/*
 * Copyright © 2021 Collabora, Ltd.
 * Author: Antonio Caggiano <antonio.caggiano@collabora.com>
 *
 * SPDX-License-Identifier: MIT
 */

#include "intel_pps_perf.h"

#include <math.h>
#include <sys/ioctl.h>
#include <util/ralloc.h>
#include <utility>

#include "drm-uapi/i915_drm.h"

#include <pps/pps.h>
#include <pps/pps_device.h>

namespace pps
{
IntelPerf::IntelPerf(const int drm_fd)
   : drm_fd {drm_fd}
   , ralloc_ctx {ralloc_context(nullptr)}
   , ralloc_cfg {ralloc_context(nullptr)}
   , cfg {intel_perf_new(ralloc_cfg)}
{
   assert(drm_fd >= 0 && "DRM fd is not valid");

   if (!intel_get_device_info_from_fd(drm_fd, &devinfo)) {
      PPS_LOG_FATAL("Failed to get devinfo");
   }

   intel_perf_init_metrics(cfg,
      &devinfo,
      drm_fd,
      false, // no pipeline statistics
      false  // no register snapshots
   );
}

IntelPerf::~IntelPerf()
{
   close();

   if (ralloc_ctx) {
      ralloc_free(ralloc_ctx);
   }

   if (ralloc_cfg) {
      ralloc_free(ralloc_cfg);
   }
}

std::vector<struct intel_perf_query_info *> IntelPerf::get_queries() const
{
   assert(cfg && "Intel perf config should be valid");
   assert(cfg->n_queries && "Intel perf queries not initialized");

   std::vector<struct intel_perf_query_info *> queries = {};

   for (int i = 0; i < cfg->n_queries; ++i) {
      struct intel_perf_query_info *query = &cfg->queries[i];
      // Skip invalid queries
      if (query && query->symbol_name) {
         queries.push_back(query);
      }
   }

   return queries;
}

// The period_exponent gives a sampling period as follows:
// sample_period = timestamp_period * 2^(period_exponent + 1)
// where timestamp_period is 80ns for Haswell+
static uint32_t get_oa_exponent(const intel_device_info *devinfo, const uint64_t sampling_period_ns)
{
   return static_cast<uint32_t>(log2(sampling_period_ns * devinfo->timestamp_frequency / 1000000000ull)) - 1;
}

bool IntelPerf::open(const uint64_t sampling_period_ns,
                     struct intel_perf_query_info *query)
{
   assert(!ctx && "Perf context should not be initialized at this point");

   ctx = intel_perf_new_context(ralloc_ctx);
   intel_perf_init_context(ctx, cfg, nullptr, nullptr, nullptr, &devinfo, 0, drm_fd);

   auto oa_exponent = get_oa_exponent(&devinfo, sampling_period_ns);

   return intel_perf_open(ctx,
      query->oa_metrics_set_id,
      query->oa_format,
      oa_exponent,
      drm_fd,
      INTEL_PERF_INVALID_CTX_ID,
      true /* enable stream immediately */);
}

void IntelPerf::close()
{
   if (ctx) {
      intel_perf_close(ctx, nullptr);
      ctx = nullptr;
   }
}

bool IntelPerf::oa_stream_ready() const
{
   assert(ctx && "Perf context was not open");
   return intel_perf_oa_stream_ready(ctx);
}

ssize_t IntelPerf::read_oa_stream(void *buf, size_t bytes) const
{
   assert(ctx && "Perf context was not open");
   return intel_perf_read_oa_stream(ctx, buf, bytes);
}

} // namespace pps