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 /* Message logging helpers with subsystem-specific prefix string. */
  28 #define LOG_PREFIX "scpi_serial: "
  29 #define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
  30 #define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
  31 #define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
  32 #define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
  33 #define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
  34
  35 #define SCPI_READ_RETRIES 100
  36 #define SCPI_READ_RETRY_TIMEOUT 10000
  37
  38 SR_PRIV int scpi_serial_open(void *priv)
  39 {
  40         struct sr_serial_dev_inst *serial = priv;
  41
  42         if (serial_open(serial, SERIAL_RDWR | SERIAL_NONBLOCK) != SR_OK)
  43                 return SR_ERR;
  44
  45         if (serial_flush(serial) != SR_OK)
  46                 return SR_ERR;
  47
  48         return SR_OK;
  49 }
  50
  51 SR_PRIV int scpi_serial_source_add(void *priv, int events, int timeout,
  52                         sr_receive_data_callback_t cb, void *cb_data)
  53 {
  54         struct sr_serial_dev_inst *serial = priv;
  55
  56         return serial_source_add(serial, events, timeout, cb, cb_data);
  57 }
  58
  59 SR_PRIV int scpi_serial_source_remove(void *priv)
  60 {
  61         struct sr_serial_dev_inst *serial = priv;
  62
  63         return serial_source_remove(serial);
  64 }
  65
  66 SR_PRIV int scpi_serial_send(void *priv, const char *command)
  67 {
  68         int len, result, written;
  69         gchar *terminated_command;
  70         struct sr_serial_dev_inst *serial = priv;
  71
  72         terminated_command = g_strconcat(command, "\n", NULL);
  73         len = strlen(terminated_command);
  74         written = 0;
  75         while (written < len) {
  76                 result = serial_write(serial, terminated_command + written, len - written);
  77                 if (result < 0) {
  78                         sr_err("Error while sending SCPI command: '%s'.", command);
  79                         g_free(terminated_command);
  80                         return SR_ERR;
  81                 }
  82                 written += result;
  83         }
  84
  85         g_free(terminated_command);
  86
  87         sr_spew("Successfully sent SCPI command: '%s'.", command);
  88
  89         return SR_OK;
  90 }
  91
  92 SR_PRIV int scpi_serial_receive(void *priv, char **scpi_response)
  93 {
  94         int len, ret;
  95         char buf[256];
  96         unsigned int i;
  97         GString *response;
  98         struct sr_serial_dev_inst *serial = priv;
  99
 100         response = g_string_sized_new(1024);
 101
 102         for (i = 0; i <= SCPI_READ_RETRIES; i++) {
 103                 while ((len = serial_read(serial, buf, sizeof(buf))) > 0)
 104                         response = g_string_append_len(response, buf, len);
 105
 106                 if (response->len > 0 &&
 107                     response->str[response->len-1] == '\n') {
 108                         sr_spew("Fetched full SCPI response.");
 109                         break;
 110                 }
 111
 112                 g_usleep(SCPI_READ_RETRY_TIMEOUT);
 113         }
 114
 115         if (response->len == 0) {
 116                 sr_dbg("No SCPI response received.");
 117                 g_string_free(response, TRUE);
 118                 *scpi_response = NULL;
 119                 return SR_ERR;
 120         } else if (response->str[response->len - 1] == '\n') {
 121                 /*
 122                  * The SCPI response contains a LF ('\n') at the end and we
 123                  * don't need this so replace it with a '\0' and decrement
 124                  * the length.
 125                  */
 126                 response->str[--response->len] = '\0';
 127                 ret = SR_OK;
 128         } else {
 129                 sr_warn("Incomplete SCPI response received!");
 130                 ret = SR_ERR;
 131         }
 132
 133         /* Minor optimization: steal the string instead of copying. */
 134         *scpi_response = response->str;
 135
 136         /* A SCPI response can be quite large, print at most 50 characters. */
 137         sr_dbg("SCPI response received (length %d): '%.50s'",
 138                response->len, response->str);
 139
 140         g_string_free(response, FALSE);
 141
 142         return ret;
 143 }
 144
 145 /* Some stubs to keep the compiler from whining. */
 146 static int scpi_serial_read(void *priv, char *buf, int maxlen)
 147 {
 148         return serial_read(priv, buf, maxlen);
 149 }
 150 static int scpi_serial_close(void *priv)
 151 {
 152         return serial_close(priv);
 153 }
 154 static void scpi_serial_free(void *priv)
 155 {
 156         return sr_serial_dev_inst_free(priv);
 157 }
 158
 159 SR_PRIV struct sr_scpi_dev_inst *scpi_serial_dev_inst_new(const char *port,
 160                 const char *serialcomm)
 161 {
 162         struct sr_scpi_dev_inst *scpi;
 163         struct sr_serial_dev_inst *serial;
 164
 165         scpi = g_try_malloc(sizeof(struct sr_scpi_dev_inst));
 166
 167         if (!(serial = sr_serial_dev_inst_new(port, serialcomm)))
 168         {
 169                 g_free(scpi);
 170                 return NULL;
 171         }
 172
 173         scpi->open = scpi_serial_open;
 174         scpi->source_add = scpi_serial_source_add;
 175         scpi->source_remove = scpi_serial_source_remove;
 176         scpi->send = scpi_serial_send;
 177         scpi->receive = scpi_serial_receive;
 178         scpi->read = scpi_serial_read;
 179         scpi->close = scpi_serial_close;
 180         scpi->free = scpi_serial_free;
 181         scpi->priv = serial;
 182
 183         return scpi;
 184 }