drivers: modem: Fix PDP context management for BG9X

The PDP context might be active.
If that's the case, the AT+QIACT command returns an error.
It's then not possible to succeed at setting up the module.

Furthermore, we apply the logic described in the Quectel Documentation :
- If there is an issue 3 consecutive times on activating/deactivating
the context, we restart the module.
- If the AT+QIDEAT command returns an error, we restart the module.

This PR is bug-fix aimed.
We leave parameterization of context ID for future enhancement.

Signed-off-by: Thomas LE ROUX <[email protected]>

Author: Thomas LE ROUX

drivers/modem/quectel-bg9x.c

@@ -961,6 +961,46 @@ static const struct setup_cmd setup_cmds[] = {
 	SETUP_CMD_NOHANDLE("AT+QICSGP=1,1,\"" MDM_APN "\",\"" MDM_USERNAME "\", \"" MDM_PASSWORD "\",1"),
 };
 
+/* Func: modem_pdp_context_active
+ * Desc: This helper function is called from modem_setup, and is
+ * used to open the PDP context. If there is trouble activating the
+ * PDP context, we try to deactive and reactive MDM_PDP_ACT_RETRY_COUNT times.
+ * If it fails, we return an error.
+ */
+static int modem_pdp_context_activate(void)
+{
+	int ret;
+	int retry_count = 0;
+
+	ret = modem_cmd_send(&mctx.iface, &mctx.cmd_handler,
+			     NULL, 0U, "AT+QIACT=1", &mdata.sem_response,
+			     MDM_CMD_TIMEOUT);
+
+	/* If there is trouble activating the PDP context, we try to deactivate/reactive it. */
+	while (ret == -EIO && retry_count < MDM_PDP_ACT_RETRY_COUNT) {
+		ret = modem_cmd_send(&mctx.iface, &mctx.cmd_handler,
+			     NULL, 0U, "AT+QIDEACT=1", &mdata.sem_response,
+			     MDM_CMD_TIMEOUT);
+
+		/* If there's any error for AT+QIDEACT, restart the module. */
+		if (ret != 0) {
+			return ret;
+		}
+
+		ret = modem_cmd_send(&mctx.iface, &mctx.cmd_handler,
+			     NULL, 0U, "AT+QIACT=1", &mdata.sem_response,
+			     MDM_CMD_TIMEOUT);
+
+		retry_count++;
+	}
+
+	if (ret == -EIO && retry_count >= MDM_PDP_ACT_RETRY_COUNT) {
+		LOG_ERR("Retried activating/deactivating too many times.");
+	}
+
+	return ret;
+}
+
 /* Func: modem_setup
  * Desc: This function is used to setup the modem from zero. The idea
  * is that this function will be called right after the modem is
@@ -1032,13 +1072,10 @@ static int modem_setup(void)
 				       &mdata.rssi_query_work,
 				       K_SECONDS(RSSI_TIMEOUT_SECS));
 
-	/* Once the network is ready, activate PDP context. */
-	ret = modem_cmd_send(&mctx.iface, &mctx.cmd_handler,
-			     NULL, 0U, "AT+QIACT=1", &mdata.sem_response,
-			     MDM_CMD_TIMEOUT);
-
-	/* Retry or Possibly Exit. */
+	/* Once the network is ready, we try to activate the PDP context. */
+	ret = modem_pdp_context_activate();
 	if (ret < 0 && init_retry_count++ < MDM_INIT_RETRY_COUNT) {
+		LOG_ERR("Error activating modem with pdp context");
 		goto restart;
 	}
 

drivers/modem/quectel-bg9x.h

@@ -36,6 +36,7 @@
 #define MDM_BASE_SOCKET_NUM		  0
 #define MDM_NETWORK_RETRY_COUNT		  10
 #define MDM_INIT_RETRY_COUNT		  10
+#define MDM_PDP_ACT_RETRY_COUNT		  3
 #define MDM_WAIT_FOR_RSSI_COUNT		  10
 #define MDM_WAIT_FOR_RSSI_DELAY		  K_SECONDS(2)
 #define BUF_ALLOC_TIMEOUT		  K_SECONDS(1)