bytes_replied;
+	uint32_t reply_result_32;
+
+	*sw_status = REG_GET(AUX_SW_STATUS, AUX_SW_REPLY_BYTE_COUNT,
+			     &bytes_replied);
+
+	/* In case HPD is LOW, exit AUX transaction */
+	if ((*sw_status & AUX_SW_STATUS__AUX_SW_HPD_DISCON_MASK))
+		return -1;
+
+	/* Need at least the status byte */
+	if (!bytes_replied)
+		return -1;
+
+	REG_UPDATE_1BY1_3(AUX_SW_DATA,
+			  AUX_SW_INDEX, 0,
+			  AUX_SW_AUTOINCREMENT_DISABLE, 1,
+			  AUX_SW_DATA_RW, 1);
+
+	REG_GET(AUX_SW_DATA, AUX_SW_DATA, &reply_result_32);
+	reply_result_32 = reply_result_32 >> 4;
+	*reply_result = (uint8_t)reply_result_32;
+
+	if (reply_result_32 == 0) { /* ACK */
+		uint32_t i = 0;
+
+		/* First byte was already used to get the command status */
+		--bytes_replied;
+
+		/* Do not overflow buffer */
+		if (bytes_replied > size)
+			return -1;
+
+		while (i < bytes_replied) {
+			uint32_t aux_sw_data_val;
+
+			REG_GET(AUX_SW_DATA, AUX_SW_DATA, &aux_sw_data_val);
+			buffer[i] = aux_sw_data_val;
+			++i;
+		}
+
+		return i;
+	}
+
+	return 0;
+}
+
+static void process_channel_reply(
+	struct aux_engine *engine,
+	struct aux_reply_transaction_data *reply)
+{
+	int bytes_replied;
+	uint8_t reply_result;
+	uint32_t sw_status;
+
+	bytes_replied = read_channel_reply(engine, reply->length, reply->data,
+					   &reply_result, &sw_status);
+
+	/* in case HPD is LOW, exit AUX transaction */
+	if ((sw_status & AUX_SW_STATUS__AUX_SW_HPD_DISCON_MASK)) {
+		reply->status = AUX_CHANNEL_OPERATION_FAILED_HPD_DISCON;
+		return;
+	}
+
+	if (bytes_replied < 0) {
+		/* Need to handle an error case...
+		 * Hopefully, upper layer function won't call this function if
+		 * the number of bytes in the reply was 0, because there was
+		 * surely an error that was asserted that should have been
+		 * handled for hot plug case, this could happens
+		 */
+		if (!(sw_status & AUX_SW_STATUS__AUX_SW_HPD_DISCON_MASK)) {
+			reply->status = AUX_TRANSACTION_REPLY_INVALID;
+			ASSERT_CRITICAL(false);
+			return;
+		}
+	} else {
+
+		switch (reply_result) {
+		case 0: /* ACK */
+			reply->status = AUX_TRANSACTION_REPLY_AUX_ACK;
+		break;
+		case 1: /* NACK */
+			reply->status = AUX_TRANSACTION_REPLY_AUX_NACK;
+		break;
+		case 2: /* DEFER */
+			reply->status = AUX_TRANSACTION_REPLY_AUX_DEFER;
+		break;
+		case 4: /* AUX ACK / I2C NACK */
+			reply->status = AUX_TRANSACTION_REPLY_I2C_NACK;
+		break;
+		case 8: /* AUX ACK / I2C DEFER */
+			reply->status = AUX_TRANSACTION_REPLY_I2C_DEFER;
+		break;
+		default:
+			reply->status = AUX_TRANSACTION_REPLY_INVALID;
+		}
+	}
+}
+
+static enum aux_channel_operation_result get_channel_status(
+	struct aux_engine *engine,
+	uint8_t *returned_bytes)
+{
+	struct aux_engine_dce110 *aux110 = FROM_AUX_ENGINE(engine);
+
+	uint32_t value;
+
+	if (returned_bytes == NULL) {
+		/*caller pass NULL pointer*/
+		ASSERT_CRITICAL(false);
+		return AUX_CHANNEL_OPERATION_FAILED_REASON_UNKNOWN;
+	}
+	*returned_bytes = 0;
+
+	/* poll to make sure that SW_DONE is asserted */
+	value = REG_WAIT(AUX_SW_STATUS, AUX_SW_DONE, 1,
+				10, aux110->timeout_period/10);
+
+	/* in case HPD is LOW, exit AUX transaction */
+	if ((value & AUX_SW_STATUS__AUX_SW_HPD_DISCON_MASK))
+		return AUX_CHANNEL_OPERATION_FAILED_HPD_DISCON;
+
+	/* Note that the following bits are set in 'status.bits'
+	 * during CTS 4.2.1.2 (FW 3.3.1):
+	 * AUX_SW_RX_MIN_COUNT_VIOL, AUX_SW_RX_INVALID_STOP,
+	 * AUX_SW_RX_RECV_NO_DET, AUX_SW_RX_RECV_INVALID_H.
+	 *
+	 * AUX_SW_RX_MIN_COUNT_VIOL is an internal,
+	 * HW debugging bit and should be ignored.
+	 */
+	if (value & AUX_SW_STATUS__AUX_SW_DONE_MASK) {
+		if ((value & AUX_SW_STATUS__AUX_SW_RX_TIMEOUT_STATE_MASK) ||
+			(value & AUX_SW_STATUS__AUX_SW_RX_TIMEOUT_MASK))
+			return AUX_CHANNEL_OPERATION_FAILED_TIMEOUT;
+
+		else if ((value & AUX_SW_STATUS__AUX_SW_RX_INVALID_STOP_MASK) ||
+			(value & AUX_SW_STATUS__AUX_SW_RX_RECV_NO_DET_MASK) ||
+			(value &
+				AUX_SW_STATUS__AUX_SW_RX_RECV_INVALID_H_MASK) ||
+			(value & AUX_SW_STATUS__AUX_SW_RX_RECV_INVALID_L_MASK))
+			return AUX_CHANNEL_OPERATION_FAILED_INVALID_REPLY;
+
+		*returned_bytes = get_reg_field_value(value,
+				AUX_SW_STATUS,
+				AUX_SW_REPLY_BYTE_COUNT);
+
+		if (*returned_bytes == 0)
+			return
+			AUX_CHANNEL_OPERATION_FAILED_INVALID_REPLY;
+		else {
+			*returned_bytes -= 1;
+			return AUX_CHANNEL_OPERATION_SUCCEEDED;
+		}
+	} else {
+		/*time_elapsed >= aux_engine->timeout_period
+		 *  AUX_SW_STATUS__AUX_SW_HPD_DISCON = at this point
+		 */
+		ASSERT_CRITICAL(false);
+		return AUX_CHANNEL_OPERATION_FAILED_TIMEOUT;
+	}
+}
+static void process_read_reply(
+	struct aux_engine *engine,
+	struct read_command_context *ctx)
+{
+	engine->funcs->process_channel_reply(engine, &ctx->reply);
+
+	switch (ctx->reply.status) {
+	case AUX_TRANSACTION_REPLY_AUX_ACK:
+		ctx->defer_retry_aux = 0;
+		if (ctx->returned_byte > ctx->current_read_length) {
+			ctx->status =
+				I2CAUX_TRANSACTION_STATUS_FAILED_PROTOCOL_ERROR;
+			ctx->operation_succeeded = false;
+		} else if (ctx->returned_byte < ctx->current_read_length) {
+			ctx->current_read_length -= ctx->returned_byte;
+
+			ctx->offset += ctx->returned_byte;
+
+			++ctx->invalid_reply_retry_aux_on_ack;
+
+			if (ctx->invalid_reply_retry_aux_on_ack >
+				AUX_INVALID_REPLY_RETRY_COUNTER) {
+				ctx->status =
+				I2CAUX_TRANSACTION_STATUS_FAILED_PROTOCOL_ERROR;
+				ctx->operation_succeeded = false;
+			}
+		} else {
+			ctx->status = I2CAUX_TRANSACTION_STATUS_SUCCEEDED;
+			ctx->transaction_complete = true;
+			ctx->operation_succeeded = true;
+		}
+	break;
+	case AUX_TRANSACTION_REPLY_AUX_NACK:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_NACK;
+		ctx->operation_succeeded = false;
+	break;
+	case AUX_TRANSACTION_REPLY_AUX_DEFER:
+		++ctx->defer_retry_aux;
+
+		if (ctx->defer_retry_aux > AUX_DEFER_RETRY_COUNTER) {
+			ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_TIMEOUT;
+			ctx->operation_succeeded = false;
+		}
+	break;
+	case AUX_TRANSACTION_REPLY_I2C_DEFER:
+		ctx->defer_retry_aux = 0;
+
+		++ctx->defer_retry_i2c;
+
+		if (ctx->defer_retry_i2c > AUX_DEFER_RETRY_COUNTER) {
+			ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_TIMEOUT;
+			ctx->operation_succeeded = false;
+		}
+	break;
+	case AUX_TRANSACTION_REPLY_HPD_DISCON:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_HPD_DISCON;
+		ctx->operation_succeeded = false;
+	break;
+	default:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_UNKNOWN;
+		ctx->operation_succeeded = false;
+	}
+}
+static void process_read_request(
+	struct aux_engine *engine,
+	struct read_command_context *ctx)
+{
+	enum aux_channel_operation_result operation_result;
+
+	engine->funcs->submit_channel_request(engine, &ctx->request);
+
+	operation_result = engine->funcs->get_channel_status(
+		engine, &ctx->returned_byte);
+
+	switch (operation_result) {
+	case AUX_CHANNEL_OPERATION_SUCCEEDED:
+		if (ctx->returned_byte > ctx->current_read_length) {
+			ctx->status =
+				I2CAUX_TRANSACTION_STATUS_FAILED_PROTOCOL_ERROR;
+			ctx->operation_succeeded = false;
+		} else {
+			ctx->timed_out_retry_aux = 0;
+			ctx->invalid_reply_retry_aux = 0;
+
+			ctx->reply.length = ctx->returned_byte;
+			ctx->reply.data = ctx->buffer;
+
+			process_read_reply(engine, ctx);
+		}
+	break;
+	case AUX_CHANNEL_OPERATION_FAILED_INVALID_REPLY:
+		++ctx->invalid_reply_retry_aux;
+
+		if (ctx->invalid_reply_retry_aux >
+			AUX_INVALID_REPLY_RETRY_COUNTER) {
+			ctx->status =
+				I2CAUX_TRANSACTION_STATUS_FAILED_PROTOCOL_ERROR;
+			ctx->operation_succeeded = false;
+		} else
+			udelay(400);
+	break;
+	case AUX_CHANNEL_OPERATION_FAILED_TIMEOUT:
+		++ctx->timed_out_retry_aux;
+
+		if (ctx->timed_out_retry_aux > AUX_TIMED_OUT_RETRY_COUNTER) {
+			ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_TIMEOUT;
+			ctx->operation_succeeded = false;
+		} else {
+			/* DP 1.2a, table 2-58:
+			 * "S3: AUX Request CMD PENDING:
+			 * retry 3 times, with 400usec wait on each"
+			 * The HW timeout is set to 550usec,
+			 * so we should not wait here
+			 */
+		}
+	break;
+	case AUX_CHANNEL_OPERATION_FAILED_HPD_DISCON:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_HPD_DISCON;
+		ctx->operation_succeeded = false;
+	break;
+	default:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_UNKNOWN;
+		ctx->operation_succeeded = false;
+	}
+}
+static bool read_command(
+	struct aux_engine *engine,
+	struct i2caux_transaction_request *request,
+	bool middle_of_transaction)
+{
+	struct read_command_context ctx;
+
+	ctx.buffer = request->payload.data;
+	ctx.current_read_length = request->payload.length;
+	ctx.offset = 0;
+	ctx.timed_out_retry_aux = 0;
+	ctx.invalid_reply_retry_aux = 0;
+	ctx.defer_retry_aux = 0;
+	ctx.defer_retry_i2c = 0;
+	ctx.invalid_reply_retry_aux_on_ack = 0;
+	ctx.transaction_complete = false;
+	ctx.operation_succeeded = true;
+
+	if (request->payload.address_space ==
+		I2CAUX_TRANSACTION_ADDRESS_SPACE_DPCD) {
+		ctx.request.type = AUX_TRANSACTION_TYPE_DP;
+		ctx.request.action = I2CAUX_TRANSACTION_ACTION_DP_READ;
+		ctx.request.address = request->payload.address;
+	} else if (request->payload.address_space ==
+		I2CAUX_TRANSACTION_ADDRESS_SPACE_I2C) {
+		ctx.request.type = AUX_TRANSACTION_TYPE_I2C;
+		ctx.request.action = middle_of_transaction ?
+			I2CAUX_TRANSACTION_ACTION_I2C_READ_MOT :
+			I2CAUX_TRANSACTION_ACTION_I2C_READ;
+		ctx.request.address = request->payload.address >> 1;
+	} else {
+		/* in DAL2, there was no return in such case */
+		BREAK_TO_DEBUGGER();
+		return false;
+	}
+
+	ctx.request.delay = 0;
+
+	do {
+		memset(ctx.buffer + ctx.offset, 0, ctx.current_read_length);
+
+		ctx.request.data = ctx.buffer + ctx.offset;
+		ctx.request.length = ctx.current_read_length;
+
+		process_read_request(engine, &ctx);
+
+		request->status = ctx.status;
+
+		if (ctx.operation_succeeded && !ctx.transaction_complete)
+			if (ctx.request.type == AUX_TRANSACTION_TYPE_I2C)
+				msleep(engine->delay);
+	} while (ctx.operation_succeeded && !ctx.transaction_complete);
+
+	if (request->payload.address_space ==
+		I2CAUX_TRANSACTION_ADDRESS_SPACE_DPCD) {
+		DC_LOG_I2C_AUX("READ: addr:0x%x  value:0x%x Result:%d",
+				request->payload.address,
+				request->payload.data[0],
+				ctx.operation_succeeded);
+	}
+
+	return ctx.operation_succeeded;
+}
+
+static void process_write_reply(
+	struct aux_engine *engine,
+	struct write_command_context *ctx)
+{
+	engine->funcs->process_channel_reply(engine, &ctx->reply);
+
+	switch (ctx->reply.status) {
+	case AUX_TRANSACTION_REPLY_AUX_ACK:
+		ctx->operation_succeeded = true;
+
+		if (ctx->returned_byte) {
+			ctx->request.action = ctx->mot ?
+			I2CAUX_TRANSACTION_ACTION_I2C_STATUS_REQUEST_MOT :
+			I2CAUX_TRANSACTION_ACTION_I2C_STATUS_REQUEST;
+
+			ctx->current_write_length = 0;
+
+			++ctx->ack_m_retry;
+
+			if (ctx->ack_m_retry > AUX_DEFER_RETRY_COUNTER) {
+				ctx->status =
+				I2CAUX_TRANSACTION_STATUS_FAILED_TIMEOUT;
+				ctx->operation_succeeded = false;
+			} else
+				udelay(300);
+		} else {
+			ctx->status = I2CAUX_TRANSACTION_STATUS_SUCCEEDED;
+			ctx->defer_retry_aux = 0;
+			ctx->ack_m_retry = 0;
+			ctx->transaction_complete = true;
+		}
+	break;
+	case AUX_TRANSACTION_REPLY_AUX_NACK:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_NACK;
+		ctx->operation_succeeded = false;
+	break;
+	case AUX_TRANSACTION_REPLY_AUX_DEFER:
+		++ctx->defer_retry_aux;
+
+		if (ctx->defer_retry_aux > ctx->max_defer_retry) {
+			ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_TIMEOUT;
+			ctx->operation_succeeded = false;
+		}
+	break;
+	case AUX_TRANSACTION_REPLY_I2C_DEFER:
+		ctx->defer_retry_aux = 0;
+		ctx->current_write_length = 0;
+
+		ctx->request.action = ctx->mot ?
+			I2CAUX_TRANSACTION_ACTION_I2C_STATUS_REQUEST_MOT :
+			I2CAUX_TRANSACTION_ACTION_I2C_STATUS_REQUEST;
+
+		++ctx->defer_retry_i2c;
+
+		if (ctx->defer_retry_i2c > ctx->max_defer_retry) {
+			ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_TIMEOUT;
+			ctx->operation_succeeded = false;
+		}
+	break;
+	case AUX_TRANSACTION_REPLY_HPD_DISCON:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_HPD_DISCON;
+		ctx->operation_succeeded = false;
+	break;
+	default:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_UNKNOWN;
+		ctx->operation_succeeded = false;
+	}
+}
+static void process_write_request(
+	struct aux_engine *engine,
+	struct write_command_context *ctx)
+{
+	enum aux_channel_operation_result operation_result;
+
+	engine->funcs->submit_channel_request(engine, &ctx->request);
+
+	operation_result = engine->funcs->get_channel_status(
+		engine, &ctx->returned_byte);
+
+	switch (operation_result) {
+	case AUX_CHANNEL_OPERATION_SUCCEEDED:
+		ctx->timed_out_retry_aux = 0;
+		ctx->invalid_reply_retry_aux = 0;
+
+		ctx->reply.length = ctx->returned_byte;
+		ctx->reply.data = ctx->reply_data;
+
+		process_write_reply(engine, ctx);
+	break;
+	case AUX_CHANNEL_OPERATION_FAILED_INVALID_REPLY:
+		++ctx->invalid_reply_retry_aux;
+
+		if (ctx->invalid_reply_retry_aux >
+			AUX_INVALID_REPLY_RETRY_COUNTER) {
+			ctx->status =
+				I2CAUX_TRANSACTION_STATUS_FAILED_PROTOCOL_ERROR;
+			ctx->operation_succeeded = false;
+		} else
+			udelay(400);
+	break;
+	case AUX_CHANNEL_OPERATION_FAILED_TIMEOUT:
+		++ctx->timed_out_retry_aux;
+
+		if (ctx->timed_out_retry_aux > AUX_TIMED_OUT_RETRY_COUNTER) {
+			ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_TIMEOUT;
+			ctx->operation_succeeded = false;
+		} else {
+			/* DP 1.2a, table 2-58:
+			 * "S3: AUX Request CMD PENDING:
+			 * retry 3 times, with 400usec wait on each"
+			 * The HW timeout is set to 550usec,
+			 * so we should not wait here
+			 */
+		}
+	break;
+	case AUX_CHANNEL_OPERATION_FAILED_HPD_DISCON:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_FAILED_HPD_DISCON;
+		ctx->operation_succeeded = false;
+	break;
+	default:
+		ctx->status = I2CAUX_TRANSACTION_STATUS_UNKNOWN;
+		ctx->operation_succeeded = false;
+	}
+}
+static bool write_command(
+	struct aux_engine *engine,
+	struct i2caux_transaction_request *request,
+	bool middle_of_transaction)
+{
+	struct write_command_context ctx;
+
+	ctx.mot = middle_of_transaction;
+	ctx.buffer = request->payload.data;
+	ctx.current_write_length = request->payload.length;
+	ctx.timed_out_retry_aux = 0;
+	ctx.invalid_reply_retry_aux = 0;
+	ctx.defer_retry_aux = 0;
+	ctx.defer_retry_i2c = 0;
+	ctx.ack_m_retry = 0;
+	ctx.transaction_complete = false;
+	ctx.operation_succeeded = true;
+
+	if (request->payload.address_space ==
+		I2CAUX_TRANSACTION_ADDRESS_SPACE_DPCD) {
+		ctx.request.type = AUX_TRANSACTION_TYPE_DP;
+		ctx.request.action = I2CAUX_TRANSACTION_ACTION_DP_WRITE;
+		ctx.request.address = request->payload.address;
+	} else if (request->payload.address_space ==
+		I2CAUX_TRANSACTION_ADDRESS_SPACE_I2C) {
+		ctx.request.type = AUX_TRANSACTION_TYPE_I2C;
+		ctx.request.action = middle_of_transaction ?
+			I2CAUX_TRANSACTION_ACTION_I2C_WRITE_MOT :
+			I2CAUX_TRANSACTION_ACTION_I2C_WRITE;
+		ctx.request.address = request->payload.address >> 1;
+	} else {
+		/* in DAL2, there was no return in such case */
+		BREAK_TO_DEBUGGER();
+		return false;
+	}
+
+	ctx.request.delay = 0;
+
+	ctx.max_defer_retry =
+		(engine->max_defer_write_retry > AUX_DEFER_RETRY_COUNTER) ?
+			engine->max_defer_write_retry : AUX_DEFER_RETRY_COUNTER;
+
+	do {
+		ctx.request.data = ctx.buffer;
+		ctx.request.length = ctx.current_write_length;
+
+		process_write_request(engine, &ctx);
+
+		request->status = ctx.status;
+
+		if (ctx.operation_succeeded && !ctx.transaction_complete)
+			if (ctx.request.type == AUX_TRANSACTION_TYPE_I2C)
+				msleep(engine->delay);
+	} while (ctx.operation_succeeded && !ctx.transaction_complete);
+
+	if (request->payload.address_space ==
+		I2CAUX_TRANSACTION_ADDRESS_SPACE_DPCD) {
+		DC_LOG_I2C_AUX("WRITE: addr:0x%x  value:0x%x Result:%d",
+				request->payload.address,
+				request->payload.data[0],
+				ctx.operation_succeeded);
+	}
+
+	return ctx.operation_succeeded;
+}
+static bool end_of_transaction_command(
+	struct aux_engine *engine,
+	struct i2caux_transaction_request *request)
+{
+	struct i2caux_transaction_request dummy_request;
+	uint8_t dummy_data;
+
+	/* [tcheng] We only need to send the stop (read with MOT = 0)
+	 * for I2C-over-Aux, not native AUX
+	 */
+
+	if (request->payload.address_space !=
+		I2CAUX_TRANSACTION_ADDRESS_SPACE_I2C)
+		return false;
+
+	dummy_request.operation = request->operation;
+	dummy_request.payload.address_space = request->payload.address_space;
+	dummy_request.payload.address = request->payload.address;
+
+	/*
+	 * Add a dummy byte due to some receiver quirk
+	 * where one byte is sent along with MOT = 0.
+	 * Ideally this should be 0.
+	 */
+
+	dummy_request.payload.length = 0;
+	dummy_request.payload.data = &dummy_data;
+
+	if (request->operation == I2CAUX_TRANSACTION_READ)
+		return read_command(engine, &dummy_request, false);
+	else
+		return write_command(engine, &dummy_request, false);
+
+	/* according Syed, it does not need now DoDummyMOT */
+}
+bool submit_request(
+	struct engine *engine,
+	struct i2caux_transaction_request *request,
+	bool middle_of_transaction)
+{
+	struct aux_engine *aux_engine = FROM_AUX_ENGINE_ENGINE(engine);
+
+	bool result;
+	bool mot_used = true;
+
+	switch (request->operation) {
+	case I2CAUX_TRANSACTION_READ:
+		result = read_command(aux_engine, request, mot_used);
+	break;
+	case I2CAUX_TRANSACTION_WRITE:
+		result = write_command(aux_engine, request, mot_used);
+	break;
+	default:
+		result = false;
+	}
+
+	/* [tcheng]
+	 * need to send stop for the last transaction to free up the AUX
+	 * if the above command fails, this would be the last transaction
+	 */
+
+	if (!middle_of_transaction || !result)
+		end_of_transaction_command(aux_engine, request);
+
+	/* mask AUX interrupt */
+
+	return result;
+}
+enum i2caux_engine_type get_engine_type(
+		const struct engine *engine)
+{
+	return I2CAUX_ENGINE_TYPE_AUX;
+}
+
+static struct aux_engine *acquire(
+	struct engine *engine,
+	struct ddc *ddc)
+{
+	struct aux_engine *aux_engine = FROM_AUX_ENGINE_ENGINE(engine);
+	enum gpio_result result;
+
+	if (aux_engine->funcs->is_engine_available) {
+		/*check whether SW could use the engine*/
+		if (!aux_engine->funcs->is_engine_available(aux_engine))
+			return NULL;
+	}
+
+	result = dal_ddc_open(ddc, GPIO_MODE_HARDWARE,
+		GPIO_DDC_CONFIG_TYPE_MODE_AUX);
+
+	if (result != GPIO_RESULT_OK)
+		return NULL;
+
+	if (!aux_engine->funcs->acquire_engine(aux_engine)) {
+		dal_ddc_close(ddc);
+		return NULL;
+	}
+
+	engine->ddc = ddc;
+
+	return aux_engine;
+}
+
+static const struct aux_engine_funcs aux_engine_funcs = {
+	.acquire_engine = acquire_engine,
+	.submit_channel_request = submit_channel_request,
+	.process_channel_reply = process_channel_reply,
+	.read_channel_reply = read_channel_reply,
+	.get_channel_status = get_channel_status,
+	.is_engine_available = is_engine_available,
+};
+
+static const struct engine_funcs engine_funcs = {
+	.release_engine = release_engine,
+	.destroy_engine = dce110_engine_destroy,
+	.submit_request = submit_request,
+	.get_engine_type = get_engine_type,
+	.acquire = acquire,
+};
+
+void dce110_engine_destroy(struct engine **engine)
+{
+
+	struct aux_engine_dce110 *engine110 = FROM_ENGINE(*engine);
+
+	kfree(engine110);
+	*engine = NULL;
+
+}
+struct aux_engine *dce110_aux_engine_construct(struct aux_engine_dce110 *aux_engine110,
+		struct dc_context *ctx,
+		uint32_t inst,
+		uint32_t timeout_period,
+		const struct dce110_aux_registers *regs)
+{
+	aux_engine110->base.base.ddc = NULL;
+	aux_engine110->base.base.ctx = ctx;
+	aux_engine110->base.delay = 0;
+	aux_engine110->base.max_defer_write_retry = 0;
+	aux_engine110->base.base.funcs = &engine_funcs;
+	aux_engine110->base.funcs = &aux_engine_funcs;
+	aux_engine110->base.base.inst = inst;
+	aux_engine110->timeout_period = timeout_period;
+	aux_engine110->regs = regs;
+
+	return &aux_engine110->base;
+}
+