#include <config.h>
#include "protocol.h"
-#define REQ_TIMEOUT_MS 500
#define DEVICE_PROCESSING_TIME_MS 80
+#define EXTRA_PROCESSING_TIME_MS 450
SR_PRIV int korad_kaxxxxp_send_cmd(struct sr_serial_dev_inst *serial,
- const char *cmd)
+ const char *cmd)
{
int ret;
return ret;
}
+/**
+ * Read a variable length non-terminated string (caller specified maximum size).
+ *
+ * @param[in] serial The serial port to read from.
+ * @param[in] count The maximum amount of data to read.
+ * @param[out] buf The buffer to read data into. Must be larger than @a count.
+ *
+ * @return The amount of received data, or negative in case of error.
+ * See @ref SR_ERR and other error codes.
+ *
+ * @internal
+ *
+ * The protocol has no concept of request/response termination. The only
+ * terminating conditions are either the caller's expected maxmimum byte
+ * count, or a period of time without receive data. It's essential to
+ * accept a longer initial period of time before the first receive data
+ * is seen. The supported devices can be very slow to respond.
+ *
+ * The protocol is text based. That's why the 'count' parameter specifies
+ * the expected number of text characters, and does not include the NUL
+ * termination which is not part of the wire protocol but gets added by
+ * the receive routine. The caller provided buffer is expected to have
+ * enough space for the text data and the NUL termination.
+ *
+ * Implementation detail: It's assumed that once receive data was seen,
+ * remaining response data will follow at wire speed. No further delays
+ * are expected beyond bitrate expectations. All normal commands in the
+ * acquisition phase are of fixed length which is known to the caller.
+ * Identification during device scan needs to deal with variable length
+ * data. Quick termination after reception is important there, as is the
+ * larger initial timeout period before receive data is seen.
+ */
SR_PRIV int korad_kaxxxxp_read_chars(struct sr_serial_dev_inst *serial,
- int count, char *buf)
+ size_t count, char *buf)
{
- int ret, received, turns;
+ int timeout_first, timeout_later, timeout;
+ size_t retries_first, retries_later, retries;
+ size_t received;
+ int ret;
+ /* Clear the buffer early, to simplify the receive code path. */
+ memset(buf, 0, count + 1);
+
+ /*
+ * This calculation is aiming for backwards compatibility with
+ * an earlier implementation. An initial timeout is used which
+ * depends on the expected response byte count, and a maximum
+ * iteration count is used for read attempts.
+ *
+ * TODO Consider an absolute initial timeout instead, to reduce
+ * accumulated rounding errors for serial timeout results. The
+ * iteration with a short period is still required for variable
+ * length responses, because otherwise the serial communication
+ * layer would spend the total amount of time waiting for the
+ * remaining bytes, while the device probe code path by design
+ * passes a larger acceptable count than the typical and legal
+ * response would occupy.
+ *
+ * After initial receive data was seen, a shorter timeout is
+ * used which corresponds to a few bytes at wire speed. Idle
+ * periods without receive data longer than this threshold are
+ * taken as the end of the response. This is not compatible to
+ * the previous implementation, but was found to work as well.
+ * And severely reduces the time spent scanning for devices.
+ */
+ timeout_first = serial_timeout(serial, count);
+ retries_first = 100;
+ timeout_later = serial_timeout(serial, 3);
+ retries_later = 1;
+
+ sr_spew("want %zu bytes, timeout/retry: init %d/%zu, later %d/%zu.",
+ count, timeout_first, retries_first,
+ timeout_later, retries_later);
+
+ /*
+ * Run a sequence of read attempts. Try with the larger timeout
+ * and a high retry count until the first receive data became
+ * available. Then continue with a short timeout and small retry
+ * count.
+ *
+ * Failed read is fatal, immediately terminates the read sequence.
+ * A timeout in the initial phase just keeps repeating. A timeout
+ * after receive data was seen regularly terminates the sequence.
+ * Successful reads of non-empty responses keep extending the
+ * read sequence until no more receive data is available.
+ */
received = 0;
- turns = 0;
-
- do {
- if ((ret = serial_read_blocking(serial, buf + received,
- count - received,
- serial_timeout(serial, count))) < 0) {
- sr_err("Error %d reading %d bytes from device.",
+ timeout = timeout_first;
+ retries = retries_first;
+ while (received < count && retries--) {
+ ret = serial_read_blocking(serial,
+ &buf[received], count - received, timeout);
+ if (ret < 0) {
+ sr_err("Error %d reading %zu bytes from device.",
ret, count);
return ret;
}
+ if (ret == 0 && !received)
+ continue;
+ if (ret == 0 && received) {
+ sr_spew("receive timed out, want %zu, received %zu.",
+ count, received);
+ break;
+ }
received += ret;
- turns++;
- } while ((received < count) && (turns < 100));
-
- buf[count] = 0;
-
- sr_spew("Received: '%s'.", buf);
+ timeout = timeout_later;
+ retries = retries_later;
+ }
+ /* TODO Escape non-printables? Seen those with status queries. */
+ sr_dbg("got %zu bytes, received: '%s'.", received, buf);
- return ret;
+ return received;
}
static void give_device_time_to_process(struct dev_context *devc)
{
int64_t sleeping_time;
- sleeping_time = devc->req_sent_at + (DEVICE_PROCESSING_TIME_MS * 1000);
- sleeping_time -= g_get_monotonic_time();
+ if (!devc->next_req_time)
+ return;
+ sleeping_time = devc->next_req_time - g_get_monotonic_time();
if (sleeping_time > 0) {
g_usleep(sleeping_time);
sr_spew("Sleeping for processing %" PRIi64 " usec", sleeping_time);
}
}
+static int64_t next_req_time(struct dev_context *devc,
+ gboolean is_set, int target)
+{
+ gboolean is_slow_device, is_long_command;
+ int64_t processing_time_us;
+
+ is_slow_device = devc->model->quirks & KORAD_QUIRK_SLOW_PROCESSING;
+ is_long_command = is_set;
+ is_long_command |= target == KAXXXXP_STATUS;
+
+ processing_time_us = DEVICE_PROCESSING_TIME_MS;
+ if (is_slow_device && is_long_command)
+ processing_time_us += EXTRA_PROCESSING_TIME_MS;
+ processing_time_us *= 1000;
+
+ return g_get_monotonic_time() + processing_time_us;
+}
+
SR_PRIV int korad_kaxxxxp_set_value(struct sr_serial_dev_inst *serial,
- int target, struct dev_context *devc)
+ int target, struct dev_context *devc)
{
- char *msg;
- const char *cmd;
- float value;
+ char msg[20];
int ret;
g_mutex_lock(&devc->rw_mutex);
give_device_time_to_process(devc);
+ msg[0] = '\0';
+ ret = SR_OK;
switch (target) {
case KAXXXXP_CURRENT:
case KAXXXXP_VOLTAGE:
case KAXXXXP_STATUS:
- sr_err("Can't set measurable parameter %d.", target);
- g_mutex_unlock(&devc->rw_mutex);
- return SR_ERR;
+ sr_err("Can't set measured value %d.", target);
+ ret = SR_ERR;
+ break;
case KAXXXXP_CURRENT_LIMIT:
- cmd = "ISET1:%05.3f";
- value = devc->set_current_limit;
+ sr_snprintf_ascii(msg, sizeof(msg),
+ "ISET1:%05.3f", devc->set_current_limit);
break;
case KAXXXXP_VOLTAGE_TARGET:
- cmd = "VSET1:%05.2f";
- value = devc->set_voltage_target;
+ sr_snprintf_ascii(msg, sizeof(msg),
+ "VSET1:%05.2f", devc->set_voltage_target);
break;
case KAXXXXP_OUTPUT:
- cmd = "OUT%01.0f";
- value = (devc->set_output_enabled) ? 1 : 0;
+ sr_snprintf_ascii(msg, sizeof(msg),
+ "OUT%1d", (devc->set_output_enabled) ? 1 : 0);
/* Set value back to recognize changes */
devc->output_enabled = devc->set_output_enabled;
break;
case KAXXXXP_BEEP:
- cmd = "BEEP%01.0f";
- value = (devc->set_beep_enabled) ? 1 : 0;
+ sr_snprintf_ascii(msg, sizeof(msg),
+ "BEEP%1d", (devc->set_beep_enabled) ? 1 : 0);
break;
case KAXXXXP_OCP:
- cmd = "OCP%01.0f";
- value = (devc->set_ocp_enabled) ? 1 : 0;
+ sr_snprintf_ascii(msg, sizeof(msg),
+ "OCP%1d", (devc->set_ocp_enabled) ? 1 : 0);
/* Set value back to recognize changes */
devc->ocp_enabled = devc->set_ocp_enabled;
break;
case KAXXXXP_OVP:
- cmd = "OVP%01.0f";
- value = (devc->set_ovp_enabled) ? 1 : 0;
+ sr_snprintf_ascii(msg, sizeof(msg),
+ "OVP%1d", (devc->set_ovp_enabled) ? 1 : 0);
/* Set value back to recognize changes */
devc->ovp_enabled = devc->set_ovp_enabled;
break;
case KAXXXXP_SAVE:
- cmd = "SAV%01.0f";
if (devc->program < 1 || devc->program > 5) {
- sr_err("Only programs 1-5 supported and %d isn't "
- "between them.", devc->program);
- g_mutex_unlock(&devc->rw_mutex);
- return SR_ERR;
+ sr_err("Program %d is not in the supported 1-5 range.",
+ devc->program);
+ ret = SR_ERR;
+ break;
}
- value = devc->program;
+ sr_snprintf_ascii(msg, sizeof(msg),
+ "SAV%1d", devc->program);
break;
case KAXXXXP_RECALL:
- cmd = "RCL%01.0f";
if (devc->program < 1 || devc->program > 5) {
- sr_err("Only programs 1-5 supported and %d isn't "
- "between them.", devc->program);
- g_mutex_unlock(&devc->rw_mutex);
- return SR_ERR;
+ sr_err("Program %d is not in the supported 1-5 range.",
+ devc->program);
+ ret = SR_ERR;
+ break;
}
- value = devc->program;
+ sr_snprintf_ascii(msg, sizeof(msg),
+ "RCL%1d", devc->program);
break;
default:
- sr_err("Don't know how to set %d.", target);
- g_mutex_unlock(&devc->rw_mutex);
- return SR_ERR;
+ sr_err("Don't know how to set target %d.", target);
+ ret = SR_ERR;
+ break;
}
- msg = g_malloc0(20 + 1);
- if (cmd)
- sr_snprintf_ascii(msg, 20, cmd, value);
-
- ret = korad_kaxxxxp_send_cmd(serial, msg);
- devc->req_sent_at = g_get_monotonic_time();
- g_free(msg);
+ if (ret == SR_OK && msg[0]) {
+ ret = korad_kaxxxxp_send_cmd(serial, msg);
+ devc->next_req_time = next_req_time(devc, TRUE, target);
+ }
g_mutex_unlock(&devc->rw_mutex);
}
SR_PRIV int korad_kaxxxxp_get_value(struct sr_serial_dev_inst *serial,
- int target, struct dev_context *devc)
+ int target, struct dev_context *devc)
{
int ret, count;
char reply[6];
float *value;
char status_byte;
+ gboolean needs_ovp_quirk;
gboolean prev_status;
g_mutex_lock(&devc->rw_mutex);
break;
default:
sr_err("Don't know how to query %d.", target);
+ ret = SR_ERR;
+ }
+ if (ret < 0) {
g_mutex_unlock(&devc->rw_mutex);
- return SR_ERR;
+ return ret;
}
- devc->req_sent_at = g_get_monotonic_time();
+ devc->next_req_time = next_req_time(devc, FALSE, target);
if ((ret = korad_kaxxxxp_read_chars(serial, count, reply)) < 0) {
g_mutex_unlock(&devc->rw_mutex);
return ret;
}
- reply[count] = 0;
-
if (value) {
sr_atof_ascii((const char *)&reply, value);
sr_dbg("value: %f", *value);
devc->output_enabled_changed = devc->output_enabled != prev_status;
/* OVP enabled, special handling for Velleman LABPS3005 quirk. */
- if ((devc->model->model_id == VELLEMAN_LABPS3005D && devc->output_enabled) ||
- devc->model->model_id != VELLEMAN_LABPS3005D) {
-
+ needs_ovp_quirk = devc->model->quirks & KORAD_QUIRK_LABPS_OVP_EN;
+ if (!needs_ovp_quirk || devc->output_enabled) {
prev_status = devc->ovp_enabled;
devc->ovp_enabled = status_byte & (1 << 7);
devc->ovp_enabled_changed = devc->ovp_enabled != prev_status;
}
SR_PRIV int korad_kaxxxxp_get_all_values(struct sr_serial_dev_inst *serial,
- struct dev_context *devc)
+ struct dev_context *devc)
{
int ret, target;