rdtech-tc: detect receive and parse errors, terminate acquisition

Pepper the code paths from main loop calls via serial reception to
data processing with return code checks and error handling. Terminate
acquisition when communication or data processing fail.

Check whether acquisition limits were reached immediately after more
values were submitted. Keep a periodic check in the main loop call to
handle duration limits.

Comment on essential steps in the execution sequence.

diff --git a/src/hardware/rdtech-tc/protocol.c b/src/hardware/rdtech-tc/protocol.c
index 36477858876cbaa588db2f15e5f67734dd2d5701..ef1ce3edcc6a7f0b8ddb740e91e2c308bf27846b 100644 (file)
--- a/src/hardware/rdtech-tc/protocol.c
+++ b/src/hardware/rdtech-tc/protocol.c
@@ -179,54 +179,67 @@ SR_PRIV int rdtech_tc_poll(const struct sr_dev_inst *sdi, gboolean force)
        return SR_OK;
 }
 
-static void handle_poll_data(const struct sr_dev_inst *sdi)
+static int handle_poll_data(struct sr_dev_inst *sdi)
 {
        struct dev_context *devc;
        uint8_t poll_pkt[TC_POLL_LEN];
        size_t i;
        GSList *ch;
+       int ret;
 
        devc = sdi->priv;
        sr_spew("Received poll packet (len: %zu).", devc->buflen);
        if (devc->buflen != TC_POLL_LEN) {
                sr_err("Unexpected poll packet length: %zu", devc->buflen);
-               return;
+               return SR_ERR_DATA;
        }
 
        if (process_poll_pkt(devc, poll_pkt) != SR_OK) {
                sr_err("Failed to process poll packet.");
-               return;
+               return SR_ERR_DATA;
        }
 
        i = 0;
        for (ch = sdi->channels; ch; ch = g_slist_next(ch)) {
-               bv_send_analog_channel(sdi, ch->data,
+               ret = bv_send_analog_channel(sdi, ch->data,
                        &devc->channels[i], poll_pkt, TC_POLL_LEN);
                i++;
+               if (ret != SR_OK)
+                       return ret;
        }
 
        sr_sw_limits_update_samples_read(&devc->limits, 1);
+       if (sr_sw_limits_check(&devc->limits))
+               sr_dev_acquisition_stop(sdi);
+
+       return SR_OK;
 }
 
-static void recv_poll_data(struct sr_dev_inst *sdi, struct sr_serial_dev_inst *serial)
+static int recv_poll_data(struct sr_dev_inst *sdi, struct sr_serial_dev_inst *serial)
 {
        struct dev_context *devc;
        int len;
+       int ret;
 
        /* Serial data arrived. */
        devc = sdi->priv;
        while (devc->buflen < TC_POLL_LEN) {
                len = serial_read_nonblocking(serial, devc->buf + devc->buflen, 1);
-               if (len < 1)
-                       return;
-
-               devc->buflen++;
+               if (len < 0)
+                       return SR_ERR_IO;
+               if (len == 0)
+                       return SR_OK;
+               devc->buflen += len;
        }
 
-       if (devc->buflen == TC_POLL_LEN)
-               handle_poll_data(sdi);
-
+       if (devc->buflen == TC_POLL_LEN) {
+               ret = handle_poll_data(sdi);
+               if (ret != SR_OK)
+                       return ret;
+       }
        devc->buflen = 0;
+
+       return SR_OK;
 }
 
 SR_PRIV int rdtech_tc_receive_data(int fd, int revents, void *cb_data)
@@ -234,6 +247,7 @@ SR_PRIV int rdtech_tc_receive_data(int fd, int revents, void *cb_data)
        struct sr_dev_inst *sdi;
        struct dev_context *devc;
        struct sr_serial_dev_inst *serial;
+       int ret;
 
        (void)fd;
 
@@ -242,16 +256,22 @@ SR_PRIV int rdtech_tc_receive_data(int fd, int revents, void *cb_data)
        if (!(devc = sdi->priv))
                return TRUE;
 
+       /* Handle availability of receive data. */
        serial = sdi->conn;
-       if (revents == G_IO_IN)
-               recv_poll_data(sdi, serial);
+       if (revents == G_IO_IN) {
+               ret = recv_poll_data(sdi, serial);
+               if (ret != SR_OK)
+                       sr_dev_acquisition_stop(sdi);
+       }
 
+       /* Check configured acquisition limits. */
        if (sr_sw_limits_check(&devc->limits)) {
                sr_dev_acquisition_stop(sdi);
                return TRUE;
        }
 
-       rdtech_tc_poll(sdi, FALSE);
+       /* Periodically retransmit measurement requests. */
+       (void)rdtech_tc_poll(sdi, FALSE);
 
        return TRUE;
 }