&scpi_libgpib_dev,
#endif
#ifdef HAVE_LIBSERIALPORT
- &scpi_serial_dev, /* must be last as it matches any resource */
+ &scpi_serial_dev, /* Must be last as it matches any resource. */
#endif
};
scpi = g_malloc(sizeof(*scpi));
*scpi = *scpi_dev;
scpi->priv = g_malloc0(scpi->priv_size);
- scpi->read_timeout_ms = 1000;
+ scpi->read_timeout_us = 1000 * 1000;
params = g_strsplit(resource, "/", 0);
if (scpi->dev_inst_new(scpi->priv, drvc, resource,
params, serialcomm) != SR_OK) {
return scpi->read_data(scpi->priv, buf, maxlen);
}
+/**
+ * Send data to SCPI device.
+ *
+ * @param scpi Previously initialised SCPI device structure.
+ * @param buf Buffer with data to send.
+ * @param len Number of bytes to send.
+ *
+ * @return Number of bytes read, or SR_ERR upon failure.
+ */
+SR_PRIV int sr_scpi_write_data(struct sr_scpi_dev_inst *scpi,
+ char *buf, int maxlen)
+{
+ return scpi->write_data(scpi->priv, buf, maxlen);
+}
+
/**
* Check whether a complete SCPI response has been received.
*
/**
* Free SCPI device.
*
- * @param scpi Previously initialized SCPI device structure.
- *
- * @return SR_OK on success, SR_ERR on failure.
+ * @param scpi Previously initialized SCPI device structure. If NULL,
+ * this function does nothing.
*/
SR_PRIV void sr_scpi_free(struct sr_scpi_dev_inst *scpi)
{
+ if (!scpi)
+ return;
+
scpi->free(scpi->priv);
g_free(scpi->priv);
g_free(scpi);
return SR_OK;
}
+/**
+ * Do a non-blocking read of up to the allocated length, and
+ * check if a timeout has occured.
+ *
+ * @param scpi Previously initialised SCPI device structure.
+ * @param response Buffer to which the response is appended.
+ * @param abs_timeout_us Absolute timeout in microseconds
+ *
+ * @return read length on success, SR_ERR* on failure.
+ */
+SR_PRIV int sr_scpi_read_response(struct sr_scpi_dev_inst *scpi,
+ GString *response, gint64 abs_timeout_us)
+{
+ int len, space;
+
+ space = response->allocated_len - response->len;
+ len = sr_scpi_read_data(scpi, &response->str[response->len], space);
+
+ if (len < 0) {
+ sr_err("Incompletely read SCPI response.");
+ return SR_ERR;
+ }
+
+ if (len > 0) {
+ g_string_set_size(response, response->len + len);
+ return len;
+ }
+
+ if (g_get_monotonic_time() > abs_timeout_us) {
+ sr_err("Timed out waiting for SCPI response.");
+ return SR_ERR_TIMEOUT;
+ }
+
+ return 0;
+}
+
SR_PRIV int sr_scpi_get_data(struct sr_scpi_dev_inst *scpi,
const char *command, GString **scpi_response)
{
- int len;
+ int ret;
GString *response;
- gint64 laststart;
- unsigned int elapsed_ms;
- unsigned int offset = 0;
int space;
+ gint64 timeout;
- if (command)
+ /* Optionally send caller provided command. */
+ if (command) {
if (sr_scpi_send(scpi, command) != SR_OK)
return SR_ERR;
+ }
+ /* Initiate SCPI read operation. */
if (sr_scpi_read_begin(scpi) != SR_OK)
return SR_ERR;
- laststart = g_get_monotonic_time();
+ /* Keep reading until completion or until timeout. */
+ timeout = g_get_monotonic_time() + scpi->read_timeout_us;
response = *scpi_response;
- offset = response->len;
-
while (!sr_scpi_read_complete(scpi)) {
+ /* Resize the buffer when free space drops below a threshold. */
space = response->allocated_len - response->len;
if (space < 128) {
- g_string_set_size(response, response->len + 1024);
- space = response->allocated_len - response->len;
- }
- len = sr_scpi_read_data(scpi, &response->str[offset], space);
- if (len < 0) {
- sr_err("Incompletely read SCPI response.");
- return SR_ERR;
- } else if (len > 0) {
- laststart = g_get_monotonic_time();
- }
- offset += len;
- g_string_set_size(response, offset);
- elapsed_ms = (g_get_monotonic_time() - laststart) / 1000;
- if (elapsed_ms >= scpi->read_timeout_ms) {
- sr_err("Timed out waiting for SCPI response.");
- return SR_ERR;
+ int oldlen = response->len;
+ g_string_set_size(response, oldlen + 1024);
+ g_string_set_size(response, oldlen);
}
+
+ /* Read another chunk of the response. */
+ ret = sr_scpi_read_response(scpi, response, timeout);
+
+ if (ret < 0)
+ return ret;
+ if (ret > 0)
+ timeout = g_get_monotonic_time() + scpi->read_timeout_us;
}
return SR_OK;
return ret;
}
+
/**
* Send a SCPI command, read the reply, parse it as binary data with a
* "definite length block" header and store the as an result in scpi_response.
{
int ret;
GString* response;
-
- char buf[10] = { 0 };
+ char buf[10];
long llen;
long datalen;
+ gint64 timeout;
+
+ if (command)
+ if (sr_scpi_send(scpi, command) != SR_OK)
+ return SR_ERR;
+ if (sr_scpi_read_begin(scpi) != SR_OK)
+ return SR_ERR;
+
+ /*
+ * Assume an initial maximum length, optionally gets adjusted below.
+ * Prepare a NULL return value for when error paths will be taken.
+ */
response = g_string_sized_new(1024);
+
+ timeout = g_get_monotonic_time() + scpi->read_timeout_us;
+
*scpi_response = NULL;
- ret = sr_scpi_get_data(scpi, command, &response);
- if (ret != SR_OK) {
- g_string_free(response, TRUE);
- return ret;
+ /* Get (the first chunk of) the response. */
+ while (response->len < 2) {
+ ret = sr_scpi_read_response(scpi, response, timeout);
+ if (ret < 0) {
+ g_string_free(response, TRUE);
+ return ret;
+ }
}
+ /*
+ * SCPI protocol data blocks are preceeded with a length spec.
+ * The length spec consists of a '#' marker, one digit which
+ * specifies the character count of the length spec, and the
+ * respective number of characters which specify the data block's
+ * length. Raw data bytes follow (thus one must no longer assume
+ * that the received input stream would be an ASCIIZ string).
+ *
+ * Get the data block length, and strip off the length spec from
+ * the input buffer, leaving just the data bytes.
+ */
if (response->str[0] != '#') {
g_string_free(response, TRUE);
return SR_ERR_DATA;
}
-
buf[0] = response->str[1];
+ buf[1] = '\0';
ret = sr_atol(buf, &llen);
if ((ret != SR_OK) || (llen == 0)) {
g_string_free(response, TRUE);
return ret;
}
+ while (response->len < (unsigned long)(2 + llen)) {
+ ret = sr_scpi_read_response(scpi, response, timeout);
+ if (ret < 0) {
+ g_string_free(response, TRUE);
+ return ret;
+ }
+ }
+
memcpy(buf, &response->str[2], llen);
+ buf[llen] = '\0';
ret = sr_atol(buf, &datalen);
if ((ret != SR_OK) || (datalen == 0)) {
g_string_free(response, TRUE);
return ret;
}
-
- // strip header
g_string_erase(response, 0, 2 + llen);
+ /*
+ * If the initially assumed length does not cover the data block
+ * length, then re-allocate the buffer size to the now known
+ * length, and keep reading more chunks of response data.
+ */
if (response->len < (unsigned long)(datalen)) {
int oldlen = response->len;
g_string_set_size(response, datalen);
}
while (response->len < (unsigned long)(datalen)) {
- if (sr_scpi_get_data(scpi, NULL, &response) != SR_OK) {
+ ret = sr_scpi_read_response(scpi, response, timeout);
+ if (ret < 0) {
g_string_free(response, TRUE);
return ret;
}
+ if (ret > 0)
+ timeout = g_get_monotonic_time() + scpi->read_timeout_us;
}
+ /* Convert received data to byte array. */
*scpi_response = g_byte_array_new_take(
(guint8*)g_string_free(response, FALSE), datalen);
- return ret;
+ return SR_OK;
}
-
/**
* Send the *IDN? SCPI command, receive the reply, parse it and store the
* reply as a sr_scpi_hw_info structure in the supplied scpi_response pointer.
/**
* Free a sr_scpi_hw_info struct.
*
- * @param hw_info Pointer to the struct to free.
- *
- * This function is safe to call with a NULL pointer.
+ * @param hw_info Pointer to the struct to free. If NULL, this
+ * function does nothing.
*/
SR_PRIV void sr_scpi_hw_info_free(struct sr_scpi_hw_info *hw_info)
{
- if (hw_info) {
- g_free(hw_info->manufacturer);
- g_free(hw_info->model);
- g_free(hw_info->serial_number);
- g_free(hw_info->firmware_version);
- g_free(hw_info);
- }
+ if (!hw_info)
+ return;
+
+ g_free(hw_info->manufacturer);
+ g_free(hw_info->model);
+ g_free(hw_info->serial_number);
+ g_free(hw_info->firmware_version);
+ g_free(hw_info);
}
projects / libsigrok.git / blobdiff