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