osmocom-bb/src/host/virt_phy/src/virt_prim_pm.c

#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <osmocom/gsm/gsm_utils.h>
#include <osmocom/gsm/protocol/gsm_08_58.h>
#include <osmocom/core/msgb.h>
#include <virtphy/l1ctl_sap.h>
#include <virtphy/virt_l1_sched.h>
#include <osmocom/core/gsmtap.h>
#include <virtphy/logging.h>
#include <l1ctl_proto.h>

static struct l1_model_ms *l1_model_ms = NULL;

/**
 * @brief Change the signal strength for a given arfcn.
 *
 * Should be called if a msg is received on the virtual layer. The configured signal level reduction is applied.
 *
 * @param [in] arfcn to change sig str for.
 * @param [in] sig_lev the measured signal level value.
 */
uint16_t prim_pm_set_sig_strength(uint16_t arfcn, int16_t sig_lev) {
	if(l1_model_ms->state->pm.timeout_s > 0 || l1_model_ms->state->pm.timeout_us > 0) {
		osmo_timer_schedule(&l1_model_ms->state->pm.meas.arfcn_sig_lev_timers[arfcn], l1_model_ms->state->pm.timeout_s, l1_model_ms->state->pm.timeout_us);
	}
	l1_model_ms->state->pm.meas.arfcn_sig_lev_dbm[arfcn] = sig_lev - l1_model_ms->state->pm.meas.arfcn_sig_lev_red_dbm[arfcn];
	DEBUGP(DL1C, "Power measurement set for arfcn %u. Set signal level to %d (== rxlev: %u).\n", arfcn, l1_model_ms->state->pm.meas.arfcn_sig_lev_dbm[arfcn], dbm2rxlev(l1_model_ms->state->pm.meas.arfcn_sig_lev_dbm[arfcn]));
	return l1_model_ms->state->pm.meas.arfcn_sig_lev_dbm[arfcn];
}

void prim_pm_timer_cb(void *data) {
	// reset the signal level to bad value if no messages have been received from that rfcn for a given time
	DEBUGP(DL1C,
	       "Timeout occurred for arfcn, signal level reset to worst value.\n");
	*((int16_t*)data) = MIN_SIG_LEV_DBM;
}

/**
 * @brief Handler for received L1CTL_PM_REQ from L23.
 *
 * -- power measurement request --
 *
 * @param [in] msg the received message.
 *
 * Process power measurement for a given range of arfcns to calculate signal power and connection quality.
 *
 * Note: This should only be called after a certain time so some messages have already been received.
 *
 */
void l1ctl_rx_pm_req(struct msgb *msg)
{
	struct l1ctl_hdr *l1h = (struct l1ctl_hdr *)msg->data;
	struct l1ctl_pm_req *pm_req = (struct l1ctl_pm_req *)l1h->data;
	struct msgb *resp_msg = l1ctl_msgb_alloc(L1CTL_PM_CONF);
	uint16_t arfcn_next;
	// convert to host order
	pm_req->range.band_arfcn_from = ntohs(pm_req->range.band_arfcn_from);
	pm_req->range.band_arfcn_to = ntohs(pm_req->range.band_arfcn_to);

	DEBUGP(DL1C,
	                "Received from l23 - L1CTL_PM_REQ TYPE=%u, FROM=%d, TO=%d\n",
	                pm_req->type, pm_req->range.band_arfcn_from,
	                pm_req->range.band_arfcn_to);

	for (arfcn_next = pm_req->range.band_arfcn_from;
	                arfcn_next <= pm_req->range.band_arfcn_to;
	                ++arfcn_next) {
		struct l1ctl_pm_conf *pm_conf =
		                (struct l1ctl_pm_conf *)msgb_put(resp_msg,
		                                sizeof(*pm_conf));
		pm_conf->band_arfcn = htons(arfcn_next);
		// set min and max to the value calculated for that arfcn (IGNORE UPLINKK AND  PCS AND OTHER FLAGS)
		pm_conf->pm[0] = dbm2rxlev(l1_model_ms->state->pm.meas.arfcn_sig_lev_dbm[arfcn_next & ARFCN_NO_FLAGS_MASK]);
		pm_conf->pm[1] = dbm2rxlev(l1_model_ms->state->pm.meas.arfcn_sig_lev_dbm[arfcn_next & ARFCN_NO_FLAGS_MASK]);
		if (arfcn_next == pm_req->range.band_arfcn_to) {
			struct l1ctl_hdr *resp_l1h = msgb_l1(resp_msg);
			resp_l1h->flags |= L1CTL_F_DONE;
		}
		// no more space to hold mor pm info in msgb, flush to l23
		if (msgb_tailroom(resp_msg) < sizeof(*pm_conf)) {
			l1ctl_sap_tx_to_l23(resp_msg);
			resp_msg = l1ctl_msgb_alloc(L1CTL_PM_CONF);
		}
	}
	// transmit the remaining part of pm response to l23
	if (resp_msg) {
		l1ctl_sap_tx_to_l23(resp_msg);
	}
}

/**
 * @brief Initialize virtual prim pm.
 *
 * @param [in] model the l1 model instance
 */
void prim_pm_init(struct l1_model_ms *model)
{
	int i;
	l1_model_ms = model;
	// init the signal level of all arfcns with the lowest value possible
	memset (model->state->pm.meas.arfcn_sig_lev_dbm, MIN_SIG_LEV_DBM, sizeof (int16_t) * 1024);
	// init timers
	for(i = 0; i < 1024; ++i) {
		l1_model_ms->state->pm.meas.arfcn_sig_lev_timers[i].cb = prim_pm_timer_cb;
		l1_model_ms->state->pm.meas.arfcn_sig_lev_timers[i].data = &l1_model_ms->state->pm.meas.arfcn_sig_lev_dbm[i];
	}
}