hardware/common/scpi_serial.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2013 poljar (Damir Jelić) <poljarinho@gmail.com>
   5  * Copyright (C) 2013 Martin Ling <martin-sigrok@earth.li>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "libsigrok.h"
  22 #include "libsigrok-internal.h"
  23
  24 #include <glib.h>
  25 #include <string.h>
  26
  27 #define LOG_PREFIX "scpi_serial"
  28
  29 #define SCPI_READ_RETRIES 100
  30 #define SCPI_READ_RETRY_TIMEOUT 10000
  31
  32 SR_PRIV int scpi_serial_open(void *priv)
  33 {
  34         struct sr_serial_dev_inst *serial = priv;
  35
  36         if (serial_open(serial, SERIAL_RDWR | SERIAL_NONBLOCK) != SR_OK)
  37                 return SR_ERR;
  38
  39         if (serial_flush(serial) != SR_OK)
  40                 return SR_ERR;
  41
  42         return SR_OK;
  43 }
  44
  45 SR_PRIV int scpi_serial_source_add(void *priv, int events, int timeout,
  46                         sr_receive_data_callback_t cb, void *cb_data)
  47 {
  48         struct sr_serial_dev_inst *serial = priv;
  49
  50         return serial_source_add(serial, events, timeout, cb, cb_data);
  51 }
  52
  53 SR_PRIV int scpi_serial_source_remove(void *priv)
  54 {
  55         struct sr_serial_dev_inst *serial = priv;
  56
  57         return serial_source_remove(serial);
  58 }
  59
  60 SR_PRIV int scpi_serial_send(void *priv, const char *command)
  61 {
  62         int len, result, written;
  63         gchar *terminated_command;
  64         struct sr_serial_dev_inst *serial = priv;
  65
  66         terminated_command = g_strconcat(command, "\n", NULL);
  67         len = strlen(terminated_command);
  68         written = 0;
  69         while (written < len) {
  70                 result = serial_write(serial, terminated_command + written, len - written);
  71                 if (result < 0) {
  72                         sr_err("Error while sending SCPI command: '%s'.", command);
  73                         g_free(terminated_command);
  74                         return SR_ERR;
  75                 }
  76                 written += result;
  77         }
  78
  79         g_free(terminated_command);
  80
  81         sr_spew("Successfully sent SCPI command: '%s'.", command);
  82
  83         return SR_OK;
  84 }
  85
  86 SR_PRIV int scpi_serial_receive(void *priv, char **scpi_response)
  87 {
  88         int len, ret;
  89         char buf[256];
  90         unsigned int i;
  91         GString *response;
  92         struct sr_serial_dev_inst *serial = priv;
  93
  94         response = g_string_sized_new(1024);
  95
  96         for (i = 0; i <= SCPI_READ_RETRIES; i++) {
  97                 while ((len = serial_read(serial, buf, sizeof(buf))) > 0)
  98                         response = g_string_append_len(response, buf, len);
  99
 100                 if (response->len > 0 &&
 101                     response->str[response->len-1] == '\n') {
 102                         sr_spew("Fetched full SCPI response.");
 103                         break;
 104                 }
 105
 106                 g_usleep(SCPI_READ_RETRY_TIMEOUT);
 107         }
 108
 109         if (response->len == 0) {
 110                 sr_dbg("No SCPI response received.");
 111                 g_string_free(response, TRUE);
 112                 *scpi_response = NULL;
 113                 return SR_ERR;
 114         } else if (response->str[response->len - 1] == '\n') {
 115                 /*
 116                  * The SCPI response contains a LF ('\n') at the end and we
 117                  * don't need this so replace it with a '\0' and decrement
 118                  * the length.
 119                  */
 120                 response->str[--response->len] = '\0';
 121                 ret = SR_OK;
 122         } else {
 123                 sr_warn("Incomplete SCPI response received!");
 124                 ret = SR_ERR;
 125         }
 126
 127         /* Minor optimization: steal the string instead of copying. */
 128         *scpi_response = response->str;
 129
 130         /* A SCPI response can be quite large, print at most 50 characters. */
 131         sr_dbg("SCPI response received (length %d): '%.50s'",
 132                response->len, response->str);
 133
 134         g_string_free(response, FALSE);
 135
 136         return ret;
 137 }
 138
 139 /* Some stubs to keep the compiler from whining. */
 140 static int scpi_serial_read(void *priv, char *buf, int maxlen)
 141 {
 142         return serial_read(priv, buf, maxlen);
 143 }
 144 static int scpi_serial_close(void *priv)
 145 {
 146         return serial_close(priv);
 147 }
 148 static void scpi_serial_free(void *priv)
 149 {
 150         return sr_serial_dev_inst_free(priv);
 151 }
 152
 153 SR_PRIV struct sr_scpi_dev_inst *scpi_serial_dev_inst_new(const char *port,
 154                 const char *serialcomm)
 155 {
 156         struct sr_scpi_dev_inst *scpi;
 157         struct sr_serial_dev_inst *serial;
 158
 159         scpi = g_try_malloc(sizeof(struct sr_scpi_dev_inst));
 160
 161         if (!(serial = sr_serial_dev_inst_new(port, serialcomm)))
 162         {
 163                 g_free(scpi);
 164                 return NULL;
 165         }
 166
 167         scpi->open = scpi_serial_open;
 168         scpi->source_add = scpi_serial_source_add;
 169         scpi->source_remove = scpi_serial_source_remove;
 170         scpi->send = scpi_serial_send;
 171         scpi->receive = scpi_serial_receive;
 172         scpi->read = scpi_serial_read;
 173         scpi->close = scpi_serial_close;
 174         scpi->free = scpi_serial_free;
 175         scpi->priv = serial;
 176
 177         return scpi;
 178 }