Review at  https://gerrit.osmocom.org/7825

fix handling of state changes in acc ramping

Take both the operative and administrative states into account
when deciding whether to start ACC ramping, and examine old/new
state values to avoid triggering ramping for a no-op state change.

This requires a fix to gsm_trx_lock_rf(): This function overwrote
the old administrative state of a trx before enqueuing a state
change request towards the BTS.
The BTS will confirm this request with an ACK, at which time a
signal is generated which the ACC ramp code listens to. We must
not overwrite the old state value until the signal has been handled,
otherwise the signal handler cannot tell what the old state was.

Tested with a virtphy setup, nanobts, and osmo-bts.

This is a port of osmo-bsc commit cda994edb20d24032d6ab4e916d0e9411671cfc0

Change-Id: I235d2c5fa962f2f338e77d0c11502921b37f4c36
Related: OS#2591
---
M openbsc/src/libbsc/abis_nm.c
M openbsc/src/libbsc/acc_ramp.c
M openbsc/src/libbsc/bsc_init.c
3 files changed, 113 insertions(+), 37 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/openbsc refs/changes/25/7825/1

diff --git a/openbsc/src/libbsc/abis_nm.c b/openbsc/src/libbsc/abis_nm.c
index 8eadfa8..cbb255a 100644
--- a/openbsc/src/libbsc/abis_nm.c
+++ b/openbsc/src/libbsc/abis_nm.c
@@ -2797,13 +2797,17 @@
 {
        uint8_t new_state = locked ? NM_STATE_LOCKED : NM_STATE_UNLOCKED;
 
-       LOGP(DNM, LOGL_NOTICE, "(bts=%d,trx=%d) Changing adm. state %s -> %s 
[%s]\n", trx->bts->nr, trx->nr,
+
+       if (!trx->bts || !trx->bts->oml_link) {
+               /* Set initial state which will be sent when BTS connects. */
+               trx->mo.nm_state.administrative = new_state;
+               return;
+       }
+
+       LOGP(DNM, LOGL_NOTICE, "(bts=%d,trx=%d) Requesting administrative state 
change %s -> %s [%s]\n",
+            trx->bts->nr, trx->nr,
             get_value_string(abis_nm_adm_state_names, 
trx->mo.nm_state.administrative),
             get_value_string(abis_nm_adm_state_names, new_state), reason);
-
-       trx->mo.nm_state.administrative = new_state;
-       if (!trx->bts || !trx->bts->oml_link)
-               return;
 
        abis_nm_chg_adm_state(trx->bts, NM_OC_RADIO_CARRIER,
                              trx->bts->bts_nr, trx->nr, 0xff,
diff --git a/openbsc/src/libbsc/acc_ramp.c b/openbsc/src/libbsc/acc_ramp.c
index 6e64109..c90d087 100644
--- a/openbsc/src/libbsc/acc_ramp.c
+++ b/openbsc/src/libbsc/acc_ramp.c
@@ -28,6 +28,7 @@
 #include <openbsc/gsm_data.h>
 #include <openbsc/chan_alloc.h>
 #include <openbsc/signal.h>
+#include <openbsc/abis_nm.h>
 
 /*
  * Check if an ACC has been permanently barred for a BTS,
@@ -144,6 +145,7 @@
        struct nm_statechg_signal_data *nsd = signal_data;
        struct acc_ramp *acc_ramp = handler_data;
        struct gsm_bts_trx *trx = NULL;
+       bool trigger_ramping = false, abort_ramping = false;
 
        /* Handled signals map to an Administrative State Change ACK, or a 
State Changed Event Report. */
        if (signal != S_NM_STATECHG_ADM && signal != S_NM_STATECHG_OPER)
@@ -154,37 +156,109 @@
 
        trx = nsd->obj;
 
+       LOGP(DRSL, LOGL_DEBUG, "(bts=%d,trx=%d) ACC RAMP: administrative state 
%s -> %s\n",
+           acc_ramp->bts->nr, trx->nr,
+           get_value_string(abis_nm_adm_state_names, 
nsd->old_state->administrative),
+           get_value_string(abis_nm_adm_state_names, 
nsd->new_state->administrative));
+       LOGP(DRSL, LOGL_DEBUG, "(bts=%d,trx=%d) ACC RAMP: operational state %s 
-> %s\n",
+           acc_ramp->bts->nr, trx->nr,
+           abis_nm_opstate_name(nsd->old_state->operational),
+           abis_nm_opstate_name(nsd->new_state->operational));
+
        /* We only care about state changes of the first TRX. */
        if (trx->nr != 0)
                return 0;
 
        /* RSL must already be up. We cannot send RACH system information to 
the BTS otherwise. */
-       if (trx->rsl_link == NULL)
+       if (trx->rsl_link == NULL) {
+               LOGP(DRSL, LOGL_DEBUG, "(bts=%d,trx=%d) ACC RAMP: ignoring 
state change because RSL link is down\n",
+                    acc_ramp->bts->nr, trx->nr);
                return 0;
-
-       /* Trigger or abort ACC ramping based on the new 'RF lock' state of 
this TRX. */
-       switch (nsd->new_state->administrative) {
-       case NM_STATE_UNLOCKED:
-               /*
-                * Do not re-trigger ACC ramping if ramping is already in 
progress.
-                * A BTS might send several "unlock" change events: One in the 
Administrative
-                * State Change ACK, and/or another in a State Changed Event 
Report.
-                * For instance, the nanobts is known to send both.
-                */
-               if (!osmo_timer_pending(&acc_ramp->step_timer))
-                       acc_ramp_trigger(acc_ramp);
-               break;
-       case NM_STATE_LOCKED:
-       case NM_STATE_SHUTDOWN:
-               acc_ramp_abort(acc_ramp);
-               break;
-       case NM_STATE_NULL:
-               break;
-       default:
-               LOGP(DRSL, LOGL_NOTICE, "(bts=%d) ACC RAMP: unrecognized 
administrative state '0x%x' reported for TRX 0\n",
-                   acc_ramp->bts->nr, nsd->new_state->administrative);
-               break;
        }
+
+       /* Trigger or abort ACC ramping based on the new state of this TRX. */
+       if (nsd->old_state->administrative != nsd->new_state->administrative) {
+               switch (nsd->new_state->administrative) {
+               case NM_STATE_UNLOCKED:
+                       if (nsd->old_state->operational != 
nsd->new_state->operational) {
+                               /*
+                                * Administrative and operational state have 
both changed.
+                                * Trigger ramping only if TRX 0 will be both 
enabled and unlocked.
+                                */
+                               if (nsd->new_state->operational == 
NM_OPSTATE_ENABLED)
+                                       trigger_ramping = true;
+                               else
+                                       LOGP(DRSL, LOGL_DEBUG, "(bts=%d,trx=%d) 
ACC RAMP: ignoring state change "
+                                            "because TRX is transitioning into 
operational state '%s'\n",
+                                            acc_ramp->bts->nr, trx->nr,
+                                            
abis_nm_opstate_name(nsd->new_state->operational));
+                       } else {
+                               /*
+                                * Operational state has not changed.
+                                * Trigger ramping only if TRX 0 is already 
usable.
+                                */
+                               if (trx_is_usable(trx))
+                                       trigger_ramping = true;
+                               else
+                                       LOGP(DRSL, LOGL_DEBUG, "(bts=%d,trx=%d) 
ACC RAMP: ignoring state change "
+                                            "because TRX is not usable\n", 
acc_ramp->bts->nr, trx->nr);
+                       }
+                       break;
+               case NM_STATE_LOCKED:
+               case NM_STATE_SHUTDOWN:
+                       abort_ramping = true;
+                       break;
+               case NM_STATE_NULL:
+               default:
+                       LOGP(DRSL, LOGL_NOTICE, "(bts=%d) ACC RAMP: 
unrecognized administrative state '0x%x' "
+                           "reported for TRX 0\n", acc_ramp->bts->nr, 
nsd->new_state->administrative);
+                       break;
+               }
+       }
+       if (nsd->old_state->operational != nsd->new_state->operational) {
+               switch (nsd->new_state->operational) {
+               case NM_OPSTATE_ENABLED:
+                       if (nsd->old_state->administrative != 
nsd->new_state->administrative) {
+                               /*
+                                * Administrative and operational state have 
both changed.
+                                * Trigger ramping only if TRX 0 will be both 
enabled and unlocked.
+                                */
+                               if (nsd->new_state->administrative == 
NM_STATE_UNLOCKED)
+                                       trigger_ramping = true;
+                               else
+                                       LOGP(DRSL, LOGL_DEBUG, "(bts=%d,trx=%d) 
ACC RAMP: ignoring state change "
+                                            "because TRX is transitioning into 
administrative state '%s'\n",
+                                            acc_ramp->bts->nr, trx->nr,
+                                            
get_value_string(abis_nm_adm_state_names, nsd->new_state->administrative));
+                       } else {
+                               /*
+                                * Administrative state has not changed.
+                                * Trigger ramping only if TRX 0 is already 
unlocked.
+                                */
+                               if (trx->mo.nm_state.administrative == 
NM_STATE_UNLOCKED)
+                                       trigger_ramping = true;
+                               else
+                                       LOGP(DRSL, LOGL_DEBUG, "(bts=%d,trx=%d) 
ACC RAMP: ignoring state change "
+                                            "because TRX is in administrative 
state '%s'\n",
+                                            acc_ramp->bts->nr, trx->nr,
+                                            
get_value_string(abis_nm_adm_state_names, trx->mo.nm_state.administrative));
+                       }
+                       break;
+               case NM_OPSTATE_DISABLED:
+                       abort_ramping = true;
+                       break;
+               case NM_OPSTATE_NULL:
+               default:
+                       LOGP(DRSL, LOGL_NOTICE, "(bts=%d) ACC RAMP: 
unrecognized operational state '0x%x' "
+                            "reported for TRX 0\n", acc_ramp->bts->nr, 
nsd->new_state->administrative);
+                       break;
+               }
+       }
+
+       if (trigger_ramping)
+               acc_ramp_trigger(acc_ramp);
+       else if (abort_ramping)
+               acc_ramp_abort(acc_ramp);
 
        return 0;
 }
@@ -270,13 +344,9 @@
        acc_ramp_abort(acc_ramp);
 
        if (acc_ramp_is_enabled(acc_ramp)) {
-               struct gsm_bts_trx *trx0 = gsm_bts_trx_by_nr(acc_ramp->bts, 0);
-               /* TRX 0 should be usable and unlocked, otherwise starting ACC 
ramping is pointless. */
-               if (trx0 && trx_is_usable(trx0) && 
trx0->mo.nm_state.administrative == NM_STATE_UNLOCKED) {
-                       /* Set all available ACCs to barred and start ramping 
up. */
-                       barr_all_accs(acc_ramp);
-                       do_acc_ramping_step(acc_ramp);
-               }
+               /* Set all available ACCs to barred and start ramping up. */
+               barr_all_accs(acc_ramp);
+               do_acc_ramping_step(acc_ramp);
        }
 }
 
diff --git a/openbsc/src/libbsc/bsc_init.c b/openbsc/src/libbsc/bsc_init.c
index 120955b..21ed2e1 100644
--- a/openbsc/src/libbsc/bsc_init.c
+++ b/openbsc/src/libbsc/bsc_init.c
@@ -318,8 +318,10 @@
        /*
         * Trigger ACC ramping before sending system information to BTS.
         * This ensures that RACH control in system information is configured 
correctly.
+        * TRX 0 should be usable and unlocked, otherwise starting ACC ramping 
is pointless.
         */
-       acc_ramp_trigger(&trx->bts->acc_ramp);
+       if (trx_is_usable(trx) && trx->mo.nm_state.administrative == 
NM_STATE_UNLOCKED)
+               acc_ramp_trigger(&trx->bts->acc_ramp);
 
        gsm_bts_trx_set_system_infos(trx);
 

-- 
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I235d2c5fa962f2f338e77d0c11502921b37f4c36
Gerrit-PatchSet: 1
Gerrit-Project: openbsc
Gerrit-Branch: master
Gerrit-Owner: Stefan Sperling <ssperl...@sysmocom.de>

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