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Cellular network API addition: read EMM reject cause.
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It is now possible to read the last 3GPP EMM reject cause sent by the network during registration: see uCellNetGetLastEmmRejectCause().

Test: 1 2 6.1 6.2.0 6.2.1 12.0 14 20 21 25 29 30 cellNet
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@RobMeades
RobMeades committed Jan 29, 2024
1 parent 978d3a0 commit daa6c76
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Showing 4 changed files with 238 additions and 102 deletions.
11 changes: 11 additions & 0 deletions cell/api/u_cell_net.h
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Original file line number Diff line number Diff line change
Expand Up @@ -761,6 +761,17 @@ int32_t uCellNetSetBaseStationConnectionStatusCallback(uDeviceHandle_t cellHandl
uCellNetStatus_t uCellNetGetNetworkStatus(uDeviceHandle_t cellHandle,
uCellNetRegDomain_t domain);

/** Get the last EMM reject cause value sent by the network; not
* supported by all module types (for example SARA-R4 series
* modules do not support this).
*
* @param cellHandle the handle of the cellular instance.
* @return on success the last EMM cause from the network,
* see appendix A.3 of the AT commands manual,
* else negative error code.
*/
int32_t uCellNetGetLastEmmRejectCause(uDeviceHandle_t cellHandle);

/** Get a value indicating whether the module is registered on
* the network, roaming or home networks.
*
Expand Down
284 changes: 182 additions & 102 deletions cell/src/u_cell_net.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1061,6 +1061,145 @@ static int32_t readNextScanItem(uCellPrivateInstance_t *pInstance,
return errorCodeOrNumber;
}

// Read the last EMM cause sent by the network.
static int32_t getEmmRejectCause(const uCellPrivateInstance_t *pInstance)
{
int32_t errorCodeOrEmmCause = (int32_t) U_ERROR_COMMON_NOT_SUPPORTED;
uAtClientHandle_t atHandle = pInstance->atHandle;
int32_t x = -1;
char buffer[32]; // Enough room for "EMM cause"

if (!U_CELL_PRIVATE_MODULE_IS_SARA_R4(pInstance->pModule->moduleType)) {
uAtClientLock(atHandle);
uAtClientCommandStart(atHandle, "AT+CEER");
uAtClientCommandStop(atHandle);
// Should get back +CEER: <type>[,<cause>,<error_description>]
uAtClientResponseStart(atHandle, "+CEER:");
// Read <type>
uAtClientReadString(atHandle, buffer, sizeof(buffer), false);
// Read <cause>
x = uAtClientReadInt(atHandle);
// Skip <error_description>
uAtClientSkipParameters(atHandle, 1);
uAtClientResponseStop(atHandle);
errorCodeOrEmmCause = uAtClientUnlock(atHandle);
if ((errorCodeOrEmmCause == 0) && (x >= 0) &&
(strncmp(buffer, "EMM cause", sizeof(buffer)) == 0)) {
errorCodeOrEmmCause = x;
}
}

return errorCodeOrEmmCause;
}

// Handle the response to the CxREG command, where regType
// is an index into gRegTypes[].
static void handleCxRegResponse(uCellPrivateInstance_t *pInstance, int32_t regType)
{
uCellNetStatus_t status = U_CELL_NET_STATUS_UNKNOWN;
uAtClientHandle_t atHandle = pInstance->atHandle;
int32_t firstInt;
int32_t status3gpp;
int32_t skippedParameters = 1;
int32_t rat3gpp = -1;
bool gotUrc = false;
char buffer[U_CELL_PRIVATE_CELL_ID_LOGICAL_SIZE + 1]; // +1 for terminator

uAtClientResponseStart(atHandle, gRegTypes[regType].pResponseStr);

// It is possible for the module to spit-out
// a "+CxREG: y" URC while we're waiting for
// the "+CxREG: x,y" response from the AT+CxREG
// command. So the first integer might either by the mode
// we set, <n>, being sent back to us or it might be the
// <status> value of the URC. The dodge to distinguish the
// two is based on the fact that our values for <n> match status
// values that mean "not registered", so we can do this:
// (a) if the first integer matches the <n>/mode
// parameter from the AT+CxREG=<n>,... command, then either
// i) this is the response we were expecting and
// the status etc. parameters follow, or,
// ii) this is a URC with a value indicating we are not
// registered and hence will not be followed
// by any further parameters,
// (b) if the first integer does not match <n> then this
// is a URC and the first integer is the <status> value.

// ...except if this is LENA-R8 which, just to be different,
// and only for the +CREG command, omits the <n> for both the
// information response and the URC cases.
if ((regType != 0 /* not CREG */) ||
(pInstance->pModule->moduleType != U_CELL_MODULE_TYPE_LENA_R8)) {
firstInt = uAtClientReadInt(atHandle);
status3gpp = uAtClientReadInt(atHandle);
if ((firstInt == U_CELL_NET_CREG_OR_CGREG_TYPE) ||
(firstInt == U_CELL_NET_CEREG_TYPE)) {
// case (a.i) or (a.ii)
if (status3gpp < 0) {
// case (a.ii)
gotUrc = true;
status3gpp = firstInt;
uAtClientClearError(atHandle);
}
} else {
// case (b), it's the URC
gotUrc = true;
status3gpp = firstInt;
}
} else {
// LENA-R8 +CREG information response
status3gpp = uAtClientReadInt(atHandle);
}
if (gotUrc) {
// Read the actual response, which should follow
uAtClientResponseStart(atHandle,
gRegTypes[regType].pResponseStr);
uAtClientReadInt(atHandle);
status3gpp = uAtClientReadInt(atHandle);
}
if ((status3gpp >= 0) &&
(status3gpp < (int32_t) (sizeof(g3gppStatusToCellStatus) /
sizeof(g3gppStatusToCellStatus[0])))) {
status = g3gppStatusToCellStatus[status3gpp];
}
if (U_CELL_NET_STATUS_MEANS_REGISTERED(status)) {
// Skip <lac>/<tac>
if ((regType == 2 /* CEREG */) && (gRegTypes[regType].type == 4) &&
(((pInstance->pModule->moduleType == U_CELL_MODULE_TYPE_SARA_R410M_02B) ||
(pInstance->pModule->moduleType == U_CELL_MODULE_TYPE_SARA_R412M_02B)) ||
((pInstance->pModule->moduleType == U_CELL_MODULE_TYPE_LARA_R6) &&
!gotUrc))) {
// SARA-R41x-02B modules, and LARA-R6 modules but only in the
// non-URC case, sneak an extra <rac_or_mme> parameter in between
// <tac> and <ci> when U_CELL_NET_CEREG_TYPE is 4 so we need to
// skip an additional parameter
skippedParameters++;
}
uAtClientSkipParameters(atHandle, skippedParameters);
// Read CI, which is hex, encoded as an 8-digit string
if (uAtClientReadString(atHandle, buffer, sizeof(buffer), false) > 0) {
pInstance->radioParameters.cellIdLogical = strtol(buffer, NULL, 16);
}
// Read the RAT that we're on
rat3gpp = uAtClientReadInt(atHandle);
if (rat3gpp < 0) {
if (regType == 2 /* CEREG */) {
// LARA-R6 sometime misses out the RAT in the +CEREG
// response; we need something...
rat3gpp = 7; // LTE
} else if (regType == 1 /* CGREG */) {
// LENA-R8 frequently misses out the RAT in the +CGREG
// response; we need something...
rat3gpp = 3; // GSM/GPRS/EDGE
}
}
}
// Set the status
setNetworkStatus(pInstance, status, rat3gpp, regType, false);

uAtClientResponseStop(atHandle);
}

// Register with the cellular network
static int32_t registerNetwork(uCellPrivateInstance_t *pInstance,
const char *pMccMnc)
Expand All @@ -1070,14 +1209,7 @@ static int32_t registerNetwork(uCellPrivateInstance_t *pInstance,
bool keepGoing = true;
bool deviceErrorDetected = false;
int32_t regType;
int32_t firstInt;
int32_t status3gpp;
uCellNetStatus_t status;
int32_t skippedParameters = 1;
int32_t rat3gpp = -1;
bool gotUrc;
size_t errorCount = 0;
char buffer[U_CELL_PRIVATE_CELL_ID_LOGICAL_SIZE + 1]; // +1 for terminator

// Come out of airplane mode and try to register
// Wait for flip time to expire first though
Expand Down Expand Up @@ -1156,104 +1288,13 @@ static int32_t registerNetwork(uCellPrivateInstance_t *pInstance,
// one at a time.
if (gRegTypes[regType].supportedRatsBitmap &
pInstance->pModule->supportedRatsBitmap) {
status = U_CELL_NET_STATUS_UNKNOWN;
uAtClientLock(atHandle);
uAtClientTimeoutSet(atHandle,
pInstance->pModule->responseMaxWaitMs);
uAtClientCommandStart(atHandle, gRegTypes[regType].pQueryStr);
uAtClientCommandStop(atHandle);
uAtClientResponseStart(atHandle, gRegTypes[regType].pResponseStr);
// It is possible for the module to spit-out
// a "+CxREG: y" URC while we're waiting for
// the "+CxREG: x,y" response from the AT+CxREG
// command. So the first integer might either by the mode
// we set, <n>, being sent back to us or it might be the
// <status> value of the URC. The dodge to distinguish the
// two is based on the fact that our values for <n> match status
// values that mean "not registered", so we can do this:
// (a) if the first integer matches the <n>/mode
// parameter from the AT+CxREG=<n>,... command, then either
// i) this is the response we were expecting and
// the status etc. parameters follow, or,
// ii) this is a URC with a value indicating we are not
// registered and hence will not be followed
// by any further parameters,
// (b) if the first integer does not match <n> then this
// is a URC and the first integer is the <status> value.

// ...except if this is LENA-R8 which, just to be different,
// and only for the +CREG command, omits the <n> for both the
// information response and the URC cases.
gotUrc = false;
if ((regType != 0 /* not CREG */) ||
(pInstance->pModule->moduleType != U_CELL_MODULE_TYPE_LENA_R8)) {
firstInt = uAtClientReadInt(atHandle);
status3gpp = uAtClientReadInt(atHandle);
if ((firstInt == U_CELL_NET_CREG_OR_CGREG_TYPE) ||
(firstInt == U_CELL_NET_CEREG_TYPE)) {
// case (a.i) or (a.ii)
if (status3gpp < 0) {
// case (a.ii)
gotUrc = true;
status3gpp = firstInt;
uAtClientClearError(atHandle);
}
} else {
// case (b), it's the URC
gotUrc = true;
status3gpp = firstInt;
}
} else {
// LENA-R8 +CREG information response
status3gpp = uAtClientReadInt(atHandle);
}
if (gotUrc) {
// Read the actual response, which should follow
uAtClientResponseStart(atHandle,
gRegTypes[regType].pResponseStr);
uAtClientReadInt(atHandle);
status3gpp = uAtClientReadInt(atHandle);
}
if ((status3gpp >= 0) &&
(status3gpp < (int32_t) (sizeof(g3gppStatusToCellStatus) /
sizeof(g3gppStatusToCellStatus[0])))) {
status = g3gppStatusToCellStatus[status3gpp];
}
if (U_CELL_NET_STATUS_MEANS_REGISTERED(status)) {
// Skip <lac>/<tac>
if ((regType == 2 /* CEREG */) && (gRegTypes[regType].type == 4) &&
(((pInstance->pModule->moduleType == U_CELL_MODULE_TYPE_SARA_R410M_02B) ||
(pInstance->pModule->moduleType == U_CELL_MODULE_TYPE_SARA_R412M_02B)) ||
((pInstance->pModule->moduleType == U_CELL_MODULE_TYPE_LARA_R6) &&
!gotUrc))) {
// SARA-R41x-02B modules, and LARA-R6 modules but only in the
// non-URC case, sneak an extra <rac_or_mme> parameter in between
// <tac> and <ci> when U_CELL_NET_CEREG_TYPE is 4 so we need to
// skip an additional parameter
skippedParameters++;
}
uAtClientSkipParameters(atHandle, skippedParameters);
// Read CI, which is hex, encoded as an 8-digit string
if (uAtClientReadString(atHandle, buffer, sizeof(buffer), false) > 0) {
pInstance->radioParameters.cellIdLogical = strtol(buffer, NULL, 16);
}
// Read the RAT that we're on
rat3gpp = uAtClientReadInt(atHandle);
if (rat3gpp < 0) {
if (regType == 2 /* CEREG */) {
// LARA-R6 sometime misses out the RAT in the +CEREG
// response; we need something...
rat3gpp = 7; // LTE
} else if (regType == 1 /* CGREG */) {
// LENA-R8 frequently misses out the RAT in the +CGREG
// response; we need something...
rat3gpp = 3; // GSM/GPRS/EDGE
}
}
}
// Set the status
setNetworkStatus(pInstance, status, rat3gpp, regType, false);
uAtClientResponseStop(atHandle);
// Handle the response to the CxREG command
handleCxRegResponse(pInstance, regType);
if (uAtClientUnlock(atHandle) != 0) {
// We're prodding the module pretty often
// while it is busy, it is possible for
Expand Down Expand Up @@ -2452,6 +2493,9 @@ int32_t uCellNetConnect(uDeviceHandle_t cellHandle,
} while ((errorCode != 0) && (pApnConfig != NULL) &&
(*pApnConfig != '\0') && keepGoingLocalCb(pInstance));

// Populate, or reset, the last EMM cause
pInstance->lastEmmRejectCause = getEmmRejectCause(pInstance);

if (errorCode == 0) {
// Remember the MCC/MNC in case we need to deactivate
// and reactivate context later and that causes
Expand All @@ -2477,7 +2521,6 @@ int32_t uCellNetConnect(uDeviceHandle_t cellHandle,
// Take away the callback again
pInstance->pKeepGoingCallback = NULL;
pInstance->startTimeMs = 0;

}
} else {
uPortLog("U_CELL_NET: already connected.\n");
Expand Down Expand Up @@ -2542,6 +2585,9 @@ int32_t uCellNetRegister(uDeviceHandle_t cellHandle,
errorCode = waitAttach(pInstance);
}

// Populate, or reset, the last EMM cause
pInstance->lastEmmRejectCause = getEmmRejectCause(pInstance);

if (errorCode == 0) {
// Remember the MCC/MNC in case we need to deactivate
// and reactivate context later and that causes
Expand All @@ -2565,7 +2611,6 @@ int32_t uCellNetRegister(uDeviceHandle_t cellHandle,
// Take away the callback again
pInstance->pKeepGoingCallback = NULL;
pInstance->startTimeMs = 0;

}
}

Expand Down Expand Up @@ -2690,6 +2735,8 @@ int32_t uCellNetActivate(uDeviceHandle_t cellHandle,
// be registered but not attached.
errorCode = waitAttach(pInstance);
}
// Update again, in case of failure
pInstance->lastEmmRejectCause = getEmmRejectCause(pInstance);
if (errorCode != 0) {
// Switch radio off after failure
radioOff(pInstance);
Expand Down Expand Up @@ -2781,6 +2828,8 @@ int32_t uCellNetDeactivate(uDeviceHandle_t cellHandle,
if (errorCode != 0) {
uPortLog("U_CELL_NET: unable to deactivate context.\n");
}
// Populate, or reset, the last EMM cause
pInstance->lastEmmRejectCause = getEmmRejectCause(pInstance);
}
}

Expand Down Expand Up @@ -2833,6 +2882,8 @@ int32_t uCellNetDisconnect(uDeviceHandle_t cellHandle,
} else {
uPortLog("U_CELL_NET: unable to disconnect.\n");
}
// Populate, or reset, the last EMM cause
pInstance->lastEmmRejectCause = getEmmRejectCause(pInstance);
}

U_PORT_MUTEX_UNLOCK(gUCellPrivateMutex);
Expand Down Expand Up @@ -3254,6 +3305,35 @@ uCellNetStatus_t uCellNetGetNetworkStatus(uDeviceHandle_t cellHandle,
return (uCellNetStatus_t) errorCodeOrStatus;
}

// Get the last EMM cause sent by the network.
int32_t uCellNetGetLastEmmRejectCause(uDeviceHandle_t cellHandle)
{
int32_t errorCodeOrEmmCause = (int32_t) U_ERROR_COMMON_NOT_INITIALISED;
uCellPrivateInstance_t *pInstance;

if (gUCellPrivateMutex != NULL) {

U_PORT_MUTEX_LOCK(gUCellPrivateMutex);

pInstance = pUCellPrivateGetInstance(cellHandle);
errorCodeOrEmmCause = (int32_t) U_ERROR_COMMON_INVALID_PARAMETER;
if (pInstance != NULL) {
// Retrieve the stored value, which may hold a
// reject cause from a registration atttempt
errorCodeOrEmmCause = pInstance->lastEmmRejectCause;
if (errorCodeOrEmmCause == 0) {
// If there wasn't a stored value, check again
// in case something has happened since
errorCodeOrEmmCause = getEmmRejectCause(pInstance);
}
}

U_PORT_MUTEX_UNLOCK(gUCellPrivateMutex);
}

return errorCodeOrEmmCause;
}

// Get a value whether the module is registered on the network.
bool uCellNetIsRegistered(uDeviceHandle_t cellHandle)
{
Expand Down
1 change: 1 addition & 0 deletions cell/src/u_cell_private.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -446,6 +446,7 @@ typedef struct uCellPrivateInstance_t {
networkStatus[U_CELL_PRIVATE_NET_REG_TYPE_MAX_NUM]; /**< Registation status for each type, separating CREG, CGREG and CEREG. */
uCellNetRat_t
rat[U_CELL_PRIVATE_NET_REG_TYPE_MAX_NUM]; /**< The active RAT for each registration type. */
int32_t lastEmmRejectCause; /**< Used by uCellNetGetLastEmmRejectCause() only. */
uCellPrivateRadioParameters_t radioParameters; /**< The radio parameters. */
int32_t startTimeMs; /**< Used while connecting and scanning. */
int32_t connectedAtMs; /**< When a connection was last established,
Expand Down
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