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 BUFFER_SIZE 1024
  30
  31 struct scpi_serial {
  32         struct sr_serial_dev_inst *serial;
  33         char buffer[BUFFER_SIZE];
  34         size_t count;
  35         size_t read;
  36 };
  37
  38 static int scpi_serial_dev_inst_new(void *priv, struct drv_context *drvc,
  39                 const char *resource, char **params, const char *serialcomm)
  40 {
  41         struct scpi_serial *sscpi = priv;
  42
  43         (void)drvc;
  44         (void)params;
  45
  46         if (!(sscpi->serial = sr_serial_dev_inst_new(resource, serialcomm)))
  47                 return SR_ERR;
  48
  49         return SR_OK;
  50 }
  51
  52 static int scpi_serial_open(void *priv)
  53 {
  54         struct scpi_serial *sscpi = priv;
  55         struct sr_serial_dev_inst *serial = sscpi->serial;
  56
  57         if (serial_open(serial, SERIAL_RDWR | SERIAL_NONBLOCK) != SR_OK)
  58                 return SR_ERR;
  59
  60         if (serial_flush(serial) != SR_OK)
  61                 return SR_ERR;
  62
  63         sscpi->count = 0;
  64         sscpi->read = 0;
  65
  66         return SR_OK;
  67 }
  68
  69 static int scpi_serial_source_add(void *priv, int events, int timeout,
  70                         sr_receive_data_callback_t cb, void *cb_data)
  71 {
  72         struct scpi_serial *sscpi = priv;
  73         struct sr_serial_dev_inst *serial = sscpi->serial;
  74
  75         return serial_source_add(serial, events, timeout, cb, cb_data);
  76 }
  77
  78 static int scpi_serial_source_remove(void *priv)
  79 {
  80         struct scpi_serial *sscpi = priv;
  81         struct sr_serial_dev_inst *serial = sscpi->serial;
  82
  83         return serial_source_remove(serial);
  84 }
  85
  86 static int scpi_serial_send(void *priv, const char *command)
  87 {
  88         int len, result, written;
  89         gchar *terminated_command;
  90         struct scpi_serial *sscpi = priv;
  91         struct sr_serial_dev_inst *serial = sscpi->serial;
  92
  93         terminated_command = g_strconcat(command, "\n", NULL);
  94         len = strlen(terminated_command);
  95         written = 0;
  96         while (written < len) {
  97                 result = serial_write(serial, terminated_command + written, len - written);
  98                 if (result < 0) {
  99                         sr_err("Error while sending SCPI command: '%s'.", command);
 100                         g_free(terminated_command);
 101                         return SR_ERR;
 102                 }
 103                 written += result;
 104         }
 105
 106         g_free(terminated_command);
 107
 108         sr_spew("Successfully sent SCPI command: '%s'.", command);
 109
 110         return SR_OK;
 111 }
 112
 113 static int scpi_serial_read_begin(void *priv)
 114 {
 115         (void) priv;
 116
 117         return SR_OK;
 118 }
 119
 120 static int scpi_serial_read_data(void *priv, char *buf, int maxlen)
 121 {
 122         struct scpi_serial *sscpi = priv;
 123         int len, ret;
 124
 125         len = BUFFER_SIZE - sscpi->count;
 126
 127         /* Try to read new data into the buffer if there is space. */
 128         if (len > 0) {
 129                 ret = serial_read(sscpi->serial, sscpi->buffer + sscpi->read,
 130                                 BUFFER_SIZE - sscpi->count);
 131
 132                 if (ret < 0)
 133                         return ret;
 134
 135                 sscpi->count += ret;
 136
 137                 if (ret > 0)
 138                         sr_spew("Read %d bytes into buffer.", ret);
 139         }
 140
 141         /* Return as many bytes as possible from buffer, excluding any trailing newline. */
 142         if (sscpi->read < sscpi->count) {
 143                 len = sscpi->count - sscpi->read;
 144                 if (len > maxlen)
 145                         len = maxlen;
 146                 if (sscpi->buffer[sscpi->read + len - 1] == '\n')
 147                         len--;
 148                 sr_spew("Returning %d bytes from buffer.", len);
 149                 memcpy(buf, sscpi->buffer + sscpi->read, len);
 150                 sscpi->read += len;
 151                 if (sscpi->read == BUFFER_SIZE) {
 152                         sr_spew("Resetting buffer.");
 153                         sscpi->count = 0;
 154                         sscpi->read = 0;
 155                 }
 156                 return len;
 157         }
 158
 159         return 0;
 160 }
 161
 162 static int scpi_serial_read_complete(void *priv)
 163 {
 164         struct scpi_serial *sscpi = priv;
 165
 166         /* If the next character is a newline, discard it and report complete. */
 167         if (sscpi->read < sscpi->count && sscpi->buffer[sscpi->read] == '\n') {
 168                 sscpi->read++;
 169                 return 1;
 170         } else {
 171                 return 0;
 172         }
 173 }
 174
 175 static int scpi_serial_close(void *priv)
 176 {
 177         struct scpi_serial *sscpi = priv;
 178
 179         return serial_close(sscpi->serial);
 180 }
 181
 182 static void scpi_serial_free(void *priv)
 183 {
 184         struct scpi_serial *sscpi = priv;
 185
 186         sr_serial_dev_inst_free(sscpi->serial);
 187 }
 188
 189 SR_PRIV const struct sr_scpi_dev_inst scpi_serial_dev = {
 190         .name          = "serial",
 191         .prefix        = "",
 192         .priv_size     = sizeof(struct scpi_serial),
 193         .dev_inst_new  = scpi_serial_dev_inst_new,
 194         .open          = scpi_serial_open,
 195         .source_add    = scpi_serial_source_add,
 196         .source_remove = scpi_serial_source_remove,
 197         .send          = scpi_serial_send,
 198         .read_begin    = scpi_serial_read_begin,
 199         .read_data     = scpi_serial_read_data,
 200         .read_complete = scpi_serial_read_complete,
 201         .close         = scpi_serial_close,
 202         .free          = scpi_serial_free,
 203 };