Modify soft devices to synchronize TSEL=-2 timestamps

Use dbLinkDoLocked() to ensure a timestamp set by TSEL=-2
comes from the same update as the value.

documentation/RELEASE_NOTES.html

@@ -20,6 +20,17 @@
 
 -->
 
+<h3>Synchronized Timestamps with TSEL=-2</h3>
+
+<p>Most Soft Channel input device support routines have supported fetching the
+timestamp through the INP link along with the input data. However before now
+there was no guarantee that the timestamp provided by a CA link came from the
+same update as the data, since the two were read at separate times without
+maintaining a lock on the CA input buffer. This shortcoming has been fixed as
+part of the new link support code, which allows code using a link to pass a
+subroutine to the link type to be run with the link locked. The subroutine may
+make multiple requests for metadata from the link, but must not block.</p>
+
 <h3>Device Support Address Type <tt>JSON_LINK</tt></h3>
 
 <p>Device support may be written to expect hardware addresses in the new

src/std/dev/devAaiSoft.c

@@ -75,11 +75,11 @@ static long init_record(aaiRecord *prec)
     return 0;
 }
 
-static long read_aai(aaiRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
+    aaiRecord *prec = (aaiRecord *) pinp->precord;
     long nRequest = prec->nelm;
-    long status = dbGetLink(prec->simm == menuYesNoYES ? &prec->siol :
-        &prec->inp, prec->ftvl, prec->bptr, 0, &nRequest);
+    long status = dbGetLink(pinp, prec->ftvl, prec->bptr, 0, &nRequest);
 
     if (!status && nRequest > 0) {
         prec->nord = nRequest;
@@ -87,7 +87,18 @@ static long read_aai(aaiRecord *prec)
 
         if (dbLinkIsConstant(&prec->tsel) &&
             prec->tse == epicsTimeEventDeviceTime)
-            dbGetTimeStamp(&prec->inp, &prec->time);
+            dbGetTimeStamp(pinp, &prec->time);
     }
     return status;
 }
+
+static long read_aai(aaiRecord *prec)
+{
+    struct link *pinp = prec->simm == menuYesNoYES ? &prec->siol : &prec->inp;
+    long status = dbLinkDoLocked(pinp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(pinp, NULL);
+
+    return status;
+}

src/std/dev/devAiSoft.c

@@ -57,29 +57,43 @@ static long init_record(aiRecord *prec)
     return 0;
 }
 
+static long readLocked(struct link *pinp, void *dummy)
+{
+    aiRecord *prec = (aiRecord *) pinp->precord;
+    double val;
+    long status = dbGetLink(pinp, DBR_DOUBLE, &val, 0, 0);
+
+    if (status) return status;
+
+    /* Apply smoothing algorithm */
+    if (prec->smoo != 0.0 && prec->dpvt && finite(prec->val))
+        prec->val = val * (1.00 - prec->smoo) + (prec->val * prec->smoo);
+    else
+        prec->val = val;
+
+    prec->udf = FALSE;
+    prec->dpvt = &devAiSoft;        /* Any non-zero value */
+
+    if (dbLinkIsConstant(&prec->tsel) &&
+        prec->tse == epicsTimeEventDeviceTime)
+        dbGetTimeStamp(pinp, &prec->time);
+
+    return 0;
+}
+
 static long read_ai(aiRecord *prec)
 {
-    double val;
+    long status;
 
     if (dbLinkIsConstant(&prec->inp))
         return 2;
 
-    if (!dbGetLink(&prec->inp, DBR_DOUBLE, &val, 0, 0)) {
+    status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
 
-        /* Apply smoothing algorithm */
-        if (prec->smoo != 0.0 && prec->dpvt && finite(prec->val))
-            prec->val = val * (1.00 - prec->smoo) + (prec->val * prec->smoo);
-        else
-            prec->val = val;
-
-        prec->udf = FALSE;
-        prec->dpvt = &devAiSoft;        /* Any non-zero value */
-
-        if (dbLinkIsConstant(&prec->tsel) &&
-            prec->tse == epicsTimeEventDeviceTime)
-            dbGetTimeStamp(&prec->inp, &prec->time);
-    } else {
+    if (status)
         prec->dpvt = NULL;
-    }
+
     return 2;
 }

src/std/dev/devAiSoftRaw.c

@@ -55,12 +55,26 @@ static long init_record(aiRecord *prec)
     return 0;
 }
 
-static long read_ai(aiRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    if (!dbGetLink(&prec->inp, DBR_LONG, &prec->rval, 0, 0) &&
-        dbLinkIsConstant(&prec->tsel) &&
+    aiRecord *prec = (aiRecord *) pinp->precord;
+    long status = dbGetLink(pinp, DBR_LONG, &prec->rval, 0, 0);
+
+    if (status) return status;
+
+    if (dbLinkIsConstant(&prec->tsel) &&
         prec->tse == epicsTimeEventDeviceTime)
-        dbGetTimeStamp(&prec->inp, &prec->time);
+        dbGetTimeStamp(pinp, &prec->time);
 
     return 0;
 }
+
+static long read_ai(aiRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devBiSoft.c

@@ -53,13 +53,25 @@ static long init_record(biRecord *prec)
     return 0;
 }
 
-static long read_bi(biRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    if (!dbGetLink(&prec->inp, DBR_USHORT, &prec->val, 0, 0)) {
+    biRecord *prec = (biRecord *) pinp->precord;
+
+    if (!dbGetLink(pinp, DBR_USHORT, &prec->val, 0, 0)) {
         prec->udf = FALSE;
         if (dbLinkIsConstant(&prec->tsel) &&
             prec->tse == epicsTimeEventDeviceTime)
-            dbGetTimeStamp(&prec->inp, &prec->time);
+            dbGetTimeStamp(pinp, &prec->time);
     }
     return 2;
 }
+
+static long read_bi(biRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devBiSoftRaw.c

@@ -52,12 +52,24 @@ static long init_record(biRecord *prec)
     return 0;
 }
 
-static long read_bi(biRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    if (!dbGetLink(&prec->inp, DBR_ULONG, &prec->rval, 0, 0) &&
+    biRecord *prec = (biRecord *) pinp->precord;
+
+    if (!dbGetLink(pinp, DBR_ULONG, &prec->rval, 0, 0) &&
         dbLinkIsConstant(&prec->tsel) &&
         prec->tse == epicsTimeEventDeviceTime)
-        dbGetTimeStamp(&prec->inp, &prec->time);
+        dbGetTimeStamp(pinp, &prec->time);
 
     return 0;
 }
+
+static long read_bi(biRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devEventSoft.c

@@ -53,13 +53,14 @@ static long init_record(eventRecord *prec)
     return 0;
 }
 
-static long read_event(eventRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
+    eventRecord *prec = (eventRecord *) pinp->precord;
     long status;
     char newEvent[MAX_STRING_SIZE];
 
-    if (!dbLinkIsConstant(&prec->inp)) {
-        status = dbGetLink(&prec->inp, DBR_STRING, newEvent, 0, 0);
+    if (!dbLinkIsConstant(pinp)) {
+        status = dbGetLink(pinp, DBR_STRING, newEvent, 0, 0);
         if (status) return status;
         if (strcmp(newEvent, prec->val) != 0) {
             strcpy(prec->val, newEvent);
@@ -69,6 +70,16 @@ static long read_event(eventRecord *prec)
     prec->udf = FALSE;
     if (dbLinkIsConstant(&prec->tsel) &&
         prec->tse == epicsTimeEventDeviceTime)
-        dbGetTimeStamp(&prec->inp, &prec->time);
+        dbGetTimeStamp(pinp, &prec->time);
     return 0;
 }
+
+static long read_event(eventRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devLiSoft.c

@@ -54,14 +54,24 @@ static long init_record(longinRecord *prec)
     return 0;
 }
 
-static long read_longin(longinRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    long status;
+    longinRecord *prec = (longinRecord *) pinp->precord;
+    long status = dbGetLink(pinp, DBR_LONG, &prec->val, 0, 0);
 
-    status = dbGetLink(&prec->inp, DBR_LONG, &prec->val, 0, 0);
     if (!status &&
         dbLinkIsConstant(&prec->tsel) &&
         prec->tse == epicsTimeEventDeviceTime)
-        dbGetTimeStamp(&prec->inp, &prec->time);
+        dbGetTimeStamp(pinp, &prec->time);
+    return status;
+}
+
+static long read_longin(longinRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
     return status;
 }

src/std/dev/devLsiSoft.c

@@ -24,14 +24,25 @@ static long init_record(lsiRecord *prec)
     return 0;
 }
 
-static long read_string(lsiRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    long status = dbGetLinkLS(&prec->inp, prec->val, prec->sizv, &prec->len);
+    lsiRecord *prec = (lsiRecord *) pinp->precord;
+    long status = dbGetLinkLS(pinp, prec->val, prec->sizv, &prec->len);
 
     if (!status &&
         dbLinkIsConstant(&prec->tsel) &&
         prec->tse == epicsTimeEventDeviceTime)
-        dbGetTimeStamp(&prec->inp, &prec->time);
+        dbGetTimeStamp(pinp, &prec->time);
+
+    return status;
+}
+
+static long read_string(lsiRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
 
     return status;
 }

src/std/dev/devMbbiDirectSoft.c

@@ -54,13 +54,25 @@ static long init_record(mbbiDirectRecord *prec)
     return 0;
 }
 
-static long read_mbbi(mbbiDirectRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    if (!dbGetLink(&prec->inp, DBR_USHORT, &prec->val, 0, 0)) {
+    mbbiDirectRecord *prec = (mbbiDirectRecord *) pinp->precord;
+
+    if (!dbGetLink(pinp, DBR_USHORT, &prec->val, 0, 0)) {
         prec->udf = FALSE;
         if (dbLinkIsConstant(&prec->tsel) &&
             prec->tse == epicsTimeEventDeviceTime)
-            dbGetTimeStamp(&prec->inp, &prec->time);
+            dbGetTimeStamp(pinp, &prec->time);
     }
     return 2;
 }
+
+static long read_mbbi(mbbiDirectRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devMbbiSoft.c

@@ -54,14 +54,26 @@ static long init_record(mbbiRecord *prec)
     return 0;
 }
 
-static long read_mbbi(mbbiRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    if (!dbGetLink(&prec->inp, DBR_USHORT, &prec->val, 0, 0)) {
+    mbbiRecord *prec = (mbbiRecord *) pinp->precord;
+
+    if (!dbGetLink(pinp, DBR_USHORT, &prec->val, 0, 0)) {
         prec->udf = FALSE;
 
         if (dbLinkIsConstant(&prec->tsel) &&
             prec->tse == epicsTimeEventDeviceTime)
-            dbGetTimeStamp(&prec->inp, &prec->time);
+            dbGetTimeStamp(pinp, &prec->time);
     }
     return 2;
 }
+
+static long read_mbbi(mbbiRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devMbbiSoftRaw.c

@@ -58,13 +58,25 @@ static long init_record(mbbiRecord *prec)
     return 0;
 }
 
-static long read_mbbi(mbbiRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    if (!dbGetLink(&prec->inp, DBR_LONG, &prec->rval, 0, 0)) {
+    mbbiRecord *prec = (mbbiRecord *) pinp->precord;
+
+    if (!dbGetLink(pinp, DBR_LONG, &prec->rval, 0, 0)) {
         prec->rval &= prec->mask;
         if (dbLinkIsConstant(&prec->tsel) &&
             prec->tse == epicsTimeEventDeviceTime)
-            dbGetTimeStamp(&prec->inp, &prec->time);
+            dbGetTimeStamp(pinp, &prec->time);
     }
     return 0;
 }
+
+static long read_mbbi(mbbiRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devSASoft.c

@@ -60,18 +60,19 @@ static long init_record(subArrayRecord *prec)
     return status;
 }
 
-static long read_sa(subArrayRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
+    subArrayRecord *prec = (subArrayRecord *) pinp->precord;
     long nRequest = prec->indx + prec->nelm;
     long ecount;
 
     if (nRequest > prec->malm)
         nRequest = prec->malm;
 
-    if (dbLinkIsConstant(&prec->inp))
+    if (dbLinkIsConstant(pinp))
         nRequest = prec->nord;
     else
-        dbGetLink(&prec->inp, prec->ftvl, prec->bptr, 0, &nRequest);
+        dbGetLink(pinp, prec->ftvl, prec->bptr, 0, &nRequest);
 
     ecount = nRequest - prec->indx;
     if (ecount > 0) {
@@ -89,7 +90,17 @@ static long read_sa(subArrayRecord *prec)
     if (nRequest > 0 &&
         dbLinkIsConstant(&prec->tsel) &&
         prec->tse == epicsTimeEventDeviceTime)
-        dbGetTimeStamp(&prec->inp, &prec->time);
+        dbGetTimeStamp(pinp, &prec->time);
 
     return 0;
 }
+
+static long read_sa(subArrayRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devSiSoft.c

@@ -55,17 +55,27 @@ static long init_record(stringinRecord *prec)
     return 0;
 }
 
-static long read_stringin(stringinRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
-    long status;
+    stringinRecord *prec = (stringinRecord *) pinp->precord;
+    long status = dbGetLink(pinp, DBR_STRING, prec->val, 0, 0);
 
-    status = dbGetLink(&prec->inp, DBR_STRING, prec->val, 0, 0);
     if (!status) {
-        if (!dbLinkIsConstant(&prec->inp))
+        if (!dbLinkIsConstant(pinp))
             prec->udf = FALSE;
         if (dbLinkIsConstant(&prec->tsel) &&
             prec->tse == epicsTimeEventDeviceTime)
-            dbGetTimeStamp(&prec->inp, &prec->time);
+            dbGetTimeStamp(pinp, &prec->time);
     }
     return status;
 }
+
+static long read_stringin(stringinRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}

src/std/dev/devWfSoft.c

@@ -61,10 +61,11 @@ static long init_record(waveformRecord *prec)
     return status;
 }
 
-static long read_wf(waveformRecord *prec)
+static long readLocked(struct link *pinp, void *dummy)
 {
+    waveformRecord *prec = (waveformRecord *) pinp->precord;
     long nRequest = prec->nelm;
-    long status = dbGetLink(&prec->inp, prec->ftvl, prec->bptr, 0, &nRequest);
+    long status = dbGetLink(pinp, prec->ftvl, prec->bptr, 0, &nRequest);
 
     if (!status && nRequest > 0) {
         prec->nord = nRequest;
@@ -72,7 +73,17 @@ static long read_wf(waveformRecord *prec)
 
         if (dbLinkIsConstant(&prec->tsel) &&
             prec->tse == epicsTimeEventDeviceTime)
-            dbGetTimeStamp(&prec->inp, &prec->time);
+            dbGetTimeStamp(pinp, &prec->time);
     }
     return status;
 }
+
+static long read_wf(waveformRecord *prec)
+{
+    long status = dbLinkDoLocked(&prec->inp, readLocked, NULL);
+
+    if (status == S_db_noLSET)
+        status = readLocked(&prec->inp, NULL);
+
+    return status;
+}