Make SCPI functions device independent, with separate serial backend.

[libsigrok.git] / hardware / common / scpi_serial.c

diff --git a/hardware/common/scpi_serial.c b/hardware/common/scpi_serial.c
new file mode 100644 (file)
index 0000000..cbe51b0
--- /dev/null
+++ b/hardware/common/scpi_serial.c
@@ -0,0 +1,159 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2013 poljar (Damir Jelić) <poljarinho@gmail.com>
+ * Copyright (C) 2013 Martin Ling <martin-sigrok@earth.li>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "libsigrok.h"
+#include "libsigrok-internal.h"
+
+#include <glib.h>
+#include <string.h>
+
+/* Message logging helpers with subsystem-specific prefix string. */
+#define LOG_PREFIX "scpi_serial: "
+#define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
+#define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
+#define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
+#define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
+#define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
+
+#define SCPI_READ_RETRIES 100
+#define SCPI_READ_RETRY_TIMEOUT 10000
+
+SR_PRIV int scpi_serial_open(void *priv)
+{
+       struct sr_serial_dev_inst *serial = priv;
+
+       return serial_open(serial, SERIAL_RDWR | SERIAL_NONBLOCK);
+}
+
+SR_PRIV int scpi_serial_source_add(void *priv, int events, int timeout,
+                       sr_receive_data_callback_t cb, void *cb_data)
+{
+       struct sr_serial_dev_inst *serial = priv;
+
+       return sr_source_add(serial->fd, events, timeout, cb, cb_data);
+}
+
+SR_PRIV int scpi_serial_source_remove(void *priv)
+{
+       struct sr_serial_dev_inst *serial = priv;
+
+       return sr_source_remove(serial->fd);
+}
+
+SR_PRIV int scpi_serial_send(void *priv, const char *command)
+{
+       int len, out;
+       gchar *terminated_command;
+       struct sr_serial_dev_inst *serial = priv;
+
+       terminated_command = g_strconcat(command, "\n", NULL);
+       len = strlen(terminated_command);
+       out = serial_write(serial, terminated_command, len);
+       g_free(terminated_command);
+
+       if (out != len) {
+               sr_dbg("Only sent %d/%d bytes of SCPI command: '%s'.", out,
+                      len, command);
+               return SR_ERR;
+       }
+
+       sr_spew("Successfully sent SCPI command: '%s'.", command);
+
+       return SR_OK;
+}
+
+SR_PRIV int scpi_serial_receive(void *priv, char **scpi_response)
+{
+       int len, ret;
+       char buf[256];
+       unsigned int i;
+       GString *response;
+       struct sr_serial_dev_inst *serial = priv;
+
+       response = g_string_sized_new(1024);
+
+       for (i = 0; i <= SCPI_READ_RETRIES; i++) {
+               while ((len = serial_read(serial, buf, sizeof(buf))) > 0)
+                       response = g_string_append_len(response, buf, len);
+
+               if (response->len > 0 &&
+                   response->str[response->len-1] == '\n') {
+                       sr_spew("Fetched full SCPI response.");
+                       break;
+               }
+
+               g_usleep(SCPI_READ_RETRY_TIMEOUT);
+       }
+
+       if (response->len == 0) {
+               sr_dbg("No SCPI response received.");
+               g_string_free(response, TRUE);
+               *scpi_response = NULL;
+               return SR_ERR;
+       } else if (response->str[response->len - 1] == '\n') {
+               /*
+                * The SCPI response contains a LF ('\n') at the end and we
+                * don't need this so replace it with a '\0' and decrement
+                * the length.
+                */
+               response->str[--response->len] = '\0';
+               ret = SR_OK;
+       } else {
+               sr_warn("Incomplete SCPI response received!");
+               ret = SR_ERR;
+       }
+
+       /* Minor optimization: steal the string instead of copying. */
+       *scpi_response = response->str;
+
+       /* A SCPI response can be quite large, print at most 50 characters. */
+       sr_dbg("SCPI response received (length %d): '%.50s'",
+              response->len, response->str);
+
+       g_string_free(response, FALSE);
+
+       return ret;
+}
+
+SR_PRIV struct sr_scpi_dev_inst *scpi_serial_dev_inst_new(const char *port,
+               const char *serialcomm)
+{
+       struct sr_scpi_dev_inst *scpi;
+       struct sr_serial_dev_inst *serial;
+
+       scpi = g_try_malloc(sizeof(struct sr_scpi_dev_inst));
+
+       if (!(serial = sr_serial_dev_inst_new(port, serialcomm)))
+       {
+               g_free(scpi);
+               return NULL;
+       }
+
+       scpi->open = scpi_serial_open;
+       scpi->source_add = scpi_serial_source_add;
+       scpi->source_remove = scpi_serial_source_remove;
+       scpi->send = scpi_serial_send;
+       scpi->receive = scpi_serial_receive;
+       scpi->close = serial_close;
+       scpi->free = sr_serial_dev_inst_free;
+       scpi->priv = serial;
+
+       return scpi;
+}