text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Copyright(C) 2015-2018 Linaro Limited.
   *
   * Author: Tor Jeremiassen <tor@ti.com>
   * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
   */
  
  #include <linux/err.h>
  #include <linux/list.h>
  #include <linux/zalloc.h>
  #include <stdlib.h>
  #include <opencsd/c_api/opencsd_c_api.h>
  #include <opencsd/etmv4/trc_pkt_types_etmv4.h>
  #include <opencsd/ocsd_if_types.h>
  
  #include "cs-etm.h"
  #include "cs-etm-decoder.h"
  #include "intlist.h"
  
  /* use raw logging */
  #ifdef CS_DEBUG_RAW
  #define CS_LOG_RAW_FRAMES
  #ifdef CS_RAW_PACKED
  #define CS_RAW_DEBUG_FLAGS (OCSD_DFRMTR_UNPACKED_RAW_OUT | \
  			    OCSD_DFRMTR_PACKED_RAW_OUT)
  #else
  #define CS_RAW_DEBUG_FLAGS (OCSD_DFRMTR_UNPACKED_RAW_OUT)
  #endif
  #endif
  
  struct cs_etm_decoder {
  	void *data;
  	void (*packet_printer)(const char *msg);
  	dcd_tree_handle_t dcd_tree;
  	cs_etm_mem_cb_type mem_access;
  	ocsd_datapath_resp_t prev_return;
  };
  
  static u32
  cs_etm_decoder__mem_access(const void *context,
  			   const ocsd_vaddr_t address,
  			   const ocsd_mem_space_acc_t mem_space __maybe_unused,
  			   const u8 trace_chan_id,
  			   const u32 req_size,
  			   u8 *buffer)
  {
  	struct cs_etm_decoder *decoder = (struct cs_etm_decoder *) context;
  
  	return decoder->mem_access(decoder->data, trace_chan_id,
  				   address, req_size, buffer);
  }
  
  int cs_etm_decoder__add_mem_access_cb(struct cs_etm_decoder *decoder,
  				      u64 start, u64 end,
  				      cs_etm_mem_cb_type cb_func)
  {
  	decoder->mem_access = cb_func;
  
  	if (ocsd_dt_add_callback_trcid_mem_acc(decoder->dcd_tree, start, end,
  					       OCSD_MEM_SPACE_ANY,
  					       cs_etm_decoder__mem_access,
  					       decoder))
  		return -1;
  
  	return 0;
  }
  
  int cs_etm_decoder__reset(struct cs_etm_decoder *decoder)
  {
  	ocsd_datapath_resp_t dp_ret;
  
  	decoder->prev_return = OCSD_RESP_CONT;
  
  	dp_ret = ocsd_dt_process_data(decoder->dcd_tree, OCSD_OP_RESET,
  				      0, 0, NULL, NULL);
  	if (OCSD_DATA_RESP_IS_FATAL(dp_ret))
  		return -1;
  
  	return 0;
  }
  
  int cs_etm_decoder__get_packet(struct cs_etm_packet_queue *packet_queue,
  			       struct cs_etm_packet *packet)
  {
  	if (!packet_queue || !packet)
  		return -EINVAL;
  
  	/* Nothing to do, might as well just return */
  	if (packet_queue->packet_count == 0)
  		return 0;
  	/*
  	 * The queueing process in function cs_etm_decoder__buffer_packet()
  	 * increments the tail *before* using it.  This is somewhat counter
  	 * intuitive but it has the advantage of centralizing tail management
  	 * at a single location.  Because of that we need to follow the same
  	 * heuristic with the head, i.e we increment it before using its
  	 * value.  Otherwise the first element of the packet queue is not
  	 * used.
  	 */
  	packet_queue->head = (packet_queue->head + 1) &
  			     (CS_ETM_PACKET_MAX_BUFFER - 1);
  
  	*packet = packet_queue->packet_buffer[packet_queue->head];
  
  	packet_queue->packet_count--;
  
  	return 1;
  }
  
  static int cs_etm_decoder__gen_etmv3_config(struct cs_etm_trace_params *params,
  					    ocsd_etmv3_cfg *config)
  {
  	config->reg_idr = params->etmv3.reg_idr;
  	config->reg_ctrl = params->etmv3.reg_ctrl;
  	config->reg_ccer = params->etmv3.reg_ccer;
  	config->reg_trc_id = params->etmv3.reg_trc_id;
  	config->arch_ver = ARCH_V7;
  	config->core_prof = profile_CortexA;
  
  	return 0;
  }
  
  static void cs_etm_decoder__gen_etmv4_config(struct cs_etm_trace_params *params,
  					     ocsd_etmv4_cfg *config)
  {
  	config->reg_configr = params->etmv4.reg_configr;
  	config->reg_traceidr = params->etmv4.reg_traceidr;
  	config->reg_idr0 = params->etmv4.reg_idr0;
  	config->reg_idr1 = params->etmv4.reg_idr1;
  	config->reg_idr2 = params->etmv4.reg_idr2;
  	config->reg_idr8 = params->etmv4.reg_idr8;
  	config->reg_idr9 = 0;
  	config->reg_idr10 = 0;
  	config->reg_idr11 = 0;
  	config->reg_idr12 = 0;
  	config->reg_idr13 = 0;
  	config->arch_ver = ARCH_V8;
  	config->core_prof = profile_CortexA;
  }
  
  static void cs_etm_decoder__print_str_cb(const void *p_context,
  					 const char *msg,
  					 const int str_len)
  {
  	if (p_context && str_len)
  		((struct cs_etm_decoder *)p_context)->packet_printer(msg);
  }
  
  static int
  cs_etm_decoder__init_def_logger_printing(struct cs_etm_decoder_params *d_params,
  					 struct cs_etm_decoder *decoder)
  {
  	int ret = 0;
  
  	if (d_params->packet_printer == NULL)
  		return -1;
  
  	decoder->packet_printer = d_params->packet_printer;
  
  	/*
  	 * Set up a library default logger to process any printers
  	 * (packet/raw frame) we add later.
  	 */
  	ret = ocsd_def_errlog_init(OCSD_ERR_SEV_ERROR, 1);
  	if (ret != 0)
  		return -1;
  
  	/* no stdout / err / file output */
  	ret = ocsd_def_errlog_config_output(C_API_MSGLOGOUT_FLG_NONE, NULL);
  	if (ret != 0)
  		return -1;
  
  	/*
  	 * Set the string CB for the default logger, passes strings to
  	 * perf print logger.
  	 */
  	ret = ocsd_def_errlog_set_strprint_cb(decoder->dcd_tree,
  					      (void *)decoder,
  					      cs_etm_decoder__print_str_cb);
  	if (ret != 0)
  		ret = -1;
  
  	return 0;
  }
  
  #ifdef CS_LOG_RAW_FRAMES
  static void
  cs_etm_decoder__init_raw_frame_logging(struct cs_etm_decoder_params *d_params,
  				       struct cs_etm_decoder *decoder)
  {
  	/* Only log these during a --dump operation */
  	if (d_params->operation == CS_ETM_OPERATION_PRINT) {
  		/* set up a library default logger to process the
  		 *  raw frame printer we add later
  		 */
  		ocsd_def_errlog_init(OCSD_ERR_SEV_ERROR, 1);
  
  		/* no stdout / err / file output */
  		ocsd_def_errlog_config_output(C_API_MSGLOGOUT_FLG_NONE, NULL);
  
  		/* set the string CB for the default logger,
  		 * passes strings to perf print logger.
  		 */
  		ocsd_def_errlog_set_strprint_cb(decoder->dcd_tree,
  						(void *)decoder,
  						cs_etm_decoder__print_str_cb);
  
  		/* use the built in library printer for the raw frames */
  		ocsd_dt_set_raw_frame_printer(decoder->dcd_tree,
  					      CS_RAW_DEBUG_FLAGS);
  	}
  }
  #else
  static void
  cs_etm_decoder__init_raw_frame_logging(
  		struct cs_etm_decoder_params *d_params __maybe_unused,
  		struct cs_etm_decoder *decoder __maybe_unused)
  {
  }
  #endif
  
  static int cs_etm_decoder__create_packet_printer(struct cs_etm_decoder *decoder,
  						 const char *decoder_name,
  						 void *trace_config)
  {
  	u8 csid;
  
  	if (ocsd_dt_create_decoder(decoder->dcd_tree, decoder_name,
  				   OCSD_CREATE_FLG_PACKET_PROC,
  				   trace_config, &csid))
  		return -1;
  
  	if (ocsd_dt_set_pkt_protocol_printer(decoder->dcd_tree, csid, 0))
  		return -1;
  
  	return 0;
  }
  
  static int
  cs_etm_decoder__create_etm_packet_printer(struct cs_etm_trace_params *t_params,
  					  struct cs_etm_decoder *decoder)
  {
  	const char *decoder_name;
  	ocsd_etmv3_cfg config_etmv3;
  	ocsd_etmv4_cfg trace_config_etmv4;
  	void *trace_config;
  
  	switch (t_params->protocol) {
  	case CS_ETM_PROTO_ETMV3:
  	case CS_ETM_PROTO_PTM:
  		cs_etm_decoder__gen_etmv3_config(t_params, &config_etmv3);
  		decoder_name = (t_params->protocol == CS_ETM_PROTO_ETMV3) ?
  							OCSD_BUILTIN_DCD_ETMV3 :
  							OCSD_BUILTIN_DCD_PTM;
  		trace_config = &config_etmv3;
  		break;
  	case CS_ETM_PROTO_ETMV4i:
  		cs_etm_decoder__gen_etmv4_config(t_params, &trace_config_etmv4);
  		decoder_name = OCSD_BUILTIN_DCD_ETMV4I;
  		trace_config = &trace_config_etmv4;
  		break;
  	default:
  		return -1;
  	}
  
  	return cs_etm_decoder__create_packet_printer(decoder,
  						     decoder_name,
  						     trace_config);
  }
  
  static ocsd_datapath_resp_t
  cs_etm_decoder__do_soft_timestamp(struct cs_etm_queue *etmq,
  				  struct cs_etm_packet_queue *packet_queue,
  				  const uint8_t trace_chan_id)
  {
  	/* No timestamp packet has been received, nothing to do */
  	if (!packet_queue->timestamp)
  		return OCSD_RESP_CONT;
  
  	packet_queue->timestamp = packet_queue->next_timestamp;
  
  	/* Estimate the timestamp for the next range packet */
  	packet_queue->next_timestamp += packet_queue->instr_count;
  	packet_queue->instr_count = 0;
  
  	/* Tell the front end which traceid_queue needs attention */
  	cs_etm__etmq_set_traceid_queue_timestamp(etmq, trace_chan_id);
  
  	return OCSD_RESP_WAIT;
  }
  
  static ocsd_datapath_resp_t
  cs_etm_decoder__do_hard_timestamp(struct cs_etm_queue *etmq,
  				  const ocsd_generic_trace_elem *elem,
  				  const uint8_t trace_chan_id)
  {
  	struct cs_etm_packet_queue *packet_queue;
  
  	/* First get the packet queue for this traceID */
  	packet_queue = cs_etm__etmq_get_packet_queue(etmq, trace_chan_id);
  	if (!packet_queue)
  		return OCSD_RESP_FATAL_SYS_ERR;
  
  	/*
  	 * We've seen a timestamp packet before - simply record the new value.
  	 * Function do_soft_timestamp() will report the value to the front end,
  	 * hence asking the decoder to keep decoding rather than stopping.
  	 */
  	if (packet_queue->timestamp) {
  		packet_queue->next_timestamp = elem->timestamp;
  		return OCSD_RESP_CONT;
  	}
  
  	/*
  	 * This is the first timestamp we've seen since the beginning of traces
  	 * or a discontinuity.  Since timestamps packets are generated *after*
  	 * range packets have been generated, we need to estimate the time at
  	 * which instructions started by substracting the number of instructions
  	 * executed to the timestamp.
  	 */
  	packet_queue->timestamp = elem->timestamp - packet_queue->instr_count;
  	packet_queue->next_timestamp = elem->timestamp;
  	packet_queue->instr_count = 0;
  
  	/* Tell the front end which traceid_queue needs attention */
  	cs_etm__etmq_set_traceid_queue_timestamp(etmq, trace_chan_id);
  
  	/* Halt processing until we are being told to proceed */
  	return OCSD_RESP_WAIT;
  }
  
  static void
  cs_etm_decoder__reset_timestamp(struct cs_etm_packet_queue *packet_queue)
  {
  	packet_queue->timestamp = 0;
  	packet_queue->next_timestamp = 0;
  	packet_queue->instr_count = 0;
  }
  
  static ocsd_datapath_resp_t
  cs_etm_decoder__buffer_packet(struct cs_etm_packet_queue *packet_queue,
  			      const u8 trace_chan_id,
  			      enum cs_etm_sample_type sample_type)
  {
  	u32 et = 0;
  	int cpu;
  
  	if (packet_queue->packet_count >= CS_ETM_PACKET_MAX_BUFFER - 1)
  		return OCSD_RESP_FATAL_SYS_ERR;
  
  	if (cs_etm__get_cpu(trace_chan_id, &cpu) < 0)
  		return OCSD_RESP_FATAL_SYS_ERR;
  
  	et = packet_queue->tail;
  	et = (et + 1) & (CS_ETM_PACKET_MAX_BUFFER - 1);
  	packet_queue->tail = et;
  	packet_queue->packet_count++;
  
  	packet_queue->packet_buffer[et].sample_type = sample_type;
  	packet_queue->packet_buffer[et].isa = CS_ETM_ISA_UNKNOWN;
  	packet_queue->packet_buffer[et].cpu = cpu;
  	packet_queue->packet_buffer[et].start_addr = CS_ETM_INVAL_ADDR;
  	packet_queue->packet_buffer[et].end_addr = CS_ETM_INVAL_ADDR;
  	packet_queue->packet_buffer[et].instr_count = 0;
  	packet_queue->packet_buffer[et].last_instr_taken_branch = false;
  	packet_queue->packet_buffer[et].last_instr_size = 0;
  	packet_queue->packet_buffer[et].last_instr_type = 0;
  	packet_queue->packet_buffer[et].last_instr_subtype = 0;
  	packet_queue->packet_buffer[et].last_instr_cond = 0;
  	packet_queue->packet_buffer[et].flags = 0;
  	packet_queue->packet_buffer[et].exception_number = UINT32_MAX;
  	packet_queue->packet_buffer[et].trace_chan_id = trace_chan_id;
  
  	if (packet_queue->packet_count == CS_ETM_PACKET_MAX_BUFFER - 1)
  		return OCSD_RESP_WAIT;
  
  	return OCSD_RESP_CONT;
  }
  
  static ocsd_datapath_resp_t
  cs_etm_decoder__buffer_range(struct cs_etm_queue *etmq,
  			     struct cs_etm_packet_queue *packet_queue,
  			     const ocsd_generic_trace_elem *elem,
  			     const uint8_t trace_chan_id)
  {
  	int ret = 0;
  	struct cs_etm_packet *packet;
  
  	ret = cs_etm_decoder__buffer_packet(packet_queue, trace_chan_id,
  					    CS_ETM_RANGE);
  	if (ret != OCSD_RESP_CONT && ret != OCSD_RESP_WAIT)
  		return ret;
  
  	packet = &packet_queue->packet_buffer[packet_queue->tail];
  
  	switch (elem->isa) {
  	case ocsd_isa_aarch64:
  		packet->isa = CS_ETM_ISA_A64;
  		break;
  	case ocsd_isa_arm:
  		packet->isa = CS_ETM_ISA_A32;
  		break;
  	case ocsd_isa_thumb2:
  		packet->isa = CS_ETM_ISA_T32;
  		break;
  	case ocsd_isa_tee:
  	case ocsd_isa_jazelle:
  	case ocsd_isa_custom:
  	case ocsd_isa_unknown:
  	default:
  		packet->isa = CS_ETM_ISA_UNKNOWN;
  	}
  
  	packet->start_addr = elem->st_addr;
  	packet->end_addr = elem->en_addr;
  	packet->instr_count = elem->num_instr_range;
  	packet->last_instr_type = elem->last_i_type;
  	packet->last_instr_subtype = elem->last_i_subtype;
  	packet->last_instr_cond = elem->last_instr_cond;
  
  	switch (elem->last_i_type) {
  	case OCSD_INSTR_BR:
  	case OCSD_INSTR_BR_INDIRECT:
  		packet->last_instr_taken_branch = elem->last_instr_exec;
  		break;
  	case OCSD_INSTR_ISB:
  	case OCSD_INSTR_DSB_DMB:
  	case OCSD_INSTR_WFI_WFE:
  	case OCSD_INSTR_OTHER:
  	default:
  		packet->last_instr_taken_branch = false;
  		break;
  	}
  
  	packet->last_instr_size = elem->last_instr_sz;
  
  	/* per-thread scenario, no need to generate a timestamp */
  	if (cs_etm__etmq_is_timeless(etmq))
  		goto out;
  
  	/*
  	 * The packet queue is full and we haven't seen a timestamp (had we
  	 * seen one the packet queue wouldn't be full).  Let the front end
  	 * deal with it.
  	 */
  	if (ret == OCSD_RESP_WAIT)
  		goto out;
  
  	packet_queue->instr_count += elem->num_instr_range;
  	/* Tell the front end we have a new timestamp to process */
  	ret = cs_etm_decoder__do_soft_timestamp(etmq, packet_queue,
  						trace_chan_id);
  out:
  	return ret;
  }
  
  static ocsd_datapath_resp_t
  cs_etm_decoder__buffer_discontinuity(struct cs_etm_packet_queue *queue,
  				     const uint8_t trace_chan_id)
  {
  	/*
  	 * Something happened and who knows when we'll get new traces so
  	 * reset time statistics.
  	 */
  	cs_etm_decoder__reset_timestamp(queue);
  	return cs_etm_decoder__buffer_packet(queue, trace_chan_id,
  					     CS_ETM_DISCONTINUITY);
  }
  
  static ocsd_datapath_resp_t
  cs_etm_decoder__buffer_exception(struct cs_etm_packet_queue *queue,
  				 const ocsd_generic_trace_elem *elem,
  				 const uint8_t trace_chan_id)
  {	int ret = 0;
  	struct cs_etm_packet *packet;
  
  	ret = cs_etm_decoder__buffer_packet(queue, trace_chan_id,
  					    CS_ETM_EXCEPTION);
  	if (ret != OCSD_RESP_CONT && ret != OCSD_RESP_WAIT)
  		return ret;
  
  	packet = &queue->packet_buffer[queue->tail];
  	packet->exception_number = elem->exception_number;
  
  	return ret;
  }
  
  static ocsd_datapath_resp_t
  cs_etm_decoder__buffer_exception_ret(struct cs_etm_packet_queue *queue,
  				     const uint8_t trace_chan_id)
  {
  	return cs_etm_decoder__buffer_packet(queue, trace_chan_id,
  					     CS_ETM_EXCEPTION_RET);
  }
  
  static ocsd_datapath_resp_t
  cs_etm_decoder__set_tid(struct cs_etm_queue *etmq,
  			struct cs_etm_packet_queue *packet_queue,
  			const ocsd_generic_trace_elem *elem,
  			const uint8_t trace_chan_id)
  {
  	pid_t tid;
  
  	/* Ignore PE_CONTEXT packets that don't have a valid contextID */
  	if (!elem->context.ctxt_id_valid)
  		return OCSD_RESP_CONT;
  
  	tid =  elem->context.context_id;
  	if (cs_etm__etmq_set_tid(etmq, tid, trace_chan_id))
  		return OCSD_RESP_FATAL_SYS_ERR;
  
  	/*
  	 * A timestamp is generated after a PE_CONTEXT element so make sure
  	 * to rely on that coming one.
  	 */
  	cs_etm_decoder__reset_timestamp(packet_queue);
  
  	return OCSD_RESP_CONT;
  }
  
  static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
  				const void *context,
  				const ocsd_trc_index_t indx __maybe_unused,
  				const u8 trace_chan_id __maybe_unused,
  				const ocsd_generic_trace_elem *elem)
  {
  	ocsd_datapath_resp_t resp = OCSD_RESP_CONT;
  	struct cs_etm_decoder *decoder = (struct cs_etm_decoder *) context;
  	struct cs_etm_queue *etmq = decoder->data;
  	struct cs_etm_packet_queue *packet_queue;
  
  	/* First get the packet queue for this traceID */
  	packet_queue = cs_etm__etmq_get_packet_queue(etmq, trace_chan_id);
  	if (!packet_queue)
  		return OCSD_RESP_FATAL_SYS_ERR;
  
  	switch (elem->elem_type) {
  	case OCSD_GEN_TRC_ELEM_UNKNOWN:
  		break;
  	case OCSD_GEN_TRC_ELEM_EO_TRACE:
  	case OCSD_GEN_TRC_ELEM_NO_SYNC:
  	case OCSD_GEN_TRC_ELEM_TRACE_ON:
  		resp = cs_etm_decoder__buffer_discontinuity(packet_queue,
  							    trace_chan_id);
  		break;
  	case OCSD_GEN_TRC_ELEM_INSTR_RANGE:
  		resp = cs_etm_decoder__buffer_range(etmq, packet_queue, elem,
  						    trace_chan_id);
  		break;
  	case OCSD_GEN_TRC_ELEM_EXCEPTION:
  		resp = cs_etm_decoder__buffer_exception(packet_queue, elem,
  							trace_chan_id);
  		break;
  	case OCSD_GEN_TRC_ELEM_EXCEPTION_RET:
  		resp = cs_etm_decoder__buffer_exception_ret(packet_queue,
  							    trace_chan_id);
  		break;
  	case OCSD_GEN_TRC_ELEM_TIMESTAMP:
  		resp = cs_etm_decoder__do_hard_timestamp(etmq, elem,
  							 trace_chan_id);
  		break;
  	case OCSD_GEN_TRC_ELEM_PE_CONTEXT:
  		resp = cs_etm_decoder__set_tid(etmq, packet_queue,
  					       elem, trace_chan_id);
  		break;
  	case OCSD_GEN_TRC_ELEM_ADDR_NACC:
  	case OCSD_GEN_TRC_ELEM_CYCLE_COUNT:
  	case OCSD_GEN_TRC_ELEM_ADDR_UNKNOWN:
  	case OCSD_GEN_TRC_ELEM_EVENT:
  	case OCSD_GEN_TRC_ELEM_SWTRACE:
  	case OCSD_GEN_TRC_ELEM_CUSTOM:
  	default:
  		break;
  	}
  
  	return resp;
  }
  
  static int cs_etm_decoder__create_etm_packet_decoder(
  					struct cs_etm_trace_params *t_params,
  					struct cs_etm_decoder *decoder)
  {
  	const char *decoder_name;
  	ocsd_etmv3_cfg config_etmv3;
  	ocsd_etmv4_cfg trace_config_etmv4;
  	void *trace_config;
  	u8 csid;
  
  	switch (t_params->protocol) {
  	case CS_ETM_PROTO_ETMV3:
  	case CS_ETM_PROTO_PTM:
  		cs_etm_decoder__gen_etmv3_config(t_params, &config_etmv3);
  		decoder_name = (t_params->protocol == CS_ETM_PROTO_ETMV3) ?
  							OCSD_BUILTIN_DCD_ETMV3 :
  							OCSD_BUILTIN_DCD_PTM;
  		trace_config = &config_etmv3;
  		break;
  	case CS_ETM_PROTO_ETMV4i:
  		cs_etm_decoder__gen_etmv4_config(t_params, &trace_config_etmv4);
  		decoder_name = OCSD_BUILTIN_DCD_ETMV4I;
  		trace_config = &trace_config_etmv4;
  		break;
  	default:
  		return -1;
  	}
  
  	if (ocsd_dt_create_decoder(decoder->dcd_tree,
  				     decoder_name,
  				     OCSD_CREATE_FLG_FULL_DECODER,
  				     trace_config, &csid))
  		return -1;
  
  	if (ocsd_dt_set_gen_elem_outfn(decoder->dcd_tree,
  				       cs_etm_decoder__gen_trace_elem_printer,
  				       decoder))
  		return -1;
  
  	return 0;
  }
  
  static int
  cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
  				   struct cs_etm_trace_params *t_params,
  				   struct cs_etm_decoder *decoder)
  {
  	if (d_params->operation == CS_ETM_OPERATION_PRINT)
  		return cs_etm_decoder__create_etm_packet_printer(t_params,
  								 decoder);
  	else if (d_params->operation == CS_ETM_OPERATION_DECODE)
  		return cs_etm_decoder__create_etm_packet_decoder(t_params,
  								 decoder);
  
  	return -1;
  }
  
  struct cs_etm_decoder *
  cs_etm_decoder__new(int num_cpu, struct cs_etm_decoder_params *d_params,
  		    struct cs_etm_trace_params t_params[])
  {
  	struct cs_etm_decoder *decoder;
  	ocsd_dcd_tree_src_t format;
  	u32 flags;
  	int i, ret;
  
  	if ((!t_params) || (!d_params))
  		return NULL;
  
  	decoder = zalloc(sizeof(*decoder));
  
  	if (!decoder)
  		return NULL;
  
  	decoder->data = d_params->data;
  	decoder->prev_return = OCSD_RESP_CONT;
  	format = (d_params->formatted ? OCSD_TRC_SRC_FRAME_FORMATTED :
  					 OCSD_TRC_SRC_SINGLE);
  	flags = 0;
  	flags |= (d_params->fsyncs ? OCSD_DFRMTR_HAS_FSYNCS : 0);
  	flags |= (d_params->hsyncs ? OCSD_DFRMTR_HAS_HSYNCS : 0);
  	flags |= (d_params->frame_aligned ? OCSD_DFRMTR_FRAME_MEM_ALIGN : 0);
  
  	/*
  	 * Drivers may add barrier frames when used with perf, set up to
  	 * handle this. Barriers const of FSYNC packet repeated 4 times.
  	 */
  	flags |= OCSD_DFRMTR_RESET_ON_4X_FSYNC;
  
  	/* Create decode tree for the data source */
  	decoder->dcd_tree = ocsd_create_dcd_tree(format, flags);
  
  	if (decoder->dcd_tree == 0)
  		goto err_free_decoder;
  
  	/* init library print logging support */
  	ret = cs_etm_decoder__init_def_logger_printing(d_params, decoder);
  	if (ret != 0)
  		goto err_free_decoder;
  
  	/* init raw frame logging if required */
  	cs_etm_decoder__init_raw_frame_logging(d_params, decoder);
  
  	for (i = 0; i < num_cpu; i++) {
  		ret = cs_etm_decoder__create_etm_decoder(d_params,
  							 &t_params[i],
  							 decoder);
  		if (ret != 0)
  			goto err_free_decoder;
  	}
  
  	return decoder;
  
  err_free_decoder:
  	cs_etm_decoder__free(decoder);
  	return NULL;
  }
  
  int cs_etm_decoder__process_data_block(struct cs_etm_decoder *decoder,
  				       u64 indx, const u8 *buf,
  				       size_t len, size_t *consumed)
  {
  	int ret = 0;
  	ocsd_datapath_resp_t cur = OCSD_RESP_CONT;
  	ocsd_datapath_resp_t prev_return = decoder->prev_return;
  	size_t processed = 0;
  	u32 count;
  
  	while (processed < len) {
  		if (OCSD_DATA_RESP_IS_WAIT(prev_return)) {
  			cur = ocsd_dt_process_data(decoder->dcd_tree,
  						   OCSD_OP_FLUSH,
  						   0,
  						   0,
  						   NULL,
  						   NULL);
  		} else if (OCSD_DATA_RESP_IS_CONT(prev_return)) {
  			cur = ocsd_dt_process_data(decoder->dcd_tree,
  						   OCSD_OP_DATA,
  						   indx + processed,
  						   len - processed,
  						   &buf[processed],
  						   &count);
  			processed += count;
  		} else {
  			ret = -EINVAL;
  			break;
  		}
  
  		/*
  		 * Return to the input code if the packet buffer is full.
  		 * Flushing will get done once the packet buffer has been
  		 * processed.
  		 */
  		if (OCSD_DATA_RESP_IS_WAIT(cur))
  			break;
  
  		prev_return = cur;
  	}
  
  	decoder->prev_return = cur;
  	*consumed = processed;
  
  	return ret;
  }
  
  void cs_etm_decoder__free(struct cs_etm_decoder *decoder)
  {
  	if (!decoder)
  		return;
  
  	ocsd_destroy_dcd_tree(decoder->dcd_tree);
  	decoder->dcd_tree = NULL;
  	free(decoder);
  }
  