smol-gilbraltar/clock.c

#include <assert.h>
#include <log.h>
#include <mbox.h>
#include <mem.h>
#include <tag.h>

#define PROPTAG_GET_CLOCK_RATE 0x00030002
#define PROPTAG_GET_CLOCK_RATE_MEASURED 0x00030047

uint32_t gilbraltar_get_rate_of_clock(uint32_t cid) {
  uint32_t proptag0[] __attribute__((aligned(16))) = {
      8 * 4, CODE_REQUEST, PROPTAG_GET_CLOCK_RATE, 2 * 4, 1 * 4, cid,
      0,     PROPTAG_END};

  for (int i = 0; i < sizeof(proptag0) / 4; i++)
    gilbraltar_log(DEBUG, "%08lx[%d]: %04x\r\n", (uintptr_t)proptag0, i,
                   proptag0[i]);

  assert(gilbraltar_mbox_write_read((uintptr_t)&proptag0));

  if (proptag0[6] != 0)
    return proptag0[6];

  uint32_t proptag1[] __attribute__((aligned(16))) = {
      8 * 4, CODE_REQUEST, PROPTAG_GET_CLOCK_RATE_MEASURED, 2 * 4, 1 * 4, cid,
      0,     PROPTAG_END};

  assert(gilbraltar_mbox_write_read((uintptr_t)&proptag1));

  return proptag1[6];
}