layer23: modem: Delay GPRS attach at startup until modem is ready

Wait until SIM is ready, network system information ws obtained and
it announced the MS is able to use GPRS against it.

Change-Id: I5029d9e8a47b8544b3b803c4db6352269bac3c0e

src/host/layer23/include/osmocom/bb/modem/modem.h

@@ -3,4 +3,16 @@
 #include <stdbool.h>
 
 int modem_start(void);
+int modem_gprs_attach_if_needed(struct osmocom_ms *ms);
 
+enum modem_state {
+	MODEM_ST_IDLE,
+	MODEM_ST_ATTACHING,
+	MODEM_ST_ATTACHED
+};
+
+struct modem_app {
+	struct osmocom_ms *ms;
+	enum modem_state modem_state;
+};
+extern struct modem_app app_data;

src/host/layer23/src/modem/app_modem.c

@@ -54,14 +54,58 @@
 #include <osmocom/bb/modem/sm.h>
 #include <osmocom/bb/modem/vty.h>
 #include <osmocom/bb/modem/grr.h>
+#include <osmocom/bb/modem/modem.h>
 
 #include <l1ctl_proto.h>
 
 #include "config.h"
 
-static struct {
-	struct osmocom_ms *ms;
-} app_data;
+struct modem_app app_data;
+
+static bool modem_can_gprs_attach(const struct osmocom_ms *ms)
+{
+	const struct gsm_subscriber *subscr = &ms->subscr;
+	const struct gsm322_cellsel *cs = &ms->cellsel;
+	const struct gsm48_sysinfo *si = &cs->sel_si;
+
+	if (!subscr->sim_valid)
+		goto ret_false;
+
+	if (!si->si1 || !si->si3 || !si->si4 || !si->si13)
+		goto ret_false;
+
+	if (!si->gprs.supported)
+		goto ret_false;
+
+	return true;
+
+ret_false:
+	LOGP(DRLCMAC, LOGL_INFO, "Delaying GPRS attach, waiting for:%s%s%s%s%s%s\n",
+	     subscr->sim_valid ? "" : " imsi",
+	     si->si1 ? "" : " si1",
+	     si->si3 ? "" : " si3",
+	     si->si4 ? "" : " si4",
+	     si->si13 ? "" : " si13",
+	     si->gprs.supported ? "" : " GprsIndicator");
+	return false;
+}
+
+int modem_gprs_attach_if_needed(struct osmocom_ms *ms)
+{
+	int rc;
+
+	if (app_data.modem_state != MODEM_ST_IDLE)
+		return 0;
+
+	if (!modem_can_gprs_attach(ms))
+		return 0;
+
+	app_data.modem_state = MODEM_ST_ATTACHING;
+	rc = modem_gmm_gmmreg_attach_req(ms);
+	if (rc < 0)
+		app_data.modem_state = MODEM_ST_IDLE;
+	return rc;
+}
 
 /* Local network-originated IP packet, needs to be sent via SNDCP/LLC (GPRS) towards GSM network */
 static int modem_tun_data_ind_cb(struct osmo_tundev *tun, struct msgb *msg)
@@ -126,7 +170,7 @@ static int modem_l23_subscr_signal_cb(unsigned int subsys, unsigned int signal,
 	switch (signal) {
 	case S_L23_SUBSCR_SIM_ATTACHED:
 		ms = signal_data;
-		modem_gmm_gmmreg_attach_req(ms);
+		modem_gprs_attach_if_needed(ms);
 		break;
 	case S_L23_SUBSCR_SIM_DETACHED:
 		ms = signal_data;

src/host/layer23/src/modem/gmm.c

@@ -44,6 +44,7 @@
 #include <osmocom/bb/common/apn.h>
 #include <osmocom/bb/common/ms.h>
 #include <osmocom/bb/modem/gmm.h>
+#include <osmocom/bb/modem/modem.h>
 
 static int modem_gmm_prim_up_cb(struct osmo_gprs_gmm_prim *gmm_prim, void *user_data)
 {
@@ -59,10 +60,13 @@ static int modem_gmm_prim_up_cb(struct osmo_gprs_gmm_prim *gmm_prim, void *user_
 				LOGP(DGMM, LOGL_NOTICE, "%s(): Rx %s: Attach success P-TMSI=0x%08x\n",
 				     __func__, pdu_name, gmm_prim->gmmreg.attach_cnf.acc.allocated_ptmsi);
 				ms->subscr.ptmsi = gmm_prim->gmmreg.attach_cnf.acc.allocated_ptmsi;
+				app_data.modem_state = MODEM_ST_ATTACHED;
 			} else {
 				uint8_t cause = gmm_prim->gmmreg.attach_cnf.rej.cause;
 				LOGP(DGMM, LOGL_ERROR, "%s(): Rx %s: Attach rejected, cause=%u (%s)\n",
 				     __func__, pdu_name, cause, get_value_string(gsm48_gmm_cause_names, cause));
+				app_data.modem_state = MODEM_ST_IDLE;
+				modem_gprs_attach_if_needed(ms);
 			}
 			break;
 		case OSMO_PRIM(OSMO_GPRS_GMM_GMMREG_SIM_AUTH, PRIM_OP_INDICATION):

src/host/layer23/src/modem/grr.c

@@ -40,6 +40,7 @@
 #include <osmocom/bb/common/sysinfo.h>
 #include <osmocom/bb/common/l1ctl.h>
 #include <osmocom/bb/common/ms.h>
+#include <osmocom/bb/modem/modem.h>
 
 #include <osmocom/bb/mobile/gsm322.h>
 #include <osmocom/bb/mobile/gsm48_rr.h>
@@ -115,6 +116,7 @@ static int grr_handle_si1(struct osmocom_ms *ms, struct msgb *msg)
 		return rc;
 	}
 
+	modem_gprs_attach_if_needed(ms);
 	return 0;
 }
 
@@ -150,6 +152,7 @@ static int grr_handle_si3(struct osmocom_ms *ms, struct msgb *msg)
 	LOGP(DRR, LOGL_NOTICE, "Found GPRS Indicator (RA Colour %u, SI13 on BCCH %s)\n",
 	     cs->sel_si.gprs.ra_colour, cs->sel_si.gprs.si13_pos ? "Ext" : "Norm");
 
+	modem_gprs_attach_if_needed(ms);
 	return 0;
 }
 
@@ -177,6 +180,7 @@ static int grr_handle_si4(struct osmocom_ms *ms, struct msgb *msg)
 	LOGP(DRR, LOGL_NOTICE, "Found GPRS Indicator (RA Colour %u, SI13 on BCCH %s)\n",
 	     cs->sel_si.gprs.ra_colour, cs->sel_si.gprs.si13_pos ? "Ext" : "Norm");
 
+	modem_gprs_attach_if_needed(ms);
 	return 0;
 }
 
@@ -198,6 +202,8 @@ static int grr_handle_si13(struct osmocom_ms *ms, struct msgb *msg)
 	/* Forward SI13 to RLC/MAC layer */
 	rlcmac_prim = osmo_gprs_rlcmac_prim_alloc_l1ctl_ccch_data_ind(0 /* TODO: fn */, msgb_l3(msg));
 	rc = osmo_gprs_rlcmac_prim_lower_up(rlcmac_prim);
+
+	modem_gprs_attach_if_needed(ms);
 	return rc;
 }