Support for serial port "touch" functionality using libserialport (#1507)

This makes it possible to upload to boards like the Arduino Leonardo and Arduino Nano Every wwithout using an external tool to enter bootloader mode

Co-authored-by: Stefan Rueger <[email protected]>

Author: MCUdude

src/avrdude.1

@@ -29,6 +29,7 @@
 .Nm
 .Fl p Ar partno
 .Op Fl b Ar baudrate
+.Op Fl r
 .Op Fl B Ar bitclock
 .Op Fl c Ar programmer-id
 .Op Fl C Ar config-file
@@ -365,6 +366,14 @@ for more information run avrdude -p x/h.
 .It Fl b Ar baudrate
 Override the RS-232 connection baud rate specified in the respective
 programmer's entry of the configuration file.
+.It Fl r
+Opens the serial port at 1200 baud and immediately closes it, waits 400 ms
+for each -r on the command line and then establishes communication with
+the programmer. This is commonly known as a "1200bps touch", and is used
+to trigger programming mode for certain boards like Arduino Leonardo,
+Arduino Micro/Pro Micro and the Arduino Nano Every. Longer waits, and
+therefore multiple -r options, are sometimes needed for slower, less
+powerful hosts.
 .It Fl B Ar bitclock
 Specify the bit clock period for the JTAG, PDI, TPI, UPDI, or ISP
 interface. The value is a floating-point number in microseconds.

src/doc/avrdude.texi

@@ -469,6 +469,15 @@ ATmega328P MCU properties; for more information run @code{avrdude -p x/h}.
 Override the RS-232 connection baud rate specified in the respective
 programmer's entry of the configuration file.
 
+@item -r
+Opens the serial port at 1200 baud and immediately closes it, waits 400 ms
+for each @code{-r} on the command line and then establishes communication
+with the programmer. This is commonly known as a "1200bps touch", and is
+used to trigger programming mode for certain boards like Arduino Leonardo,
+Arduino Micro/Pro Micro and the Arduino Nano Every. Longer waits, and
+therefore multiple @code{-r} options, are sometimes needed for slower, less
+powerful hosts.
+
 @item -B @var{bitclock}
 Specify the bit clock period for the JTAG, PDI, TPI, UPDI, or ISP
 interface. The value is a floating-point number in microseconds.

src/libavrdude.h

@@ -668,6 +668,7 @@ struct serial_device {
   int (*open)(const char *port, union pinfo pinfo, union filedescriptor *fd);
   int (*setparams)(const union filedescriptor *fd, long baud, unsigned long cflags);
   void (*close)(union filedescriptor *fd);
+  void (*rawclose)(union filedescriptor *fd); // Don't restore terminal attributes (Linux)
 
   int (*send)(const union filedescriptor *fd, const unsigned char * buf, size_t buflen);
   int (*recv)(const union filedescriptor *fd, unsigned char * buf, size_t buflen);
@@ -691,6 +692,7 @@ extern struct serial_device usbhid_serdev;
 #define serial_open (serdev->open)
 #define serial_setparams (serdev->setparams)
 #define serial_close (serdev->close)
+#define serial_rawclose (serdev->rawclose)
 #define serial_send (serdev->send)
 #define serial_recv (serdev->recv)
 #define serial_drain (serdev->drain)
@@ -1252,6 +1254,7 @@ extern "C" {
 int setport_from_serialadapter(char **portp, const SERIALADAPTER *ser, const char *sernum);
 int setport_from_vid_pid(char **portp, int vid, int pid, const char *sernum);
 int list_available_serialports(LISTID programmers);
+int touch_serialport(char **portp, int baudrate, int nwaits);
 
 int str_starts(const char *str, const char *starts);
 int str_eq(const char *str1, const char *str2);

src/main.c

@@ -237,6 +237,8 @@ static void usage(void)
     "  -D                     Disable auto erase for flash memory; implies -A\n"
     "  -i <delay>             ISP Clock Delay [in microseconds]\n"
     "  -P <port>              Connection; -P ?s or -P ?sa lists serial ones\n"
+    "  -r                     Reconnect to -P port after \"touching\" it; wait\n"
+    "                         400 ms for each -r; needed for some USB boards\n"
     "  -F                     Override invalid signature or initial checks\n"
     "  -e                     Perform a chip erase\n"
     "  -O                     Perform RC oscillator calibration (see AVR053)\n"
@@ -526,6 +528,7 @@ int main(int argc, char * argv [])
   char  * e;           /* for strtod() error checking */
   const char  *errstr; /* for str_int() error checking */
   int     baudrate;    /* override default programmer baud rate */
+  int     touch_1200bps; /* "touch" serial port prior to programming */
   double  bitclock;    /* Specify programmer bit clock (JTAG ICE) */
   int     ispdelay;    /* Specify the delay for ISP clock */
   int     init_ok;     /* Device initialization worked well */
@@ -612,6 +615,7 @@ int main(int argc, char * argv [])
   explicit_e    = 0;
   verbose       = 0;
   baudrate      = 0;
+  touch_1200bps = 0;
   bitclock      = 0.0;
   ispdelay      = 0;
   is_open       = 0;
@@ -635,7 +639,7 @@ int main(int argc, char * argv [])
   /*
    * process command line arguments
    */
-  while ((ch = getopt(argc,argv,"?Ab:B:c:C:DeE:Fi:l:np:OP:qstT:U:uvVx:yY:")) != -1) {
+  while ((ch = getopt(argc,argv,"?Ab:B:c:C:DeE:Fi:l:np:OP:qrstT:U:uvVx:yY:")) != -1) {
 
     switch (ch) {
       case 'b': /* override default programmer baud rate */
@@ -766,6 +770,10 @@ int main(int argc, char * argv [])
         quell_progress++ ;
         break;
 
+      case 'r' :
+        touch_1200bps++;
+        break;
+
       case 't': /* enter terminal mode */
         ladd(updates, cmd_update("interactive terminal"));
         break;
@@ -1175,6 +1183,13 @@ int main(int argc, char * argv [])
     }
   }
 
+  if(port[0] == 0 || str_eq(port, "unknown")) {
+    msg_error("\n");
+    pmsg_error("no port has been specified on the command line or in the config file\n");
+    imsg_error("specify a port using the -P option and try again\n\n");
+    exit(1);
+  }
+
   /*
    * Divide a serialadapter port string into tokens separated by colons.
    * There are two ways such a port string can be presented:
@@ -1229,18 +1244,12 @@ int main(int argc, char * argv [])
     }
     for (int i = 0; i < 4; i++)
       free(port_tok[i]);
+    if(touch_1200bps && touch_serialport(&port, 1200, touch_1200bps) < 0)
+      goto skipopen;
   }
 
-  /*
-   * open the programmer
-   */
-  if (port[0] == 0) {
-    msg_error("\n");
-    pmsg_error("no port has been specified on the command line or in the config file\n");
-    imsg_error("specify a port using the -P option and try again\n\n");
-    exit(1);
-  }
 
+  // Open the programmer
   if (verbose > 0) {
     imsg_notice("Using Port                    : %s\n", port);
     imsg_notice("Using Programmer              : %s\n", pgmid);
@@ -1266,9 +1275,13 @@ int main(int argc, char * argv [])
 
   rc = pgm->open(pgm, port);
   if (rc < 0) {
-    pmsg_error("unable to open programmer %s on port %s\n", pgmid, port);
-    if (print_ports && pgm->conntype == CONNTYPE_SERIAL)
+    pmsg_error("unable to open port %s for programmer %s\n", port, pgmid);
+skipopen:
+    if (print_ports && pgm->conntype == CONNTYPE_SERIAL) {
       list_available_serialports(programmers);
+      if(touch_1200bps == 1)
+        pmsg_info("alternatively, try -rr or -rrr for longer delays\n");
+    }
     exitrc = 1;
     pgm->ppidata = 0; /* clear all bits at exit */
     goto main_exit;

src/ser_avrdoper.c

@@ -352,6 +352,7 @@ struct serial_device avrdoper_serdev =
 {
   .open = avrdoper_open,
   .close = avrdoper_close,
+  .rawclose = avrdoper_close,
   .send = avrdoper_send,
   .recv = avrdoper_recv,
   .drain = avrdoper_drain,

src/ser_posix.c

@@ -352,7 +352,6 @@ static int net_open(const char *port, union filedescriptor *fdp) {
   return ret;
 }
 
-
 static int ser_set_dtr_rts(const union filedescriptor *fdp, int is_on) {
   unsigned int	ctl;
   int           r;
@@ -431,6 +430,11 @@ static void ser_close(union filedescriptor *fd) {
   close(fd->ifd);
 }
 
+// Close but don't restore attributes
+static void ser_rawclose(union filedescriptor *fd) {
+  saved_original_termios = 0;
+  close(fd->ifd);
+}
 
 static int ser_send(const union filedescriptor *fd, const unsigned char * buf, size_t buflen) {
   int rc;
@@ -598,6 +602,7 @@ struct serial_device serial_serdev =
   .open = ser_open,
   .setparams = ser_setparams,
   .close = ser_close,
+  .rawclose = ser_rawclose,
   .send = ser_send,
   .recv = ser_recv,
   .drain = ser_drain,

src/ser_win32.c

@@ -756,6 +756,7 @@ struct serial_device serial_serdev =
   .open = ser_open,
   .setparams = ser_setparams,
   .close = ser_close,
+  .rawclose = ser_close,
   .send = ser_send,
   .recv = ser_recv,
   .drain = ser_drain,

src/serialadapter.c

@@ -21,6 +21,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "avrdude.h"
 #include "libavrdude.h"
@@ -130,6 +131,13 @@ static SERPORT *get_libserialport_data(int *np) {
   return sp;
 }
 
+// Free memory allocated from get_libserialport_data()
+static void free_libserialport_data(SERPORT *sp, int n) {
+  for(int k = 0; sp && k < n; k++)
+    free(sp[k].sernum), free(sp[k].port);
+  free(sp);
+}
+
 // Returns a NULL-terminated malloc'd list of items in SERPORT list spa that are not in spb
 SERPORT **sa_spa_not_spb(SERPORT *spa, int na, SERPORT *spb, int nb) {
   SERPORT **ret = cfg_malloc(__func__, (na+1)*sizeof*ret);
@@ -266,10 +274,7 @@ int setport_from_serialadapter(char **portp, const SERIALADAPTER *sea, const cha
       if(m == 0 || sa_num_matches_by_sea(sea, sernum, sp+i, 1) == 1)
         sa_print_specs(sp, n, i);
   }
-
-  for(int k = 0; k < n; k++)
-    free(sp[k].sernum), free(sp[k].port);
-  free(sp);
+  free_libserialport_data(sp, n);
 
   return rv;
 }
@@ -294,14 +299,62 @@ int setport_from_vid_pid(char **portp, int vid, int pid, const char *sernum) {
       if(m == 0 || sa_num_matches_by_ids(vid, pid, sernum, sp+i, 1) == 1)
         sa_print_specs(sp, n, i);
   }
-
-  for(int k = 0; k < n; k++)
-    free(sp[k].sernum), free(sp[k].port);
-  free(sp);
+  free_libserialport_data(sp, n);
 
   return rv;
 }
 
+// Potentially change port *portp after opening & closing it with baudrate
+int touch_serialport(char **portp, int baudrate, int nwaits) {
+  int i, n1, n2;
+  SERPORT *sp1, *sp2, **diff;
+  sp1 = get_libserialport_data(&n1);
+  if(!sp1 || n1 <= 0 || !portp)
+    return -1;
+
+  pmsg_info("touching serial port %s at %d baud\n", *portp, baudrate);
+
+  union pinfo pinfo;
+  union filedescriptor fd;
+  pinfo.serialinfo.baud = baudrate;
+  pinfo.serialinfo.cflags = SERIAL_8N1;
+  if(serial_open(*portp, pinfo, &fd) == -1) {
+    pmsg_error("%s() failed to open port %s at %d baud\n", __func__, *portp, baudrate);
+    return -1;
+  }
+  serial_set_dtr_rts(&fd, 1);
+  usleep(100);
+  serial_set_dtr_rts(&fd, 0);
+  serial_rawclose(&fd);
+
+  const int nloops = 32, nap = 50;
+#if (defined(__arm__) || defined(__aarch64__)) && !defined(__APPLE__)
+  nwaits += 2;
+#endif
+  pmsg_info("waiting for new port...");
+  usleep(400*1000*nwaits);
+  for(i = nloops; i > 0; i--) {
+    usleep(nap*1000);
+    if((sp2 = get_libserialport_data(&n2))) {
+      diff = sa_spa_not_spb(sp2, n2, sp1, n1);
+      if(*diff && diff[0]->port && !diff[1]) { // Exactly one new port sprung up
+        pmsg_notice("new port %s discovered\n", (*diff)->port);
+        if(*portp)
+          free(*portp);
+        *portp = cfg_strdup(__func__, (*diff)->port);
+        msg_info(" %d ms:", (nloops-i+1)*nap + nwaits*400);
+        i = -1;                 // Leave loop
+      }
+      free(diff); 
+      free_libserialport_data(sp2, n2);
+    }
+  }
+  free_libserialport_data(sp1, n1);
+  msg_info(" using %s port %s\n", i<0? "new": "same", *portp);
+
+  return 0;
+}
+
 // List available serial ports
 int list_available_serialports(LISTID programmers) {
   // Get serial port information from libserialport
@@ -344,6 +397,11 @@ int list_available_serialports(LISTID programmers) {
   return -1;
 }
 
+int touch_serialport(char **portp, int baudrate, int nwaits) {
+  pmsg_error("avrdude built without libserialport support; please compile again with libserialport installed\n");
+  return -1;
+}
+
 #endif
 
 void list_serialadapters(FILE *fp, const char *prefix, LISTID programmers) {

src/usb_hidapi.c

@@ -318,6 +318,7 @@ static int usbhid_drain(const union filedescriptor *fd, int display) {
 struct serial_device usbhid_serdev = {
   .open = usbhid_open,
   .close = usbhid_close,
+  .rawclose = usbhid_close,
   .send = usbhid_send,
   .recv = usbhid_recv,
   .drain = usbhid_drain,

src/usb_libusb.c

@@ -578,6 +578,7 @@ struct serial_device usb_serdev =
 {
   .open = usbdev_open,
   .close = usbdev_close,
+  .rawclose = usbdev_close,
   .send = usbdev_send,
   .recv = usbdev_recv,
   .drain = usbdev_drain,
@@ -591,6 +592,7 @@ struct serial_device usb_serdev_frame =
 {
   .open = usbdev_open,
   .close = usbdev_close,
+  .rawclose = usbdev_close,
   .send = usbdev_send,
   .recv = usbdev_recv_frame,
   .drain = usbdev_drain,