--- /dev/null
+/*
+ * 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;
+}
+