open-standards/wai/oer-conformance/settle/zephyr/src/main.c

/* SPDX-License-Identifier: Apache-2.0 */
/* Settlement node on Zephyr: reads "A <id>" or "B <id>" lines on the console (the charger link or the sensor task),
   runs the keystone loop, and writes one OER/2 receipt per line. Energy fields come from a meter driver; this
   skeleton uses a cycle counter for compute and constants for the rest until the rail meter is wired in. */
#include <zephyr/kernel.h>
#include <zephyr/sys/printk.h>
#include <zephyr/console/console.h>
#include <zephyr/drivers/entropy.h>
#include <string.h>
#include <stdlib.h>
#include "settle.h"

static settle_ctx_t ctx;
static char out[4096];
static uint32_t cycles_now(void){ return k_cycle_get_32(); }

int main(void){
  uint8_t seed[32];
  const struct device *ent = DEVICE_DT_GET(DT_CHOSEN(zephyr_entropy));
  if (device_is_ready(ent)) entropy_get_entropy(ent, seed, sizeof seed); else memset(seed, 0x5a, sizeof seed);
  /* In production the seed lives in the signing element (OpenTitan or ATECC608) and never in RAM. */
  settle_init(&ctx, seed, 300.0, 86400.0);
  console_getline_init();
  printk("settle node ready\n");
  int64_t last_ms = k_uptime_get();
  const double standby_w = 1.8e-3, shared_w = 0.0;
  while (1) {
    char *line = console_getline();
    if (!line || strlen(line) < 3) continue;
    char cls = line[0]; uint32_t id = (uint32_t)strtoul(line + 2, NULL, 10);
    int64_t now_ms = k_uptime_get(); uint32_t c0 = cycles_now();
    settle_meter_t m;
    m.movement_j = cls == 'A' ? 2.3e-6 : 0;            /* wired charger link: replace with the meter's reading */
    m.idle_alloc_j = standby_w * (now_ms - last_ms) / 1000.0;
    m.shared_alloc_j = shared_w * (now_ms - last_ms) / 1000.0;
    m.upstream_j = 0; m.method = "calibrated_model"; m.weakest_how = "projected"; m.weakest_input = "standby_w";
    m.compute_j = 0; m.latency_s = 0;
    settle_result_t res;
    int rc = settle_decide(&ctx, cls, id, now_ms / 1000.0, &m, out, sizeof out, &res);
    uint32_t cyc = cycles_now() - c0;
    (void)cyc; /* the next receipt's compute_j = cyc * ctx.cycle_j; a two-pass emit would put it on this one */
    if (rc == 0) printk("%s\n", out); else printk("{\"error\":\"decide\",\"rc\":%d}\n", rc);
    last_ms = now_ms;
  }
  return 0;
}